i w' fmd' i' ^Wiia fm<& ridhk úoHdj 12 fYa%Ksh iïm;a fmd; 04 tallh - mod¾:fha jdhq uh wjia :dj 05 tallh - Yla ;s úoHdj úoHd fomd¾;fïka;=j úoHd yd ;dlaIK mSGh cd;sl wOHdmk wdh;kh uyr.u www.nie.lk
i
w fmd i ^Wiia fmltamp
ridhk uacuteoHdj
12 fYaKsh
iiumlma fmd
04 tallh - modfrac34fha jdhquh wjiadj
05 tallh - Ylas uacuteoHdj
uacuteoHd fomdfrac34fiumlka=j uacuteoHd yd dlaIK mSGh
cdsl wOHdmk wdhkh uyru
wwwnielk
ii
ridhk uacuteoHdj
iiumlma fmd
12 fYaKsh
copy cdsl wOHdmk wdhkh
mltuq uqoslashKh ndash 2019
uacuteoHd fomdfrac34fiumlka=j
uacuteoHd yd dlaIK mSGh
cdsl wOHdmk wdhkh
YS xld
mldYkh ( uqoslashKdh
cdsl wOHdmk wdhkh
uyru
YS xld
iii
wOHCI ckrdafa mKsuacutevh
wOHdmkfha =KdaulNdjh jfrac34Okh lsIacuteu i|yd cdsl wOHdmk wdhkh jszligka jr
wjiadkql+ mshjr kq nhs wodlt uacuteIhhka i|yd wsffrac34l iiumlma fmda ilia lsIacuteu tjka
tla mshjrls
cdsl wOHdmk wdhkfha uacuteIhudd ixjfrac34Ok lKavdhua cdsl uacuteYaj uacuteoHdj uacuteoaj=ka
iy mdiea moaOsfha mltmqreyuml =rejreka uska wsffrac34l iiumlma fmda ilia lr we 2017 sect
lshdaul lrk o wfmdi ^Wiia fmltamp kj uacuteIh ksfrac34foaYhg wkqj fuu wsffrac34l iiumlma
fmda shd wes ksid isiqkag wodlt uacuteIh lreKq msltsn|j wjfndaOh mqiquesta llt yels wr
jvda ModhS bfkqiuml bekaugraveiuml lshdldrliuml ieiqiuml lsrSug =rejrekag fiumljd mrsYSkh l
yel
cdsl wOHdmk wdhkfha ldfrac34h uKavfha idudethlhskag iy ndysr uacuteIh lafIafha uacuteoaja
uacutefYaIhkag Tn fj fuu fdr=re nd sectu i|yd Tjqkafa YdiaSh odhlajh nd sectu
fjkqfjka udfa wjxl lDdj mlt lsIacuteug leueafntilde
wdpdfrac34h agrave ta wdfrac34 fEcirc =Kfialr
wOHlaI ckrda
cdsl wOHdmk wdhkh
uyru
iv
wOHCIjrhdfa mKsuacutevh
2017 jfrac34Ifha isg YS xldfotilde idudkH wOHdmk moaOsfha wfmdi ^Wiia fmltamp i|yd
dfrac34lSlrKhg la llt kj uacuteIhuddjla lshdaul fotilde bka woyia jkafka fufla mejs
uacuteIhuddj hdjaldSk lsIacuteuls fiuml ldfrac34hfha sect wfmdi ^Wiia fmltamp ridhk uacuteoHdj
fNsl uacuteoHdj yd Ocircj uacuteoHdj hk uacuteIhj uacuteIh ikaOdrfhaa uacuteIh wdlDsfhaa uacuteIhudd
oslashjHja hiuml hiuml ixfYdaOk isyuml l wr Bg iudoacutej bfkqiuml-bekaugravefiuml lufotildeofhaa
wehSiuml yd lafiarelrKfhaa hiuml hiuml fjkiaugraveiuml wfmalaId lrk Egrave uacuteIhudfotilde wvx=
uacuteIh lreKqj mudKh uacuteYd jYfhka wvq lrk o wr bfkqiuml-bekaugravefiuml wkqqlufha
hiuml hiuml fjkiaugraveiuml o isyuml lrkq eicirc h mejs uacuteIhudd oslashjHhla jQ =re udfrac34fdamfoaY ixyh
fjkqjg =re wafmdla ydividekajd fok Egrave
Wiia fmlt uacuteoHd uacuteIh i|yd bxSis NdIdfjka iiumlmdEgrave wkafrac34cdsl jYfhka msltsa ka
mszligYSkh miqsh uacuteIhudd lshdaul lsIacutefiuml sect wHjYH uacuteh tfya uacuteuacuteO fmltfmda Nduacute
lsIacutefiuml sect mriamruacutefrdaO uacuteIh lreKq i|yka ugraveua foaYSh uacuteIhuddfotilde iSud wNsNjd sh uacuteIh
lreKq tajdfha we=iquesta ugraveua ksid =reNj=kag yd isiqkag ta ka mszligyrKh myiq jQfha
ke fiuml kah Tn wg ma jkafka ta wjYHdj imqrdSug a Waidyhl msMhla
fi h
tneuacuteka fiuml kah u`ska foaYSh uacuteIhuddfotilde iSudjg hgaj ish ujqNdIdfjka wodlt uacuteIh
ikaOdrh mszligyrKh lsIacuteug isiqkag wjiadj iid we tfuka u uacuteuacuteO ka wsffrac34l mkas
jeks uQdYhjska wjYH fdr=re nd ekSu fjkqjg uacuteIhuddj u`ska wfmalaIs
fdr=re =reNj=kag yd isiqkag ksjerEgravej nd ekSug fiuml kah Wmldszlig jkq we
uacuteIh iiumlkaO uacutefYaI =reNj=ka yd uacuteYajuacuteoHd wdpdfrac34hjreka uacuteiska iiumlmdEgrave fiuml kah
cdsl wOHdmk wdhkfha uacuteIhud lntildegqfjka o wOHhk uKavfhka o mdl iNdfjka o
wkquesh nd Tn wg ma jk neuacuteka bylt mntildesfhka hq= nj ksfrac34foaY llt yels h
wdpdfrac34h ta atilde wfidal o isajd
wOHlaI
uacuteoHd fomdfrac34fiumlka=j
cdsl wOHdmk wdhkh
v
wkqYdilajh wdpdfrac34h agrave ta wdfrac34 fEcirc =Kfialr
wOHlaI ckrda cdsl wOHdmk wdhkh
weumllaIKh wdpdfrac34h ta auml ta o isajd
wOHlaI uacuteoHd fomdfrac34fiumlka=j
cdsl wOHdmk wdhkh
uacuteIh kdhlajh tiuml tia uacuteluisxy
iyldr lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j cdsl wOHdmk wdhkh
wNHkar ixialrK uKavh ta fla jvqfa uhd
fcHIaG lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j OcircOcircmStia fmffrac34rd ntildeh
iyldr lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j ugrave rdcqfoajka uhd
iyldr lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j
lfrac34D uKavh wdpdfrac34h viacuteotilde tiuml ta agrave nKavdr - ridhk uacuteoHd fomdfrac34fiumlka=j fmardfoKsh
uacuteYajuacuteoHdh (04 yd 05 jk tallh) wdpdfrac34h olaIsld jkakswdrEacuteNtilde - ridhk uacuteoHd fomdfrac34fiumlka=j YS chjfrac34Okmqr
uacuteYajuacuteoHdh (04 jk tallh)
ndysr ixialrK uKavh fcHIaG uydpdfrac34h tia mS plusmnrKsh - ridhk uacuteoHd fomdfrac34fiumlka=j YS chjfrac34Okmqr
uacuteYajuacuteoHdh
fcHIaG uydpdfrac34h tiuml atilde mS o fldiad - ridhk uacuteoHd fomdfrac34fiumlka=j fldltU uacuteYajuacuteoHdh fcHIaG uydpdfrac34h tEacute tiuml atilde tiuml mshka - ridhk uacuteoHd fomdfrac34fiumlka=j fmardfoKsh uacuteYajuacuteoHdh
uydpdfrac34h iqoka shkfa - ridhk uacuteoHd fomdfrac34fiumlka=j YS chjfrac34Okmqr uacuteYajuacuteoHdh fla atilde nkayuml l=udr uhd - ksfhdacH flduidszligia wOHdmk mldYk fomdfrac34fiumlka=j
wOHdmk fomdfrac34fiumlka=j uqEgraved w=fldar ntildeh - =re fiajh 1 mcdmS ndsld uacuteoHdh fydrK Egravemsld fkaisxy ntildeh - =re fiajh 1-(uacuteYdntildel) ldkad uacuteyumly fldltU 07
iStatiuml fmffrac34rd fufkuacuteh - =re fiajh 1 fotildeaia l=uszlig uacuteoHdh fudrgqj uacute fla viacute atilde idsld udOuacute ntildeh - =re fiajh 1 uqiasiuml ldkad uacuteyumly fldltU 04 tEacute tiuml atildeatilde sectmsld ueKsfla ntildeh - =re fiajh 1 uacuteydr uyd foauacute ndsld uacuteyumly lsszlignafdv
vi
NdId ixialrKh
cha mshoiqka uhd mOdk Wm lfrac34D - isiquestntildeK
fala yjqia fldltU 10
uqa msgqj
wdfrac34 wdfrac34 fla msrK ntildeh cdsl wOHdmk wdhkh
uacuteuacuteO iydh viacute mS mS ugraverjfrac34Ok ntildeh ux jesmsaacuteh uhd rxetha ohdjxY uhd
(
vii
mgqk
wOHCI ckrda=ntildehfa mKsuacutevhhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip iii
wOHCI=udfa mKsuacutevhhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip iv
uacuteIhudd lntildegqj helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip v
04 tallh - modfrac34fha jdhquh wjiadjhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip01-27
11 modfrac34fha wjiad =fkys wxY= ieleiau iy tajdfha ofrac34YSh CIK helliphelliphelliphelliphelliphellip02
12 jdhquh wjiadj helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip05
121 jdhq kshu
122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)
123 pdaia kshuh (WIaKajndashmszligud iiumlnkaOh)
124 wejdacircfrda kshuh (mudK-mszligud iiumlnkaOh)
125 ujqsl mszligudj (Vm)
126 ixhqla jdhq ioacutelrKh
13 fvdaagkafa wdxYsl mSvk kshuh helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip16
131 ujq Ndh wkqidrfhka wdxYsl mSvkh
14 jdhq msltsn`o pdl wKqljdoh helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip18
141 pdl wKqljdofha mszligmQfrac34K jdhqjla i|yd Wmlamk
142 pdl wKqljdofha ioacutelrKh
143 jfrac34 uOHkH uQ fotildeh iy uOHkH fotildeh
144 ueialafja-fndaaUumliaudka jHdmash
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh helliphelliphelliphelliphelliphellip23
151 jeka vrsquojdaia ioacutelrKh
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
05 tallh - Ylas uacuteoHdjhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip28-54
21 dm-ridhksl uacuteoHdfotilde yd dms uacuteoHdfotilde uQsl mo helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip29 211 moaOsh jgmsgdj yd iSudj 212 moaOs jfrac34
213 moaOshl =K
214 moaOshl wjiadj
215 tkaeamsh (H)
216 dmh
22 uacuteuacuteO dm-ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd helliphelliphelliphelliphelliphelliphellip34
iiumlu tkaeams uacutemfrac34hdi 221 dmodhl yd dmdjfYdaIl lshdjs
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh
23 oesi tkaeamsh fyja whksl ixfhdahl Wamdok tkaeamsh(helliphelliphelliphelliphelliphelliphelliphellip47 fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj ridhksl mslshdjl iiumlu helliphelliphelliphellip49
tkafgdms fjki siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
1
wkafrac34 h
1 1 modfrac34fha wjiad =fkys wxY= ieleiau
iy tajdfha ofrac34YSh CIK
1 2 jdhquh wjiadj
1 2 1 jdhq kshu
bull mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq
ioacutelrKh
bull mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ
Kkh lsIacuteiuml
1 2 2 fndhsa kshuh
(mSvk-mszligud iiumlnkaOh)
1 2 3 pdaia kshuh
(WIaKajndashmszligud iiumlnkaOh)
1 2 4 wej dacircfrda kshuh
(mudK-mszligud iiumlnkaOh)
1 2 5 ujqsl mszligudj (Vm)
1 2 6 ixhqla jdhq ioacutelrKh
1 3 fvdaagkaf a wdxYsl mSvk kshuh
1 3 1 ujq Nd h wkqidrfhka
wdxYsl mSvkh
1 4 jdhq msltsn`o pdl wKql jdoh
1 4 1 pdl wKql jdofha mszligmQfrac34K jdhqjla
i|yd Wmlamk
1 4 2 pdl wKql jdofha ioacutelrKh
1 4 3 jfrac34 uOHkH uQ fotilde h iy
uOHkH fotilde h
1 4 4 ueialafja--fndaaUumliaudka jHdmash
1 5 daauacutel jdhqjg eltfmk mszligEgrave
mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
1 5 1 jeka vrsquojdaia ioacutelrKh
1 5 2 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
1 modfrac34fha jdhquh
wjiadj
2
ye|skaugraveu
uacuteYajfha wes ishiquest oE iquacutefYaIS ridhksl wkkHdjlska hqla h modfrac34fha l=vdu wxY=j
mrudKqj nj wms oksuq irj oelajqjfyda ridhk uacuteoHdj hkq ldquomodfrac34h iy tys isyumljk
uacutemfrac34hdi msltsn|j wOHkhrdquo fi wfrac34 oelauacute h yel modfrac34h hkq wjldYhla wama
lr kakd ialkaOhla iys acutekEu fohla jk wr th oelsh yels yd weaSug yels
^mia ch wdsectamp fohla fi fuka u jdh jeks wmg fkdfmfkk fohla o uacuteh yel
ixhqsh yd =K mokiuml lr f k oslashjH ntildeYK uQoslashjH fuka u mrudKq iy wKq wdsect uacuteuacuteO
wdldr fuys sect y`yumlkd yels h ishiquestu oslashjH gtk oslashj iy jdhq fig wvqu rntildeka uQsl
wjiad =klska mejsh yels h gtkhl sect wxY= =ltska ne`oS tlsfklg lsUumlgqj lsishiuml
ksYaNtilde jHqyhlg ksYaNtilde yevhla iysj weisIacuteu ksid tajdg pkh ugravefiuml yelshdj wvq
h oslashjhl wxY= tlsfklg lsUumlgqj wea tlsfklg iadkShj bd Egraveka ne|S kes neuacuteka
ikaikaokdaulj gtkhl sect g jvd fotilde fhka pkh uacuteh yels h wxY= wr yumlr wkqj
oslashj yd gtkjg jvd jdhq fndfyda fjkia fotilde jdhqjlsect wxY= tlsfklska fjka ugrave wes yumlr
wxY=jl mudKhg ikaikaokdaulj uacuteYd ugraveu fya=fjka wxY=jg ksoyfia yeisIacuteug
bv we tneuacuteka jdhq wxY= wr wdlfrac34Yk n bd l=vd fyda fkd sksh yels riuml ugraveu
fya=fjka wmg jdhq wxY= fjka fjka j ielsh yels neuacuteka WIaKajh yd mSvkh u
mokiuml jQ iuyr lams myiqfjka mqfrdalkh llt yels fotilde
11 modfrac34fha mOdk wjiad =fkys wxY= ieleiau iy tajdfha ofrac34YSh CIK
wjldYfha bvla kakd ialkaOhla iys acutekE u fohla zmodfrac34hZ fi ye`Egravekauacuteh yels h
wmg plusmnlsh yels wska weash yels yfldlt fia u wm fkdolsk tfya yqiau kakd
jdh o oacuteg wha h mq`Ma jYfhka a l ishuml modfrac34h gtk oslashj yd jdhq hkqfjka
wjiad =klg jfrac34 SlrKh llt yels h ixhqsfhys fjkia ugraveulska fdrj modfrac34h fiuml
suacuteO wjiad wr tllska wfklg mszligjfrac34kh llt yels h ksoiqkla fi( oslashj wjiadfotilde
mjsk ch ra lsIacutefuka jdhq wjiadjg (yqudh) mszligjfrac34kh llt yels wr isisa
lsIacutefuka gtk wjiadjg ^whsiaamp ma llt yels h
gtk
^Wod( hlv weKhamp
iaOacuter yevhla yd
mszligudjla we
oslashj
^Wod( champ
iaOacuter yevhla
kes kuqa iaOacuter mszligudjla we
jdhq
^Wod( ySshiuml neAEligkamp
iaOacuter yevhla fyda
iaOacuter mszligudjla fyda ke
gtk
wxY= ^mrudKq wKq fyda whkamp
wr wdlfrac34IK n mn h
wxY= liumlmkh jk kuqa
eklska eklg
pkh fkd fotilde
oslashj
wxY= ^mrudKq wKq fyda whkamp
wr wdlfrac34IK n triuml
mn fkd fotilde wxY=jg hiuml
mudKhlg eklska eklg
pkh uacuteh yels h
jdhq
wxY= ^mrudKq wKq fyda whkamp
wr wdlfrac34IK n yumln h
wxY=jg eklska eklg
pkh uacuteh yels h
11 rEmh modfrac34fha suacuteO wjiad
wxY=j ieleiafuka yd psfhka modfrac34fha suacuteO wjiad tlsfklska fjkia fotilde
wkafrac34currenwxY= wr yumlr jdhq wjiadfotilde wecircl jk wr gtk wjiadfotilde sect th wju fotilde jdhq
wjiadjg idfmalaIj oslashj wjiadfotilde sect wxY= tlsfklg ioacutem jk wr th gtk wjiadfotilde
3
sect riuml tlsfklg ioacutem o fkd fotilde tneuacuteka luja j ixuacuteOdkh jQ wxY=uh rgdjla plusmnlsh
yelafla gtk wjiadfotilde muŒ oslashj yd jdhq wjiad foflys sect u wxY= ieliS weafa wyUq
fi h fuys msMhla fi oslashj wjiadfotilde wes wxY=jg idfmaalaIj jdhq wjiadfotilde
wes wxY=jg jvd fotilde fhka yd ksoyia fi pkh uacuteh yels h flfia jqj o gtkj
wes wxY=j psh liumlmkjg muKla iSud fotilde my 11 j =fjka plusmnlafjk mszligEgrave
modfrac34fha wxY=j ieleiau yd tys psh mszligudj yevh iiumlmSvHdj yd gtkajh jeks
ufyaalaI =Kj fjkialiumljg =vq fohs
1 1 j =j gtk oslashj yd jdhq j =Kj =Kdaul ixikaokh
=Kh gtk oslashj jdhq
yevh ksYaNtilde h wvx = n`yumlfkys
yevh kakd uqa
n`yumlfkys uq`M mszligudj
mqrd fkd mesfrhs
n`yumlfkys yevh
kakd wr
n`yumlfkys iuia
mszligudj wa lr kS
mszligudj ksYaNtilde h ksYaNtilde h wvx = n`yumlfkys
mszligudj wa lr kS
gtkajh (ρ) g cm-3 (293 K sect)
bylt w hka kS
Wod( hlv
(7 874 g cm-3)
rula bylt w hka
kS
Wod( ch
(0 997 g cm-3)
w hka mylt h
Wod( yhsvcka
(0 071g cm-3)
iiumlmSvHdj iiumlmSvkh lsIacuteu
bd yumlIalr h
iiumlmSvkh lsIacuteu bd
yumlIalr h
fnfyuacuteka iiumlmSvkh
llt yels h
igyk ( oslashj wvx = n`yumlfkys yevh kakd nj wm i`oyka lr wes wr tfia jkafka
ukaoehs issh hq= h idudkHfhka acutekE u jia=jla wkafrac34-wKql n jeks uacuteuacuteO jfrac34 fha
n u` ska tlg ne| nd kakd neuacuteka thg ksYaNtilde yevhla we icirclrhl wes fok o
c mudKhla ^mszligudjlaamp hiuml yevhla kafka mDIaAgravel wdsh ksid h oslashjh =lt mjsk
wkafrac34-wKql n ksid mDIaGh flltjffrac34 l=vd oslashj udjlhla wes fotilde icirclrfha igraveas u` ska
oslashjh u byltg aumljla wes flfrk wr mDIaAgravel wdshg jvd jeauml =reajc nh
u` ska myltg weoSula wes fotilde tuksid oslashjh byltska iu mDIaGhla iysj icirclrfha
yevh kS fufia jkafka fuu uacuteuacuteO jfrac34 fha ishuml nj nmEu ksid h flfia jqj
o mDIaAgravel wdsh =reajc nhg jvd mn jQjd kiuml cfha mDIaGh iu fkdjk
wr n`yumlfka yevh fkd kq we =reajc nhla keehs is=j fyda mDIaAgravel wdsh
fndfyda fihska bylt hhs mDIaGfha tla tla fldgilg u wfkla mDIaGh iu` yels riuml
ltx ugrave mejSug wjYH ksid tajd wr wes wdlfrac34IK wju lr ekSug fmfograve tneuacuteka
fok o mszligudjl wju mDIaAgravel lafIaMhla wes fyd`o u yevh jk f dadldr yevh
kS
ralsrSfuka fyda isiskfhka tla wjiadjl mjsk modfrac34h ja wjiadjlg mszligjfrac34kh
llt yels h WIaKajh jeauml lsIacutefiuml sect wxY=j pk fotilde h bylt hEua wxY= wr yumlr jeauml
ugraveua lrK fldg modfrac34j wjiadj fjkia fotilde ta wkqj WIaKajh jeauml lsIacutefiuml sect gtk
wjiadfotilde wes oslashjH oslashj wjiadjga oslashj wjiadfotilde wes oslashjH jdhq wjiadjga ma fotilde
WIaKajfha wvq ugraveua iu isyuml jkafka fuys uacutefdauhhs my 12 rEmfhka modfrac34h tys
wjiad wr wkafrac34-mszligjfrac34khg Ndck llt yels wdldrh fmkakqiuml flffrac34
4
12 rEmh modfrac34fha wjiad wr wkafrac34-mszligjfrac34kh
11 ksoiqk
wxY= jvda u ioacutem fi iamfrac34Y jkafka ugrave kuqa tajd wyUq fi weysIacute weafa modfrac34fha
ljr kiuml wjiadfotilde o
uacutei`yumlu oslashj wjiadj
11 j =jg wkqj wm modfrac34fha mOdk wjiad =fkys =K uacuteiar lrk uacuteg wxY=j ieliqu
yd pkh uQslj ild nd we uacutefYaIfhka u hiuml oslashjHhl wes wKq fyda mrudKqj
pkh ksid yg kakd Ylash dmc Ylash jk wr th oslashjHfha WIaKajhg wkqfdauj
iudkqmdsl fotilde tu` ska modfrac34fha wes wxY=j uOHkHh pdl Ylash uefkk neuacuteka
th wxY=j pkh fyda dmc psh i`oyd fya= fotilde
wkafrac34-wKql n u` ska wKq tlsfklg ltx ugrave mejSug fmfUk nj wm oekgua
okakd kuqa wKqj dmc Ylash u` ska wKq tlsfklska wEa ugraveug fmfograve ta wkqj
modfrac34fha mOdk wjiad =fkys mejSu wKqj wkafrac34-wKql n iy dmc Ylash
wr iu=sfhys msMhla fi ielsh yels h
wkafrac34-wKql wdlfrac34IK bd yumln jk uacuteg WIaKajh wvq lsIacutefuka dmc Ylash WIaKajhamp
wvq fkdllt fyda wKq oslashj fyda gtk fyda fi mejSug fkd fmfograve wKq tlsfklg
bd lt` ska wes uacuteg iy wkafrac34 - wKql n Wmszliguj wes uacuteg mjd iiumlmSvkh u` ska muKla
jdhq oslashj wjiadjg ma fkd fotilde flfia jqj o WIaKajh wvq lsIacuteu u` ska wKqj dmc
Ylash wvq jk uacuteg jdhq bd myiqfjka oslashj llt yels h fiuml yeisIacuteiuml my 1 3 rEmfhka
meyeEgraves llt yels h modfrac34fha mOdk wjiad =k flfrys wkafrac34-wKql nj yd dmc
Ylasfha msuacutereoaO nmEfiuml iajNdjh wmg tu` ska wjfndaO lr yels h
5
13 rEmh wkafrac34-wKql n yd dm Ylash wkqj modfrac34fha mOdk wjiad
=fkys yeisIacuteu
modfrac34fha mOdk wjiad =kla mejSug fya=j wm oekgua yodrd we oeka wm
modfrac34fha jdhquh yeisIacuteug fya= jk jdhq kshu iy jdhquh wjiAdj msltsn`o j yumlrga
ild nuq
12 jdhquh wjiadj
oeka wm idudkH WIaKaj mSvk aaj hgfa wes jdhquh wjiadfotilde mjsk oslashjHj
yeisIacuteu flfrys wjOdkh fhduq lruq
11 j =fotilde uacuteiar lr wes mszligEgrave jdhquh wjiadj my i`oyka fNsl =K wkqj uacuteiar
flffrac34
bull jdhq bd iiumlmSvH fotilde
bull jdhq ieu EgraveYdjlg u iudk whqszligka mSvkh wes lrhs
bull jdhqjg gtk iy oslashjjg jvd wvq gtkajhla we
bull jdhqj yevh iy mszligudj ksH fkd fotilde tajd wvx = Ndckfha yevh iy mszligudj
kS
bull jdhq lsis u hdkasl nmEulska fdrj iiumlmQfrac34Kfhka u iy iudkj tlsfkl
iuOtilde ntildeY fotilde
jdhqjl irdjhg fya= jkafka tu wKq wr mjsk n fkd ssbquoh yels ugraveuhs tajdfha
yeisIacuteu mIacutelaIKdaul wOHhkhkaf ka nd a msM u` ska fidhd kakd o fmdyuml jdhq kshujg (miqj idlEacutePd flffrac34iexcl) wkqj isyuml fotilde fiuml jdhq kshu hkq jdhqjl ueksh
yels =K wr mjsk iiumlnkaOd fotilde ueksh yels =K iuyrla jk mSvkh mszligudj
WIaKajh iy mudKh ^ujq fyda ialkaOhamp jeks tajd bd jeo a jkafka fiuml uacutepH
wr mjsk iiumlnkaOd jdhqjl mOdk wjiad (5 jk tallfha sect wfrac34 olajkq efiacuteiexcl) uacuteiar lrk ksid h tlsfkl yd ne`yumlKq fiuml uacutepHhka jdhq kshu iQ lsIacuteug uQsl
ugrave we
121 jdhq kshu
wm idlEacutePd lsIacuteug hk jdhq kshu uacuteoHdhka lsysm fokl= uacuteiska jdhqj fNsl =K
mokiumlj isyuml lrk o mIacutelaIKjska nd a msM fotilde mSvkh WIaKajh mszligudj iy
jdhq mudKh hk uacutepH wr mjsk iiumlnkaOd fuys sect ild nk wr tajd u` ska
6
modfrac34fha jdhquh wjiadj msltsn`o udkj jfrac34 hdg mfhdackja jk fdr=re rdYshla
mldY fotilde
mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq ioacutelrKh
jdhq wKq wr wkafrac34-wKql n fkdues nj Wmlamkh flffrac34 o tndivide jdhqjla mszligmQfrac34K
jdhqjla fi ye`Egravekafotilde tkiuml mszligmQfrac34K jdhqjl wKq wr wdlfrac34IK fyda uacutelfrac34IK fyda
n fkd mjS tfuka u jdhqj oud wes Ndckfha mszligudj iu` ieipoundfiuml sect jdhq wxY=jl
mszligudj fkdild yeszligh yels h
jdhqjl ksrfmalaI WIaKajh (T) mSvkh (P) mszligudj (V) iy oslashjH mudKh ^n ujqamp
jdhquh yeisIacuteu flfrys nmdk idOl fotilde P T V iy n wr iiumlnkaOdj my
mldYkfhka ksrEmKh flffrac34
fuh mszligmQfrac34K jdhq ioacutelrKh fyda mszligmQfrac34K jdhq kshuh fi oelafjk wr R hkq ieu
jdhqjlg u fmdyuml w hla wes jdhq kshh fotilde fok o acutekE u WIaKajhl sect yd
mSvkhl sect by iiumlnkaOdjg wkql+j yeisfrk acutekE u jdhqjla mszligmQfrac34K jdhqjla fi
y`yumlkajkq efiacute
fuu aaj hgfa oS mszligmQfrac34K jdhq ujq 1 la i|yd 0 degC sect yd 1 atm sect R kshfha w h
my wdldrhg Kkh l yel (0 degC sect yd 1 atm yssect mszligmqfrac34K jdhqjl 1 mol l mszligudj
22 414 dm3 fotilde)
mszligmQfrac34K jdhq ioacutelrKh by uacutepH yr wr wes iiumlnkaOdj jk nj wmg fmfkk
wr acutekE u jdhqjl wjiadj tuOtildeska uacuteiar flfrk ksid th wjiad ioacutelrKh fi
o ye|skafotilde
mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ Kkh lsIacuteiuml
mszligmQfrac34K jdhq ioacutelrKh u` ska wmg mszligudj WIaKajh mSvkh fyda ujq mudKh hk
tajdhska =kla sect wes uacuteg wfkla rdYsh ksfrac34Kh llt yels h jdhqjl ujq mudKh okakd
uacuteg tys ujqsl ialkaOh Nduacutefhka tys ialkaOh o Kkh llt yels h tfuka u
tu` ska jdhqjl gtkajh o ksfrac34Kh llt yels h mszligmQfrac34K jdhq kshfha w hg eltfmk
mszligEgrave wfkl=a rdYsj tall Nduacute lsIacuteu bd jeo a jk nj ul nd hq= h
idudkHfhka mSvkh atm Pa bar torr jeks tall jska mldY llt yels h tneuacuteka fiuml
eguml uacutei`oSfiuml sect my 1 2 j =fotilde sect wes mSvk tallj mszligjfrac34k Tng Wootilde jkq we
12 j =j mSvkh i`oyd jk tall
mSvk tallh Pa bar atm torr mmHg
1 Pa 1 N m-2 10-5 9 87 times 10-6 7 5 times 10-3
1 bar 100000 1bar 0 987 750 061 atm 101325 1 01325 1 atm 7601 torr mmHg 133 32 1 3332 times 10-3 1 3158 times 10-3 1 torr 1 mmHg
7
12 ksoiqk
jdhq isskavrhl mszligudj 0950 dm3 fotilde hiuml mSvkhla hgfa sect fiuml isskavrh oslashj
fmdfmakajska (C3H8) msIacute we isskavrh ysia jQ uacuteg jdhqf daSh mSvkh yd WIaKajh
hgfa sect tys fmdfmaka jdhqj hiuml mudKhla bsszlig fotilde
(i) wjg mszligirfha aaj 25degC iy 750 torr (1 torr = 133 52 Pa) kiuml isskavrh
ysiaj wes uacuteg tys bsszlig ugrave wes fmdfmaka jdhq ujq mudKh fldmuK o
(wNHkar mSvkh ndysr mSvkhg iudk uacuteg oS)
(ii) isskavrfha bsszlig ugrave wes fmdfmaka jdhq ialkaOh Kkh lrkak
(iii) isskavrfha bsszlig ugrave wes fmdfmaka jdhqfotilde gtkajh Kkh lrkak
uacutei`yumlu (i) mltuqj sect wes fdr=re iudfdapkh lrkak
WIaKajh T = (25 + 273) K = 298 K mSvkh P = 750 torr times 13332 Pa 1 torr = 99990 Pa mszligudj V = 0 950 dm3 = 0 950 times 10-3 m3
n fkdokakd moh fotilde
PV = nRT Nduacutefhka
(ii) fmdfmakays (C3H8) ujqsl ialkaOh = 44 g mol-1
fmdfmakays ialkaOh = 0 038 mol times 44 g mol-1 = 1 672 g
(iii) fmdfmakays gtkajh = ialkaOh mszligudj = = 1 76 g dm-3
by ksoiqk iel+ uacuteg mszligmQfrac34K jdhq kshuh uacuteuacuteO wdldrjska bEgraveszligma llt yels nj
fmkS hk wr my oelafjk mszligEgrave ir fjkia lsIacuteulska fok o jdhqjl ialkaOh
iy gtkajh fiuacuteh yels h
PV = nRT
P = RT
zwnjzwnj P = CRT
fuys zC Zhkq idkaoslashKhhs
j o PV = nRT iiumlnkaOdj my mszligEgrave o mldY llt yels h
PV = RT
fuys m hkq ialkaOh jk wr M hkq jdhqfotilde ujqsl ialkaOhhs
P = RT fi o suacuteh yels h
8
gtkajh (d) =
there4 P =
uacutefYaIs aaj hgfA fjka jdhq kshu jHqamkak lsIacutefiuml sect mszligmQfrac34K jdhq kshuh uQsl
moku fi lshd lrhs
122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)mdashksh WIaKajhla hgfa wes iaOacuter jdhq mudKhl (ialkaOhl) mSvkh jdhqfotilde mszligudjg
msfdauj uacutepkh fotilde (fyda iudkqmdsl) fotilde˜ fndhsa kshuh hkqfjka ye`Egravekafjk
fuh tfia kiuml lrk oafoa 17 jeks ishjfia sect WIaKajh ksh jQ aaj hgfa fjkia
jk mSvkha iu jdhqjl mszligudj uacutepkh jk wdldrh whsszligIa cdsl uacuteoHdhl= jQ
frdnUuml fndhsa (1627- 1691) uacuteiska wOHhkh lsIacutefuka miqj h tys Ksuh wdldrh
my oelafotilde
my plusmnlafjk mszligEgrave fndhsa kshuh jHqamkak lsIacuteu i`oyd mszligmQfrac34K jdhq kshuh fhdod
yelsh PV= nRT
jdhqfjys mudKh yd moaOsfhys WIaKajh kshj mjajd kakd oafoa kiuml nT =Ksh
kshhla fotilde R o kshhla jk neuacuteka nRT =Ksh o kshhla (k) fotilde
PV = k (kshhla)
tkiuml ksh WIaKajfha sect ksh jdhq mudKhl mSvkfhaa mszligudfotildea =Ksh kshhla
fotilde fuh fndhsa kshuh mldY lrk fjka wdldrhls
ksh T WIaKajhl wes ksh jdhq mudKhl mszligudj V1 o mSvkh P1 o kiuml yd th V2
mszligudjg yd P2 mSvkhg ma llt uacuteg fndhsa kshuhg wkqj
14 rEmh u` ska fndhsa kshufha idiumlmodhsl miadszligl ksrEmK folla fmkakqiuml flffrac34
14 rEmfha (a) u` ska ixikaokh i`oyd uacuteuacuteO WIaKajj sect PV = k miadr lr we
k w h WIaKajh u muKla r`od mjsk ksid fok o jdhq ialkaOhla i`oyd w`Egravek
o ieu jlhla i`oyd u k ys w h tlsfklg fjkia fotilde bylt WIaKajj sect mszligudfotilde
midrKh ksid plh byltg f dia wes nj ielsh hq= h tfuka u WIaKajh ksh
uacuteg jdhqfotilde mSvkh wvla jk uacuteg mszligudj fo =K jk nj ul nd hq= h
9
1 4 rEmh uacuteuacuteO ksh WIaKajj sect (a) mszligudj (V) iuOtilde (b) 1 V iuOtilde
mSvkfha fjkia ugraveu
14 (b) rEmh u` ska P g tosrsfhka ys miadrh ksrEmKh fotilde th uQ laIHh yryd hk
ir ffrac34Ldjls fndhsa uacuteiska lrk o mIacutelaIKjg wkqj nd kakd o fuu miadr
u` ska jdhqjg bylt iiumlmSvHdjla wes nj mudKdaulj fmkajd foa tkiuml fok o
jdhq ialkaOhla iiumlmSvkh llt uacuteg tl u mudKhlska wes wKq ixLHdj l=vd mszligudjla
=lt mesffrac34 fiuml wkqj bylt mSvkj sect jdhqj gtkajh jeauml fotilde
igyk fok o jdhqjl gtkajh d ialkaOh m o mszligudj v o jk uacuteg d = ioacutelrKfhka
fok nj wms oksuq tuksid ksh WIaKajfhasect
hkqfjka suacuteh yels h
1 3 ksoiqk
ksh WIaKajhla hgfa wes okakd jdhq ujq mudKhl mszligudj fo =K llt uacuteg
mSvkfha isyuml jk fjkia ugraveu Kkh lrkak
uacutei`yumlu V1 =V V2 = 2V P1 = P P2 = fndhsa kshuh fhsectfuka P1V1 = P2V2
P times V = P2 times 2VP2 = P 2 there4kj mSvkh uqa mSvkfhka wvla fotilde
10
1 4 ksoiqk
ldur WIaKajfha sect neumlkhla yhsvcka jdhqj okakd mudKhlska mqrjd we jdhqf daSh
mSvkfha sect (100 kPa) tu jdhq mudKh 2 50 dm3 l mszligudjla kS tu WIaKajfha sect u
we=lt mSvkh 20 kPa ugraveug neumlkfha mszligudj fldmuK uacuteh llt hq= o
uacutei`yumlu P1 = 100 kPa P2 = 20 kPa V1 = 2 5 dm3 V2 = fndhsa kshuh fhsectfuka P1V1 = P2V2
100 kPa times 2 5 dm3 = 20 kPa times V2 there4V2 = 12 5 dm3 neumlkfha mszligudj 12 5 dm3 olajd jeauml llt hq= h
123 pdaia kshuh (WIaKaj-mszligud iiumlnkaOh)cdlaia pdaia iy fcdaIma f a-umliela hk uacuteoHdhkaf a yeoEIacuteiuml u ska fmkajd sect wes mszligEgrave
ksh mSvkhl sect fok o ksH jdhq mudKhl ^ialkaOhamp mszligudj WIaKajha iu`
jeauml jk wr isisa lsIacuteua iu` wvq fotilde tfuka u WIaKajfhA isyuml jk ieu fiaishia
wxYlhl fjkila mdid ^jeauml ugraveu fyda wvq ugraveuamp mszligudj 0degC sect jdhqfotilde wdriumlNl mszligudfjka idOlhlska fjkia jk nj ^jeauml ugraveu fyda wvq ugraveuamp fidhd f k we
0 degC sect iy t degC ys sect jdhqfotilde mszligudj msltsfjltska V0 iy Vt hhs Wmlamkh lruq tuacuteg
fuu aajfha sect WIaKajh i`oyd kj mszligudKhla wfrac34 olajd we tuacuteg tu mszligudKhg
wkqj
t degC i`oyd Tt = 273 15 + t uOtildeska nd fok wr
0 degC i`oyd T0 = 273 15 uOtildeska nd fohs
fuu kj WIaKaj mszligudKh flauacuteka WIaKaj mszligudKh (K) fyja ksrfmalaI WIaKaj
mszligudKh fi ye`Egravekafotilde ndash 273 15 degC (0 K) hkak dm sl Y+kHh fi wfrac34 oelafjk
wr th ffioaOdkaslj lt` d uacuteh yels wju WIaKajh fotilde
fmdyumlfotilde a uacuteg ksh mSvkfha sect (V1 T1) isg (V2 T2) olajd isyuml jk fjkila i`oyd
11
tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg
wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde
jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys
WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg
yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h
PV = nRTV = nRT P
ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde
zwnjzwnjzwnjzwnjV prop T fyda V = kT
pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka
WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd
Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect
ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh
lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34
15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde
uacutepkh
12
1 5 ksoiqk
ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml
jk WIaKaj fjki Kkh lrkak
uacutei`yumlu
T1 = T V1 = V V2 = 3V T2 =
T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh
wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h
hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi
efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg
lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr
kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde
1 6 ksoiqk
23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde
tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki
Kkh lrkak
uacutei`yumlu
T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =
jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka
V2 = 2 03 dm3
mszligudfotilde isyumljk fjki = 0 03 dm3
124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=
jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj
lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla
hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)
fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h
13
jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda
kshh (NA fyda L) fi ye|skafotilde
my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka
wjfndaO lr yels h
fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl
u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud
follg by iiumlnkaOdj fhsectfuka
P iy T ksh uacuteg sect (R iy NA kshhka fotilde )
irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud
=lt iudk wKq ixLdjla wvx= fotilde (V α N)
by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd
mszligmQfrac34K jdhq ioacutelrKh nd yels h
by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka
k = R jQ uacuteg
P V = n R T
14
125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka
fi wmg suacuteh yels h
iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd
mszligudj (Vm) tl u w hla uacuteh hq= ksid th
fi Kkh llt yels h
tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u
mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34
bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu
aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj
22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi
ksrEmKh flffrac34
bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde
fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde
igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde
V = k n = k (m M) tneuacuteka M = k (m V) = k d
1 7 ksoiqk
298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud
iudk nj fmkajkak
uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe
VHe = nHeRTHe PHe
VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3
15
PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =
PNeVNe = nNeRTNe
VNe = nNeRTNe PNe
VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa
VNe = 24 4 dm3
tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq
wa lr kakd mszligud iudk fotilde
126 ixhqla jdhq kshuh
jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj
tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka
T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla
fi suacuteh yels h
fuh ixhqla jdhq kshuh fi ye|skafotilde
1 8 ksoiqk
25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o
uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh
P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3
T1 = 25 + 273 = 298 K
V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =
P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa
16
13 fvdaagkaf a wdxYsl mSvk kshuh
fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm
yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk
wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml
ishuml jdhq odhl fotilde
jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj
wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde
ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla
iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs
fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh
fi yeEgravekafotilde
A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska
PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde
my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka
jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha
we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh
PT hehs o isuq
PV = nRT
A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )
B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )
jdhq ntildeYKh i`oyd nT = PTV RT
iy nT = nA + nB
tu ksid PTV RT = (PAV RT) + (PBV RT)
iq`M llt uacuteg PT = PA + PB
fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl
131 ujq Nd h wkqidrfhka wdxYsl mSvkh
T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq
ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde
fvdaagkaf a kshuhg wkqj PT = PA + PB
PA iy PB mldYk fjk fjk u PT jska fnsectfuka
17
tu ksid
fi suacuteh yels h
hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk
fotilde
1 9 ksoiqk
(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla
tla jdhqfotilde wdxYsl mSvkh Kkh lrkak
(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd
lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq
ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak
uacutei`yumlu
18
fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK
u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd
fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj
tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla
fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re
uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq
irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq
efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj
u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk
nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja
ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj
mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=
jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes
lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect
tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh
wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K
jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl
1 10 ksoiqk
my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs
iskak
2KClO3(s) rarr2KCl(s) + 3O2(g)
27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute
27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh
Kkh lrkak
uacutei`yumlu
fvdaagkaf a kshuhg wkqj
Piuia = PTlaiscka + Pch
PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa
mszligmQfrac34K jdhq ioacutelrKh fhsectfuka
14 jdhq msltsn`o pdl wKqljdoh
by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(
fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks
mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla
nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka
uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml
jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh
llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad
fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd
fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj
yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde
19
141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde
wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd
uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr
wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS
wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh
u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka
gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska
jdhqj bylt iiumlmSvHdj meyeEgraves fotilde
bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu
jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO
wKqjg uacuteuacuteO fotilde mjS
fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg
ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash
jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk
ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde
bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS
fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq
wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj
fuu ska mldY flffrac34
fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh
mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt
uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka
jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr
iiumlnkaOdjh my ioacutelrKfhka nd foa
jyumlrga my oelafjk lreKq plusmnlauacuteh yels h
bull jdhq wxY= tlsfklska iajdhaj yeisffrac34
jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska
iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda
fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj
wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml
Wmlamkfhka meyeEgraves fotilde
bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla
u` ska mSvkhla wes fotilde
fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect
ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl
isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug
20
fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml
jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq
ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj
jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml
fotilde
142 pdl wKqljdofha ioacutelrKh
my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla
fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34
by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes
wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka
wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34
uOHkH fotilde h fi wfrac34 olajkq efiacute
143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h
my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu
jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg
jfrac34 uOHkH uQ fotilde h fotilde
jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla
jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=
Kkla i`oyd ioacutelrKh ild nuq
N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)
PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka
21
tu ksid jfrac34 uOHkH uQ fotilde h
fi suacuteh yels h
1 11 ksoiqk
25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak
uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1
by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj
fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama
lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml
pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh
u` ska th my oelafjk mszligEgrave idOkh llt yels h
fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt
yel
kB hkq fndaaUumliaudka kshh fotilde
22
wKqjla i`oyd
ujqhla i`oyd
fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq
fotilde
144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml
N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag
pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq
efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave
mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes
lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde
jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash
fi ye|skafotilde
16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--
fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd
fotilde jHdmash
23
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka
wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea
jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd
idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute
ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr
^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17
rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla
i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34
17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj
iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha
sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka
daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh
17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd
Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir
ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla
mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy
ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh
yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr
jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml
ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej
jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla
fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh
fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs
17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska
o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska
daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka
iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk
wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh
hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd
mszligudj (V)
mSvk
h (
P)
24
jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj
o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga
meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg
jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke
fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka
lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS
jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru
ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml
yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj
sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK
n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde
mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd
laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect
(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g
jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda
ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel
jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt
WIaKaj fotilde
daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o
WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel
fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg
jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml
fuh mltuq ioacutelrKfha wdfoaYfhka
fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH
ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk
nj wmg fmfka
fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh
pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we
tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj
hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h
mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq
wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt
jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect
jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia
PV mszligmQfrac34K
daauacutel
25
jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq
wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka
yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=
h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka
wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel
jdhq mszligmQfrac34K aajfhka wm ukh fotilde
151 jeka vrsquo jdaia ioacutelrKh
fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa
sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K
jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk
wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq
mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel
jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid
daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH
fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj
iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk
Egrave
bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka
kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka
mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka
igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash
iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg
fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh
mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde
1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj
ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh
by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK
fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde
gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq
mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde
fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg
iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq
msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect
moaOsfha mSvkh my mldYkfhka nd fohs
26
bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL
fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr
tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk
mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka
wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks
fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq
kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh
fi kej suacuteh yels h
fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh
fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql
nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia
flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha
wkafrac34--mszligjfrac34kh l yels fotilde
ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs
wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj
yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde
igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys
sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde
ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha
lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh
iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla
fi o yeisszligh yels ugraveu h
bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla
oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi
mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS
30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc
oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi
muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu
WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla
oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde
( )2
aP V b RTV
+ minus =
27
19 rEmh CO2 j ldm igyk
1 3 j =j - ioacutelrK idrdxYh
jdhq kshuh intildelrKhksh j mjsk
idOl
mszligmQfrac34K jdhq kshuh PV = nRT ke
fndhsa kshuh n iy T
pdaia kshuh V = kT n iy P
wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T
wKql pdl ioacutelrKh
idudkH fotilde h
jfrac34 uOHkH fotilde h
jfrac34 uOHkH fotilde h
fvdaagkaf a wdxYsl mSvk
kshuh
PA = xA PT
PT = PA + PB + PC
iiumlmSvHd idOlh jdhq ujq 1la i|yd
jeka vZjdaia ioacutelrKh
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
ii
ridhk uacuteoHdj
iiumlma fmd
12 fYaKsh
copy cdsl wOHdmk wdhkh
mltuq uqoslashKh ndash 2019
uacuteoHd fomdfrac34fiumlka=j
uacuteoHd yd dlaIK mSGh
cdsl wOHdmk wdhkh
YS xld
mldYkh ( uqoslashKdh
cdsl wOHdmk wdhkh
uyru
YS xld
iii
wOHCI ckrdafa mKsuacutevh
wOHdmkfha =KdaulNdjh jfrac34Okh lsIacuteu i|yd cdsl wOHdmk wdhkh jszligka jr
wjiadkql+ mshjr kq nhs wodlt uacuteIhhka i|yd wsffrac34l iiumlma fmda ilia lsIacuteu tjka
tla mshjrls
cdsl wOHdmk wdhkfha uacuteIhudd ixjfrac34Ok lKavdhua cdsl uacuteYaj uacuteoHdj uacuteoaj=ka
iy mdiea moaOsfha mltmqreyuml =rejreka uska wsffrac34l iiumlma fmda ilia lr we 2017 sect
lshdaul lrk o wfmdi ^Wiia fmltamp kj uacuteIh ksfrac34foaYhg wkqj fuu wsffrac34l iiumlma
fmda shd wes ksid isiqkag wodlt uacuteIh lreKq msltsn|j wjfndaOh mqiquesta llt yels wr
jvda ModhS bfkqiuml bekaugraveiuml lshdldrliuml ieiqiuml lsrSug =rejrekag fiumljd mrsYSkh l
yel
cdsl wOHdmk wdhkfha ldfrac34h uKavfha idudethlhskag iy ndysr uacuteIh lafIafha uacuteoaja
uacutefYaIhkag Tn fj fuu fdr=re nd sectu i|yd Tjqkafa YdiaSh odhlajh nd sectu
fjkqfjka udfa wjxl lDdj mlt lsIacuteug leueafntilde
wdpdfrac34h agrave ta wdfrac34 fEcirc =Kfialr
wOHlaI ckrda
cdsl wOHdmk wdhkh
uyru
iv
wOHCIjrhdfa mKsuacutevh
2017 jfrac34Ifha isg YS xldfotilde idudkH wOHdmk moaOsfha wfmdi ^Wiia fmltamp i|yd
dfrac34lSlrKhg la llt kj uacuteIhuddjla lshdaul fotilde bka woyia jkafka fufla mejs
uacuteIhuddj hdjaldSk lsIacuteuls fiuml ldfrac34hfha sect wfmdi ^Wiia fmltamp ridhk uacuteoHdj
fNsl uacuteoHdj yd Ocircj uacuteoHdj hk uacuteIhj uacuteIh ikaOdrfhaa uacuteIh wdlDsfhaa uacuteIhudd
oslashjHja hiuml hiuml ixfYdaOk isyuml l wr Bg iudoacutej bfkqiuml-bekaugravefiuml lufotildeofhaa
wehSiuml yd lafiarelrKfhaa hiuml hiuml fjkiaugraveiuml wfmalaId lrk Egrave uacuteIhudfotilde wvx=
uacuteIh lreKqj mudKh uacuteYd jYfhka wvq lrk o wr bfkqiuml-bekaugravefiuml wkqqlufha
hiuml hiuml fjkiaugraveiuml o isyuml lrkq eicirc h mejs uacuteIhudd oslashjHhla jQ =re udfrac34fdamfoaY ixyh
fjkqjg =re wafmdla ydividekajd fok Egrave
Wiia fmlt uacuteoHd uacuteIh i|yd bxSis NdIdfjka iiumlmdEgrave wkafrac34cdsl jYfhka msltsa ka
mszligYSkh miqsh uacuteIhudd lshdaul lsIacutefiuml sect wHjYH uacuteh tfya uacuteuacuteO fmltfmda Nduacute
lsIacutefiuml sect mriamruacutefrdaO uacuteIh lreKq i|yka ugraveua foaYSh uacuteIhuddfotilde iSud wNsNjd sh uacuteIh
lreKq tajdfha we=iquesta ugraveua ksid =reNj=kag yd isiqkag ta ka mszligyrKh myiq jQfha
ke fiuml kah Tn wg ma jkafka ta wjYHdj imqrdSug a Waidyhl msMhla
fi h
tneuacuteka fiuml kah u`ska foaYSh uacuteIhuddfotilde iSudjg hgaj ish ujqNdIdfjka wodlt uacuteIh
ikaOdrh mszligyrKh lsIacuteug isiqkag wjiadj iid we tfuka u uacuteuacuteO ka wsffrac34l mkas
jeks uQdYhjska wjYH fdr=re nd ekSu fjkqjg uacuteIhuddj u`ska wfmalaIs
fdr=re =reNj=kag yd isiqkag ksjerEgravej nd ekSug fiuml kah Wmldszlig jkq we
uacuteIh iiumlkaO uacutefYaI =reNj=ka yd uacuteYajuacuteoHd wdpdfrac34hjreka uacuteiska iiumlmdEgrave fiuml kah
cdsl wOHdmk wdhkfha uacuteIhud lntildegqfjka o wOHhk uKavfhka o mdl iNdfjka o
wkquesh nd Tn wg ma jk neuacuteka bylt mntildesfhka hq= nj ksfrac34foaY llt yels h
wdpdfrac34h ta atilde wfidal o isajd
wOHlaI
uacuteoHd fomdfrac34fiumlka=j
cdsl wOHdmk wdhkh
v
wkqYdilajh wdpdfrac34h agrave ta wdfrac34 fEcirc =Kfialr
wOHlaI ckrda cdsl wOHdmk wdhkh
weumllaIKh wdpdfrac34h ta auml ta o isajd
wOHlaI uacuteoHd fomdfrac34fiumlka=j
cdsl wOHdmk wdhkh
uacuteIh kdhlajh tiuml tia uacuteluisxy
iyldr lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j cdsl wOHdmk wdhkh
wNHkar ixialrK uKavh ta fla jvqfa uhd
fcHIaG lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j OcircOcircmStia fmffrac34rd ntildeh
iyldr lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j ugrave rdcqfoajka uhd
iyldr lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j
lfrac34D uKavh wdpdfrac34h viacuteotilde tiuml ta agrave nKavdr - ridhk uacuteoHd fomdfrac34fiumlka=j fmardfoKsh
uacuteYajuacuteoHdh (04 yd 05 jk tallh) wdpdfrac34h olaIsld jkakswdrEacuteNtilde - ridhk uacuteoHd fomdfrac34fiumlka=j YS chjfrac34Okmqr
uacuteYajuacuteoHdh (04 jk tallh)
ndysr ixialrK uKavh fcHIaG uydpdfrac34h tia mS plusmnrKsh - ridhk uacuteoHd fomdfrac34fiumlka=j YS chjfrac34Okmqr
uacuteYajuacuteoHdh
fcHIaG uydpdfrac34h tiuml atilde mS o fldiad - ridhk uacuteoHd fomdfrac34fiumlka=j fldltU uacuteYajuacuteoHdh fcHIaG uydpdfrac34h tEacute tiuml atilde tiuml mshka - ridhk uacuteoHd fomdfrac34fiumlka=j fmardfoKsh uacuteYajuacuteoHdh
uydpdfrac34h iqoka shkfa - ridhk uacuteoHd fomdfrac34fiumlka=j YS chjfrac34Okmqr uacuteYajuacuteoHdh fla atilde nkayuml l=udr uhd - ksfhdacH flduidszligia wOHdmk mldYk fomdfrac34fiumlka=j
wOHdmk fomdfrac34fiumlka=j uqEgraved w=fldar ntildeh - =re fiajh 1 mcdmS ndsld uacuteoHdh fydrK Egravemsld fkaisxy ntildeh - =re fiajh 1-(uacuteYdntildel) ldkad uacuteyumly fldltU 07
iStatiuml fmffrac34rd fufkuacuteh - =re fiajh 1 fotildeaia l=uszlig uacuteoHdh fudrgqj uacute fla viacute atilde idsld udOuacute ntildeh - =re fiajh 1 uqiasiuml ldkad uacuteyumly fldltU 04 tEacute tiuml atildeatilde sectmsld ueKsfla ntildeh - =re fiajh 1 uacuteydr uyd foauacute ndsld uacuteyumly lsszlignafdv
vi
NdId ixialrKh
cha mshoiqka uhd mOdk Wm lfrac34D - isiquestntildeK
fala yjqia fldltU 10
uqa msgqj
wdfrac34 wdfrac34 fla msrK ntildeh cdsl wOHdmk wdhkh
uacuteuacuteO iydh viacute mS mS ugraverjfrac34Ok ntildeh ux jesmsaacuteh uhd rxetha ohdjxY uhd
(
vii
mgqk
wOHCI ckrda=ntildehfa mKsuacutevhhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip iii
wOHCI=udfa mKsuacutevhhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip iv
uacuteIhudd lntildegqj helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip v
04 tallh - modfrac34fha jdhquh wjiadjhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip01-27
11 modfrac34fha wjiad =fkys wxY= ieleiau iy tajdfha ofrac34YSh CIK helliphelliphelliphelliphelliphellip02
12 jdhquh wjiadj helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip05
121 jdhq kshu
122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)
123 pdaia kshuh (WIaKajndashmszligud iiumlnkaOh)
124 wejdacircfrda kshuh (mudK-mszligud iiumlnkaOh)
125 ujqsl mszligudj (Vm)
126 ixhqla jdhq ioacutelrKh
13 fvdaagkafa wdxYsl mSvk kshuh helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip16
131 ujq Ndh wkqidrfhka wdxYsl mSvkh
14 jdhq msltsn`o pdl wKqljdoh helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip18
141 pdl wKqljdofha mszligmQfrac34K jdhqjla i|yd Wmlamk
142 pdl wKqljdofha ioacutelrKh
143 jfrac34 uOHkH uQ fotildeh iy uOHkH fotildeh
144 ueialafja-fndaaUumliaudka jHdmash
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh helliphelliphelliphelliphelliphellip23
151 jeka vrsquojdaia ioacutelrKh
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
05 tallh - Ylas uacuteoHdjhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip28-54
21 dm-ridhksl uacuteoHdfotilde yd dms uacuteoHdfotilde uQsl mo helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip29 211 moaOsh jgmsgdj yd iSudj 212 moaOs jfrac34
213 moaOshl =K
214 moaOshl wjiadj
215 tkaeamsh (H)
216 dmh
22 uacuteuacuteO dm-ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd helliphelliphelliphelliphelliphelliphellip34
iiumlu tkaeams uacutemfrac34hdi 221 dmodhl yd dmdjfYdaIl lshdjs
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh
23 oesi tkaeamsh fyja whksl ixfhdahl Wamdok tkaeamsh(helliphelliphelliphelliphelliphelliphelliphellip47 fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj ridhksl mslshdjl iiumlu helliphelliphelliphellip49
tkafgdms fjki siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
1
wkafrac34 h
1 1 modfrac34fha wjiad =fkys wxY= ieleiau
iy tajdfha ofrac34YSh CIK
1 2 jdhquh wjiadj
1 2 1 jdhq kshu
bull mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq
ioacutelrKh
bull mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ
Kkh lsIacuteiuml
1 2 2 fndhsa kshuh
(mSvk-mszligud iiumlnkaOh)
1 2 3 pdaia kshuh
(WIaKajndashmszligud iiumlnkaOh)
1 2 4 wej dacircfrda kshuh
(mudK-mszligud iiumlnkaOh)
1 2 5 ujqsl mszligudj (Vm)
1 2 6 ixhqla jdhq ioacutelrKh
1 3 fvdaagkaf a wdxYsl mSvk kshuh
1 3 1 ujq Nd h wkqidrfhka
wdxYsl mSvkh
1 4 jdhq msltsn`o pdl wKql jdoh
1 4 1 pdl wKql jdofha mszligmQfrac34K jdhqjla
i|yd Wmlamk
1 4 2 pdl wKql jdofha ioacutelrKh
1 4 3 jfrac34 uOHkH uQ fotilde h iy
uOHkH fotilde h
1 4 4 ueialafja--fndaaUumliaudka jHdmash
1 5 daauacutel jdhqjg eltfmk mszligEgrave
mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
1 5 1 jeka vrsquojdaia ioacutelrKh
1 5 2 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
1 modfrac34fha jdhquh
wjiadj
2
ye|skaugraveu
uacuteYajfha wes ishiquest oE iquacutefYaIS ridhksl wkkHdjlska hqla h modfrac34fha l=vdu wxY=j
mrudKqj nj wms oksuq irj oelajqjfyda ridhk uacuteoHdj hkq ldquomodfrac34h iy tys isyumljk
uacutemfrac34hdi msltsn|j wOHkhrdquo fi wfrac34 oelauacute h yel modfrac34h hkq wjldYhla wama
lr kakd ialkaOhla iys acutekEu fohla jk wr th oelsh yels yd weaSug yels
^mia ch wdsectamp fohla fi fuka u jdh jeks wmg fkdfmfkk fohla o uacuteh yel
ixhqsh yd =K mokiuml lr f k oslashjH ntildeYK uQoslashjH fuka u mrudKq iy wKq wdsect uacuteuacuteO
wdldr fuys sect y`yumlkd yels h ishiquestu oslashjH gtk oslashj iy jdhq fig wvqu rntildeka uQsl
wjiad =klska mejsh yels h gtkhl sect wxY= =ltska ne`oS tlsfklg lsUumlgqj lsishiuml
ksYaNtilde jHqyhlg ksYaNtilde yevhla iysj weisIacuteu ksid tajdg pkh ugravefiuml yelshdj wvq
h oslashjhl wxY= tlsfklg lsUumlgqj wea tlsfklg iadkShj bd Egraveka ne|S kes neuacuteka
ikaikaokdaulj gtkhl sect g jvd fotilde fhka pkh uacuteh yels h wxY= wr yumlr wkqj
oslashj yd gtkjg jvd jdhq fndfyda fjkia fotilde jdhqjlsect wxY= tlsfklska fjka ugrave wes yumlr
wxY=jl mudKhg ikaikaokdaulj uacuteYd ugraveu fya=fjka wxY=jg ksoyfia yeisIacuteug
bv we tneuacuteka jdhq wxY= wr wdlfrac34Yk n bd l=vd fyda fkd sksh yels riuml ugraveu
fya=fjka wmg jdhq wxY= fjka fjka j ielsh yels neuacuteka WIaKajh yd mSvkh u
mokiuml jQ iuyr lams myiqfjka mqfrdalkh llt yels fotilde
11 modfrac34fha mOdk wjiad =fkys wxY= ieleiau iy tajdfha ofrac34YSh CIK
wjldYfha bvla kakd ialkaOhla iys acutekE u fohla zmodfrac34hZ fi ye`Egravekauacuteh yels h
wmg plusmnlsh yels wska weash yels yfldlt fia u wm fkdolsk tfya yqiau kakd
jdh o oacuteg wha h mq`Ma jYfhka a l ishuml modfrac34h gtk oslashj yd jdhq hkqfjka
wjiad =klg jfrac34 SlrKh llt yels h ixhqsfhys fjkia ugraveulska fdrj modfrac34h fiuml
suacuteO wjiad wr tllska wfklg mszligjfrac34kh llt yels h ksoiqkla fi( oslashj wjiadfotilde
mjsk ch ra lsIacutefuka jdhq wjiadjg (yqudh) mszligjfrac34kh llt yels wr isisa
lsIacutefuka gtk wjiadjg ^whsiaamp ma llt yels h
gtk
^Wod( hlv weKhamp
iaOacuter yevhla yd
mszligudjla we
oslashj
^Wod( champ
iaOacuter yevhla
kes kuqa iaOacuter mszligudjla we
jdhq
^Wod( ySshiuml neAEligkamp
iaOacuter yevhla fyda
iaOacuter mszligudjla fyda ke
gtk
wxY= ^mrudKq wKq fyda whkamp
wr wdlfrac34IK n mn h
wxY= liumlmkh jk kuqa
eklska eklg
pkh fkd fotilde
oslashj
wxY= ^mrudKq wKq fyda whkamp
wr wdlfrac34IK n triuml
mn fkd fotilde wxY=jg hiuml
mudKhlg eklska eklg
pkh uacuteh yels h
jdhq
wxY= ^mrudKq wKq fyda whkamp
wr wdlfrac34IK n yumln h
wxY=jg eklska eklg
pkh uacuteh yels h
11 rEmh modfrac34fha suacuteO wjiad
wxY=j ieleiafuka yd psfhka modfrac34fha suacuteO wjiad tlsfklska fjkia fotilde
wkafrac34currenwxY= wr yumlr jdhq wjiadfotilde wecircl jk wr gtk wjiadfotilde sect th wju fotilde jdhq
wjiadjg idfmalaIj oslashj wjiadfotilde sect wxY= tlsfklg ioacutem jk wr th gtk wjiadfotilde
3
sect riuml tlsfklg ioacutem o fkd fotilde tneuacuteka luja j ixuacuteOdkh jQ wxY=uh rgdjla plusmnlsh
yelafla gtk wjiadfotilde muŒ oslashj yd jdhq wjiad foflys sect u wxY= ieliS weafa wyUq
fi h fuys msMhla fi oslashj wjiadfotilde wes wxY=jg idfmaalaIj jdhq wjiadfotilde
wes wxY=jg jvd fotilde fhka yd ksoyia fi pkh uacuteh yels h flfia jqj o gtkj
wes wxY=j psh liumlmkjg muKla iSud fotilde my 11 j =fjka plusmnlafjk mszligEgrave
modfrac34fha wxY=j ieleiau yd tys psh mszligudj yevh iiumlmSvHdj yd gtkajh jeks
ufyaalaI =Kj fjkialiumljg =vq fohs
1 1 j =j gtk oslashj yd jdhq j =Kj =Kdaul ixikaokh
=Kh gtk oslashj jdhq
yevh ksYaNtilde h wvx = n`yumlfkys
yevh kakd uqa
n`yumlfkys uq`M mszligudj
mqrd fkd mesfrhs
n`yumlfkys yevh
kakd wr
n`yumlfkys iuia
mszligudj wa lr kS
mszligudj ksYaNtilde h ksYaNtilde h wvx = n`yumlfkys
mszligudj wa lr kS
gtkajh (ρ) g cm-3 (293 K sect)
bylt w hka kS
Wod( hlv
(7 874 g cm-3)
rula bylt w hka
kS
Wod( ch
(0 997 g cm-3)
w hka mylt h
Wod( yhsvcka
(0 071g cm-3)
iiumlmSvHdj iiumlmSvkh lsIacuteu
bd yumlIalr h
iiumlmSvkh lsIacuteu bd
yumlIalr h
fnfyuacuteka iiumlmSvkh
llt yels h
igyk ( oslashj wvx = n`yumlfkys yevh kakd nj wm i`oyka lr wes wr tfia jkafka
ukaoehs issh hq= h idudkHfhka acutekE u jia=jla wkafrac34-wKql n jeks uacuteuacuteO jfrac34 fha
n u` ska tlg ne| nd kakd neuacuteka thg ksYaNtilde yevhla we icirclrhl wes fok o
c mudKhla ^mszligudjlaamp hiuml yevhla kafka mDIaAgravel wdsh ksid h oslashjh =lt mjsk
wkafrac34-wKql n ksid mDIaGh flltjffrac34 l=vd oslashj udjlhla wes fotilde icirclrfha igraveas u` ska
oslashjh u byltg aumljla wes flfrk wr mDIaAgravel wdshg jvd jeauml =reajc nh
u` ska myltg weoSula wes fotilde tuksid oslashjh byltska iu mDIaGhla iysj icirclrfha
yevh kS fufia jkafka fuu uacuteuacuteO jfrac34 fha ishuml nj nmEu ksid h flfia jqj
o mDIaAgravel wdsh =reajc nhg jvd mn jQjd kiuml cfha mDIaGh iu fkdjk
wr n`yumlfka yevh fkd kq we =reajc nhla keehs is=j fyda mDIaAgravel wdsh
fndfyda fihska bylt hhs mDIaGfha tla tla fldgilg u wfkla mDIaGh iu` yels riuml
ltx ugrave mejSug wjYH ksid tajd wr wes wdlfrac34IK wju lr ekSug fmfograve tneuacuteka
fok o mszligudjl wju mDIaAgravel lafIaMhla wes fyd`o u yevh jk f dadldr yevh
kS
ralsrSfuka fyda isiskfhka tla wjiadjl mjsk modfrac34h ja wjiadjlg mszligjfrac34kh
llt yels h WIaKajh jeauml lsIacutefiuml sect wxY=j pk fotilde h bylt hEua wxY= wr yumlr jeauml
ugraveua lrK fldg modfrac34j wjiadj fjkia fotilde ta wkqj WIaKajh jeauml lsIacutefiuml sect gtk
wjiadfotilde wes oslashjH oslashj wjiadjga oslashj wjiadfotilde wes oslashjH jdhq wjiadjga ma fotilde
WIaKajfha wvq ugraveua iu isyuml jkafka fuys uacutefdauhhs my 12 rEmfhka modfrac34h tys
wjiad wr wkafrac34-mszligjfrac34khg Ndck llt yels wdldrh fmkakqiuml flffrac34
4
12 rEmh modfrac34fha wjiad wr wkafrac34-mszligjfrac34kh
11 ksoiqk
wxY= jvda u ioacutem fi iamfrac34Y jkafka ugrave kuqa tajd wyUq fi weysIacute weafa modfrac34fha
ljr kiuml wjiadfotilde o
uacutei`yumlu oslashj wjiadj
11 j =jg wkqj wm modfrac34fha mOdk wjiad =fkys =K uacuteiar lrk uacuteg wxY=j ieliqu
yd pkh uQslj ild nd we uacutefYaIfhka u hiuml oslashjHhl wes wKq fyda mrudKqj
pkh ksid yg kakd Ylash dmc Ylash jk wr th oslashjHfha WIaKajhg wkqfdauj
iudkqmdsl fotilde tu` ska modfrac34fha wes wxY=j uOHkHh pdl Ylash uefkk neuacuteka
th wxY=j pkh fyda dmc psh i`oyd fya= fotilde
wkafrac34-wKql n u` ska wKq tlsfklg ltx ugrave mejSug fmfUk nj wm oekgua
okakd kuqa wKqj dmc Ylash u` ska wKq tlsfklska wEa ugraveug fmfograve ta wkqj
modfrac34fha mOdk wjiad =fkys mejSu wKqj wkafrac34-wKql n iy dmc Ylash
wr iu=sfhys msMhla fi ielsh yels h
wkafrac34-wKql wdlfrac34IK bd yumln jk uacuteg WIaKajh wvq lsIacutefuka dmc Ylash WIaKajhamp
wvq fkdllt fyda wKq oslashj fyda gtk fyda fi mejSug fkd fmfograve wKq tlsfklg
bd lt` ska wes uacuteg iy wkafrac34 - wKql n Wmszliguj wes uacuteg mjd iiumlmSvkh u` ska muKla
jdhq oslashj wjiadjg ma fkd fotilde flfia jqj o WIaKajh wvq lsIacuteu u` ska wKqj dmc
Ylash wvq jk uacuteg jdhq bd myiqfjka oslashj llt yels h fiuml yeisIacuteiuml my 1 3 rEmfhka
meyeEgraves llt yels h modfrac34fha mOdk wjiad =k flfrys wkafrac34-wKql nj yd dmc
Ylasfha msuacutereoaO nmEfiuml iajNdjh wmg tu` ska wjfndaO lr yels h
5
13 rEmh wkafrac34-wKql n yd dm Ylash wkqj modfrac34fha mOdk wjiad
=fkys yeisIacuteu
modfrac34fha mOdk wjiad =kla mejSug fya=j wm oekgua yodrd we oeka wm
modfrac34fha jdhquh yeisIacuteug fya= jk jdhq kshu iy jdhquh wjiAdj msltsn`o j yumlrga
ild nuq
12 jdhquh wjiadj
oeka wm idudkH WIaKaj mSvk aaj hgfa wes jdhquh wjiadfotilde mjsk oslashjHj
yeisIacuteu flfrys wjOdkh fhduq lruq
11 j =fotilde uacuteiar lr wes mszligEgrave jdhquh wjiadj my i`oyka fNsl =K wkqj uacuteiar
flffrac34
bull jdhq bd iiumlmSvH fotilde
bull jdhq ieu EgraveYdjlg u iudk whqszligka mSvkh wes lrhs
bull jdhqjg gtk iy oslashjjg jvd wvq gtkajhla we
bull jdhqj yevh iy mszligudj ksH fkd fotilde tajd wvx = Ndckfha yevh iy mszligudj
kS
bull jdhq lsis u hdkasl nmEulska fdrj iiumlmQfrac34Kfhka u iy iudkj tlsfkl
iuOtilde ntildeY fotilde
jdhqjl irdjhg fya= jkafka tu wKq wr mjsk n fkd ssbquoh yels ugraveuhs tajdfha
yeisIacuteu mIacutelaIKdaul wOHhkhkaf ka nd a msM u` ska fidhd kakd o fmdyuml jdhq kshujg (miqj idlEacutePd flffrac34iexcl) wkqj isyuml fotilde fiuml jdhq kshu hkq jdhqjl ueksh
yels =K wr mjsk iiumlnkaOd fotilde ueksh yels =K iuyrla jk mSvkh mszligudj
WIaKajh iy mudKh ^ujq fyda ialkaOhamp jeks tajd bd jeo a jkafka fiuml uacutepH
wr mjsk iiumlnkaOd jdhqjl mOdk wjiad (5 jk tallfha sect wfrac34 olajkq efiacuteiexcl) uacuteiar lrk ksid h tlsfkl yd ne`yumlKq fiuml uacutepHhka jdhq kshu iQ lsIacuteug uQsl
ugrave we
121 jdhq kshu
wm idlEacutePd lsIacuteug hk jdhq kshu uacuteoHdhka lsysm fokl= uacuteiska jdhqj fNsl =K
mokiumlj isyuml lrk o mIacutelaIKjska nd a msM fotilde mSvkh WIaKajh mszligudj iy
jdhq mudKh hk uacutepH wr mjsk iiumlnkaOd fuys sect ild nk wr tajd u` ska
6
modfrac34fha jdhquh wjiadj msltsn`o udkj jfrac34 hdg mfhdackja jk fdr=re rdYshla
mldY fotilde
mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq ioacutelrKh
jdhq wKq wr wkafrac34-wKql n fkdues nj Wmlamkh flffrac34 o tndivide jdhqjla mszligmQfrac34K
jdhqjla fi ye`Egravekafotilde tkiuml mszligmQfrac34K jdhqjl wKq wr wdlfrac34IK fyda uacutelfrac34IK fyda
n fkd mjS tfuka u jdhqj oud wes Ndckfha mszligudj iu` ieipoundfiuml sect jdhq wxY=jl
mszligudj fkdild yeszligh yels h
jdhqjl ksrfmalaI WIaKajh (T) mSvkh (P) mszligudj (V) iy oslashjH mudKh ^n ujqamp
jdhquh yeisIacuteu flfrys nmdk idOl fotilde P T V iy n wr iiumlnkaOdj my
mldYkfhka ksrEmKh flffrac34
fuh mszligmQfrac34K jdhq ioacutelrKh fyda mszligmQfrac34K jdhq kshuh fi oelafjk wr R hkq ieu
jdhqjlg u fmdyuml w hla wes jdhq kshh fotilde fok o acutekE u WIaKajhl sect yd
mSvkhl sect by iiumlnkaOdjg wkql+j yeisfrk acutekE u jdhqjla mszligmQfrac34K jdhqjla fi
y`yumlkajkq efiacute
fuu aaj hgfa oS mszligmQfrac34K jdhq ujq 1 la i|yd 0 degC sect yd 1 atm sect R kshfha w h
my wdldrhg Kkh l yel (0 degC sect yd 1 atm yssect mszligmqfrac34K jdhqjl 1 mol l mszligudj
22 414 dm3 fotilde)
mszligmQfrac34K jdhq ioacutelrKh by uacutepH yr wr wes iiumlnkaOdj jk nj wmg fmfkk
wr acutekE u jdhqjl wjiadj tuOtildeska uacuteiar flfrk ksid th wjiad ioacutelrKh fi
o ye|skafotilde
mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ Kkh lsIacuteiuml
mszligmQfrac34K jdhq ioacutelrKh u` ska wmg mszligudj WIaKajh mSvkh fyda ujq mudKh hk
tajdhska =kla sect wes uacuteg wfkla rdYsh ksfrac34Kh llt yels h jdhqjl ujq mudKh okakd
uacuteg tys ujqsl ialkaOh Nduacutefhka tys ialkaOh o Kkh llt yels h tfuka u
tu` ska jdhqjl gtkajh o ksfrac34Kh llt yels h mszligmQfrac34K jdhq kshfha w hg eltfmk
mszligEgrave wfkl=a rdYsj tall Nduacute lsIacuteu bd jeo a jk nj ul nd hq= h
idudkHfhka mSvkh atm Pa bar torr jeks tall jska mldY llt yels h tneuacuteka fiuml
eguml uacutei`oSfiuml sect my 1 2 j =fotilde sect wes mSvk tallj mszligjfrac34k Tng Wootilde jkq we
12 j =j mSvkh i`oyd jk tall
mSvk tallh Pa bar atm torr mmHg
1 Pa 1 N m-2 10-5 9 87 times 10-6 7 5 times 10-3
1 bar 100000 1bar 0 987 750 061 atm 101325 1 01325 1 atm 7601 torr mmHg 133 32 1 3332 times 10-3 1 3158 times 10-3 1 torr 1 mmHg
7
12 ksoiqk
jdhq isskavrhl mszligudj 0950 dm3 fotilde hiuml mSvkhla hgfa sect fiuml isskavrh oslashj
fmdfmakajska (C3H8) msIacute we isskavrh ysia jQ uacuteg jdhqf daSh mSvkh yd WIaKajh
hgfa sect tys fmdfmaka jdhqj hiuml mudKhla bsszlig fotilde
(i) wjg mszligirfha aaj 25degC iy 750 torr (1 torr = 133 52 Pa) kiuml isskavrh
ysiaj wes uacuteg tys bsszlig ugrave wes fmdfmaka jdhq ujq mudKh fldmuK o
(wNHkar mSvkh ndysr mSvkhg iudk uacuteg oS)
(ii) isskavrfha bsszlig ugrave wes fmdfmaka jdhq ialkaOh Kkh lrkak
(iii) isskavrfha bsszlig ugrave wes fmdfmaka jdhqfotilde gtkajh Kkh lrkak
uacutei`yumlu (i) mltuqj sect wes fdr=re iudfdapkh lrkak
WIaKajh T = (25 + 273) K = 298 K mSvkh P = 750 torr times 13332 Pa 1 torr = 99990 Pa mszligudj V = 0 950 dm3 = 0 950 times 10-3 m3
n fkdokakd moh fotilde
PV = nRT Nduacutefhka
(ii) fmdfmakays (C3H8) ujqsl ialkaOh = 44 g mol-1
fmdfmakays ialkaOh = 0 038 mol times 44 g mol-1 = 1 672 g
(iii) fmdfmakays gtkajh = ialkaOh mszligudj = = 1 76 g dm-3
by ksoiqk iel+ uacuteg mszligmQfrac34K jdhq kshuh uacuteuacuteO wdldrjska bEgraveszligma llt yels nj
fmkS hk wr my oelafjk mszligEgrave ir fjkia lsIacuteulska fok o jdhqjl ialkaOh
iy gtkajh fiuacuteh yels h
PV = nRT
P = RT
zwnjzwnj P = CRT
fuys zC Zhkq idkaoslashKhhs
j o PV = nRT iiumlnkaOdj my mszligEgrave o mldY llt yels h
PV = RT
fuys m hkq ialkaOh jk wr M hkq jdhqfotilde ujqsl ialkaOhhs
P = RT fi o suacuteh yels h
8
gtkajh (d) =
there4 P =
uacutefYaIs aaj hgfA fjka jdhq kshu jHqamkak lsIacutefiuml sect mszligmQfrac34K jdhq kshuh uQsl
moku fi lshd lrhs
122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)mdashksh WIaKajhla hgfa wes iaOacuter jdhq mudKhl (ialkaOhl) mSvkh jdhqfotilde mszligudjg
msfdauj uacutepkh fotilde (fyda iudkqmdsl) fotilde˜ fndhsa kshuh hkqfjka ye`Egravekafjk
fuh tfia kiuml lrk oafoa 17 jeks ishjfia sect WIaKajh ksh jQ aaj hgfa fjkia
jk mSvkha iu jdhqjl mszligudj uacutepkh jk wdldrh whsszligIa cdsl uacuteoHdhl= jQ
frdnUuml fndhsa (1627- 1691) uacuteiska wOHhkh lsIacutefuka miqj h tys Ksuh wdldrh
my oelafotilde
my plusmnlafjk mszligEgrave fndhsa kshuh jHqamkak lsIacuteu i`oyd mszligmQfrac34K jdhq kshuh fhdod
yelsh PV= nRT
jdhqfjys mudKh yd moaOsfhys WIaKajh kshj mjajd kakd oafoa kiuml nT =Ksh
kshhla fotilde R o kshhla jk neuacuteka nRT =Ksh o kshhla (k) fotilde
PV = k (kshhla)
tkiuml ksh WIaKajfha sect ksh jdhq mudKhl mSvkfhaa mszligudfotildea =Ksh kshhla
fotilde fuh fndhsa kshuh mldY lrk fjka wdldrhls
ksh T WIaKajhl wes ksh jdhq mudKhl mszligudj V1 o mSvkh P1 o kiuml yd th V2
mszligudjg yd P2 mSvkhg ma llt uacuteg fndhsa kshuhg wkqj
14 rEmh u` ska fndhsa kshufha idiumlmodhsl miadszligl ksrEmK folla fmkakqiuml flffrac34
14 rEmfha (a) u` ska ixikaokh i`oyd uacuteuacuteO WIaKajj sect PV = k miadr lr we
k w h WIaKajh u muKla r`od mjsk ksid fok o jdhq ialkaOhla i`oyd w`Egravek
o ieu jlhla i`oyd u k ys w h tlsfklg fjkia fotilde bylt WIaKajj sect mszligudfotilde
midrKh ksid plh byltg f dia wes nj ielsh hq= h tfuka u WIaKajh ksh
uacuteg jdhqfotilde mSvkh wvla jk uacuteg mszligudj fo =K jk nj ul nd hq= h
9
1 4 rEmh uacuteuacuteO ksh WIaKajj sect (a) mszligudj (V) iuOtilde (b) 1 V iuOtilde
mSvkfha fjkia ugraveu
14 (b) rEmh u` ska P g tosrsfhka ys miadrh ksrEmKh fotilde th uQ laIHh yryd hk
ir ffrac34Ldjls fndhsa uacuteiska lrk o mIacutelaIKjg wkqj nd kakd o fuu miadr
u` ska jdhqjg bylt iiumlmSvHdjla wes nj mudKdaulj fmkajd foa tkiuml fok o
jdhq ialkaOhla iiumlmSvkh llt uacuteg tl u mudKhlska wes wKq ixLHdj l=vd mszligudjla
=lt mesffrac34 fiuml wkqj bylt mSvkj sect jdhqj gtkajh jeauml fotilde
igyk fok o jdhqjl gtkajh d ialkaOh m o mszligudj v o jk uacuteg d = ioacutelrKfhka
fok nj wms oksuq tuksid ksh WIaKajfhasect
hkqfjka suacuteh yels h
1 3 ksoiqk
ksh WIaKajhla hgfa wes okakd jdhq ujq mudKhl mszligudj fo =K llt uacuteg
mSvkfha isyuml jk fjkia ugraveu Kkh lrkak
uacutei`yumlu V1 =V V2 = 2V P1 = P P2 = fndhsa kshuh fhsectfuka P1V1 = P2V2
P times V = P2 times 2VP2 = P 2 there4kj mSvkh uqa mSvkfhka wvla fotilde
10
1 4 ksoiqk
ldur WIaKajfha sect neumlkhla yhsvcka jdhqj okakd mudKhlska mqrjd we jdhqf daSh
mSvkfha sect (100 kPa) tu jdhq mudKh 2 50 dm3 l mszligudjla kS tu WIaKajfha sect u
we=lt mSvkh 20 kPa ugraveug neumlkfha mszligudj fldmuK uacuteh llt hq= o
uacutei`yumlu P1 = 100 kPa P2 = 20 kPa V1 = 2 5 dm3 V2 = fndhsa kshuh fhsectfuka P1V1 = P2V2
100 kPa times 2 5 dm3 = 20 kPa times V2 there4V2 = 12 5 dm3 neumlkfha mszligudj 12 5 dm3 olajd jeauml llt hq= h
123 pdaia kshuh (WIaKaj-mszligud iiumlnkaOh)cdlaia pdaia iy fcdaIma f a-umliela hk uacuteoHdhkaf a yeoEIacuteiuml u ska fmkajd sect wes mszligEgrave
ksh mSvkhl sect fok o ksH jdhq mudKhl ^ialkaOhamp mszligudj WIaKajha iu`
jeauml jk wr isisa lsIacuteua iu` wvq fotilde tfuka u WIaKajfhA isyuml jk ieu fiaishia
wxYlhl fjkila mdid ^jeauml ugraveu fyda wvq ugraveuamp mszligudj 0degC sect jdhqfotilde wdriumlNl mszligudfjka idOlhlska fjkia jk nj ^jeauml ugraveu fyda wvq ugraveuamp fidhd f k we
0 degC sect iy t degC ys sect jdhqfotilde mszligudj msltsfjltska V0 iy Vt hhs Wmlamkh lruq tuacuteg
fuu aajfha sect WIaKajh i`oyd kj mszligudKhla wfrac34 olajd we tuacuteg tu mszligudKhg
wkqj
t degC i`oyd Tt = 273 15 + t uOtildeska nd fok wr
0 degC i`oyd T0 = 273 15 uOtildeska nd fohs
fuu kj WIaKaj mszligudKh flauacuteka WIaKaj mszligudKh (K) fyja ksrfmalaI WIaKaj
mszligudKh fi ye`Egravekafotilde ndash 273 15 degC (0 K) hkak dm sl Y+kHh fi wfrac34 oelafjk
wr th ffioaOdkaslj lt` d uacuteh yels wju WIaKajh fotilde
fmdyumlfotilde a uacuteg ksh mSvkfha sect (V1 T1) isg (V2 T2) olajd isyuml jk fjkila i`oyd
11
tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg
wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde
jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys
WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg
yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h
PV = nRTV = nRT P
ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde
zwnjzwnjzwnjzwnjV prop T fyda V = kT
pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka
WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd
Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect
ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh
lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34
15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde
uacutepkh
12
1 5 ksoiqk
ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml
jk WIaKaj fjki Kkh lrkak
uacutei`yumlu
T1 = T V1 = V V2 = 3V T2 =
T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh
wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h
hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi
efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg
lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr
kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde
1 6 ksoiqk
23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde
tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki
Kkh lrkak
uacutei`yumlu
T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =
jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka
V2 = 2 03 dm3
mszligudfotilde isyumljk fjki = 0 03 dm3
124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=
jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj
lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla
hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)
fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h
13
jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda
kshh (NA fyda L) fi ye|skafotilde
my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka
wjfndaO lr yels h
fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl
u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud
follg by iiumlnkaOdj fhsectfuka
P iy T ksh uacuteg sect (R iy NA kshhka fotilde )
irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud
=lt iudk wKq ixLdjla wvx= fotilde (V α N)
by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd
mszligmQfrac34K jdhq ioacutelrKh nd yels h
by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka
k = R jQ uacuteg
P V = n R T
14
125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka
fi wmg suacuteh yels h
iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd
mszligudj (Vm) tl u w hla uacuteh hq= ksid th
fi Kkh llt yels h
tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u
mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34
bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu
aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj
22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi
ksrEmKh flffrac34
bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde
fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde
igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde
V = k n = k (m M) tneuacuteka M = k (m V) = k d
1 7 ksoiqk
298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud
iudk nj fmkajkak
uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe
VHe = nHeRTHe PHe
VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3
15
PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =
PNeVNe = nNeRTNe
VNe = nNeRTNe PNe
VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa
VNe = 24 4 dm3
tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq
wa lr kakd mszligud iudk fotilde
126 ixhqla jdhq kshuh
jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj
tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka
T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla
fi suacuteh yels h
fuh ixhqla jdhq kshuh fi ye|skafotilde
1 8 ksoiqk
25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o
uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh
P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3
T1 = 25 + 273 = 298 K
V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =
P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa
16
13 fvdaagkaf a wdxYsl mSvk kshuh
fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm
yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk
wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml
ishuml jdhq odhl fotilde
jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj
wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde
ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla
iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs
fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh
fi yeEgravekafotilde
A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska
PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde
my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka
jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha
we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh
PT hehs o isuq
PV = nRT
A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )
B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )
jdhq ntildeYKh i`oyd nT = PTV RT
iy nT = nA + nB
tu ksid PTV RT = (PAV RT) + (PBV RT)
iq`M llt uacuteg PT = PA + PB
fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl
131 ujq Nd h wkqidrfhka wdxYsl mSvkh
T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq
ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde
fvdaagkaf a kshuhg wkqj PT = PA + PB
PA iy PB mldYk fjk fjk u PT jska fnsectfuka
17
tu ksid
fi suacuteh yels h
hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk
fotilde
1 9 ksoiqk
(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla
tla jdhqfotilde wdxYsl mSvkh Kkh lrkak
(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd
lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq
ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak
uacutei`yumlu
18
fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK
u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd
fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj
tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla
fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re
uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq
irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq
efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj
u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk
nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja
ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj
mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=
jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes
lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect
tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh
wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K
jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl
1 10 ksoiqk
my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs
iskak
2KClO3(s) rarr2KCl(s) + 3O2(g)
27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute
27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh
Kkh lrkak
uacutei`yumlu
fvdaagkaf a kshuhg wkqj
Piuia = PTlaiscka + Pch
PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa
mszligmQfrac34K jdhq ioacutelrKh fhsectfuka
14 jdhq msltsn`o pdl wKqljdoh
by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(
fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks
mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla
nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka
uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml
jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh
llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad
fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd
fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj
yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde
19
141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde
wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd
uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr
wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS
wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh
u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka
gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska
jdhqj bylt iiumlmSvHdj meyeEgraves fotilde
bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu
jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO
wKqjg uacuteuacuteO fotilde mjS
fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg
ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash
jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk
ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde
bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS
fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq
wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj
fuu ska mldY flffrac34
fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh
mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt
uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka
jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr
iiumlnkaOdjh my ioacutelrKfhka nd foa
jyumlrga my oelafjk lreKq plusmnlauacuteh yels h
bull jdhq wxY= tlsfklska iajdhaj yeisffrac34
jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska
iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda
fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj
wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml
Wmlamkfhka meyeEgraves fotilde
bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla
u` ska mSvkhla wes fotilde
fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect
ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl
isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug
20
fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml
jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq
ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj
jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml
fotilde
142 pdl wKqljdofha ioacutelrKh
my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla
fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34
by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes
wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka
wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34
uOHkH fotilde h fi wfrac34 olajkq efiacute
143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h
my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu
jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg
jfrac34 uOHkH uQ fotilde h fotilde
jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla
jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=
Kkla i`oyd ioacutelrKh ild nuq
N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)
PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka
21
tu ksid jfrac34 uOHkH uQ fotilde h
fi suacuteh yels h
1 11 ksoiqk
25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak
uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1
by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj
fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama
lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml
pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh
u` ska th my oelafjk mszligEgrave idOkh llt yels h
fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt
yel
kB hkq fndaaUumliaudka kshh fotilde
22
wKqjla i`oyd
ujqhla i`oyd
fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq
fotilde
144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml
N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag
pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq
efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave
mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes
lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde
jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash
fi ye|skafotilde
16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--
fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd
fotilde jHdmash
23
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka
wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea
jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd
idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute
ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr
^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17
rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla
i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34
17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj
iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha
sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka
daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh
17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd
Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir
ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla
mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy
ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh
yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr
jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml
ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej
jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla
fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh
fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs
17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska
o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska
daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka
iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk
wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh
hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd
mszligudj (V)
mSvk
h (
P)
24
jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj
o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga
meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg
jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke
fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka
lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS
jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru
ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml
yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj
sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK
n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde
mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd
laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect
(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g
jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda
ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel
jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt
WIaKaj fotilde
daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o
WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel
fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg
jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml
fuh mltuq ioacutelrKfha wdfoaYfhka
fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH
ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk
nj wmg fmfka
fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh
pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we
tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj
hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h
mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq
wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt
jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect
jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia
PV mszligmQfrac34K
daauacutel
25
jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq
wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka
yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=
h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka
wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel
jdhq mszligmQfrac34K aajfhka wm ukh fotilde
151 jeka vrsquo jdaia ioacutelrKh
fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa
sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K
jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk
wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq
mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel
jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid
daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH
fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj
iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk
Egrave
bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka
kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka
mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka
igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash
iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg
fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh
mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde
1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj
ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh
by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK
fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde
gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq
mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde
fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg
iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq
msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect
moaOsfha mSvkh my mldYkfhka nd fohs
26
bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL
fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr
tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk
mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka
wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks
fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq
kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh
fi kej suacuteh yels h
fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh
fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql
nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia
flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha
wkafrac34--mszligjfrac34kh l yels fotilde
ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs
wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj
yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde
igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys
sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde
ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha
lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh
iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla
fi o yeisszligh yels ugraveu h
bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla
oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi
mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS
30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc
oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi
muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu
WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla
oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde
( )2
aP V b RTV
+ minus =
27
19 rEmh CO2 j ldm igyk
1 3 j =j - ioacutelrK idrdxYh
jdhq kshuh intildelrKhksh j mjsk
idOl
mszligmQfrac34K jdhq kshuh PV = nRT ke
fndhsa kshuh n iy T
pdaia kshuh V = kT n iy P
wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T
wKql pdl ioacutelrKh
idudkH fotilde h
jfrac34 uOHkH fotilde h
jfrac34 uOHkH fotilde h
fvdaagkaf a wdxYsl mSvk
kshuh
PA = xA PT
PT = PA + PB + PC
iiumlmSvHd idOlh jdhq ujq 1la i|yd
jeka vZjdaia ioacutelrKh
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
iii
wOHCI ckrdafa mKsuacutevh
wOHdmkfha =KdaulNdjh jfrac34Okh lsIacuteu i|yd cdsl wOHdmk wdhkh jszligka jr
wjiadkql+ mshjr kq nhs wodlt uacuteIhhka i|yd wsffrac34l iiumlma fmda ilia lsIacuteu tjka
tla mshjrls
cdsl wOHdmk wdhkfha uacuteIhudd ixjfrac34Ok lKavdhua cdsl uacuteYaj uacuteoHdj uacuteoaj=ka
iy mdiea moaOsfha mltmqreyuml =rejreka uska wsffrac34l iiumlma fmda ilia lr we 2017 sect
lshdaul lrk o wfmdi ^Wiia fmltamp kj uacuteIh ksfrac34foaYhg wkqj fuu wsffrac34l iiumlma
fmda shd wes ksid isiqkag wodlt uacuteIh lreKq msltsn|j wjfndaOh mqiquesta llt yels wr
jvda ModhS bfkqiuml bekaugraveiuml lshdldrliuml ieiqiuml lsrSug =rejrekag fiumljd mrsYSkh l
yel
cdsl wOHdmk wdhkfha ldfrac34h uKavfha idudethlhskag iy ndysr uacuteIh lafIafha uacuteoaja
uacutefYaIhkag Tn fj fuu fdr=re nd sectu i|yd Tjqkafa YdiaSh odhlajh nd sectu
fjkqfjka udfa wjxl lDdj mlt lsIacuteug leueafntilde
wdpdfrac34h agrave ta wdfrac34 fEcirc =Kfialr
wOHlaI ckrda
cdsl wOHdmk wdhkh
uyru
iv
wOHCIjrhdfa mKsuacutevh
2017 jfrac34Ifha isg YS xldfotilde idudkH wOHdmk moaOsfha wfmdi ^Wiia fmltamp i|yd
dfrac34lSlrKhg la llt kj uacuteIhuddjla lshdaul fotilde bka woyia jkafka fufla mejs
uacuteIhuddj hdjaldSk lsIacuteuls fiuml ldfrac34hfha sect wfmdi ^Wiia fmltamp ridhk uacuteoHdj
fNsl uacuteoHdj yd Ocircj uacuteoHdj hk uacuteIhj uacuteIh ikaOdrfhaa uacuteIh wdlDsfhaa uacuteIhudd
oslashjHja hiuml hiuml ixfYdaOk isyuml l wr Bg iudoacutej bfkqiuml-bekaugravefiuml lufotildeofhaa
wehSiuml yd lafiarelrKfhaa hiuml hiuml fjkiaugraveiuml wfmalaId lrk Egrave uacuteIhudfotilde wvx=
uacuteIh lreKqj mudKh uacuteYd jYfhka wvq lrk o wr bfkqiuml-bekaugravefiuml wkqqlufha
hiuml hiuml fjkiaugraveiuml o isyuml lrkq eicirc h mejs uacuteIhudd oslashjHhla jQ =re udfrac34fdamfoaY ixyh
fjkqjg =re wafmdla ydividekajd fok Egrave
Wiia fmlt uacuteoHd uacuteIh i|yd bxSis NdIdfjka iiumlmdEgrave wkafrac34cdsl jYfhka msltsa ka
mszligYSkh miqsh uacuteIhudd lshdaul lsIacutefiuml sect wHjYH uacuteh tfya uacuteuacuteO fmltfmda Nduacute
lsIacutefiuml sect mriamruacutefrdaO uacuteIh lreKq i|yka ugraveua foaYSh uacuteIhuddfotilde iSud wNsNjd sh uacuteIh
lreKq tajdfha we=iquesta ugraveua ksid =reNj=kag yd isiqkag ta ka mszligyrKh myiq jQfha
ke fiuml kah Tn wg ma jkafka ta wjYHdj imqrdSug a Waidyhl msMhla
fi h
tneuacuteka fiuml kah u`ska foaYSh uacuteIhuddfotilde iSudjg hgaj ish ujqNdIdfjka wodlt uacuteIh
ikaOdrh mszligyrKh lsIacuteug isiqkag wjiadj iid we tfuka u uacuteuacuteO ka wsffrac34l mkas
jeks uQdYhjska wjYH fdr=re nd ekSu fjkqjg uacuteIhuddj u`ska wfmalaIs
fdr=re =reNj=kag yd isiqkag ksjerEgravej nd ekSug fiuml kah Wmldszlig jkq we
uacuteIh iiumlkaO uacutefYaI =reNj=ka yd uacuteYajuacuteoHd wdpdfrac34hjreka uacuteiska iiumlmdEgrave fiuml kah
cdsl wOHdmk wdhkfha uacuteIhud lntildegqfjka o wOHhk uKavfhka o mdl iNdfjka o
wkquesh nd Tn wg ma jk neuacuteka bylt mntildesfhka hq= nj ksfrac34foaY llt yels h
wdpdfrac34h ta atilde wfidal o isajd
wOHlaI
uacuteoHd fomdfrac34fiumlka=j
cdsl wOHdmk wdhkh
v
wkqYdilajh wdpdfrac34h agrave ta wdfrac34 fEcirc =Kfialr
wOHlaI ckrda cdsl wOHdmk wdhkh
weumllaIKh wdpdfrac34h ta auml ta o isajd
wOHlaI uacuteoHd fomdfrac34fiumlka=j
cdsl wOHdmk wdhkh
uacuteIh kdhlajh tiuml tia uacuteluisxy
iyldr lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j cdsl wOHdmk wdhkh
wNHkar ixialrK uKavh ta fla jvqfa uhd
fcHIaG lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j OcircOcircmStia fmffrac34rd ntildeh
iyldr lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j ugrave rdcqfoajka uhd
iyldr lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j
lfrac34D uKavh wdpdfrac34h viacuteotilde tiuml ta agrave nKavdr - ridhk uacuteoHd fomdfrac34fiumlka=j fmardfoKsh
uacuteYajuacuteoHdh (04 yd 05 jk tallh) wdpdfrac34h olaIsld jkakswdrEacuteNtilde - ridhk uacuteoHd fomdfrac34fiumlka=j YS chjfrac34Okmqr
uacuteYajuacuteoHdh (04 jk tallh)
ndysr ixialrK uKavh fcHIaG uydpdfrac34h tia mS plusmnrKsh - ridhk uacuteoHd fomdfrac34fiumlka=j YS chjfrac34Okmqr
uacuteYajuacuteoHdh
fcHIaG uydpdfrac34h tiuml atilde mS o fldiad - ridhk uacuteoHd fomdfrac34fiumlka=j fldltU uacuteYajuacuteoHdh fcHIaG uydpdfrac34h tEacute tiuml atilde tiuml mshka - ridhk uacuteoHd fomdfrac34fiumlka=j fmardfoKsh uacuteYajuacuteoHdh
uydpdfrac34h iqoka shkfa - ridhk uacuteoHd fomdfrac34fiumlka=j YS chjfrac34Okmqr uacuteYajuacuteoHdh fla atilde nkayuml l=udr uhd - ksfhdacH flduidszligia wOHdmk mldYk fomdfrac34fiumlka=j
wOHdmk fomdfrac34fiumlka=j uqEgraved w=fldar ntildeh - =re fiajh 1 mcdmS ndsld uacuteoHdh fydrK Egravemsld fkaisxy ntildeh - =re fiajh 1-(uacuteYdntildel) ldkad uacuteyumly fldltU 07
iStatiuml fmffrac34rd fufkuacuteh - =re fiajh 1 fotildeaia l=uszlig uacuteoHdh fudrgqj uacute fla viacute atilde idsld udOuacute ntildeh - =re fiajh 1 uqiasiuml ldkad uacuteyumly fldltU 04 tEacute tiuml atildeatilde sectmsld ueKsfla ntildeh - =re fiajh 1 uacuteydr uyd foauacute ndsld uacuteyumly lsszlignafdv
vi
NdId ixialrKh
cha mshoiqka uhd mOdk Wm lfrac34D - isiquestntildeK
fala yjqia fldltU 10
uqa msgqj
wdfrac34 wdfrac34 fla msrK ntildeh cdsl wOHdmk wdhkh
uacuteuacuteO iydh viacute mS mS ugraverjfrac34Ok ntildeh ux jesmsaacuteh uhd rxetha ohdjxY uhd
(
vii
mgqk
wOHCI ckrda=ntildehfa mKsuacutevhhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip iii
wOHCI=udfa mKsuacutevhhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip iv
uacuteIhudd lntildegqj helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip v
04 tallh - modfrac34fha jdhquh wjiadjhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip01-27
11 modfrac34fha wjiad =fkys wxY= ieleiau iy tajdfha ofrac34YSh CIK helliphelliphelliphelliphelliphellip02
12 jdhquh wjiadj helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip05
121 jdhq kshu
122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)
123 pdaia kshuh (WIaKajndashmszligud iiumlnkaOh)
124 wejdacircfrda kshuh (mudK-mszligud iiumlnkaOh)
125 ujqsl mszligudj (Vm)
126 ixhqla jdhq ioacutelrKh
13 fvdaagkafa wdxYsl mSvk kshuh helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip16
131 ujq Ndh wkqidrfhka wdxYsl mSvkh
14 jdhq msltsn`o pdl wKqljdoh helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip18
141 pdl wKqljdofha mszligmQfrac34K jdhqjla i|yd Wmlamk
142 pdl wKqljdofha ioacutelrKh
143 jfrac34 uOHkH uQ fotildeh iy uOHkH fotildeh
144 ueialafja-fndaaUumliaudka jHdmash
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh helliphelliphelliphelliphelliphellip23
151 jeka vrsquojdaia ioacutelrKh
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
05 tallh - Ylas uacuteoHdjhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip28-54
21 dm-ridhksl uacuteoHdfotilde yd dms uacuteoHdfotilde uQsl mo helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip29 211 moaOsh jgmsgdj yd iSudj 212 moaOs jfrac34
213 moaOshl =K
214 moaOshl wjiadj
215 tkaeamsh (H)
216 dmh
22 uacuteuacuteO dm-ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd helliphelliphelliphelliphelliphelliphellip34
iiumlu tkaeams uacutemfrac34hdi 221 dmodhl yd dmdjfYdaIl lshdjs
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh
23 oesi tkaeamsh fyja whksl ixfhdahl Wamdok tkaeamsh(helliphelliphelliphelliphelliphelliphelliphellip47 fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj ridhksl mslshdjl iiumlu helliphelliphelliphellip49
tkafgdms fjki siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
1
wkafrac34 h
1 1 modfrac34fha wjiad =fkys wxY= ieleiau
iy tajdfha ofrac34YSh CIK
1 2 jdhquh wjiadj
1 2 1 jdhq kshu
bull mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq
ioacutelrKh
bull mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ
Kkh lsIacuteiuml
1 2 2 fndhsa kshuh
(mSvk-mszligud iiumlnkaOh)
1 2 3 pdaia kshuh
(WIaKajndashmszligud iiumlnkaOh)
1 2 4 wej dacircfrda kshuh
(mudK-mszligud iiumlnkaOh)
1 2 5 ujqsl mszligudj (Vm)
1 2 6 ixhqla jdhq ioacutelrKh
1 3 fvdaagkaf a wdxYsl mSvk kshuh
1 3 1 ujq Nd h wkqidrfhka
wdxYsl mSvkh
1 4 jdhq msltsn`o pdl wKql jdoh
1 4 1 pdl wKql jdofha mszligmQfrac34K jdhqjla
i|yd Wmlamk
1 4 2 pdl wKql jdofha ioacutelrKh
1 4 3 jfrac34 uOHkH uQ fotilde h iy
uOHkH fotilde h
1 4 4 ueialafja--fndaaUumliaudka jHdmash
1 5 daauacutel jdhqjg eltfmk mszligEgrave
mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
1 5 1 jeka vrsquojdaia ioacutelrKh
1 5 2 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
1 modfrac34fha jdhquh
wjiadj
2
ye|skaugraveu
uacuteYajfha wes ishiquest oE iquacutefYaIS ridhksl wkkHdjlska hqla h modfrac34fha l=vdu wxY=j
mrudKqj nj wms oksuq irj oelajqjfyda ridhk uacuteoHdj hkq ldquomodfrac34h iy tys isyumljk
uacutemfrac34hdi msltsn|j wOHkhrdquo fi wfrac34 oelauacute h yel modfrac34h hkq wjldYhla wama
lr kakd ialkaOhla iys acutekEu fohla jk wr th oelsh yels yd weaSug yels
^mia ch wdsectamp fohla fi fuka u jdh jeks wmg fkdfmfkk fohla o uacuteh yel
ixhqsh yd =K mokiuml lr f k oslashjH ntildeYK uQoslashjH fuka u mrudKq iy wKq wdsect uacuteuacuteO
wdldr fuys sect y`yumlkd yels h ishiquestu oslashjH gtk oslashj iy jdhq fig wvqu rntildeka uQsl
wjiad =klska mejsh yels h gtkhl sect wxY= =ltska ne`oS tlsfklg lsUumlgqj lsishiuml
ksYaNtilde jHqyhlg ksYaNtilde yevhla iysj weisIacuteu ksid tajdg pkh ugravefiuml yelshdj wvq
h oslashjhl wxY= tlsfklg lsUumlgqj wea tlsfklg iadkShj bd Egraveka ne|S kes neuacuteka
ikaikaokdaulj gtkhl sect g jvd fotilde fhka pkh uacuteh yels h wxY= wr yumlr wkqj
oslashj yd gtkjg jvd jdhq fndfyda fjkia fotilde jdhqjlsect wxY= tlsfklska fjka ugrave wes yumlr
wxY=jl mudKhg ikaikaokdaulj uacuteYd ugraveu fya=fjka wxY=jg ksoyfia yeisIacuteug
bv we tneuacuteka jdhq wxY= wr wdlfrac34Yk n bd l=vd fyda fkd sksh yels riuml ugraveu
fya=fjka wmg jdhq wxY= fjka fjka j ielsh yels neuacuteka WIaKajh yd mSvkh u
mokiuml jQ iuyr lams myiqfjka mqfrdalkh llt yels fotilde
11 modfrac34fha mOdk wjiad =fkys wxY= ieleiau iy tajdfha ofrac34YSh CIK
wjldYfha bvla kakd ialkaOhla iys acutekE u fohla zmodfrac34hZ fi ye`Egravekauacuteh yels h
wmg plusmnlsh yels wska weash yels yfldlt fia u wm fkdolsk tfya yqiau kakd
jdh o oacuteg wha h mq`Ma jYfhka a l ishuml modfrac34h gtk oslashj yd jdhq hkqfjka
wjiad =klg jfrac34 SlrKh llt yels h ixhqsfhys fjkia ugraveulska fdrj modfrac34h fiuml
suacuteO wjiad wr tllska wfklg mszligjfrac34kh llt yels h ksoiqkla fi( oslashj wjiadfotilde
mjsk ch ra lsIacutefuka jdhq wjiadjg (yqudh) mszligjfrac34kh llt yels wr isisa
lsIacutefuka gtk wjiadjg ^whsiaamp ma llt yels h
gtk
^Wod( hlv weKhamp
iaOacuter yevhla yd
mszligudjla we
oslashj
^Wod( champ
iaOacuter yevhla
kes kuqa iaOacuter mszligudjla we
jdhq
^Wod( ySshiuml neAEligkamp
iaOacuter yevhla fyda
iaOacuter mszligudjla fyda ke
gtk
wxY= ^mrudKq wKq fyda whkamp
wr wdlfrac34IK n mn h
wxY= liumlmkh jk kuqa
eklska eklg
pkh fkd fotilde
oslashj
wxY= ^mrudKq wKq fyda whkamp
wr wdlfrac34IK n triuml
mn fkd fotilde wxY=jg hiuml
mudKhlg eklska eklg
pkh uacuteh yels h
jdhq
wxY= ^mrudKq wKq fyda whkamp
wr wdlfrac34IK n yumln h
wxY=jg eklska eklg
pkh uacuteh yels h
11 rEmh modfrac34fha suacuteO wjiad
wxY=j ieleiafuka yd psfhka modfrac34fha suacuteO wjiad tlsfklska fjkia fotilde
wkafrac34currenwxY= wr yumlr jdhq wjiadfotilde wecircl jk wr gtk wjiadfotilde sect th wju fotilde jdhq
wjiadjg idfmalaIj oslashj wjiadfotilde sect wxY= tlsfklg ioacutem jk wr th gtk wjiadfotilde
3
sect riuml tlsfklg ioacutem o fkd fotilde tneuacuteka luja j ixuacuteOdkh jQ wxY=uh rgdjla plusmnlsh
yelafla gtk wjiadfotilde muŒ oslashj yd jdhq wjiad foflys sect u wxY= ieliS weafa wyUq
fi h fuys msMhla fi oslashj wjiadfotilde wes wxY=jg idfmaalaIj jdhq wjiadfotilde
wes wxY=jg jvd fotilde fhka yd ksoyia fi pkh uacuteh yels h flfia jqj o gtkj
wes wxY=j psh liumlmkjg muKla iSud fotilde my 11 j =fjka plusmnlafjk mszligEgrave
modfrac34fha wxY=j ieleiau yd tys psh mszligudj yevh iiumlmSvHdj yd gtkajh jeks
ufyaalaI =Kj fjkialiumljg =vq fohs
1 1 j =j gtk oslashj yd jdhq j =Kj =Kdaul ixikaokh
=Kh gtk oslashj jdhq
yevh ksYaNtilde h wvx = n`yumlfkys
yevh kakd uqa
n`yumlfkys uq`M mszligudj
mqrd fkd mesfrhs
n`yumlfkys yevh
kakd wr
n`yumlfkys iuia
mszligudj wa lr kS
mszligudj ksYaNtilde h ksYaNtilde h wvx = n`yumlfkys
mszligudj wa lr kS
gtkajh (ρ) g cm-3 (293 K sect)
bylt w hka kS
Wod( hlv
(7 874 g cm-3)
rula bylt w hka
kS
Wod( ch
(0 997 g cm-3)
w hka mylt h
Wod( yhsvcka
(0 071g cm-3)
iiumlmSvHdj iiumlmSvkh lsIacuteu
bd yumlIalr h
iiumlmSvkh lsIacuteu bd
yumlIalr h
fnfyuacuteka iiumlmSvkh
llt yels h
igyk ( oslashj wvx = n`yumlfkys yevh kakd nj wm i`oyka lr wes wr tfia jkafka
ukaoehs issh hq= h idudkHfhka acutekE u jia=jla wkafrac34-wKql n jeks uacuteuacuteO jfrac34 fha
n u` ska tlg ne| nd kakd neuacuteka thg ksYaNtilde yevhla we icirclrhl wes fok o
c mudKhla ^mszligudjlaamp hiuml yevhla kafka mDIaAgravel wdsh ksid h oslashjh =lt mjsk
wkafrac34-wKql n ksid mDIaGh flltjffrac34 l=vd oslashj udjlhla wes fotilde icirclrfha igraveas u` ska
oslashjh u byltg aumljla wes flfrk wr mDIaAgravel wdshg jvd jeauml =reajc nh
u` ska myltg weoSula wes fotilde tuksid oslashjh byltska iu mDIaGhla iysj icirclrfha
yevh kS fufia jkafka fuu uacuteuacuteO jfrac34 fha ishuml nj nmEu ksid h flfia jqj
o mDIaAgravel wdsh =reajc nhg jvd mn jQjd kiuml cfha mDIaGh iu fkdjk
wr n`yumlfka yevh fkd kq we =reajc nhla keehs is=j fyda mDIaAgravel wdsh
fndfyda fihska bylt hhs mDIaGfha tla tla fldgilg u wfkla mDIaGh iu` yels riuml
ltx ugrave mejSug wjYH ksid tajd wr wes wdlfrac34IK wju lr ekSug fmfograve tneuacuteka
fok o mszligudjl wju mDIaAgravel lafIaMhla wes fyd`o u yevh jk f dadldr yevh
kS
ralsrSfuka fyda isiskfhka tla wjiadjl mjsk modfrac34h ja wjiadjlg mszligjfrac34kh
llt yels h WIaKajh jeauml lsIacutefiuml sect wxY=j pk fotilde h bylt hEua wxY= wr yumlr jeauml
ugraveua lrK fldg modfrac34j wjiadj fjkia fotilde ta wkqj WIaKajh jeauml lsIacutefiuml sect gtk
wjiadfotilde wes oslashjH oslashj wjiadjga oslashj wjiadfotilde wes oslashjH jdhq wjiadjga ma fotilde
WIaKajfha wvq ugraveua iu isyuml jkafka fuys uacutefdauhhs my 12 rEmfhka modfrac34h tys
wjiad wr wkafrac34-mszligjfrac34khg Ndck llt yels wdldrh fmkakqiuml flffrac34
4
12 rEmh modfrac34fha wjiad wr wkafrac34-mszligjfrac34kh
11 ksoiqk
wxY= jvda u ioacutem fi iamfrac34Y jkafka ugrave kuqa tajd wyUq fi weysIacute weafa modfrac34fha
ljr kiuml wjiadfotilde o
uacutei`yumlu oslashj wjiadj
11 j =jg wkqj wm modfrac34fha mOdk wjiad =fkys =K uacuteiar lrk uacuteg wxY=j ieliqu
yd pkh uQslj ild nd we uacutefYaIfhka u hiuml oslashjHhl wes wKq fyda mrudKqj
pkh ksid yg kakd Ylash dmc Ylash jk wr th oslashjHfha WIaKajhg wkqfdauj
iudkqmdsl fotilde tu` ska modfrac34fha wes wxY=j uOHkHh pdl Ylash uefkk neuacuteka
th wxY=j pkh fyda dmc psh i`oyd fya= fotilde
wkafrac34-wKql n u` ska wKq tlsfklg ltx ugrave mejSug fmfUk nj wm oekgua
okakd kuqa wKqj dmc Ylash u` ska wKq tlsfklska wEa ugraveug fmfograve ta wkqj
modfrac34fha mOdk wjiad =fkys mejSu wKqj wkafrac34-wKql n iy dmc Ylash
wr iu=sfhys msMhla fi ielsh yels h
wkafrac34-wKql wdlfrac34IK bd yumln jk uacuteg WIaKajh wvq lsIacutefuka dmc Ylash WIaKajhamp
wvq fkdllt fyda wKq oslashj fyda gtk fyda fi mejSug fkd fmfograve wKq tlsfklg
bd lt` ska wes uacuteg iy wkafrac34 - wKql n Wmszliguj wes uacuteg mjd iiumlmSvkh u` ska muKla
jdhq oslashj wjiadjg ma fkd fotilde flfia jqj o WIaKajh wvq lsIacuteu u` ska wKqj dmc
Ylash wvq jk uacuteg jdhq bd myiqfjka oslashj llt yels h fiuml yeisIacuteiuml my 1 3 rEmfhka
meyeEgraves llt yels h modfrac34fha mOdk wjiad =k flfrys wkafrac34-wKql nj yd dmc
Ylasfha msuacutereoaO nmEfiuml iajNdjh wmg tu` ska wjfndaO lr yels h
5
13 rEmh wkafrac34-wKql n yd dm Ylash wkqj modfrac34fha mOdk wjiad
=fkys yeisIacuteu
modfrac34fha mOdk wjiad =kla mejSug fya=j wm oekgua yodrd we oeka wm
modfrac34fha jdhquh yeisIacuteug fya= jk jdhq kshu iy jdhquh wjiAdj msltsn`o j yumlrga
ild nuq
12 jdhquh wjiadj
oeka wm idudkH WIaKaj mSvk aaj hgfa wes jdhquh wjiadfotilde mjsk oslashjHj
yeisIacuteu flfrys wjOdkh fhduq lruq
11 j =fotilde uacuteiar lr wes mszligEgrave jdhquh wjiadj my i`oyka fNsl =K wkqj uacuteiar
flffrac34
bull jdhq bd iiumlmSvH fotilde
bull jdhq ieu EgraveYdjlg u iudk whqszligka mSvkh wes lrhs
bull jdhqjg gtk iy oslashjjg jvd wvq gtkajhla we
bull jdhqj yevh iy mszligudj ksH fkd fotilde tajd wvx = Ndckfha yevh iy mszligudj
kS
bull jdhq lsis u hdkasl nmEulska fdrj iiumlmQfrac34Kfhka u iy iudkj tlsfkl
iuOtilde ntildeY fotilde
jdhqjl irdjhg fya= jkafka tu wKq wr mjsk n fkd ssbquoh yels ugraveuhs tajdfha
yeisIacuteu mIacutelaIKdaul wOHhkhkaf ka nd a msM u` ska fidhd kakd o fmdyuml jdhq kshujg (miqj idlEacutePd flffrac34iexcl) wkqj isyuml fotilde fiuml jdhq kshu hkq jdhqjl ueksh
yels =K wr mjsk iiumlnkaOd fotilde ueksh yels =K iuyrla jk mSvkh mszligudj
WIaKajh iy mudKh ^ujq fyda ialkaOhamp jeks tajd bd jeo a jkafka fiuml uacutepH
wr mjsk iiumlnkaOd jdhqjl mOdk wjiad (5 jk tallfha sect wfrac34 olajkq efiacuteiexcl) uacuteiar lrk ksid h tlsfkl yd ne`yumlKq fiuml uacutepHhka jdhq kshu iQ lsIacuteug uQsl
ugrave we
121 jdhq kshu
wm idlEacutePd lsIacuteug hk jdhq kshu uacuteoHdhka lsysm fokl= uacuteiska jdhqj fNsl =K
mokiumlj isyuml lrk o mIacutelaIKjska nd a msM fotilde mSvkh WIaKajh mszligudj iy
jdhq mudKh hk uacutepH wr mjsk iiumlnkaOd fuys sect ild nk wr tajd u` ska
6
modfrac34fha jdhquh wjiadj msltsn`o udkj jfrac34 hdg mfhdackja jk fdr=re rdYshla
mldY fotilde
mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq ioacutelrKh
jdhq wKq wr wkafrac34-wKql n fkdues nj Wmlamkh flffrac34 o tndivide jdhqjla mszligmQfrac34K
jdhqjla fi ye`Egravekafotilde tkiuml mszligmQfrac34K jdhqjl wKq wr wdlfrac34IK fyda uacutelfrac34IK fyda
n fkd mjS tfuka u jdhqj oud wes Ndckfha mszligudj iu` ieipoundfiuml sect jdhq wxY=jl
mszligudj fkdild yeszligh yels h
jdhqjl ksrfmalaI WIaKajh (T) mSvkh (P) mszligudj (V) iy oslashjH mudKh ^n ujqamp
jdhquh yeisIacuteu flfrys nmdk idOl fotilde P T V iy n wr iiumlnkaOdj my
mldYkfhka ksrEmKh flffrac34
fuh mszligmQfrac34K jdhq ioacutelrKh fyda mszligmQfrac34K jdhq kshuh fi oelafjk wr R hkq ieu
jdhqjlg u fmdyuml w hla wes jdhq kshh fotilde fok o acutekE u WIaKajhl sect yd
mSvkhl sect by iiumlnkaOdjg wkql+j yeisfrk acutekE u jdhqjla mszligmQfrac34K jdhqjla fi
y`yumlkajkq efiacute
fuu aaj hgfa oS mszligmQfrac34K jdhq ujq 1 la i|yd 0 degC sect yd 1 atm sect R kshfha w h
my wdldrhg Kkh l yel (0 degC sect yd 1 atm yssect mszligmqfrac34K jdhqjl 1 mol l mszligudj
22 414 dm3 fotilde)
mszligmQfrac34K jdhq ioacutelrKh by uacutepH yr wr wes iiumlnkaOdj jk nj wmg fmfkk
wr acutekE u jdhqjl wjiadj tuOtildeska uacuteiar flfrk ksid th wjiad ioacutelrKh fi
o ye|skafotilde
mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ Kkh lsIacuteiuml
mszligmQfrac34K jdhq ioacutelrKh u` ska wmg mszligudj WIaKajh mSvkh fyda ujq mudKh hk
tajdhska =kla sect wes uacuteg wfkla rdYsh ksfrac34Kh llt yels h jdhqjl ujq mudKh okakd
uacuteg tys ujqsl ialkaOh Nduacutefhka tys ialkaOh o Kkh llt yels h tfuka u
tu` ska jdhqjl gtkajh o ksfrac34Kh llt yels h mszligmQfrac34K jdhq kshfha w hg eltfmk
mszligEgrave wfkl=a rdYsj tall Nduacute lsIacuteu bd jeo a jk nj ul nd hq= h
idudkHfhka mSvkh atm Pa bar torr jeks tall jska mldY llt yels h tneuacuteka fiuml
eguml uacutei`oSfiuml sect my 1 2 j =fotilde sect wes mSvk tallj mszligjfrac34k Tng Wootilde jkq we
12 j =j mSvkh i`oyd jk tall
mSvk tallh Pa bar atm torr mmHg
1 Pa 1 N m-2 10-5 9 87 times 10-6 7 5 times 10-3
1 bar 100000 1bar 0 987 750 061 atm 101325 1 01325 1 atm 7601 torr mmHg 133 32 1 3332 times 10-3 1 3158 times 10-3 1 torr 1 mmHg
7
12 ksoiqk
jdhq isskavrhl mszligudj 0950 dm3 fotilde hiuml mSvkhla hgfa sect fiuml isskavrh oslashj
fmdfmakajska (C3H8) msIacute we isskavrh ysia jQ uacuteg jdhqf daSh mSvkh yd WIaKajh
hgfa sect tys fmdfmaka jdhqj hiuml mudKhla bsszlig fotilde
(i) wjg mszligirfha aaj 25degC iy 750 torr (1 torr = 133 52 Pa) kiuml isskavrh
ysiaj wes uacuteg tys bsszlig ugrave wes fmdfmaka jdhq ujq mudKh fldmuK o
(wNHkar mSvkh ndysr mSvkhg iudk uacuteg oS)
(ii) isskavrfha bsszlig ugrave wes fmdfmaka jdhq ialkaOh Kkh lrkak
(iii) isskavrfha bsszlig ugrave wes fmdfmaka jdhqfotilde gtkajh Kkh lrkak
uacutei`yumlu (i) mltuqj sect wes fdr=re iudfdapkh lrkak
WIaKajh T = (25 + 273) K = 298 K mSvkh P = 750 torr times 13332 Pa 1 torr = 99990 Pa mszligudj V = 0 950 dm3 = 0 950 times 10-3 m3
n fkdokakd moh fotilde
PV = nRT Nduacutefhka
(ii) fmdfmakays (C3H8) ujqsl ialkaOh = 44 g mol-1
fmdfmakays ialkaOh = 0 038 mol times 44 g mol-1 = 1 672 g
(iii) fmdfmakays gtkajh = ialkaOh mszligudj = = 1 76 g dm-3
by ksoiqk iel+ uacuteg mszligmQfrac34K jdhq kshuh uacuteuacuteO wdldrjska bEgraveszligma llt yels nj
fmkS hk wr my oelafjk mszligEgrave ir fjkia lsIacuteulska fok o jdhqjl ialkaOh
iy gtkajh fiuacuteh yels h
PV = nRT
P = RT
zwnjzwnj P = CRT
fuys zC Zhkq idkaoslashKhhs
j o PV = nRT iiumlnkaOdj my mszligEgrave o mldY llt yels h
PV = RT
fuys m hkq ialkaOh jk wr M hkq jdhqfotilde ujqsl ialkaOhhs
P = RT fi o suacuteh yels h
8
gtkajh (d) =
there4 P =
uacutefYaIs aaj hgfA fjka jdhq kshu jHqamkak lsIacutefiuml sect mszligmQfrac34K jdhq kshuh uQsl
moku fi lshd lrhs
122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)mdashksh WIaKajhla hgfa wes iaOacuter jdhq mudKhl (ialkaOhl) mSvkh jdhqfotilde mszligudjg
msfdauj uacutepkh fotilde (fyda iudkqmdsl) fotilde˜ fndhsa kshuh hkqfjka ye`Egravekafjk
fuh tfia kiuml lrk oafoa 17 jeks ishjfia sect WIaKajh ksh jQ aaj hgfa fjkia
jk mSvkha iu jdhqjl mszligudj uacutepkh jk wdldrh whsszligIa cdsl uacuteoHdhl= jQ
frdnUuml fndhsa (1627- 1691) uacuteiska wOHhkh lsIacutefuka miqj h tys Ksuh wdldrh
my oelafotilde
my plusmnlafjk mszligEgrave fndhsa kshuh jHqamkak lsIacuteu i`oyd mszligmQfrac34K jdhq kshuh fhdod
yelsh PV= nRT
jdhqfjys mudKh yd moaOsfhys WIaKajh kshj mjajd kakd oafoa kiuml nT =Ksh
kshhla fotilde R o kshhla jk neuacuteka nRT =Ksh o kshhla (k) fotilde
PV = k (kshhla)
tkiuml ksh WIaKajfha sect ksh jdhq mudKhl mSvkfhaa mszligudfotildea =Ksh kshhla
fotilde fuh fndhsa kshuh mldY lrk fjka wdldrhls
ksh T WIaKajhl wes ksh jdhq mudKhl mszligudj V1 o mSvkh P1 o kiuml yd th V2
mszligudjg yd P2 mSvkhg ma llt uacuteg fndhsa kshuhg wkqj
14 rEmh u` ska fndhsa kshufha idiumlmodhsl miadszligl ksrEmK folla fmkakqiuml flffrac34
14 rEmfha (a) u` ska ixikaokh i`oyd uacuteuacuteO WIaKajj sect PV = k miadr lr we
k w h WIaKajh u muKla r`od mjsk ksid fok o jdhq ialkaOhla i`oyd w`Egravek
o ieu jlhla i`oyd u k ys w h tlsfklg fjkia fotilde bylt WIaKajj sect mszligudfotilde
midrKh ksid plh byltg f dia wes nj ielsh hq= h tfuka u WIaKajh ksh
uacuteg jdhqfotilde mSvkh wvla jk uacuteg mszligudj fo =K jk nj ul nd hq= h
9
1 4 rEmh uacuteuacuteO ksh WIaKajj sect (a) mszligudj (V) iuOtilde (b) 1 V iuOtilde
mSvkfha fjkia ugraveu
14 (b) rEmh u` ska P g tosrsfhka ys miadrh ksrEmKh fotilde th uQ laIHh yryd hk
ir ffrac34Ldjls fndhsa uacuteiska lrk o mIacutelaIKjg wkqj nd kakd o fuu miadr
u` ska jdhqjg bylt iiumlmSvHdjla wes nj mudKdaulj fmkajd foa tkiuml fok o
jdhq ialkaOhla iiumlmSvkh llt uacuteg tl u mudKhlska wes wKq ixLHdj l=vd mszligudjla
=lt mesffrac34 fiuml wkqj bylt mSvkj sect jdhqj gtkajh jeauml fotilde
igyk fok o jdhqjl gtkajh d ialkaOh m o mszligudj v o jk uacuteg d = ioacutelrKfhka
fok nj wms oksuq tuksid ksh WIaKajfhasect
hkqfjka suacuteh yels h
1 3 ksoiqk
ksh WIaKajhla hgfa wes okakd jdhq ujq mudKhl mszligudj fo =K llt uacuteg
mSvkfha isyuml jk fjkia ugraveu Kkh lrkak
uacutei`yumlu V1 =V V2 = 2V P1 = P P2 = fndhsa kshuh fhsectfuka P1V1 = P2V2
P times V = P2 times 2VP2 = P 2 there4kj mSvkh uqa mSvkfhka wvla fotilde
10
1 4 ksoiqk
ldur WIaKajfha sect neumlkhla yhsvcka jdhqj okakd mudKhlska mqrjd we jdhqf daSh
mSvkfha sect (100 kPa) tu jdhq mudKh 2 50 dm3 l mszligudjla kS tu WIaKajfha sect u
we=lt mSvkh 20 kPa ugraveug neumlkfha mszligudj fldmuK uacuteh llt hq= o
uacutei`yumlu P1 = 100 kPa P2 = 20 kPa V1 = 2 5 dm3 V2 = fndhsa kshuh fhsectfuka P1V1 = P2V2
100 kPa times 2 5 dm3 = 20 kPa times V2 there4V2 = 12 5 dm3 neumlkfha mszligudj 12 5 dm3 olajd jeauml llt hq= h
123 pdaia kshuh (WIaKaj-mszligud iiumlnkaOh)cdlaia pdaia iy fcdaIma f a-umliela hk uacuteoHdhkaf a yeoEIacuteiuml u ska fmkajd sect wes mszligEgrave
ksh mSvkhl sect fok o ksH jdhq mudKhl ^ialkaOhamp mszligudj WIaKajha iu`
jeauml jk wr isisa lsIacuteua iu` wvq fotilde tfuka u WIaKajfhA isyuml jk ieu fiaishia
wxYlhl fjkila mdid ^jeauml ugraveu fyda wvq ugraveuamp mszligudj 0degC sect jdhqfotilde wdriumlNl mszligudfjka idOlhlska fjkia jk nj ^jeauml ugraveu fyda wvq ugraveuamp fidhd f k we
0 degC sect iy t degC ys sect jdhqfotilde mszligudj msltsfjltska V0 iy Vt hhs Wmlamkh lruq tuacuteg
fuu aajfha sect WIaKajh i`oyd kj mszligudKhla wfrac34 olajd we tuacuteg tu mszligudKhg
wkqj
t degC i`oyd Tt = 273 15 + t uOtildeska nd fok wr
0 degC i`oyd T0 = 273 15 uOtildeska nd fohs
fuu kj WIaKaj mszligudKh flauacuteka WIaKaj mszligudKh (K) fyja ksrfmalaI WIaKaj
mszligudKh fi ye`Egravekafotilde ndash 273 15 degC (0 K) hkak dm sl Y+kHh fi wfrac34 oelafjk
wr th ffioaOdkaslj lt` d uacuteh yels wju WIaKajh fotilde
fmdyumlfotilde a uacuteg ksh mSvkfha sect (V1 T1) isg (V2 T2) olajd isyuml jk fjkila i`oyd
11
tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg
wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde
jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys
WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg
yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h
PV = nRTV = nRT P
ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde
zwnjzwnjzwnjzwnjV prop T fyda V = kT
pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka
WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd
Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect
ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh
lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34
15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde
uacutepkh
12
1 5 ksoiqk
ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml
jk WIaKaj fjki Kkh lrkak
uacutei`yumlu
T1 = T V1 = V V2 = 3V T2 =
T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh
wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h
hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi
efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg
lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr
kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde
1 6 ksoiqk
23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde
tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki
Kkh lrkak
uacutei`yumlu
T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =
jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka
V2 = 2 03 dm3
mszligudfotilde isyumljk fjki = 0 03 dm3
124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=
jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj
lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla
hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)
fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h
13
jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda
kshh (NA fyda L) fi ye|skafotilde
my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka
wjfndaO lr yels h
fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl
u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud
follg by iiumlnkaOdj fhsectfuka
P iy T ksh uacuteg sect (R iy NA kshhka fotilde )
irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud
=lt iudk wKq ixLdjla wvx= fotilde (V α N)
by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd
mszligmQfrac34K jdhq ioacutelrKh nd yels h
by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka
k = R jQ uacuteg
P V = n R T
14
125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka
fi wmg suacuteh yels h
iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd
mszligudj (Vm) tl u w hla uacuteh hq= ksid th
fi Kkh llt yels h
tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u
mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34
bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu
aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj
22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi
ksrEmKh flffrac34
bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde
fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde
igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde
V = k n = k (m M) tneuacuteka M = k (m V) = k d
1 7 ksoiqk
298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud
iudk nj fmkajkak
uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe
VHe = nHeRTHe PHe
VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3
15
PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =
PNeVNe = nNeRTNe
VNe = nNeRTNe PNe
VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa
VNe = 24 4 dm3
tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq
wa lr kakd mszligud iudk fotilde
126 ixhqla jdhq kshuh
jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj
tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka
T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla
fi suacuteh yels h
fuh ixhqla jdhq kshuh fi ye|skafotilde
1 8 ksoiqk
25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o
uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh
P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3
T1 = 25 + 273 = 298 K
V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =
P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa
16
13 fvdaagkaf a wdxYsl mSvk kshuh
fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm
yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk
wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml
ishuml jdhq odhl fotilde
jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj
wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde
ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla
iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs
fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh
fi yeEgravekafotilde
A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska
PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde
my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka
jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha
we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh
PT hehs o isuq
PV = nRT
A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )
B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )
jdhq ntildeYKh i`oyd nT = PTV RT
iy nT = nA + nB
tu ksid PTV RT = (PAV RT) + (PBV RT)
iq`M llt uacuteg PT = PA + PB
fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl
131 ujq Nd h wkqidrfhka wdxYsl mSvkh
T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq
ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde
fvdaagkaf a kshuhg wkqj PT = PA + PB
PA iy PB mldYk fjk fjk u PT jska fnsectfuka
17
tu ksid
fi suacuteh yels h
hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk
fotilde
1 9 ksoiqk
(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla
tla jdhqfotilde wdxYsl mSvkh Kkh lrkak
(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd
lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq
ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak
uacutei`yumlu
18
fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK
u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd
fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj
tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla
fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re
uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq
irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq
efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj
u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk
nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja
ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj
mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=
jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes
lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect
tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh
wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K
jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl
1 10 ksoiqk
my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs
iskak
2KClO3(s) rarr2KCl(s) + 3O2(g)
27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute
27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh
Kkh lrkak
uacutei`yumlu
fvdaagkaf a kshuhg wkqj
Piuia = PTlaiscka + Pch
PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa
mszligmQfrac34K jdhq ioacutelrKh fhsectfuka
14 jdhq msltsn`o pdl wKqljdoh
by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(
fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks
mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla
nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka
uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml
jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh
llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad
fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd
fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj
yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde
19
141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde
wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd
uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr
wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS
wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh
u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka
gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska
jdhqj bylt iiumlmSvHdj meyeEgraves fotilde
bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu
jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO
wKqjg uacuteuacuteO fotilde mjS
fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg
ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash
jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk
ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde
bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS
fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq
wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj
fuu ska mldY flffrac34
fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh
mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt
uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka
jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr
iiumlnkaOdjh my ioacutelrKfhka nd foa
jyumlrga my oelafjk lreKq plusmnlauacuteh yels h
bull jdhq wxY= tlsfklska iajdhaj yeisffrac34
jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska
iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda
fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj
wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml
Wmlamkfhka meyeEgraves fotilde
bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla
u` ska mSvkhla wes fotilde
fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect
ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl
isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug
20
fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml
jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq
ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj
jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml
fotilde
142 pdl wKqljdofha ioacutelrKh
my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla
fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34
by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes
wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka
wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34
uOHkH fotilde h fi wfrac34 olajkq efiacute
143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h
my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu
jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg
jfrac34 uOHkH uQ fotilde h fotilde
jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla
jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=
Kkla i`oyd ioacutelrKh ild nuq
N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)
PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka
21
tu ksid jfrac34 uOHkH uQ fotilde h
fi suacuteh yels h
1 11 ksoiqk
25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak
uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1
by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj
fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama
lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml
pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh
u` ska th my oelafjk mszligEgrave idOkh llt yels h
fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt
yel
kB hkq fndaaUumliaudka kshh fotilde
22
wKqjla i`oyd
ujqhla i`oyd
fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq
fotilde
144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml
N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag
pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq
efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave
mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes
lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde
jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash
fi ye|skafotilde
16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--
fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd
fotilde jHdmash
23
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka
wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea
jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd
idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute
ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr
^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17
rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla
i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34
17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj
iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha
sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka
daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh
17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd
Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir
ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla
mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy
ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh
yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr
jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml
ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej
jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla
fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh
fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs
17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska
o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska
daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka
iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk
wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh
hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd
mszligudj (V)
mSvk
h (
P)
24
jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj
o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga
meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg
jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke
fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka
lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS
jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru
ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml
yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj
sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK
n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde
mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd
laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect
(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g
jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda
ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel
jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt
WIaKaj fotilde
daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o
WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel
fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg
jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml
fuh mltuq ioacutelrKfha wdfoaYfhka
fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH
ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk
nj wmg fmfka
fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh
pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we
tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj
hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h
mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq
wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt
jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect
jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia
PV mszligmQfrac34K
daauacutel
25
jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq
wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka
yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=
h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka
wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel
jdhq mszligmQfrac34K aajfhka wm ukh fotilde
151 jeka vrsquo jdaia ioacutelrKh
fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa
sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K
jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk
wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq
mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel
jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid
daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH
fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj
iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk
Egrave
bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka
kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka
mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka
igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash
iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg
fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh
mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde
1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj
ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh
by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK
fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde
gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq
mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde
fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg
iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq
msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect
moaOsfha mSvkh my mldYkfhka nd fohs
26
bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL
fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr
tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk
mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka
wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks
fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq
kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh
fi kej suacuteh yels h
fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh
fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql
nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia
flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha
wkafrac34--mszligjfrac34kh l yels fotilde
ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs
wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj
yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde
igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys
sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde
ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha
lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh
iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla
fi o yeisszligh yels ugraveu h
bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla
oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi
mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS
30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc
oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi
muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu
WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla
oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde
( )2
aP V b RTV
+ minus =
27
19 rEmh CO2 j ldm igyk
1 3 j =j - ioacutelrK idrdxYh
jdhq kshuh intildelrKhksh j mjsk
idOl
mszligmQfrac34K jdhq kshuh PV = nRT ke
fndhsa kshuh n iy T
pdaia kshuh V = kT n iy P
wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T
wKql pdl ioacutelrKh
idudkH fotilde h
jfrac34 uOHkH fotilde h
jfrac34 uOHkH fotilde h
fvdaagkaf a wdxYsl mSvk
kshuh
PA = xA PT
PT = PA + PB + PC
iiumlmSvHd idOlh jdhq ujq 1la i|yd
jeka vZjdaia ioacutelrKh
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
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Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
iv
wOHCIjrhdfa mKsuacutevh
2017 jfrac34Ifha isg YS xldfotilde idudkH wOHdmk moaOsfha wfmdi ^Wiia fmltamp i|yd
dfrac34lSlrKhg la llt kj uacuteIhuddjla lshdaul fotilde bka woyia jkafka fufla mejs
uacuteIhuddj hdjaldSk lsIacuteuls fiuml ldfrac34hfha sect wfmdi ^Wiia fmltamp ridhk uacuteoHdj
fNsl uacuteoHdj yd Ocircj uacuteoHdj hk uacuteIhj uacuteIh ikaOdrfhaa uacuteIh wdlDsfhaa uacuteIhudd
oslashjHja hiuml hiuml ixfYdaOk isyuml l wr Bg iudoacutej bfkqiuml-bekaugravefiuml lufotildeofhaa
wehSiuml yd lafiarelrKfhaa hiuml hiuml fjkiaugraveiuml wfmalaId lrk Egrave uacuteIhudfotilde wvx=
uacuteIh lreKqj mudKh uacuteYd jYfhka wvq lrk o wr bfkqiuml-bekaugravefiuml wkqqlufha
hiuml hiuml fjkiaugraveiuml o isyuml lrkq eicirc h mejs uacuteIhudd oslashjHhla jQ =re udfrac34fdamfoaY ixyh
fjkqjg =re wafmdla ydividekajd fok Egrave
Wiia fmlt uacuteoHd uacuteIh i|yd bxSis NdIdfjka iiumlmdEgrave wkafrac34cdsl jYfhka msltsa ka
mszligYSkh miqsh uacuteIhudd lshdaul lsIacutefiuml sect wHjYH uacuteh tfya uacuteuacuteO fmltfmda Nduacute
lsIacutefiuml sect mriamruacutefrdaO uacuteIh lreKq i|yka ugraveua foaYSh uacuteIhuddfotilde iSud wNsNjd sh uacuteIh
lreKq tajdfha we=iquesta ugraveua ksid =reNj=kag yd isiqkag ta ka mszligyrKh myiq jQfha
ke fiuml kah Tn wg ma jkafka ta wjYHdj imqrdSug a Waidyhl msMhla
fi h
tneuacuteka fiuml kah u`ska foaYSh uacuteIhuddfotilde iSudjg hgaj ish ujqNdIdfjka wodlt uacuteIh
ikaOdrh mszligyrKh lsIacuteug isiqkag wjiadj iid we tfuka u uacuteuacuteO ka wsffrac34l mkas
jeks uQdYhjska wjYH fdr=re nd ekSu fjkqjg uacuteIhuddj u`ska wfmalaIs
fdr=re =reNj=kag yd isiqkag ksjerEgravej nd ekSug fiuml kah Wmldszlig jkq we
uacuteIh iiumlkaO uacutefYaI =reNj=ka yd uacuteYajuacuteoHd wdpdfrac34hjreka uacuteiska iiumlmdEgrave fiuml kah
cdsl wOHdmk wdhkfha uacuteIhud lntildegqfjka o wOHhk uKavfhka o mdl iNdfjka o
wkquesh nd Tn wg ma jk neuacuteka bylt mntildesfhka hq= nj ksfrac34foaY llt yels h
wdpdfrac34h ta atilde wfidal o isajd
wOHlaI
uacuteoHd fomdfrac34fiumlka=j
cdsl wOHdmk wdhkh
v
wkqYdilajh wdpdfrac34h agrave ta wdfrac34 fEcirc =Kfialr
wOHlaI ckrda cdsl wOHdmk wdhkh
weumllaIKh wdpdfrac34h ta auml ta o isajd
wOHlaI uacuteoHd fomdfrac34fiumlka=j
cdsl wOHdmk wdhkh
uacuteIh kdhlajh tiuml tia uacuteluisxy
iyldr lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j cdsl wOHdmk wdhkh
wNHkar ixialrK uKavh ta fla jvqfa uhd
fcHIaG lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j OcircOcircmStia fmffrac34rd ntildeh
iyldr lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j ugrave rdcqfoajka uhd
iyldr lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j
lfrac34D uKavh wdpdfrac34h viacuteotilde tiuml ta agrave nKavdr - ridhk uacuteoHd fomdfrac34fiumlka=j fmardfoKsh
uacuteYajuacuteoHdh (04 yd 05 jk tallh) wdpdfrac34h olaIsld jkakswdrEacuteNtilde - ridhk uacuteoHd fomdfrac34fiumlka=j YS chjfrac34Okmqr
uacuteYajuacuteoHdh (04 jk tallh)
ndysr ixialrK uKavh fcHIaG uydpdfrac34h tia mS plusmnrKsh - ridhk uacuteoHd fomdfrac34fiumlka=j YS chjfrac34Okmqr
uacuteYajuacuteoHdh
fcHIaG uydpdfrac34h tiuml atilde mS o fldiad - ridhk uacuteoHd fomdfrac34fiumlka=j fldltU uacuteYajuacuteoHdh fcHIaG uydpdfrac34h tEacute tiuml atilde tiuml mshka - ridhk uacuteoHd fomdfrac34fiumlka=j fmardfoKsh uacuteYajuacuteoHdh
uydpdfrac34h iqoka shkfa - ridhk uacuteoHd fomdfrac34fiumlka=j YS chjfrac34Okmqr uacuteYajuacuteoHdh fla atilde nkayuml l=udr uhd - ksfhdacH flduidszligia wOHdmk mldYk fomdfrac34fiumlka=j
wOHdmk fomdfrac34fiumlka=j uqEgraved w=fldar ntildeh - =re fiajh 1 mcdmS ndsld uacuteoHdh fydrK Egravemsld fkaisxy ntildeh - =re fiajh 1-(uacuteYdntildel) ldkad uacuteyumly fldltU 07
iStatiuml fmffrac34rd fufkuacuteh - =re fiajh 1 fotildeaia l=uszlig uacuteoHdh fudrgqj uacute fla viacute atilde idsld udOuacute ntildeh - =re fiajh 1 uqiasiuml ldkad uacuteyumly fldltU 04 tEacute tiuml atildeatilde sectmsld ueKsfla ntildeh - =re fiajh 1 uacuteydr uyd foauacute ndsld uacuteyumly lsszlignafdv
vi
NdId ixialrKh
cha mshoiqka uhd mOdk Wm lfrac34D - isiquestntildeK
fala yjqia fldltU 10
uqa msgqj
wdfrac34 wdfrac34 fla msrK ntildeh cdsl wOHdmk wdhkh
uacuteuacuteO iydh viacute mS mS ugraverjfrac34Ok ntildeh ux jesmsaacuteh uhd rxetha ohdjxY uhd
(
vii
mgqk
wOHCI ckrda=ntildehfa mKsuacutevhhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip iii
wOHCI=udfa mKsuacutevhhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip iv
uacuteIhudd lntildegqj helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip v
04 tallh - modfrac34fha jdhquh wjiadjhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip01-27
11 modfrac34fha wjiad =fkys wxY= ieleiau iy tajdfha ofrac34YSh CIK helliphelliphelliphelliphelliphellip02
12 jdhquh wjiadj helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip05
121 jdhq kshu
122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)
123 pdaia kshuh (WIaKajndashmszligud iiumlnkaOh)
124 wejdacircfrda kshuh (mudK-mszligud iiumlnkaOh)
125 ujqsl mszligudj (Vm)
126 ixhqla jdhq ioacutelrKh
13 fvdaagkafa wdxYsl mSvk kshuh helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip16
131 ujq Ndh wkqidrfhka wdxYsl mSvkh
14 jdhq msltsn`o pdl wKqljdoh helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip18
141 pdl wKqljdofha mszligmQfrac34K jdhqjla i|yd Wmlamk
142 pdl wKqljdofha ioacutelrKh
143 jfrac34 uOHkH uQ fotildeh iy uOHkH fotildeh
144 ueialafja-fndaaUumliaudka jHdmash
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh helliphelliphelliphelliphelliphellip23
151 jeka vrsquojdaia ioacutelrKh
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
05 tallh - Ylas uacuteoHdjhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip28-54
21 dm-ridhksl uacuteoHdfotilde yd dms uacuteoHdfotilde uQsl mo helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip29 211 moaOsh jgmsgdj yd iSudj 212 moaOs jfrac34
213 moaOshl =K
214 moaOshl wjiadj
215 tkaeamsh (H)
216 dmh
22 uacuteuacuteO dm-ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd helliphelliphelliphelliphelliphelliphellip34
iiumlu tkaeams uacutemfrac34hdi 221 dmodhl yd dmdjfYdaIl lshdjs
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh
23 oesi tkaeamsh fyja whksl ixfhdahl Wamdok tkaeamsh(helliphelliphelliphelliphelliphelliphelliphellip47 fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj ridhksl mslshdjl iiumlu helliphelliphelliphellip49
tkafgdms fjki siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
1
wkafrac34 h
1 1 modfrac34fha wjiad =fkys wxY= ieleiau
iy tajdfha ofrac34YSh CIK
1 2 jdhquh wjiadj
1 2 1 jdhq kshu
bull mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq
ioacutelrKh
bull mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ
Kkh lsIacuteiuml
1 2 2 fndhsa kshuh
(mSvk-mszligud iiumlnkaOh)
1 2 3 pdaia kshuh
(WIaKajndashmszligud iiumlnkaOh)
1 2 4 wej dacircfrda kshuh
(mudK-mszligud iiumlnkaOh)
1 2 5 ujqsl mszligudj (Vm)
1 2 6 ixhqla jdhq ioacutelrKh
1 3 fvdaagkaf a wdxYsl mSvk kshuh
1 3 1 ujq Nd h wkqidrfhka
wdxYsl mSvkh
1 4 jdhq msltsn`o pdl wKql jdoh
1 4 1 pdl wKql jdofha mszligmQfrac34K jdhqjla
i|yd Wmlamk
1 4 2 pdl wKql jdofha ioacutelrKh
1 4 3 jfrac34 uOHkH uQ fotilde h iy
uOHkH fotilde h
1 4 4 ueialafja--fndaaUumliaudka jHdmash
1 5 daauacutel jdhqjg eltfmk mszligEgrave
mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
1 5 1 jeka vrsquojdaia ioacutelrKh
1 5 2 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
1 modfrac34fha jdhquh
wjiadj
2
ye|skaugraveu
uacuteYajfha wes ishiquest oE iquacutefYaIS ridhksl wkkHdjlska hqla h modfrac34fha l=vdu wxY=j
mrudKqj nj wms oksuq irj oelajqjfyda ridhk uacuteoHdj hkq ldquomodfrac34h iy tys isyumljk
uacutemfrac34hdi msltsn|j wOHkhrdquo fi wfrac34 oelauacute h yel modfrac34h hkq wjldYhla wama
lr kakd ialkaOhla iys acutekEu fohla jk wr th oelsh yels yd weaSug yels
^mia ch wdsectamp fohla fi fuka u jdh jeks wmg fkdfmfkk fohla o uacuteh yel
ixhqsh yd =K mokiuml lr f k oslashjH ntildeYK uQoslashjH fuka u mrudKq iy wKq wdsect uacuteuacuteO
wdldr fuys sect y`yumlkd yels h ishiquestu oslashjH gtk oslashj iy jdhq fig wvqu rntildeka uQsl
wjiad =klska mejsh yels h gtkhl sect wxY= =ltska ne`oS tlsfklg lsUumlgqj lsishiuml
ksYaNtilde jHqyhlg ksYaNtilde yevhla iysj weisIacuteu ksid tajdg pkh ugravefiuml yelshdj wvq
h oslashjhl wxY= tlsfklg lsUumlgqj wea tlsfklg iadkShj bd Egraveka ne|S kes neuacuteka
ikaikaokdaulj gtkhl sect g jvd fotilde fhka pkh uacuteh yels h wxY= wr yumlr wkqj
oslashj yd gtkjg jvd jdhq fndfyda fjkia fotilde jdhqjlsect wxY= tlsfklska fjka ugrave wes yumlr
wxY=jl mudKhg ikaikaokdaulj uacuteYd ugraveu fya=fjka wxY=jg ksoyfia yeisIacuteug
bv we tneuacuteka jdhq wxY= wr wdlfrac34Yk n bd l=vd fyda fkd sksh yels riuml ugraveu
fya=fjka wmg jdhq wxY= fjka fjka j ielsh yels neuacuteka WIaKajh yd mSvkh u
mokiuml jQ iuyr lams myiqfjka mqfrdalkh llt yels fotilde
11 modfrac34fha mOdk wjiad =fkys wxY= ieleiau iy tajdfha ofrac34YSh CIK
wjldYfha bvla kakd ialkaOhla iys acutekE u fohla zmodfrac34hZ fi ye`Egravekauacuteh yels h
wmg plusmnlsh yels wska weash yels yfldlt fia u wm fkdolsk tfya yqiau kakd
jdh o oacuteg wha h mq`Ma jYfhka a l ishuml modfrac34h gtk oslashj yd jdhq hkqfjka
wjiad =klg jfrac34 SlrKh llt yels h ixhqsfhys fjkia ugraveulska fdrj modfrac34h fiuml
suacuteO wjiad wr tllska wfklg mszligjfrac34kh llt yels h ksoiqkla fi( oslashj wjiadfotilde
mjsk ch ra lsIacutefuka jdhq wjiadjg (yqudh) mszligjfrac34kh llt yels wr isisa
lsIacutefuka gtk wjiadjg ^whsiaamp ma llt yels h
gtk
^Wod( hlv weKhamp
iaOacuter yevhla yd
mszligudjla we
oslashj
^Wod( champ
iaOacuter yevhla
kes kuqa iaOacuter mszligudjla we
jdhq
^Wod( ySshiuml neAEligkamp
iaOacuter yevhla fyda
iaOacuter mszligudjla fyda ke
gtk
wxY= ^mrudKq wKq fyda whkamp
wr wdlfrac34IK n mn h
wxY= liumlmkh jk kuqa
eklska eklg
pkh fkd fotilde
oslashj
wxY= ^mrudKq wKq fyda whkamp
wr wdlfrac34IK n triuml
mn fkd fotilde wxY=jg hiuml
mudKhlg eklska eklg
pkh uacuteh yels h
jdhq
wxY= ^mrudKq wKq fyda whkamp
wr wdlfrac34IK n yumln h
wxY=jg eklska eklg
pkh uacuteh yels h
11 rEmh modfrac34fha suacuteO wjiad
wxY=j ieleiafuka yd psfhka modfrac34fha suacuteO wjiad tlsfklska fjkia fotilde
wkafrac34currenwxY= wr yumlr jdhq wjiadfotilde wecircl jk wr gtk wjiadfotilde sect th wju fotilde jdhq
wjiadjg idfmalaIj oslashj wjiadfotilde sect wxY= tlsfklg ioacutem jk wr th gtk wjiadfotilde
3
sect riuml tlsfklg ioacutem o fkd fotilde tneuacuteka luja j ixuacuteOdkh jQ wxY=uh rgdjla plusmnlsh
yelafla gtk wjiadfotilde muŒ oslashj yd jdhq wjiad foflys sect u wxY= ieliS weafa wyUq
fi h fuys msMhla fi oslashj wjiadfotilde wes wxY=jg idfmaalaIj jdhq wjiadfotilde
wes wxY=jg jvd fotilde fhka yd ksoyia fi pkh uacuteh yels h flfia jqj o gtkj
wes wxY=j psh liumlmkjg muKla iSud fotilde my 11 j =fjka plusmnlafjk mszligEgrave
modfrac34fha wxY=j ieleiau yd tys psh mszligudj yevh iiumlmSvHdj yd gtkajh jeks
ufyaalaI =Kj fjkialiumljg =vq fohs
1 1 j =j gtk oslashj yd jdhq j =Kj =Kdaul ixikaokh
=Kh gtk oslashj jdhq
yevh ksYaNtilde h wvx = n`yumlfkys
yevh kakd uqa
n`yumlfkys uq`M mszligudj
mqrd fkd mesfrhs
n`yumlfkys yevh
kakd wr
n`yumlfkys iuia
mszligudj wa lr kS
mszligudj ksYaNtilde h ksYaNtilde h wvx = n`yumlfkys
mszligudj wa lr kS
gtkajh (ρ) g cm-3 (293 K sect)
bylt w hka kS
Wod( hlv
(7 874 g cm-3)
rula bylt w hka
kS
Wod( ch
(0 997 g cm-3)
w hka mylt h
Wod( yhsvcka
(0 071g cm-3)
iiumlmSvHdj iiumlmSvkh lsIacuteu
bd yumlIalr h
iiumlmSvkh lsIacuteu bd
yumlIalr h
fnfyuacuteka iiumlmSvkh
llt yels h
igyk ( oslashj wvx = n`yumlfkys yevh kakd nj wm i`oyka lr wes wr tfia jkafka
ukaoehs issh hq= h idudkHfhka acutekE u jia=jla wkafrac34-wKql n jeks uacuteuacuteO jfrac34 fha
n u` ska tlg ne| nd kakd neuacuteka thg ksYaNtilde yevhla we icirclrhl wes fok o
c mudKhla ^mszligudjlaamp hiuml yevhla kafka mDIaAgravel wdsh ksid h oslashjh =lt mjsk
wkafrac34-wKql n ksid mDIaGh flltjffrac34 l=vd oslashj udjlhla wes fotilde icirclrfha igraveas u` ska
oslashjh u byltg aumljla wes flfrk wr mDIaAgravel wdshg jvd jeauml =reajc nh
u` ska myltg weoSula wes fotilde tuksid oslashjh byltska iu mDIaGhla iysj icirclrfha
yevh kS fufia jkafka fuu uacuteuacuteO jfrac34 fha ishuml nj nmEu ksid h flfia jqj
o mDIaAgravel wdsh =reajc nhg jvd mn jQjd kiuml cfha mDIaGh iu fkdjk
wr n`yumlfka yevh fkd kq we =reajc nhla keehs is=j fyda mDIaAgravel wdsh
fndfyda fihska bylt hhs mDIaGfha tla tla fldgilg u wfkla mDIaGh iu` yels riuml
ltx ugrave mejSug wjYH ksid tajd wr wes wdlfrac34IK wju lr ekSug fmfograve tneuacuteka
fok o mszligudjl wju mDIaAgravel lafIaMhla wes fyd`o u yevh jk f dadldr yevh
kS
ralsrSfuka fyda isiskfhka tla wjiadjl mjsk modfrac34h ja wjiadjlg mszligjfrac34kh
llt yels h WIaKajh jeauml lsIacutefiuml sect wxY=j pk fotilde h bylt hEua wxY= wr yumlr jeauml
ugraveua lrK fldg modfrac34j wjiadj fjkia fotilde ta wkqj WIaKajh jeauml lsIacutefiuml sect gtk
wjiadfotilde wes oslashjH oslashj wjiadjga oslashj wjiadfotilde wes oslashjH jdhq wjiadjga ma fotilde
WIaKajfha wvq ugraveua iu isyuml jkafka fuys uacutefdauhhs my 12 rEmfhka modfrac34h tys
wjiad wr wkafrac34-mszligjfrac34khg Ndck llt yels wdldrh fmkakqiuml flffrac34
4
12 rEmh modfrac34fha wjiad wr wkafrac34-mszligjfrac34kh
11 ksoiqk
wxY= jvda u ioacutem fi iamfrac34Y jkafka ugrave kuqa tajd wyUq fi weysIacute weafa modfrac34fha
ljr kiuml wjiadfotilde o
uacutei`yumlu oslashj wjiadj
11 j =jg wkqj wm modfrac34fha mOdk wjiad =fkys =K uacuteiar lrk uacuteg wxY=j ieliqu
yd pkh uQslj ild nd we uacutefYaIfhka u hiuml oslashjHhl wes wKq fyda mrudKqj
pkh ksid yg kakd Ylash dmc Ylash jk wr th oslashjHfha WIaKajhg wkqfdauj
iudkqmdsl fotilde tu` ska modfrac34fha wes wxY=j uOHkHh pdl Ylash uefkk neuacuteka
th wxY=j pkh fyda dmc psh i`oyd fya= fotilde
wkafrac34-wKql n u` ska wKq tlsfklg ltx ugrave mejSug fmfUk nj wm oekgua
okakd kuqa wKqj dmc Ylash u` ska wKq tlsfklska wEa ugraveug fmfograve ta wkqj
modfrac34fha mOdk wjiad =fkys mejSu wKqj wkafrac34-wKql n iy dmc Ylash
wr iu=sfhys msMhla fi ielsh yels h
wkafrac34-wKql wdlfrac34IK bd yumln jk uacuteg WIaKajh wvq lsIacutefuka dmc Ylash WIaKajhamp
wvq fkdllt fyda wKq oslashj fyda gtk fyda fi mejSug fkd fmfograve wKq tlsfklg
bd lt` ska wes uacuteg iy wkafrac34 - wKql n Wmszliguj wes uacuteg mjd iiumlmSvkh u` ska muKla
jdhq oslashj wjiadjg ma fkd fotilde flfia jqj o WIaKajh wvq lsIacuteu u` ska wKqj dmc
Ylash wvq jk uacuteg jdhq bd myiqfjka oslashj llt yels h fiuml yeisIacuteiuml my 1 3 rEmfhka
meyeEgraves llt yels h modfrac34fha mOdk wjiad =k flfrys wkafrac34-wKql nj yd dmc
Ylasfha msuacutereoaO nmEfiuml iajNdjh wmg tu` ska wjfndaO lr yels h
5
13 rEmh wkafrac34-wKql n yd dm Ylash wkqj modfrac34fha mOdk wjiad
=fkys yeisIacuteu
modfrac34fha mOdk wjiad =kla mejSug fya=j wm oekgua yodrd we oeka wm
modfrac34fha jdhquh yeisIacuteug fya= jk jdhq kshu iy jdhquh wjiAdj msltsn`o j yumlrga
ild nuq
12 jdhquh wjiadj
oeka wm idudkH WIaKaj mSvk aaj hgfa wes jdhquh wjiadfotilde mjsk oslashjHj
yeisIacuteu flfrys wjOdkh fhduq lruq
11 j =fotilde uacuteiar lr wes mszligEgrave jdhquh wjiadj my i`oyka fNsl =K wkqj uacuteiar
flffrac34
bull jdhq bd iiumlmSvH fotilde
bull jdhq ieu EgraveYdjlg u iudk whqszligka mSvkh wes lrhs
bull jdhqjg gtk iy oslashjjg jvd wvq gtkajhla we
bull jdhqj yevh iy mszligudj ksH fkd fotilde tajd wvx = Ndckfha yevh iy mszligudj
kS
bull jdhq lsis u hdkasl nmEulska fdrj iiumlmQfrac34Kfhka u iy iudkj tlsfkl
iuOtilde ntildeY fotilde
jdhqjl irdjhg fya= jkafka tu wKq wr mjsk n fkd ssbquoh yels ugraveuhs tajdfha
yeisIacuteu mIacutelaIKdaul wOHhkhkaf ka nd a msM u` ska fidhd kakd o fmdyuml jdhq kshujg (miqj idlEacutePd flffrac34iexcl) wkqj isyuml fotilde fiuml jdhq kshu hkq jdhqjl ueksh
yels =K wr mjsk iiumlnkaOd fotilde ueksh yels =K iuyrla jk mSvkh mszligudj
WIaKajh iy mudKh ^ujq fyda ialkaOhamp jeks tajd bd jeo a jkafka fiuml uacutepH
wr mjsk iiumlnkaOd jdhqjl mOdk wjiad (5 jk tallfha sect wfrac34 olajkq efiacuteiexcl) uacuteiar lrk ksid h tlsfkl yd ne`yumlKq fiuml uacutepHhka jdhq kshu iQ lsIacuteug uQsl
ugrave we
121 jdhq kshu
wm idlEacutePd lsIacuteug hk jdhq kshu uacuteoHdhka lsysm fokl= uacuteiska jdhqj fNsl =K
mokiumlj isyuml lrk o mIacutelaIKjska nd a msM fotilde mSvkh WIaKajh mszligudj iy
jdhq mudKh hk uacutepH wr mjsk iiumlnkaOd fuys sect ild nk wr tajd u` ska
6
modfrac34fha jdhquh wjiadj msltsn`o udkj jfrac34 hdg mfhdackja jk fdr=re rdYshla
mldY fotilde
mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq ioacutelrKh
jdhq wKq wr wkafrac34-wKql n fkdues nj Wmlamkh flffrac34 o tndivide jdhqjla mszligmQfrac34K
jdhqjla fi ye`Egravekafotilde tkiuml mszligmQfrac34K jdhqjl wKq wr wdlfrac34IK fyda uacutelfrac34IK fyda
n fkd mjS tfuka u jdhqj oud wes Ndckfha mszligudj iu` ieipoundfiuml sect jdhq wxY=jl
mszligudj fkdild yeszligh yels h
jdhqjl ksrfmalaI WIaKajh (T) mSvkh (P) mszligudj (V) iy oslashjH mudKh ^n ujqamp
jdhquh yeisIacuteu flfrys nmdk idOl fotilde P T V iy n wr iiumlnkaOdj my
mldYkfhka ksrEmKh flffrac34
fuh mszligmQfrac34K jdhq ioacutelrKh fyda mszligmQfrac34K jdhq kshuh fi oelafjk wr R hkq ieu
jdhqjlg u fmdyuml w hla wes jdhq kshh fotilde fok o acutekE u WIaKajhl sect yd
mSvkhl sect by iiumlnkaOdjg wkql+j yeisfrk acutekE u jdhqjla mszligmQfrac34K jdhqjla fi
y`yumlkajkq efiacute
fuu aaj hgfa oS mszligmQfrac34K jdhq ujq 1 la i|yd 0 degC sect yd 1 atm sect R kshfha w h
my wdldrhg Kkh l yel (0 degC sect yd 1 atm yssect mszligmqfrac34K jdhqjl 1 mol l mszligudj
22 414 dm3 fotilde)
mszligmQfrac34K jdhq ioacutelrKh by uacutepH yr wr wes iiumlnkaOdj jk nj wmg fmfkk
wr acutekE u jdhqjl wjiadj tuOtildeska uacuteiar flfrk ksid th wjiad ioacutelrKh fi
o ye|skafotilde
mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ Kkh lsIacuteiuml
mszligmQfrac34K jdhq ioacutelrKh u` ska wmg mszligudj WIaKajh mSvkh fyda ujq mudKh hk
tajdhska =kla sect wes uacuteg wfkla rdYsh ksfrac34Kh llt yels h jdhqjl ujq mudKh okakd
uacuteg tys ujqsl ialkaOh Nduacutefhka tys ialkaOh o Kkh llt yels h tfuka u
tu` ska jdhqjl gtkajh o ksfrac34Kh llt yels h mszligmQfrac34K jdhq kshfha w hg eltfmk
mszligEgrave wfkl=a rdYsj tall Nduacute lsIacuteu bd jeo a jk nj ul nd hq= h
idudkHfhka mSvkh atm Pa bar torr jeks tall jska mldY llt yels h tneuacuteka fiuml
eguml uacutei`oSfiuml sect my 1 2 j =fotilde sect wes mSvk tallj mszligjfrac34k Tng Wootilde jkq we
12 j =j mSvkh i`oyd jk tall
mSvk tallh Pa bar atm torr mmHg
1 Pa 1 N m-2 10-5 9 87 times 10-6 7 5 times 10-3
1 bar 100000 1bar 0 987 750 061 atm 101325 1 01325 1 atm 7601 torr mmHg 133 32 1 3332 times 10-3 1 3158 times 10-3 1 torr 1 mmHg
7
12 ksoiqk
jdhq isskavrhl mszligudj 0950 dm3 fotilde hiuml mSvkhla hgfa sect fiuml isskavrh oslashj
fmdfmakajska (C3H8) msIacute we isskavrh ysia jQ uacuteg jdhqf daSh mSvkh yd WIaKajh
hgfa sect tys fmdfmaka jdhqj hiuml mudKhla bsszlig fotilde
(i) wjg mszligirfha aaj 25degC iy 750 torr (1 torr = 133 52 Pa) kiuml isskavrh
ysiaj wes uacuteg tys bsszlig ugrave wes fmdfmaka jdhq ujq mudKh fldmuK o
(wNHkar mSvkh ndysr mSvkhg iudk uacuteg oS)
(ii) isskavrfha bsszlig ugrave wes fmdfmaka jdhq ialkaOh Kkh lrkak
(iii) isskavrfha bsszlig ugrave wes fmdfmaka jdhqfotilde gtkajh Kkh lrkak
uacutei`yumlu (i) mltuqj sect wes fdr=re iudfdapkh lrkak
WIaKajh T = (25 + 273) K = 298 K mSvkh P = 750 torr times 13332 Pa 1 torr = 99990 Pa mszligudj V = 0 950 dm3 = 0 950 times 10-3 m3
n fkdokakd moh fotilde
PV = nRT Nduacutefhka
(ii) fmdfmakays (C3H8) ujqsl ialkaOh = 44 g mol-1
fmdfmakays ialkaOh = 0 038 mol times 44 g mol-1 = 1 672 g
(iii) fmdfmakays gtkajh = ialkaOh mszligudj = = 1 76 g dm-3
by ksoiqk iel+ uacuteg mszligmQfrac34K jdhq kshuh uacuteuacuteO wdldrjska bEgraveszligma llt yels nj
fmkS hk wr my oelafjk mszligEgrave ir fjkia lsIacuteulska fok o jdhqjl ialkaOh
iy gtkajh fiuacuteh yels h
PV = nRT
P = RT
zwnjzwnj P = CRT
fuys zC Zhkq idkaoslashKhhs
j o PV = nRT iiumlnkaOdj my mszligEgrave o mldY llt yels h
PV = RT
fuys m hkq ialkaOh jk wr M hkq jdhqfotilde ujqsl ialkaOhhs
P = RT fi o suacuteh yels h
8
gtkajh (d) =
there4 P =
uacutefYaIs aaj hgfA fjka jdhq kshu jHqamkak lsIacutefiuml sect mszligmQfrac34K jdhq kshuh uQsl
moku fi lshd lrhs
122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)mdashksh WIaKajhla hgfa wes iaOacuter jdhq mudKhl (ialkaOhl) mSvkh jdhqfotilde mszligudjg
msfdauj uacutepkh fotilde (fyda iudkqmdsl) fotilde˜ fndhsa kshuh hkqfjka ye`Egravekafjk
fuh tfia kiuml lrk oafoa 17 jeks ishjfia sect WIaKajh ksh jQ aaj hgfa fjkia
jk mSvkha iu jdhqjl mszligudj uacutepkh jk wdldrh whsszligIa cdsl uacuteoHdhl= jQ
frdnUuml fndhsa (1627- 1691) uacuteiska wOHhkh lsIacutefuka miqj h tys Ksuh wdldrh
my oelafotilde
my plusmnlafjk mszligEgrave fndhsa kshuh jHqamkak lsIacuteu i`oyd mszligmQfrac34K jdhq kshuh fhdod
yelsh PV= nRT
jdhqfjys mudKh yd moaOsfhys WIaKajh kshj mjajd kakd oafoa kiuml nT =Ksh
kshhla fotilde R o kshhla jk neuacuteka nRT =Ksh o kshhla (k) fotilde
PV = k (kshhla)
tkiuml ksh WIaKajfha sect ksh jdhq mudKhl mSvkfhaa mszligudfotildea =Ksh kshhla
fotilde fuh fndhsa kshuh mldY lrk fjka wdldrhls
ksh T WIaKajhl wes ksh jdhq mudKhl mszligudj V1 o mSvkh P1 o kiuml yd th V2
mszligudjg yd P2 mSvkhg ma llt uacuteg fndhsa kshuhg wkqj
14 rEmh u` ska fndhsa kshufha idiumlmodhsl miadszligl ksrEmK folla fmkakqiuml flffrac34
14 rEmfha (a) u` ska ixikaokh i`oyd uacuteuacuteO WIaKajj sect PV = k miadr lr we
k w h WIaKajh u muKla r`od mjsk ksid fok o jdhq ialkaOhla i`oyd w`Egravek
o ieu jlhla i`oyd u k ys w h tlsfklg fjkia fotilde bylt WIaKajj sect mszligudfotilde
midrKh ksid plh byltg f dia wes nj ielsh hq= h tfuka u WIaKajh ksh
uacuteg jdhqfotilde mSvkh wvla jk uacuteg mszligudj fo =K jk nj ul nd hq= h
9
1 4 rEmh uacuteuacuteO ksh WIaKajj sect (a) mszligudj (V) iuOtilde (b) 1 V iuOtilde
mSvkfha fjkia ugraveu
14 (b) rEmh u` ska P g tosrsfhka ys miadrh ksrEmKh fotilde th uQ laIHh yryd hk
ir ffrac34Ldjls fndhsa uacuteiska lrk o mIacutelaIKjg wkqj nd kakd o fuu miadr
u` ska jdhqjg bylt iiumlmSvHdjla wes nj mudKdaulj fmkajd foa tkiuml fok o
jdhq ialkaOhla iiumlmSvkh llt uacuteg tl u mudKhlska wes wKq ixLHdj l=vd mszligudjla
=lt mesffrac34 fiuml wkqj bylt mSvkj sect jdhqj gtkajh jeauml fotilde
igyk fok o jdhqjl gtkajh d ialkaOh m o mszligudj v o jk uacuteg d = ioacutelrKfhka
fok nj wms oksuq tuksid ksh WIaKajfhasect
hkqfjka suacuteh yels h
1 3 ksoiqk
ksh WIaKajhla hgfa wes okakd jdhq ujq mudKhl mszligudj fo =K llt uacuteg
mSvkfha isyuml jk fjkia ugraveu Kkh lrkak
uacutei`yumlu V1 =V V2 = 2V P1 = P P2 = fndhsa kshuh fhsectfuka P1V1 = P2V2
P times V = P2 times 2VP2 = P 2 there4kj mSvkh uqa mSvkfhka wvla fotilde
10
1 4 ksoiqk
ldur WIaKajfha sect neumlkhla yhsvcka jdhqj okakd mudKhlska mqrjd we jdhqf daSh
mSvkfha sect (100 kPa) tu jdhq mudKh 2 50 dm3 l mszligudjla kS tu WIaKajfha sect u
we=lt mSvkh 20 kPa ugraveug neumlkfha mszligudj fldmuK uacuteh llt hq= o
uacutei`yumlu P1 = 100 kPa P2 = 20 kPa V1 = 2 5 dm3 V2 = fndhsa kshuh fhsectfuka P1V1 = P2V2
100 kPa times 2 5 dm3 = 20 kPa times V2 there4V2 = 12 5 dm3 neumlkfha mszligudj 12 5 dm3 olajd jeauml llt hq= h
123 pdaia kshuh (WIaKaj-mszligud iiumlnkaOh)cdlaia pdaia iy fcdaIma f a-umliela hk uacuteoHdhkaf a yeoEIacuteiuml u ska fmkajd sect wes mszligEgrave
ksh mSvkhl sect fok o ksH jdhq mudKhl ^ialkaOhamp mszligudj WIaKajha iu`
jeauml jk wr isisa lsIacuteua iu` wvq fotilde tfuka u WIaKajfhA isyuml jk ieu fiaishia
wxYlhl fjkila mdid ^jeauml ugraveu fyda wvq ugraveuamp mszligudj 0degC sect jdhqfotilde wdriumlNl mszligudfjka idOlhlska fjkia jk nj ^jeauml ugraveu fyda wvq ugraveuamp fidhd f k we
0 degC sect iy t degC ys sect jdhqfotilde mszligudj msltsfjltska V0 iy Vt hhs Wmlamkh lruq tuacuteg
fuu aajfha sect WIaKajh i`oyd kj mszligudKhla wfrac34 olajd we tuacuteg tu mszligudKhg
wkqj
t degC i`oyd Tt = 273 15 + t uOtildeska nd fok wr
0 degC i`oyd T0 = 273 15 uOtildeska nd fohs
fuu kj WIaKaj mszligudKh flauacuteka WIaKaj mszligudKh (K) fyja ksrfmalaI WIaKaj
mszligudKh fi ye`Egravekafotilde ndash 273 15 degC (0 K) hkak dm sl Y+kHh fi wfrac34 oelafjk
wr th ffioaOdkaslj lt` d uacuteh yels wju WIaKajh fotilde
fmdyumlfotilde a uacuteg ksh mSvkfha sect (V1 T1) isg (V2 T2) olajd isyuml jk fjkila i`oyd
11
tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg
wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde
jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys
WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg
yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h
PV = nRTV = nRT P
ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde
zwnjzwnjzwnjzwnjV prop T fyda V = kT
pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka
WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd
Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect
ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh
lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34
15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde
uacutepkh
12
1 5 ksoiqk
ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml
jk WIaKaj fjki Kkh lrkak
uacutei`yumlu
T1 = T V1 = V V2 = 3V T2 =
T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh
wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h
hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi
efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg
lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr
kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde
1 6 ksoiqk
23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde
tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki
Kkh lrkak
uacutei`yumlu
T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =
jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka
V2 = 2 03 dm3
mszligudfotilde isyumljk fjki = 0 03 dm3
124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=
jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj
lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla
hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)
fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h
13
jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda
kshh (NA fyda L) fi ye|skafotilde
my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka
wjfndaO lr yels h
fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl
u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud
follg by iiumlnkaOdj fhsectfuka
P iy T ksh uacuteg sect (R iy NA kshhka fotilde )
irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud
=lt iudk wKq ixLdjla wvx= fotilde (V α N)
by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd
mszligmQfrac34K jdhq ioacutelrKh nd yels h
by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka
k = R jQ uacuteg
P V = n R T
14
125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka
fi wmg suacuteh yels h
iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd
mszligudj (Vm) tl u w hla uacuteh hq= ksid th
fi Kkh llt yels h
tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u
mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34
bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu
aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj
22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi
ksrEmKh flffrac34
bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde
fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde
igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde
V = k n = k (m M) tneuacuteka M = k (m V) = k d
1 7 ksoiqk
298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud
iudk nj fmkajkak
uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe
VHe = nHeRTHe PHe
VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3
15
PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =
PNeVNe = nNeRTNe
VNe = nNeRTNe PNe
VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa
VNe = 24 4 dm3
tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq
wa lr kakd mszligud iudk fotilde
126 ixhqla jdhq kshuh
jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj
tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka
T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla
fi suacuteh yels h
fuh ixhqla jdhq kshuh fi ye|skafotilde
1 8 ksoiqk
25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o
uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh
P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3
T1 = 25 + 273 = 298 K
V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =
P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa
16
13 fvdaagkaf a wdxYsl mSvk kshuh
fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm
yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk
wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml
ishuml jdhq odhl fotilde
jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj
wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde
ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla
iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs
fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh
fi yeEgravekafotilde
A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska
PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde
my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka
jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha
we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh
PT hehs o isuq
PV = nRT
A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )
B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )
jdhq ntildeYKh i`oyd nT = PTV RT
iy nT = nA + nB
tu ksid PTV RT = (PAV RT) + (PBV RT)
iq`M llt uacuteg PT = PA + PB
fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl
131 ujq Nd h wkqidrfhka wdxYsl mSvkh
T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq
ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde
fvdaagkaf a kshuhg wkqj PT = PA + PB
PA iy PB mldYk fjk fjk u PT jska fnsectfuka
17
tu ksid
fi suacuteh yels h
hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk
fotilde
1 9 ksoiqk
(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla
tla jdhqfotilde wdxYsl mSvkh Kkh lrkak
(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd
lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq
ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak
uacutei`yumlu
18
fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK
u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd
fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj
tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla
fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re
uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq
irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq
efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj
u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk
nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja
ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj
mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=
jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes
lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect
tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh
wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K
jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl
1 10 ksoiqk
my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs
iskak
2KClO3(s) rarr2KCl(s) + 3O2(g)
27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute
27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh
Kkh lrkak
uacutei`yumlu
fvdaagkaf a kshuhg wkqj
Piuia = PTlaiscka + Pch
PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa
mszligmQfrac34K jdhq ioacutelrKh fhsectfuka
14 jdhq msltsn`o pdl wKqljdoh
by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(
fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks
mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla
nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka
uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml
jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh
llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad
fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd
fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj
yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde
19
141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde
wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd
uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr
wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS
wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh
u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka
gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska
jdhqj bylt iiumlmSvHdj meyeEgraves fotilde
bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu
jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO
wKqjg uacuteuacuteO fotilde mjS
fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg
ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash
jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk
ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde
bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS
fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq
wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj
fuu ska mldY flffrac34
fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh
mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt
uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka
jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr
iiumlnkaOdjh my ioacutelrKfhka nd foa
jyumlrga my oelafjk lreKq plusmnlauacuteh yels h
bull jdhq wxY= tlsfklska iajdhaj yeisffrac34
jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska
iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda
fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj
wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml
Wmlamkfhka meyeEgraves fotilde
bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla
u` ska mSvkhla wes fotilde
fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect
ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl
isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug
20
fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml
jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq
ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj
jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml
fotilde
142 pdl wKqljdofha ioacutelrKh
my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla
fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34
by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes
wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka
wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34
uOHkH fotilde h fi wfrac34 olajkq efiacute
143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h
my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu
jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg
jfrac34 uOHkH uQ fotilde h fotilde
jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla
jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=
Kkla i`oyd ioacutelrKh ild nuq
N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)
PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka
21
tu ksid jfrac34 uOHkH uQ fotilde h
fi suacuteh yels h
1 11 ksoiqk
25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak
uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1
by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj
fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama
lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml
pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh
u` ska th my oelafjk mszligEgrave idOkh llt yels h
fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt
yel
kB hkq fndaaUumliaudka kshh fotilde
22
wKqjla i`oyd
ujqhla i`oyd
fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq
fotilde
144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml
N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag
pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq
efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave
mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes
lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde
jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash
fi ye|skafotilde
16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--
fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd
fotilde jHdmash
23
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka
wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea
jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd
idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute
ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr
^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17
rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla
i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34
17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj
iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha
sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka
daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh
17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd
Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir
ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla
mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy
ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh
yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr
jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml
ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej
jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla
fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh
fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs
17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska
o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska
daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka
iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk
wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh
hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd
mszligudj (V)
mSvk
h (
P)
24
jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj
o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga
meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg
jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke
fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka
lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS
jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru
ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml
yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj
sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK
n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde
mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd
laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect
(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g
jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda
ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel
jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt
WIaKaj fotilde
daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o
WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel
fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg
jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml
fuh mltuq ioacutelrKfha wdfoaYfhka
fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH
ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk
nj wmg fmfka
fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh
pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we
tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj
hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h
mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq
wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt
jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect
jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia
PV mszligmQfrac34K
daauacutel
25
jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq
wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka
yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=
h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka
wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel
jdhq mszligmQfrac34K aajfhka wm ukh fotilde
151 jeka vrsquo jdaia ioacutelrKh
fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa
sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K
jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk
wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq
mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel
jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid
daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH
fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj
iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk
Egrave
bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka
kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka
mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka
igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash
iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg
fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh
mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde
1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj
ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh
by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK
fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde
gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq
mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde
fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg
iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq
msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect
moaOsfha mSvkh my mldYkfhka nd fohs
26
bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL
fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr
tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk
mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka
wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks
fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq
kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh
fi kej suacuteh yels h
fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh
fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql
nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia
flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha
wkafrac34--mszligjfrac34kh l yels fotilde
ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs
wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj
yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde
igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys
sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde
ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha
lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh
iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla
fi o yeisszligh yels ugraveu h
bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla
oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi
mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS
30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc
oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi
muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu
WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla
oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde
( )2
aP V b RTV
+ minus =
27
19 rEmh CO2 j ldm igyk
1 3 j =j - ioacutelrK idrdxYh
jdhq kshuh intildelrKhksh j mjsk
idOl
mszligmQfrac34K jdhq kshuh PV = nRT ke
fndhsa kshuh n iy T
pdaia kshuh V = kT n iy P
wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T
wKql pdl ioacutelrKh
idudkH fotilde h
jfrac34 uOHkH fotilde h
jfrac34 uOHkH fotilde h
fvdaagkaf a wdxYsl mSvk
kshuh
PA = xA PT
PT = PA + PB + PC
iiumlmSvHd idOlh jdhq ujq 1la i|yd
jeka vZjdaia ioacutelrKh
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
v
wkqYdilajh wdpdfrac34h agrave ta wdfrac34 fEcirc =Kfialr
wOHlaI ckrda cdsl wOHdmk wdhkh
weumllaIKh wdpdfrac34h ta auml ta o isajd
wOHlaI uacuteoHd fomdfrac34fiumlka=j
cdsl wOHdmk wdhkh
uacuteIh kdhlajh tiuml tia uacuteluisxy
iyldr lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j cdsl wOHdmk wdhkh
wNHkar ixialrK uKavh ta fla jvqfa uhd
fcHIaG lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j OcircOcircmStia fmffrac34rd ntildeh
iyldr lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j ugrave rdcqfoajka uhd
iyldr lOacuteldpdfrac34h uacuteoHd fomdfrac34fiumlka=j
lfrac34D uKavh wdpdfrac34h viacuteotilde tiuml ta agrave nKavdr - ridhk uacuteoHd fomdfrac34fiumlka=j fmardfoKsh
uacuteYajuacuteoHdh (04 yd 05 jk tallh) wdpdfrac34h olaIsld jkakswdrEacuteNtilde - ridhk uacuteoHd fomdfrac34fiumlka=j YS chjfrac34Okmqr
uacuteYajuacuteoHdh (04 jk tallh)
ndysr ixialrK uKavh fcHIaG uydpdfrac34h tia mS plusmnrKsh - ridhk uacuteoHd fomdfrac34fiumlka=j YS chjfrac34Okmqr
uacuteYajuacuteoHdh
fcHIaG uydpdfrac34h tiuml atilde mS o fldiad - ridhk uacuteoHd fomdfrac34fiumlka=j fldltU uacuteYajuacuteoHdh fcHIaG uydpdfrac34h tEacute tiuml atilde tiuml mshka - ridhk uacuteoHd fomdfrac34fiumlka=j fmardfoKsh uacuteYajuacuteoHdh
uydpdfrac34h iqoka shkfa - ridhk uacuteoHd fomdfrac34fiumlka=j YS chjfrac34Okmqr uacuteYajuacuteoHdh fla atilde nkayuml l=udr uhd - ksfhdacH flduidszligia wOHdmk mldYk fomdfrac34fiumlka=j
wOHdmk fomdfrac34fiumlka=j uqEgraved w=fldar ntildeh - =re fiajh 1 mcdmS ndsld uacuteoHdh fydrK Egravemsld fkaisxy ntildeh - =re fiajh 1-(uacuteYdntildel) ldkad uacuteyumly fldltU 07
iStatiuml fmffrac34rd fufkuacuteh - =re fiajh 1 fotildeaia l=uszlig uacuteoHdh fudrgqj uacute fla viacute atilde idsld udOuacute ntildeh - =re fiajh 1 uqiasiuml ldkad uacuteyumly fldltU 04 tEacute tiuml atildeatilde sectmsld ueKsfla ntildeh - =re fiajh 1 uacuteydr uyd foauacute ndsld uacuteyumly lsszlignafdv
vi
NdId ixialrKh
cha mshoiqka uhd mOdk Wm lfrac34D - isiquestntildeK
fala yjqia fldltU 10
uqa msgqj
wdfrac34 wdfrac34 fla msrK ntildeh cdsl wOHdmk wdhkh
uacuteuacuteO iydh viacute mS mS ugraverjfrac34Ok ntildeh ux jesmsaacuteh uhd rxetha ohdjxY uhd
(
vii
mgqk
wOHCI ckrda=ntildehfa mKsuacutevhhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip iii
wOHCI=udfa mKsuacutevhhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip iv
uacuteIhudd lntildegqj helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip v
04 tallh - modfrac34fha jdhquh wjiadjhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip01-27
11 modfrac34fha wjiad =fkys wxY= ieleiau iy tajdfha ofrac34YSh CIK helliphelliphelliphelliphelliphellip02
12 jdhquh wjiadj helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip05
121 jdhq kshu
122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)
123 pdaia kshuh (WIaKajndashmszligud iiumlnkaOh)
124 wejdacircfrda kshuh (mudK-mszligud iiumlnkaOh)
125 ujqsl mszligudj (Vm)
126 ixhqla jdhq ioacutelrKh
13 fvdaagkafa wdxYsl mSvk kshuh helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip16
131 ujq Ndh wkqidrfhka wdxYsl mSvkh
14 jdhq msltsn`o pdl wKqljdoh helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip18
141 pdl wKqljdofha mszligmQfrac34K jdhqjla i|yd Wmlamk
142 pdl wKqljdofha ioacutelrKh
143 jfrac34 uOHkH uQ fotildeh iy uOHkH fotildeh
144 ueialafja-fndaaUumliaudka jHdmash
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh helliphelliphelliphelliphelliphellip23
151 jeka vrsquojdaia ioacutelrKh
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
05 tallh - Ylas uacuteoHdjhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip28-54
21 dm-ridhksl uacuteoHdfotilde yd dms uacuteoHdfotilde uQsl mo helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip29 211 moaOsh jgmsgdj yd iSudj 212 moaOs jfrac34
213 moaOshl =K
214 moaOshl wjiadj
215 tkaeamsh (H)
216 dmh
22 uacuteuacuteO dm-ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd helliphelliphelliphelliphelliphelliphellip34
iiumlu tkaeams uacutemfrac34hdi 221 dmodhl yd dmdjfYdaIl lshdjs
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh
23 oesi tkaeamsh fyja whksl ixfhdahl Wamdok tkaeamsh(helliphelliphelliphelliphelliphelliphelliphellip47 fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj ridhksl mslshdjl iiumlu helliphelliphelliphellip49
tkafgdms fjki siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
1
wkafrac34 h
1 1 modfrac34fha wjiad =fkys wxY= ieleiau
iy tajdfha ofrac34YSh CIK
1 2 jdhquh wjiadj
1 2 1 jdhq kshu
bull mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq
ioacutelrKh
bull mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ
Kkh lsIacuteiuml
1 2 2 fndhsa kshuh
(mSvk-mszligud iiumlnkaOh)
1 2 3 pdaia kshuh
(WIaKajndashmszligud iiumlnkaOh)
1 2 4 wej dacircfrda kshuh
(mudK-mszligud iiumlnkaOh)
1 2 5 ujqsl mszligudj (Vm)
1 2 6 ixhqla jdhq ioacutelrKh
1 3 fvdaagkaf a wdxYsl mSvk kshuh
1 3 1 ujq Nd h wkqidrfhka
wdxYsl mSvkh
1 4 jdhq msltsn`o pdl wKql jdoh
1 4 1 pdl wKql jdofha mszligmQfrac34K jdhqjla
i|yd Wmlamk
1 4 2 pdl wKql jdofha ioacutelrKh
1 4 3 jfrac34 uOHkH uQ fotilde h iy
uOHkH fotilde h
1 4 4 ueialafja--fndaaUumliaudka jHdmash
1 5 daauacutel jdhqjg eltfmk mszligEgrave
mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
1 5 1 jeka vrsquojdaia ioacutelrKh
1 5 2 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
1 modfrac34fha jdhquh
wjiadj
2
ye|skaugraveu
uacuteYajfha wes ishiquest oE iquacutefYaIS ridhksl wkkHdjlska hqla h modfrac34fha l=vdu wxY=j
mrudKqj nj wms oksuq irj oelajqjfyda ridhk uacuteoHdj hkq ldquomodfrac34h iy tys isyumljk
uacutemfrac34hdi msltsn|j wOHkhrdquo fi wfrac34 oelauacute h yel modfrac34h hkq wjldYhla wama
lr kakd ialkaOhla iys acutekEu fohla jk wr th oelsh yels yd weaSug yels
^mia ch wdsectamp fohla fi fuka u jdh jeks wmg fkdfmfkk fohla o uacuteh yel
ixhqsh yd =K mokiuml lr f k oslashjH ntildeYK uQoslashjH fuka u mrudKq iy wKq wdsect uacuteuacuteO
wdldr fuys sect y`yumlkd yels h ishiquestu oslashjH gtk oslashj iy jdhq fig wvqu rntildeka uQsl
wjiad =klska mejsh yels h gtkhl sect wxY= =ltska ne`oS tlsfklg lsUumlgqj lsishiuml
ksYaNtilde jHqyhlg ksYaNtilde yevhla iysj weisIacuteu ksid tajdg pkh ugravefiuml yelshdj wvq
h oslashjhl wxY= tlsfklg lsUumlgqj wea tlsfklg iadkShj bd Egraveka ne|S kes neuacuteka
ikaikaokdaulj gtkhl sect g jvd fotilde fhka pkh uacuteh yels h wxY= wr yumlr wkqj
oslashj yd gtkjg jvd jdhq fndfyda fjkia fotilde jdhqjlsect wxY= tlsfklska fjka ugrave wes yumlr
wxY=jl mudKhg ikaikaokdaulj uacuteYd ugraveu fya=fjka wxY=jg ksoyfia yeisIacuteug
bv we tneuacuteka jdhq wxY= wr wdlfrac34Yk n bd l=vd fyda fkd sksh yels riuml ugraveu
fya=fjka wmg jdhq wxY= fjka fjka j ielsh yels neuacuteka WIaKajh yd mSvkh u
mokiuml jQ iuyr lams myiqfjka mqfrdalkh llt yels fotilde
11 modfrac34fha mOdk wjiad =fkys wxY= ieleiau iy tajdfha ofrac34YSh CIK
wjldYfha bvla kakd ialkaOhla iys acutekE u fohla zmodfrac34hZ fi ye`Egravekauacuteh yels h
wmg plusmnlsh yels wska weash yels yfldlt fia u wm fkdolsk tfya yqiau kakd
jdh o oacuteg wha h mq`Ma jYfhka a l ishuml modfrac34h gtk oslashj yd jdhq hkqfjka
wjiad =klg jfrac34 SlrKh llt yels h ixhqsfhys fjkia ugraveulska fdrj modfrac34h fiuml
suacuteO wjiad wr tllska wfklg mszligjfrac34kh llt yels h ksoiqkla fi( oslashj wjiadfotilde
mjsk ch ra lsIacutefuka jdhq wjiadjg (yqudh) mszligjfrac34kh llt yels wr isisa
lsIacutefuka gtk wjiadjg ^whsiaamp ma llt yels h
gtk
^Wod( hlv weKhamp
iaOacuter yevhla yd
mszligudjla we
oslashj
^Wod( champ
iaOacuter yevhla
kes kuqa iaOacuter mszligudjla we
jdhq
^Wod( ySshiuml neAEligkamp
iaOacuter yevhla fyda
iaOacuter mszligudjla fyda ke
gtk
wxY= ^mrudKq wKq fyda whkamp
wr wdlfrac34IK n mn h
wxY= liumlmkh jk kuqa
eklska eklg
pkh fkd fotilde
oslashj
wxY= ^mrudKq wKq fyda whkamp
wr wdlfrac34IK n triuml
mn fkd fotilde wxY=jg hiuml
mudKhlg eklska eklg
pkh uacuteh yels h
jdhq
wxY= ^mrudKq wKq fyda whkamp
wr wdlfrac34IK n yumln h
wxY=jg eklska eklg
pkh uacuteh yels h
11 rEmh modfrac34fha suacuteO wjiad
wxY=j ieleiafuka yd psfhka modfrac34fha suacuteO wjiad tlsfklska fjkia fotilde
wkafrac34currenwxY= wr yumlr jdhq wjiadfotilde wecircl jk wr gtk wjiadfotilde sect th wju fotilde jdhq
wjiadjg idfmalaIj oslashj wjiadfotilde sect wxY= tlsfklg ioacutem jk wr th gtk wjiadfotilde
3
sect riuml tlsfklg ioacutem o fkd fotilde tneuacuteka luja j ixuacuteOdkh jQ wxY=uh rgdjla plusmnlsh
yelafla gtk wjiadfotilde muŒ oslashj yd jdhq wjiad foflys sect u wxY= ieliS weafa wyUq
fi h fuys msMhla fi oslashj wjiadfotilde wes wxY=jg idfmaalaIj jdhq wjiadfotilde
wes wxY=jg jvd fotilde fhka yd ksoyia fi pkh uacuteh yels h flfia jqj o gtkj
wes wxY=j psh liumlmkjg muKla iSud fotilde my 11 j =fjka plusmnlafjk mszligEgrave
modfrac34fha wxY=j ieleiau yd tys psh mszligudj yevh iiumlmSvHdj yd gtkajh jeks
ufyaalaI =Kj fjkialiumljg =vq fohs
1 1 j =j gtk oslashj yd jdhq j =Kj =Kdaul ixikaokh
=Kh gtk oslashj jdhq
yevh ksYaNtilde h wvx = n`yumlfkys
yevh kakd uqa
n`yumlfkys uq`M mszligudj
mqrd fkd mesfrhs
n`yumlfkys yevh
kakd wr
n`yumlfkys iuia
mszligudj wa lr kS
mszligudj ksYaNtilde h ksYaNtilde h wvx = n`yumlfkys
mszligudj wa lr kS
gtkajh (ρ) g cm-3 (293 K sect)
bylt w hka kS
Wod( hlv
(7 874 g cm-3)
rula bylt w hka
kS
Wod( ch
(0 997 g cm-3)
w hka mylt h
Wod( yhsvcka
(0 071g cm-3)
iiumlmSvHdj iiumlmSvkh lsIacuteu
bd yumlIalr h
iiumlmSvkh lsIacuteu bd
yumlIalr h
fnfyuacuteka iiumlmSvkh
llt yels h
igyk ( oslashj wvx = n`yumlfkys yevh kakd nj wm i`oyka lr wes wr tfia jkafka
ukaoehs issh hq= h idudkHfhka acutekE u jia=jla wkafrac34-wKql n jeks uacuteuacuteO jfrac34 fha
n u` ska tlg ne| nd kakd neuacuteka thg ksYaNtilde yevhla we icirclrhl wes fok o
c mudKhla ^mszligudjlaamp hiuml yevhla kafka mDIaAgravel wdsh ksid h oslashjh =lt mjsk
wkafrac34-wKql n ksid mDIaGh flltjffrac34 l=vd oslashj udjlhla wes fotilde icirclrfha igraveas u` ska
oslashjh u byltg aumljla wes flfrk wr mDIaAgravel wdshg jvd jeauml =reajc nh
u` ska myltg weoSula wes fotilde tuksid oslashjh byltska iu mDIaGhla iysj icirclrfha
yevh kS fufia jkafka fuu uacuteuacuteO jfrac34 fha ishuml nj nmEu ksid h flfia jqj
o mDIaAgravel wdsh =reajc nhg jvd mn jQjd kiuml cfha mDIaGh iu fkdjk
wr n`yumlfka yevh fkd kq we =reajc nhla keehs is=j fyda mDIaAgravel wdsh
fndfyda fihska bylt hhs mDIaGfha tla tla fldgilg u wfkla mDIaGh iu` yels riuml
ltx ugrave mejSug wjYH ksid tajd wr wes wdlfrac34IK wju lr ekSug fmfograve tneuacuteka
fok o mszligudjl wju mDIaAgravel lafIaMhla wes fyd`o u yevh jk f dadldr yevh
kS
ralsrSfuka fyda isiskfhka tla wjiadjl mjsk modfrac34h ja wjiadjlg mszligjfrac34kh
llt yels h WIaKajh jeauml lsIacutefiuml sect wxY=j pk fotilde h bylt hEua wxY= wr yumlr jeauml
ugraveua lrK fldg modfrac34j wjiadj fjkia fotilde ta wkqj WIaKajh jeauml lsIacutefiuml sect gtk
wjiadfotilde wes oslashjH oslashj wjiadjga oslashj wjiadfotilde wes oslashjH jdhq wjiadjga ma fotilde
WIaKajfha wvq ugraveua iu isyuml jkafka fuys uacutefdauhhs my 12 rEmfhka modfrac34h tys
wjiad wr wkafrac34-mszligjfrac34khg Ndck llt yels wdldrh fmkakqiuml flffrac34
4
12 rEmh modfrac34fha wjiad wr wkafrac34-mszligjfrac34kh
11 ksoiqk
wxY= jvda u ioacutem fi iamfrac34Y jkafka ugrave kuqa tajd wyUq fi weysIacute weafa modfrac34fha
ljr kiuml wjiadfotilde o
uacutei`yumlu oslashj wjiadj
11 j =jg wkqj wm modfrac34fha mOdk wjiad =fkys =K uacuteiar lrk uacuteg wxY=j ieliqu
yd pkh uQslj ild nd we uacutefYaIfhka u hiuml oslashjHhl wes wKq fyda mrudKqj
pkh ksid yg kakd Ylash dmc Ylash jk wr th oslashjHfha WIaKajhg wkqfdauj
iudkqmdsl fotilde tu` ska modfrac34fha wes wxY=j uOHkHh pdl Ylash uefkk neuacuteka
th wxY=j pkh fyda dmc psh i`oyd fya= fotilde
wkafrac34-wKql n u` ska wKq tlsfklg ltx ugrave mejSug fmfUk nj wm oekgua
okakd kuqa wKqj dmc Ylash u` ska wKq tlsfklska wEa ugraveug fmfograve ta wkqj
modfrac34fha mOdk wjiad =fkys mejSu wKqj wkafrac34-wKql n iy dmc Ylash
wr iu=sfhys msMhla fi ielsh yels h
wkafrac34-wKql wdlfrac34IK bd yumln jk uacuteg WIaKajh wvq lsIacutefuka dmc Ylash WIaKajhamp
wvq fkdllt fyda wKq oslashj fyda gtk fyda fi mejSug fkd fmfograve wKq tlsfklg
bd lt` ska wes uacuteg iy wkafrac34 - wKql n Wmszliguj wes uacuteg mjd iiumlmSvkh u` ska muKla
jdhq oslashj wjiadjg ma fkd fotilde flfia jqj o WIaKajh wvq lsIacuteu u` ska wKqj dmc
Ylash wvq jk uacuteg jdhq bd myiqfjka oslashj llt yels h fiuml yeisIacuteiuml my 1 3 rEmfhka
meyeEgraves llt yels h modfrac34fha mOdk wjiad =k flfrys wkafrac34-wKql nj yd dmc
Ylasfha msuacutereoaO nmEfiuml iajNdjh wmg tu` ska wjfndaO lr yels h
5
13 rEmh wkafrac34-wKql n yd dm Ylash wkqj modfrac34fha mOdk wjiad
=fkys yeisIacuteu
modfrac34fha mOdk wjiad =kla mejSug fya=j wm oekgua yodrd we oeka wm
modfrac34fha jdhquh yeisIacuteug fya= jk jdhq kshu iy jdhquh wjiAdj msltsn`o j yumlrga
ild nuq
12 jdhquh wjiadj
oeka wm idudkH WIaKaj mSvk aaj hgfa wes jdhquh wjiadfotilde mjsk oslashjHj
yeisIacuteu flfrys wjOdkh fhduq lruq
11 j =fotilde uacuteiar lr wes mszligEgrave jdhquh wjiadj my i`oyka fNsl =K wkqj uacuteiar
flffrac34
bull jdhq bd iiumlmSvH fotilde
bull jdhq ieu EgraveYdjlg u iudk whqszligka mSvkh wes lrhs
bull jdhqjg gtk iy oslashjjg jvd wvq gtkajhla we
bull jdhqj yevh iy mszligudj ksH fkd fotilde tajd wvx = Ndckfha yevh iy mszligudj
kS
bull jdhq lsis u hdkasl nmEulska fdrj iiumlmQfrac34Kfhka u iy iudkj tlsfkl
iuOtilde ntildeY fotilde
jdhqjl irdjhg fya= jkafka tu wKq wr mjsk n fkd ssbquoh yels ugraveuhs tajdfha
yeisIacuteu mIacutelaIKdaul wOHhkhkaf ka nd a msM u` ska fidhd kakd o fmdyuml jdhq kshujg (miqj idlEacutePd flffrac34iexcl) wkqj isyuml fotilde fiuml jdhq kshu hkq jdhqjl ueksh
yels =K wr mjsk iiumlnkaOd fotilde ueksh yels =K iuyrla jk mSvkh mszligudj
WIaKajh iy mudKh ^ujq fyda ialkaOhamp jeks tajd bd jeo a jkafka fiuml uacutepH
wr mjsk iiumlnkaOd jdhqjl mOdk wjiad (5 jk tallfha sect wfrac34 olajkq efiacuteiexcl) uacuteiar lrk ksid h tlsfkl yd ne`yumlKq fiuml uacutepHhka jdhq kshu iQ lsIacuteug uQsl
ugrave we
121 jdhq kshu
wm idlEacutePd lsIacuteug hk jdhq kshu uacuteoHdhka lsysm fokl= uacuteiska jdhqj fNsl =K
mokiumlj isyuml lrk o mIacutelaIKjska nd a msM fotilde mSvkh WIaKajh mszligudj iy
jdhq mudKh hk uacutepH wr mjsk iiumlnkaOd fuys sect ild nk wr tajd u` ska
6
modfrac34fha jdhquh wjiadj msltsn`o udkj jfrac34 hdg mfhdackja jk fdr=re rdYshla
mldY fotilde
mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq ioacutelrKh
jdhq wKq wr wkafrac34-wKql n fkdues nj Wmlamkh flffrac34 o tndivide jdhqjla mszligmQfrac34K
jdhqjla fi ye`Egravekafotilde tkiuml mszligmQfrac34K jdhqjl wKq wr wdlfrac34IK fyda uacutelfrac34IK fyda
n fkd mjS tfuka u jdhqj oud wes Ndckfha mszligudj iu` ieipoundfiuml sect jdhq wxY=jl
mszligudj fkdild yeszligh yels h
jdhqjl ksrfmalaI WIaKajh (T) mSvkh (P) mszligudj (V) iy oslashjH mudKh ^n ujqamp
jdhquh yeisIacuteu flfrys nmdk idOl fotilde P T V iy n wr iiumlnkaOdj my
mldYkfhka ksrEmKh flffrac34
fuh mszligmQfrac34K jdhq ioacutelrKh fyda mszligmQfrac34K jdhq kshuh fi oelafjk wr R hkq ieu
jdhqjlg u fmdyuml w hla wes jdhq kshh fotilde fok o acutekE u WIaKajhl sect yd
mSvkhl sect by iiumlnkaOdjg wkql+j yeisfrk acutekE u jdhqjla mszligmQfrac34K jdhqjla fi
y`yumlkajkq efiacute
fuu aaj hgfa oS mszligmQfrac34K jdhq ujq 1 la i|yd 0 degC sect yd 1 atm sect R kshfha w h
my wdldrhg Kkh l yel (0 degC sect yd 1 atm yssect mszligmqfrac34K jdhqjl 1 mol l mszligudj
22 414 dm3 fotilde)
mszligmQfrac34K jdhq ioacutelrKh by uacutepH yr wr wes iiumlnkaOdj jk nj wmg fmfkk
wr acutekE u jdhqjl wjiadj tuOtildeska uacuteiar flfrk ksid th wjiad ioacutelrKh fi
o ye|skafotilde
mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ Kkh lsIacuteiuml
mszligmQfrac34K jdhq ioacutelrKh u` ska wmg mszligudj WIaKajh mSvkh fyda ujq mudKh hk
tajdhska =kla sect wes uacuteg wfkla rdYsh ksfrac34Kh llt yels h jdhqjl ujq mudKh okakd
uacuteg tys ujqsl ialkaOh Nduacutefhka tys ialkaOh o Kkh llt yels h tfuka u
tu` ska jdhqjl gtkajh o ksfrac34Kh llt yels h mszligmQfrac34K jdhq kshfha w hg eltfmk
mszligEgrave wfkl=a rdYsj tall Nduacute lsIacuteu bd jeo a jk nj ul nd hq= h
idudkHfhka mSvkh atm Pa bar torr jeks tall jska mldY llt yels h tneuacuteka fiuml
eguml uacutei`oSfiuml sect my 1 2 j =fotilde sect wes mSvk tallj mszligjfrac34k Tng Wootilde jkq we
12 j =j mSvkh i`oyd jk tall
mSvk tallh Pa bar atm torr mmHg
1 Pa 1 N m-2 10-5 9 87 times 10-6 7 5 times 10-3
1 bar 100000 1bar 0 987 750 061 atm 101325 1 01325 1 atm 7601 torr mmHg 133 32 1 3332 times 10-3 1 3158 times 10-3 1 torr 1 mmHg
7
12 ksoiqk
jdhq isskavrhl mszligudj 0950 dm3 fotilde hiuml mSvkhla hgfa sect fiuml isskavrh oslashj
fmdfmakajska (C3H8) msIacute we isskavrh ysia jQ uacuteg jdhqf daSh mSvkh yd WIaKajh
hgfa sect tys fmdfmaka jdhqj hiuml mudKhla bsszlig fotilde
(i) wjg mszligirfha aaj 25degC iy 750 torr (1 torr = 133 52 Pa) kiuml isskavrh
ysiaj wes uacuteg tys bsszlig ugrave wes fmdfmaka jdhq ujq mudKh fldmuK o
(wNHkar mSvkh ndysr mSvkhg iudk uacuteg oS)
(ii) isskavrfha bsszlig ugrave wes fmdfmaka jdhq ialkaOh Kkh lrkak
(iii) isskavrfha bsszlig ugrave wes fmdfmaka jdhqfotilde gtkajh Kkh lrkak
uacutei`yumlu (i) mltuqj sect wes fdr=re iudfdapkh lrkak
WIaKajh T = (25 + 273) K = 298 K mSvkh P = 750 torr times 13332 Pa 1 torr = 99990 Pa mszligudj V = 0 950 dm3 = 0 950 times 10-3 m3
n fkdokakd moh fotilde
PV = nRT Nduacutefhka
(ii) fmdfmakays (C3H8) ujqsl ialkaOh = 44 g mol-1
fmdfmakays ialkaOh = 0 038 mol times 44 g mol-1 = 1 672 g
(iii) fmdfmakays gtkajh = ialkaOh mszligudj = = 1 76 g dm-3
by ksoiqk iel+ uacuteg mszligmQfrac34K jdhq kshuh uacuteuacuteO wdldrjska bEgraveszligma llt yels nj
fmkS hk wr my oelafjk mszligEgrave ir fjkia lsIacuteulska fok o jdhqjl ialkaOh
iy gtkajh fiuacuteh yels h
PV = nRT
P = RT
zwnjzwnj P = CRT
fuys zC Zhkq idkaoslashKhhs
j o PV = nRT iiumlnkaOdj my mszligEgrave o mldY llt yels h
PV = RT
fuys m hkq ialkaOh jk wr M hkq jdhqfotilde ujqsl ialkaOhhs
P = RT fi o suacuteh yels h
8
gtkajh (d) =
there4 P =
uacutefYaIs aaj hgfA fjka jdhq kshu jHqamkak lsIacutefiuml sect mszligmQfrac34K jdhq kshuh uQsl
moku fi lshd lrhs
122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)mdashksh WIaKajhla hgfa wes iaOacuter jdhq mudKhl (ialkaOhl) mSvkh jdhqfotilde mszligudjg
msfdauj uacutepkh fotilde (fyda iudkqmdsl) fotilde˜ fndhsa kshuh hkqfjka ye`Egravekafjk
fuh tfia kiuml lrk oafoa 17 jeks ishjfia sect WIaKajh ksh jQ aaj hgfa fjkia
jk mSvkha iu jdhqjl mszligudj uacutepkh jk wdldrh whsszligIa cdsl uacuteoHdhl= jQ
frdnUuml fndhsa (1627- 1691) uacuteiska wOHhkh lsIacutefuka miqj h tys Ksuh wdldrh
my oelafotilde
my plusmnlafjk mszligEgrave fndhsa kshuh jHqamkak lsIacuteu i`oyd mszligmQfrac34K jdhq kshuh fhdod
yelsh PV= nRT
jdhqfjys mudKh yd moaOsfhys WIaKajh kshj mjajd kakd oafoa kiuml nT =Ksh
kshhla fotilde R o kshhla jk neuacuteka nRT =Ksh o kshhla (k) fotilde
PV = k (kshhla)
tkiuml ksh WIaKajfha sect ksh jdhq mudKhl mSvkfhaa mszligudfotildea =Ksh kshhla
fotilde fuh fndhsa kshuh mldY lrk fjka wdldrhls
ksh T WIaKajhl wes ksh jdhq mudKhl mszligudj V1 o mSvkh P1 o kiuml yd th V2
mszligudjg yd P2 mSvkhg ma llt uacuteg fndhsa kshuhg wkqj
14 rEmh u` ska fndhsa kshufha idiumlmodhsl miadszligl ksrEmK folla fmkakqiuml flffrac34
14 rEmfha (a) u` ska ixikaokh i`oyd uacuteuacuteO WIaKajj sect PV = k miadr lr we
k w h WIaKajh u muKla r`od mjsk ksid fok o jdhq ialkaOhla i`oyd w`Egravek
o ieu jlhla i`oyd u k ys w h tlsfklg fjkia fotilde bylt WIaKajj sect mszligudfotilde
midrKh ksid plh byltg f dia wes nj ielsh hq= h tfuka u WIaKajh ksh
uacuteg jdhqfotilde mSvkh wvla jk uacuteg mszligudj fo =K jk nj ul nd hq= h
9
1 4 rEmh uacuteuacuteO ksh WIaKajj sect (a) mszligudj (V) iuOtilde (b) 1 V iuOtilde
mSvkfha fjkia ugraveu
14 (b) rEmh u` ska P g tosrsfhka ys miadrh ksrEmKh fotilde th uQ laIHh yryd hk
ir ffrac34Ldjls fndhsa uacuteiska lrk o mIacutelaIKjg wkqj nd kakd o fuu miadr
u` ska jdhqjg bylt iiumlmSvHdjla wes nj mudKdaulj fmkajd foa tkiuml fok o
jdhq ialkaOhla iiumlmSvkh llt uacuteg tl u mudKhlska wes wKq ixLHdj l=vd mszligudjla
=lt mesffrac34 fiuml wkqj bylt mSvkj sect jdhqj gtkajh jeauml fotilde
igyk fok o jdhqjl gtkajh d ialkaOh m o mszligudj v o jk uacuteg d = ioacutelrKfhka
fok nj wms oksuq tuksid ksh WIaKajfhasect
hkqfjka suacuteh yels h
1 3 ksoiqk
ksh WIaKajhla hgfa wes okakd jdhq ujq mudKhl mszligudj fo =K llt uacuteg
mSvkfha isyuml jk fjkia ugraveu Kkh lrkak
uacutei`yumlu V1 =V V2 = 2V P1 = P P2 = fndhsa kshuh fhsectfuka P1V1 = P2V2
P times V = P2 times 2VP2 = P 2 there4kj mSvkh uqa mSvkfhka wvla fotilde
10
1 4 ksoiqk
ldur WIaKajfha sect neumlkhla yhsvcka jdhqj okakd mudKhlska mqrjd we jdhqf daSh
mSvkfha sect (100 kPa) tu jdhq mudKh 2 50 dm3 l mszligudjla kS tu WIaKajfha sect u
we=lt mSvkh 20 kPa ugraveug neumlkfha mszligudj fldmuK uacuteh llt hq= o
uacutei`yumlu P1 = 100 kPa P2 = 20 kPa V1 = 2 5 dm3 V2 = fndhsa kshuh fhsectfuka P1V1 = P2V2
100 kPa times 2 5 dm3 = 20 kPa times V2 there4V2 = 12 5 dm3 neumlkfha mszligudj 12 5 dm3 olajd jeauml llt hq= h
123 pdaia kshuh (WIaKaj-mszligud iiumlnkaOh)cdlaia pdaia iy fcdaIma f a-umliela hk uacuteoHdhkaf a yeoEIacuteiuml u ska fmkajd sect wes mszligEgrave
ksh mSvkhl sect fok o ksH jdhq mudKhl ^ialkaOhamp mszligudj WIaKajha iu`
jeauml jk wr isisa lsIacuteua iu` wvq fotilde tfuka u WIaKajfhA isyuml jk ieu fiaishia
wxYlhl fjkila mdid ^jeauml ugraveu fyda wvq ugraveuamp mszligudj 0degC sect jdhqfotilde wdriumlNl mszligudfjka idOlhlska fjkia jk nj ^jeauml ugraveu fyda wvq ugraveuamp fidhd f k we
0 degC sect iy t degC ys sect jdhqfotilde mszligudj msltsfjltska V0 iy Vt hhs Wmlamkh lruq tuacuteg
fuu aajfha sect WIaKajh i`oyd kj mszligudKhla wfrac34 olajd we tuacuteg tu mszligudKhg
wkqj
t degC i`oyd Tt = 273 15 + t uOtildeska nd fok wr
0 degC i`oyd T0 = 273 15 uOtildeska nd fohs
fuu kj WIaKaj mszligudKh flauacuteka WIaKaj mszligudKh (K) fyja ksrfmalaI WIaKaj
mszligudKh fi ye`Egravekafotilde ndash 273 15 degC (0 K) hkak dm sl Y+kHh fi wfrac34 oelafjk
wr th ffioaOdkaslj lt` d uacuteh yels wju WIaKajh fotilde
fmdyumlfotilde a uacuteg ksh mSvkfha sect (V1 T1) isg (V2 T2) olajd isyuml jk fjkila i`oyd
11
tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg
wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde
jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys
WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg
yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h
PV = nRTV = nRT P
ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde
zwnjzwnjzwnjzwnjV prop T fyda V = kT
pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka
WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd
Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect
ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh
lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34
15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde
uacutepkh
12
1 5 ksoiqk
ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml
jk WIaKaj fjki Kkh lrkak
uacutei`yumlu
T1 = T V1 = V V2 = 3V T2 =
T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh
wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h
hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi
efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg
lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr
kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde
1 6 ksoiqk
23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde
tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki
Kkh lrkak
uacutei`yumlu
T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =
jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka
V2 = 2 03 dm3
mszligudfotilde isyumljk fjki = 0 03 dm3
124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=
jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj
lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla
hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)
fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h
13
jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda
kshh (NA fyda L) fi ye|skafotilde
my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka
wjfndaO lr yels h
fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl
u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud
follg by iiumlnkaOdj fhsectfuka
P iy T ksh uacuteg sect (R iy NA kshhka fotilde )
irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud
=lt iudk wKq ixLdjla wvx= fotilde (V α N)
by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd
mszligmQfrac34K jdhq ioacutelrKh nd yels h
by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka
k = R jQ uacuteg
P V = n R T
14
125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka
fi wmg suacuteh yels h
iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd
mszligudj (Vm) tl u w hla uacuteh hq= ksid th
fi Kkh llt yels h
tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u
mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34
bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu
aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj
22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi
ksrEmKh flffrac34
bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde
fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde
igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde
V = k n = k (m M) tneuacuteka M = k (m V) = k d
1 7 ksoiqk
298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud
iudk nj fmkajkak
uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe
VHe = nHeRTHe PHe
VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3
15
PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =
PNeVNe = nNeRTNe
VNe = nNeRTNe PNe
VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa
VNe = 24 4 dm3
tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq
wa lr kakd mszligud iudk fotilde
126 ixhqla jdhq kshuh
jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj
tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka
T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla
fi suacuteh yels h
fuh ixhqla jdhq kshuh fi ye|skafotilde
1 8 ksoiqk
25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o
uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh
P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3
T1 = 25 + 273 = 298 K
V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =
P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa
16
13 fvdaagkaf a wdxYsl mSvk kshuh
fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm
yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk
wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml
ishuml jdhq odhl fotilde
jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj
wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde
ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla
iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs
fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh
fi yeEgravekafotilde
A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska
PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde
my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka
jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha
we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh
PT hehs o isuq
PV = nRT
A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )
B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )
jdhq ntildeYKh i`oyd nT = PTV RT
iy nT = nA + nB
tu ksid PTV RT = (PAV RT) + (PBV RT)
iq`M llt uacuteg PT = PA + PB
fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl
131 ujq Nd h wkqidrfhka wdxYsl mSvkh
T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq
ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde
fvdaagkaf a kshuhg wkqj PT = PA + PB
PA iy PB mldYk fjk fjk u PT jska fnsectfuka
17
tu ksid
fi suacuteh yels h
hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk
fotilde
1 9 ksoiqk
(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla
tla jdhqfotilde wdxYsl mSvkh Kkh lrkak
(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd
lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq
ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak
uacutei`yumlu
18
fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK
u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd
fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj
tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla
fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re
uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq
irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq
efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj
u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk
nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja
ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj
mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=
jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes
lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect
tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh
wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K
jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl
1 10 ksoiqk
my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs
iskak
2KClO3(s) rarr2KCl(s) + 3O2(g)
27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute
27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh
Kkh lrkak
uacutei`yumlu
fvdaagkaf a kshuhg wkqj
Piuia = PTlaiscka + Pch
PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa
mszligmQfrac34K jdhq ioacutelrKh fhsectfuka
14 jdhq msltsn`o pdl wKqljdoh
by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(
fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks
mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla
nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka
uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml
jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh
llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad
fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd
fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj
yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde
19
141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde
wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd
uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr
wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS
wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh
u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka
gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska
jdhqj bylt iiumlmSvHdj meyeEgraves fotilde
bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu
jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO
wKqjg uacuteuacuteO fotilde mjS
fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg
ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash
jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk
ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde
bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS
fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq
wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj
fuu ska mldY flffrac34
fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh
mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt
uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka
jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr
iiumlnkaOdjh my ioacutelrKfhka nd foa
jyumlrga my oelafjk lreKq plusmnlauacuteh yels h
bull jdhq wxY= tlsfklska iajdhaj yeisffrac34
jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska
iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda
fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj
wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml
Wmlamkfhka meyeEgraves fotilde
bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla
u` ska mSvkhla wes fotilde
fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect
ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl
isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug
20
fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml
jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq
ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj
jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml
fotilde
142 pdl wKqljdofha ioacutelrKh
my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla
fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34
by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes
wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka
wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34
uOHkH fotilde h fi wfrac34 olajkq efiacute
143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h
my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu
jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg
jfrac34 uOHkH uQ fotilde h fotilde
jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla
jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=
Kkla i`oyd ioacutelrKh ild nuq
N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)
PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka
21
tu ksid jfrac34 uOHkH uQ fotilde h
fi suacuteh yels h
1 11 ksoiqk
25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak
uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1
by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj
fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama
lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml
pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh
u` ska th my oelafjk mszligEgrave idOkh llt yels h
fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt
yel
kB hkq fndaaUumliaudka kshh fotilde
22
wKqjla i`oyd
ujqhla i`oyd
fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq
fotilde
144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml
N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag
pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq
efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave
mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes
lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde
jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash
fi ye|skafotilde
16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--
fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd
fotilde jHdmash
23
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka
wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea
jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd
idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute
ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr
^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17
rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla
i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34
17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj
iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha
sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka
daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh
17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd
Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir
ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla
mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy
ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh
yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr
jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml
ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej
jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla
fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh
fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs
17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska
o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska
daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka
iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk
wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh
hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd
mszligudj (V)
mSvk
h (
P)
24
jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj
o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga
meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg
jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke
fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka
lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS
jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru
ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml
yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj
sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK
n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde
mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd
laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect
(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g
jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda
ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel
jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt
WIaKaj fotilde
daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o
WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel
fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg
jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml
fuh mltuq ioacutelrKfha wdfoaYfhka
fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH
ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk
nj wmg fmfka
fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh
pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we
tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj
hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h
mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq
wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt
jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect
jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia
PV mszligmQfrac34K
daauacutel
25
jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq
wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka
yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=
h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka
wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel
jdhq mszligmQfrac34K aajfhka wm ukh fotilde
151 jeka vrsquo jdaia ioacutelrKh
fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa
sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K
jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk
wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq
mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel
jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid
daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH
fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj
iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk
Egrave
bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka
kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka
mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka
igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash
iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg
fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh
mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde
1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj
ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh
by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK
fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde
gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq
mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde
fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg
iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq
msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect
moaOsfha mSvkh my mldYkfhka nd fohs
26
bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL
fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr
tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk
mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka
wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks
fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq
kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh
fi kej suacuteh yels h
fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh
fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql
nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia
flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha
wkafrac34--mszligjfrac34kh l yels fotilde
ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs
wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj
yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde
igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys
sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde
ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha
lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh
iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla
fi o yeisszligh yels ugraveu h
bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla
oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi
mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS
30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc
oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi
muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu
WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla
oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde
( )2
aP V b RTV
+ minus =
27
19 rEmh CO2 j ldm igyk
1 3 j =j - ioacutelrK idrdxYh
jdhq kshuh intildelrKhksh j mjsk
idOl
mszligmQfrac34K jdhq kshuh PV = nRT ke
fndhsa kshuh n iy T
pdaia kshuh V = kT n iy P
wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T
wKql pdl ioacutelrKh
idudkH fotilde h
jfrac34 uOHkH fotilde h
jfrac34 uOHkH fotilde h
fvdaagkaf a wdxYsl mSvk
kshuh
PA = xA PT
PT = PA + PB + PC
iiumlmSvHd idOlh jdhq ujq 1la i|yd
jeka vZjdaia ioacutelrKh
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
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iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
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Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
vi
NdId ixialrKh
cha mshoiqka uhd mOdk Wm lfrac34D - isiquestntildeK
fala yjqia fldltU 10
uqa msgqj
wdfrac34 wdfrac34 fla msrK ntildeh cdsl wOHdmk wdhkh
uacuteuacuteO iydh viacute mS mS ugraverjfrac34Ok ntildeh ux jesmsaacuteh uhd rxetha ohdjxY uhd
(
vii
mgqk
wOHCI ckrda=ntildehfa mKsuacutevhhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip iii
wOHCI=udfa mKsuacutevhhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip iv
uacuteIhudd lntildegqj helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip v
04 tallh - modfrac34fha jdhquh wjiadjhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip01-27
11 modfrac34fha wjiad =fkys wxY= ieleiau iy tajdfha ofrac34YSh CIK helliphelliphelliphelliphelliphellip02
12 jdhquh wjiadj helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip05
121 jdhq kshu
122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)
123 pdaia kshuh (WIaKajndashmszligud iiumlnkaOh)
124 wejdacircfrda kshuh (mudK-mszligud iiumlnkaOh)
125 ujqsl mszligudj (Vm)
126 ixhqla jdhq ioacutelrKh
13 fvdaagkafa wdxYsl mSvk kshuh helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip16
131 ujq Ndh wkqidrfhka wdxYsl mSvkh
14 jdhq msltsn`o pdl wKqljdoh helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip18
141 pdl wKqljdofha mszligmQfrac34K jdhqjla i|yd Wmlamk
142 pdl wKqljdofha ioacutelrKh
143 jfrac34 uOHkH uQ fotildeh iy uOHkH fotildeh
144 ueialafja-fndaaUumliaudka jHdmash
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh helliphelliphelliphelliphelliphellip23
151 jeka vrsquojdaia ioacutelrKh
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
05 tallh - Ylas uacuteoHdjhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip28-54
21 dm-ridhksl uacuteoHdfotilde yd dms uacuteoHdfotilde uQsl mo helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip29 211 moaOsh jgmsgdj yd iSudj 212 moaOs jfrac34
213 moaOshl =K
214 moaOshl wjiadj
215 tkaeamsh (H)
216 dmh
22 uacuteuacuteO dm-ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd helliphelliphelliphelliphelliphelliphellip34
iiumlu tkaeams uacutemfrac34hdi 221 dmodhl yd dmdjfYdaIl lshdjs
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh
23 oesi tkaeamsh fyja whksl ixfhdahl Wamdok tkaeamsh(helliphelliphelliphelliphelliphelliphelliphellip47 fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj ridhksl mslshdjl iiumlu helliphelliphelliphellip49
tkafgdms fjki siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
1
wkafrac34 h
1 1 modfrac34fha wjiad =fkys wxY= ieleiau
iy tajdfha ofrac34YSh CIK
1 2 jdhquh wjiadj
1 2 1 jdhq kshu
bull mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq
ioacutelrKh
bull mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ
Kkh lsIacuteiuml
1 2 2 fndhsa kshuh
(mSvk-mszligud iiumlnkaOh)
1 2 3 pdaia kshuh
(WIaKajndashmszligud iiumlnkaOh)
1 2 4 wej dacircfrda kshuh
(mudK-mszligud iiumlnkaOh)
1 2 5 ujqsl mszligudj (Vm)
1 2 6 ixhqla jdhq ioacutelrKh
1 3 fvdaagkaf a wdxYsl mSvk kshuh
1 3 1 ujq Nd h wkqidrfhka
wdxYsl mSvkh
1 4 jdhq msltsn`o pdl wKql jdoh
1 4 1 pdl wKql jdofha mszligmQfrac34K jdhqjla
i|yd Wmlamk
1 4 2 pdl wKql jdofha ioacutelrKh
1 4 3 jfrac34 uOHkH uQ fotilde h iy
uOHkH fotilde h
1 4 4 ueialafja--fndaaUumliaudka jHdmash
1 5 daauacutel jdhqjg eltfmk mszligEgrave
mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
1 5 1 jeka vrsquojdaia ioacutelrKh
1 5 2 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
1 modfrac34fha jdhquh
wjiadj
2
ye|skaugraveu
uacuteYajfha wes ishiquest oE iquacutefYaIS ridhksl wkkHdjlska hqla h modfrac34fha l=vdu wxY=j
mrudKqj nj wms oksuq irj oelajqjfyda ridhk uacuteoHdj hkq ldquomodfrac34h iy tys isyumljk
uacutemfrac34hdi msltsn|j wOHkhrdquo fi wfrac34 oelauacute h yel modfrac34h hkq wjldYhla wama
lr kakd ialkaOhla iys acutekEu fohla jk wr th oelsh yels yd weaSug yels
^mia ch wdsectamp fohla fi fuka u jdh jeks wmg fkdfmfkk fohla o uacuteh yel
ixhqsh yd =K mokiuml lr f k oslashjH ntildeYK uQoslashjH fuka u mrudKq iy wKq wdsect uacuteuacuteO
wdldr fuys sect y`yumlkd yels h ishiquestu oslashjH gtk oslashj iy jdhq fig wvqu rntildeka uQsl
wjiad =klska mejsh yels h gtkhl sect wxY= =ltska ne`oS tlsfklg lsUumlgqj lsishiuml
ksYaNtilde jHqyhlg ksYaNtilde yevhla iysj weisIacuteu ksid tajdg pkh ugravefiuml yelshdj wvq
h oslashjhl wxY= tlsfklg lsUumlgqj wea tlsfklg iadkShj bd Egraveka ne|S kes neuacuteka
ikaikaokdaulj gtkhl sect g jvd fotilde fhka pkh uacuteh yels h wxY= wr yumlr wkqj
oslashj yd gtkjg jvd jdhq fndfyda fjkia fotilde jdhqjlsect wxY= tlsfklska fjka ugrave wes yumlr
wxY=jl mudKhg ikaikaokdaulj uacuteYd ugraveu fya=fjka wxY=jg ksoyfia yeisIacuteug
bv we tneuacuteka jdhq wxY= wr wdlfrac34Yk n bd l=vd fyda fkd sksh yels riuml ugraveu
fya=fjka wmg jdhq wxY= fjka fjka j ielsh yels neuacuteka WIaKajh yd mSvkh u
mokiuml jQ iuyr lams myiqfjka mqfrdalkh llt yels fotilde
11 modfrac34fha mOdk wjiad =fkys wxY= ieleiau iy tajdfha ofrac34YSh CIK
wjldYfha bvla kakd ialkaOhla iys acutekE u fohla zmodfrac34hZ fi ye`Egravekauacuteh yels h
wmg plusmnlsh yels wska weash yels yfldlt fia u wm fkdolsk tfya yqiau kakd
jdh o oacuteg wha h mq`Ma jYfhka a l ishuml modfrac34h gtk oslashj yd jdhq hkqfjka
wjiad =klg jfrac34 SlrKh llt yels h ixhqsfhys fjkia ugraveulska fdrj modfrac34h fiuml
suacuteO wjiad wr tllska wfklg mszligjfrac34kh llt yels h ksoiqkla fi( oslashj wjiadfotilde
mjsk ch ra lsIacutefuka jdhq wjiadjg (yqudh) mszligjfrac34kh llt yels wr isisa
lsIacutefuka gtk wjiadjg ^whsiaamp ma llt yels h
gtk
^Wod( hlv weKhamp
iaOacuter yevhla yd
mszligudjla we
oslashj
^Wod( champ
iaOacuter yevhla
kes kuqa iaOacuter mszligudjla we
jdhq
^Wod( ySshiuml neAEligkamp
iaOacuter yevhla fyda
iaOacuter mszligudjla fyda ke
gtk
wxY= ^mrudKq wKq fyda whkamp
wr wdlfrac34IK n mn h
wxY= liumlmkh jk kuqa
eklska eklg
pkh fkd fotilde
oslashj
wxY= ^mrudKq wKq fyda whkamp
wr wdlfrac34IK n triuml
mn fkd fotilde wxY=jg hiuml
mudKhlg eklska eklg
pkh uacuteh yels h
jdhq
wxY= ^mrudKq wKq fyda whkamp
wr wdlfrac34IK n yumln h
wxY=jg eklska eklg
pkh uacuteh yels h
11 rEmh modfrac34fha suacuteO wjiad
wxY=j ieleiafuka yd psfhka modfrac34fha suacuteO wjiad tlsfklska fjkia fotilde
wkafrac34currenwxY= wr yumlr jdhq wjiadfotilde wecircl jk wr gtk wjiadfotilde sect th wju fotilde jdhq
wjiadjg idfmalaIj oslashj wjiadfotilde sect wxY= tlsfklg ioacutem jk wr th gtk wjiadfotilde
3
sect riuml tlsfklg ioacutem o fkd fotilde tneuacuteka luja j ixuacuteOdkh jQ wxY=uh rgdjla plusmnlsh
yelafla gtk wjiadfotilde muŒ oslashj yd jdhq wjiad foflys sect u wxY= ieliS weafa wyUq
fi h fuys msMhla fi oslashj wjiadfotilde wes wxY=jg idfmaalaIj jdhq wjiadfotilde
wes wxY=jg jvd fotilde fhka yd ksoyia fi pkh uacuteh yels h flfia jqj o gtkj
wes wxY=j psh liumlmkjg muKla iSud fotilde my 11 j =fjka plusmnlafjk mszligEgrave
modfrac34fha wxY=j ieleiau yd tys psh mszligudj yevh iiumlmSvHdj yd gtkajh jeks
ufyaalaI =Kj fjkialiumljg =vq fohs
1 1 j =j gtk oslashj yd jdhq j =Kj =Kdaul ixikaokh
=Kh gtk oslashj jdhq
yevh ksYaNtilde h wvx = n`yumlfkys
yevh kakd uqa
n`yumlfkys uq`M mszligudj
mqrd fkd mesfrhs
n`yumlfkys yevh
kakd wr
n`yumlfkys iuia
mszligudj wa lr kS
mszligudj ksYaNtilde h ksYaNtilde h wvx = n`yumlfkys
mszligudj wa lr kS
gtkajh (ρ) g cm-3 (293 K sect)
bylt w hka kS
Wod( hlv
(7 874 g cm-3)
rula bylt w hka
kS
Wod( ch
(0 997 g cm-3)
w hka mylt h
Wod( yhsvcka
(0 071g cm-3)
iiumlmSvHdj iiumlmSvkh lsIacuteu
bd yumlIalr h
iiumlmSvkh lsIacuteu bd
yumlIalr h
fnfyuacuteka iiumlmSvkh
llt yels h
igyk ( oslashj wvx = n`yumlfkys yevh kakd nj wm i`oyka lr wes wr tfia jkafka
ukaoehs issh hq= h idudkHfhka acutekE u jia=jla wkafrac34-wKql n jeks uacuteuacuteO jfrac34 fha
n u` ska tlg ne| nd kakd neuacuteka thg ksYaNtilde yevhla we icirclrhl wes fok o
c mudKhla ^mszligudjlaamp hiuml yevhla kafka mDIaAgravel wdsh ksid h oslashjh =lt mjsk
wkafrac34-wKql n ksid mDIaGh flltjffrac34 l=vd oslashj udjlhla wes fotilde icirclrfha igraveas u` ska
oslashjh u byltg aumljla wes flfrk wr mDIaAgravel wdshg jvd jeauml =reajc nh
u` ska myltg weoSula wes fotilde tuksid oslashjh byltska iu mDIaGhla iysj icirclrfha
yevh kS fufia jkafka fuu uacuteuacuteO jfrac34 fha ishuml nj nmEu ksid h flfia jqj
o mDIaAgravel wdsh =reajc nhg jvd mn jQjd kiuml cfha mDIaGh iu fkdjk
wr n`yumlfka yevh fkd kq we =reajc nhla keehs is=j fyda mDIaAgravel wdsh
fndfyda fihska bylt hhs mDIaGfha tla tla fldgilg u wfkla mDIaGh iu` yels riuml
ltx ugrave mejSug wjYH ksid tajd wr wes wdlfrac34IK wju lr ekSug fmfograve tneuacuteka
fok o mszligudjl wju mDIaAgravel lafIaMhla wes fyd`o u yevh jk f dadldr yevh
kS
ralsrSfuka fyda isiskfhka tla wjiadjl mjsk modfrac34h ja wjiadjlg mszligjfrac34kh
llt yels h WIaKajh jeauml lsIacutefiuml sect wxY=j pk fotilde h bylt hEua wxY= wr yumlr jeauml
ugraveua lrK fldg modfrac34j wjiadj fjkia fotilde ta wkqj WIaKajh jeauml lsIacutefiuml sect gtk
wjiadfotilde wes oslashjH oslashj wjiadjga oslashj wjiadfotilde wes oslashjH jdhq wjiadjga ma fotilde
WIaKajfha wvq ugraveua iu isyuml jkafka fuys uacutefdauhhs my 12 rEmfhka modfrac34h tys
wjiad wr wkafrac34-mszligjfrac34khg Ndck llt yels wdldrh fmkakqiuml flffrac34
4
12 rEmh modfrac34fha wjiad wr wkafrac34-mszligjfrac34kh
11 ksoiqk
wxY= jvda u ioacutem fi iamfrac34Y jkafka ugrave kuqa tajd wyUq fi weysIacute weafa modfrac34fha
ljr kiuml wjiadfotilde o
uacutei`yumlu oslashj wjiadj
11 j =jg wkqj wm modfrac34fha mOdk wjiad =fkys =K uacuteiar lrk uacuteg wxY=j ieliqu
yd pkh uQslj ild nd we uacutefYaIfhka u hiuml oslashjHhl wes wKq fyda mrudKqj
pkh ksid yg kakd Ylash dmc Ylash jk wr th oslashjHfha WIaKajhg wkqfdauj
iudkqmdsl fotilde tu` ska modfrac34fha wes wxY=j uOHkHh pdl Ylash uefkk neuacuteka
th wxY=j pkh fyda dmc psh i`oyd fya= fotilde
wkafrac34-wKql n u` ska wKq tlsfklg ltx ugrave mejSug fmfUk nj wm oekgua
okakd kuqa wKqj dmc Ylash u` ska wKq tlsfklska wEa ugraveug fmfograve ta wkqj
modfrac34fha mOdk wjiad =fkys mejSu wKqj wkafrac34-wKql n iy dmc Ylash
wr iu=sfhys msMhla fi ielsh yels h
wkafrac34-wKql wdlfrac34IK bd yumln jk uacuteg WIaKajh wvq lsIacutefuka dmc Ylash WIaKajhamp
wvq fkdllt fyda wKq oslashj fyda gtk fyda fi mejSug fkd fmfograve wKq tlsfklg
bd lt` ska wes uacuteg iy wkafrac34 - wKql n Wmszliguj wes uacuteg mjd iiumlmSvkh u` ska muKla
jdhq oslashj wjiadjg ma fkd fotilde flfia jqj o WIaKajh wvq lsIacuteu u` ska wKqj dmc
Ylash wvq jk uacuteg jdhq bd myiqfjka oslashj llt yels h fiuml yeisIacuteiuml my 1 3 rEmfhka
meyeEgraves llt yels h modfrac34fha mOdk wjiad =k flfrys wkafrac34-wKql nj yd dmc
Ylasfha msuacutereoaO nmEfiuml iajNdjh wmg tu` ska wjfndaO lr yels h
5
13 rEmh wkafrac34-wKql n yd dm Ylash wkqj modfrac34fha mOdk wjiad
=fkys yeisIacuteu
modfrac34fha mOdk wjiad =kla mejSug fya=j wm oekgua yodrd we oeka wm
modfrac34fha jdhquh yeisIacuteug fya= jk jdhq kshu iy jdhquh wjiAdj msltsn`o j yumlrga
ild nuq
12 jdhquh wjiadj
oeka wm idudkH WIaKaj mSvk aaj hgfa wes jdhquh wjiadfotilde mjsk oslashjHj
yeisIacuteu flfrys wjOdkh fhduq lruq
11 j =fotilde uacuteiar lr wes mszligEgrave jdhquh wjiadj my i`oyka fNsl =K wkqj uacuteiar
flffrac34
bull jdhq bd iiumlmSvH fotilde
bull jdhq ieu EgraveYdjlg u iudk whqszligka mSvkh wes lrhs
bull jdhqjg gtk iy oslashjjg jvd wvq gtkajhla we
bull jdhqj yevh iy mszligudj ksH fkd fotilde tajd wvx = Ndckfha yevh iy mszligudj
kS
bull jdhq lsis u hdkasl nmEulska fdrj iiumlmQfrac34Kfhka u iy iudkj tlsfkl
iuOtilde ntildeY fotilde
jdhqjl irdjhg fya= jkafka tu wKq wr mjsk n fkd ssbquoh yels ugraveuhs tajdfha
yeisIacuteu mIacutelaIKdaul wOHhkhkaf ka nd a msM u` ska fidhd kakd o fmdyuml jdhq kshujg (miqj idlEacutePd flffrac34iexcl) wkqj isyuml fotilde fiuml jdhq kshu hkq jdhqjl ueksh
yels =K wr mjsk iiumlnkaOd fotilde ueksh yels =K iuyrla jk mSvkh mszligudj
WIaKajh iy mudKh ^ujq fyda ialkaOhamp jeks tajd bd jeo a jkafka fiuml uacutepH
wr mjsk iiumlnkaOd jdhqjl mOdk wjiad (5 jk tallfha sect wfrac34 olajkq efiacuteiexcl) uacuteiar lrk ksid h tlsfkl yd ne`yumlKq fiuml uacutepHhka jdhq kshu iQ lsIacuteug uQsl
ugrave we
121 jdhq kshu
wm idlEacutePd lsIacuteug hk jdhq kshu uacuteoHdhka lsysm fokl= uacuteiska jdhqj fNsl =K
mokiumlj isyuml lrk o mIacutelaIKjska nd a msM fotilde mSvkh WIaKajh mszligudj iy
jdhq mudKh hk uacutepH wr mjsk iiumlnkaOd fuys sect ild nk wr tajd u` ska
6
modfrac34fha jdhquh wjiadj msltsn`o udkj jfrac34 hdg mfhdackja jk fdr=re rdYshla
mldY fotilde
mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq ioacutelrKh
jdhq wKq wr wkafrac34-wKql n fkdues nj Wmlamkh flffrac34 o tndivide jdhqjla mszligmQfrac34K
jdhqjla fi ye`Egravekafotilde tkiuml mszligmQfrac34K jdhqjl wKq wr wdlfrac34IK fyda uacutelfrac34IK fyda
n fkd mjS tfuka u jdhqj oud wes Ndckfha mszligudj iu` ieipoundfiuml sect jdhq wxY=jl
mszligudj fkdild yeszligh yels h
jdhqjl ksrfmalaI WIaKajh (T) mSvkh (P) mszligudj (V) iy oslashjH mudKh ^n ujqamp
jdhquh yeisIacuteu flfrys nmdk idOl fotilde P T V iy n wr iiumlnkaOdj my
mldYkfhka ksrEmKh flffrac34
fuh mszligmQfrac34K jdhq ioacutelrKh fyda mszligmQfrac34K jdhq kshuh fi oelafjk wr R hkq ieu
jdhqjlg u fmdyuml w hla wes jdhq kshh fotilde fok o acutekE u WIaKajhl sect yd
mSvkhl sect by iiumlnkaOdjg wkql+j yeisfrk acutekE u jdhqjla mszligmQfrac34K jdhqjla fi
y`yumlkajkq efiacute
fuu aaj hgfa oS mszligmQfrac34K jdhq ujq 1 la i|yd 0 degC sect yd 1 atm sect R kshfha w h
my wdldrhg Kkh l yel (0 degC sect yd 1 atm yssect mszligmqfrac34K jdhqjl 1 mol l mszligudj
22 414 dm3 fotilde)
mszligmQfrac34K jdhq ioacutelrKh by uacutepH yr wr wes iiumlnkaOdj jk nj wmg fmfkk
wr acutekE u jdhqjl wjiadj tuOtildeska uacuteiar flfrk ksid th wjiad ioacutelrKh fi
o ye|skafotilde
mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ Kkh lsIacuteiuml
mszligmQfrac34K jdhq ioacutelrKh u` ska wmg mszligudj WIaKajh mSvkh fyda ujq mudKh hk
tajdhska =kla sect wes uacuteg wfkla rdYsh ksfrac34Kh llt yels h jdhqjl ujq mudKh okakd
uacuteg tys ujqsl ialkaOh Nduacutefhka tys ialkaOh o Kkh llt yels h tfuka u
tu` ska jdhqjl gtkajh o ksfrac34Kh llt yels h mszligmQfrac34K jdhq kshfha w hg eltfmk
mszligEgrave wfkl=a rdYsj tall Nduacute lsIacuteu bd jeo a jk nj ul nd hq= h
idudkHfhka mSvkh atm Pa bar torr jeks tall jska mldY llt yels h tneuacuteka fiuml
eguml uacutei`oSfiuml sect my 1 2 j =fotilde sect wes mSvk tallj mszligjfrac34k Tng Wootilde jkq we
12 j =j mSvkh i`oyd jk tall
mSvk tallh Pa bar atm torr mmHg
1 Pa 1 N m-2 10-5 9 87 times 10-6 7 5 times 10-3
1 bar 100000 1bar 0 987 750 061 atm 101325 1 01325 1 atm 7601 torr mmHg 133 32 1 3332 times 10-3 1 3158 times 10-3 1 torr 1 mmHg
7
12 ksoiqk
jdhq isskavrhl mszligudj 0950 dm3 fotilde hiuml mSvkhla hgfa sect fiuml isskavrh oslashj
fmdfmakajska (C3H8) msIacute we isskavrh ysia jQ uacuteg jdhqf daSh mSvkh yd WIaKajh
hgfa sect tys fmdfmaka jdhqj hiuml mudKhla bsszlig fotilde
(i) wjg mszligirfha aaj 25degC iy 750 torr (1 torr = 133 52 Pa) kiuml isskavrh
ysiaj wes uacuteg tys bsszlig ugrave wes fmdfmaka jdhq ujq mudKh fldmuK o
(wNHkar mSvkh ndysr mSvkhg iudk uacuteg oS)
(ii) isskavrfha bsszlig ugrave wes fmdfmaka jdhq ialkaOh Kkh lrkak
(iii) isskavrfha bsszlig ugrave wes fmdfmaka jdhqfotilde gtkajh Kkh lrkak
uacutei`yumlu (i) mltuqj sect wes fdr=re iudfdapkh lrkak
WIaKajh T = (25 + 273) K = 298 K mSvkh P = 750 torr times 13332 Pa 1 torr = 99990 Pa mszligudj V = 0 950 dm3 = 0 950 times 10-3 m3
n fkdokakd moh fotilde
PV = nRT Nduacutefhka
(ii) fmdfmakays (C3H8) ujqsl ialkaOh = 44 g mol-1
fmdfmakays ialkaOh = 0 038 mol times 44 g mol-1 = 1 672 g
(iii) fmdfmakays gtkajh = ialkaOh mszligudj = = 1 76 g dm-3
by ksoiqk iel+ uacuteg mszligmQfrac34K jdhq kshuh uacuteuacuteO wdldrjska bEgraveszligma llt yels nj
fmkS hk wr my oelafjk mszligEgrave ir fjkia lsIacuteulska fok o jdhqjl ialkaOh
iy gtkajh fiuacuteh yels h
PV = nRT
P = RT
zwnjzwnj P = CRT
fuys zC Zhkq idkaoslashKhhs
j o PV = nRT iiumlnkaOdj my mszligEgrave o mldY llt yels h
PV = RT
fuys m hkq ialkaOh jk wr M hkq jdhqfotilde ujqsl ialkaOhhs
P = RT fi o suacuteh yels h
8
gtkajh (d) =
there4 P =
uacutefYaIs aaj hgfA fjka jdhq kshu jHqamkak lsIacutefiuml sect mszligmQfrac34K jdhq kshuh uQsl
moku fi lshd lrhs
122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)mdashksh WIaKajhla hgfa wes iaOacuter jdhq mudKhl (ialkaOhl) mSvkh jdhqfotilde mszligudjg
msfdauj uacutepkh fotilde (fyda iudkqmdsl) fotilde˜ fndhsa kshuh hkqfjka ye`Egravekafjk
fuh tfia kiuml lrk oafoa 17 jeks ishjfia sect WIaKajh ksh jQ aaj hgfa fjkia
jk mSvkha iu jdhqjl mszligudj uacutepkh jk wdldrh whsszligIa cdsl uacuteoHdhl= jQ
frdnUuml fndhsa (1627- 1691) uacuteiska wOHhkh lsIacutefuka miqj h tys Ksuh wdldrh
my oelafotilde
my plusmnlafjk mszligEgrave fndhsa kshuh jHqamkak lsIacuteu i`oyd mszligmQfrac34K jdhq kshuh fhdod
yelsh PV= nRT
jdhqfjys mudKh yd moaOsfhys WIaKajh kshj mjajd kakd oafoa kiuml nT =Ksh
kshhla fotilde R o kshhla jk neuacuteka nRT =Ksh o kshhla (k) fotilde
PV = k (kshhla)
tkiuml ksh WIaKajfha sect ksh jdhq mudKhl mSvkfhaa mszligudfotildea =Ksh kshhla
fotilde fuh fndhsa kshuh mldY lrk fjka wdldrhls
ksh T WIaKajhl wes ksh jdhq mudKhl mszligudj V1 o mSvkh P1 o kiuml yd th V2
mszligudjg yd P2 mSvkhg ma llt uacuteg fndhsa kshuhg wkqj
14 rEmh u` ska fndhsa kshufha idiumlmodhsl miadszligl ksrEmK folla fmkakqiuml flffrac34
14 rEmfha (a) u` ska ixikaokh i`oyd uacuteuacuteO WIaKajj sect PV = k miadr lr we
k w h WIaKajh u muKla r`od mjsk ksid fok o jdhq ialkaOhla i`oyd w`Egravek
o ieu jlhla i`oyd u k ys w h tlsfklg fjkia fotilde bylt WIaKajj sect mszligudfotilde
midrKh ksid plh byltg f dia wes nj ielsh hq= h tfuka u WIaKajh ksh
uacuteg jdhqfotilde mSvkh wvla jk uacuteg mszligudj fo =K jk nj ul nd hq= h
9
1 4 rEmh uacuteuacuteO ksh WIaKajj sect (a) mszligudj (V) iuOtilde (b) 1 V iuOtilde
mSvkfha fjkia ugraveu
14 (b) rEmh u` ska P g tosrsfhka ys miadrh ksrEmKh fotilde th uQ laIHh yryd hk
ir ffrac34Ldjls fndhsa uacuteiska lrk o mIacutelaIKjg wkqj nd kakd o fuu miadr
u` ska jdhqjg bylt iiumlmSvHdjla wes nj mudKdaulj fmkajd foa tkiuml fok o
jdhq ialkaOhla iiumlmSvkh llt uacuteg tl u mudKhlska wes wKq ixLHdj l=vd mszligudjla
=lt mesffrac34 fiuml wkqj bylt mSvkj sect jdhqj gtkajh jeauml fotilde
igyk fok o jdhqjl gtkajh d ialkaOh m o mszligudj v o jk uacuteg d = ioacutelrKfhka
fok nj wms oksuq tuksid ksh WIaKajfhasect
hkqfjka suacuteh yels h
1 3 ksoiqk
ksh WIaKajhla hgfa wes okakd jdhq ujq mudKhl mszligudj fo =K llt uacuteg
mSvkfha isyuml jk fjkia ugraveu Kkh lrkak
uacutei`yumlu V1 =V V2 = 2V P1 = P P2 = fndhsa kshuh fhsectfuka P1V1 = P2V2
P times V = P2 times 2VP2 = P 2 there4kj mSvkh uqa mSvkfhka wvla fotilde
10
1 4 ksoiqk
ldur WIaKajfha sect neumlkhla yhsvcka jdhqj okakd mudKhlska mqrjd we jdhqf daSh
mSvkfha sect (100 kPa) tu jdhq mudKh 2 50 dm3 l mszligudjla kS tu WIaKajfha sect u
we=lt mSvkh 20 kPa ugraveug neumlkfha mszligudj fldmuK uacuteh llt hq= o
uacutei`yumlu P1 = 100 kPa P2 = 20 kPa V1 = 2 5 dm3 V2 = fndhsa kshuh fhsectfuka P1V1 = P2V2
100 kPa times 2 5 dm3 = 20 kPa times V2 there4V2 = 12 5 dm3 neumlkfha mszligudj 12 5 dm3 olajd jeauml llt hq= h
123 pdaia kshuh (WIaKaj-mszligud iiumlnkaOh)cdlaia pdaia iy fcdaIma f a-umliela hk uacuteoHdhkaf a yeoEIacuteiuml u ska fmkajd sect wes mszligEgrave
ksh mSvkhl sect fok o ksH jdhq mudKhl ^ialkaOhamp mszligudj WIaKajha iu`
jeauml jk wr isisa lsIacuteua iu` wvq fotilde tfuka u WIaKajfhA isyuml jk ieu fiaishia
wxYlhl fjkila mdid ^jeauml ugraveu fyda wvq ugraveuamp mszligudj 0degC sect jdhqfotilde wdriumlNl mszligudfjka idOlhlska fjkia jk nj ^jeauml ugraveu fyda wvq ugraveuamp fidhd f k we
0 degC sect iy t degC ys sect jdhqfotilde mszligudj msltsfjltska V0 iy Vt hhs Wmlamkh lruq tuacuteg
fuu aajfha sect WIaKajh i`oyd kj mszligudKhla wfrac34 olajd we tuacuteg tu mszligudKhg
wkqj
t degC i`oyd Tt = 273 15 + t uOtildeska nd fok wr
0 degC i`oyd T0 = 273 15 uOtildeska nd fohs
fuu kj WIaKaj mszligudKh flauacuteka WIaKaj mszligudKh (K) fyja ksrfmalaI WIaKaj
mszligudKh fi ye`Egravekafotilde ndash 273 15 degC (0 K) hkak dm sl Y+kHh fi wfrac34 oelafjk
wr th ffioaOdkaslj lt` d uacuteh yels wju WIaKajh fotilde
fmdyumlfotilde a uacuteg ksh mSvkfha sect (V1 T1) isg (V2 T2) olajd isyuml jk fjkila i`oyd
11
tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg
wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde
jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys
WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg
yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h
PV = nRTV = nRT P
ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde
zwnjzwnjzwnjzwnjV prop T fyda V = kT
pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka
WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd
Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect
ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh
lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34
15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde
uacutepkh
12
1 5 ksoiqk
ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml
jk WIaKaj fjki Kkh lrkak
uacutei`yumlu
T1 = T V1 = V V2 = 3V T2 =
T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh
wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h
hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi
efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg
lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr
kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde
1 6 ksoiqk
23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde
tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki
Kkh lrkak
uacutei`yumlu
T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =
jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka
V2 = 2 03 dm3
mszligudfotilde isyumljk fjki = 0 03 dm3
124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=
jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj
lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla
hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)
fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h
13
jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda
kshh (NA fyda L) fi ye|skafotilde
my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka
wjfndaO lr yels h
fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl
u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud
follg by iiumlnkaOdj fhsectfuka
P iy T ksh uacuteg sect (R iy NA kshhka fotilde )
irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud
=lt iudk wKq ixLdjla wvx= fotilde (V α N)
by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd
mszligmQfrac34K jdhq ioacutelrKh nd yels h
by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka
k = R jQ uacuteg
P V = n R T
14
125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka
fi wmg suacuteh yels h
iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd
mszligudj (Vm) tl u w hla uacuteh hq= ksid th
fi Kkh llt yels h
tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u
mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34
bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu
aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj
22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi
ksrEmKh flffrac34
bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde
fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde
igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde
V = k n = k (m M) tneuacuteka M = k (m V) = k d
1 7 ksoiqk
298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud
iudk nj fmkajkak
uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe
VHe = nHeRTHe PHe
VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3
15
PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =
PNeVNe = nNeRTNe
VNe = nNeRTNe PNe
VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa
VNe = 24 4 dm3
tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq
wa lr kakd mszligud iudk fotilde
126 ixhqla jdhq kshuh
jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj
tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka
T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla
fi suacuteh yels h
fuh ixhqla jdhq kshuh fi ye|skafotilde
1 8 ksoiqk
25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o
uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh
P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3
T1 = 25 + 273 = 298 K
V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =
P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa
16
13 fvdaagkaf a wdxYsl mSvk kshuh
fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm
yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk
wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml
ishuml jdhq odhl fotilde
jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj
wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde
ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla
iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs
fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh
fi yeEgravekafotilde
A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska
PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde
my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka
jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha
we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh
PT hehs o isuq
PV = nRT
A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )
B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )
jdhq ntildeYKh i`oyd nT = PTV RT
iy nT = nA + nB
tu ksid PTV RT = (PAV RT) + (PBV RT)
iq`M llt uacuteg PT = PA + PB
fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl
131 ujq Nd h wkqidrfhka wdxYsl mSvkh
T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq
ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde
fvdaagkaf a kshuhg wkqj PT = PA + PB
PA iy PB mldYk fjk fjk u PT jska fnsectfuka
17
tu ksid
fi suacuteh yels h
hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk
fotilde
1 9 ksoiqk
(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla
tla jdhqfotilde wdxYsl mSvkh Kkh lrkak
(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd
lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq
ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak
uacutei`yumlu
18
fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK
u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd
fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj
tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla
fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re
uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq
irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq
efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj
u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk
nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja
ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj
mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=
jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes
lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect
tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh
wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K
jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl
1 10 ksoiqk
my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs
iskak
2KClO3(s) rarr2KCl(s) + 3O2(g)
27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute
27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh
Kkh lrkak
uacutei`yumlu
fvdaagkaf a kshuhg wkqj
Piuia = PTlaiscka + Pch
PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa
mszligmQfrac34K jdhq ioacutelrKh fhsectfuka
14 jdhq msltsn`o pdl wKqljdoh
by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(
fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks
mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla
nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka
uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml
jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh
llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad
fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd
fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj
yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde
19
141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde
wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd
uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr
wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS
wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh
u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka
gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska
jdhqj bylt iiumlmSvHdj meyeEgraves fotilde
bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu
jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO
wKqjg uacuteuacuteO fotilde mjS
fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg
ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash
jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk
ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde
bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS
fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq
wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj
fuu ska mldY flffrac34
fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh
mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt
uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka
jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr
iiumlnkaOdjh my ioacutelrKfhka nd foa
jyumlrga my oelafjk lreKq plusmnlauacuteh yels h
bull jdhq wxY= tlsfklska iajdhaj yeisffrac34
jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska
iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda
fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj
wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml
Wmlamkfhka meyeEgraves fotilde
bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla
u` ska mSvkhla wes fotilde
fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect
ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl
isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug
20
fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml
jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq
ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj
jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml
fotilde
142 pdl wKqljdofha ioacutelrKh
my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla
fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34
by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes
wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka
wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34
uOHkH fotilde h fi wfrac34 olajkq efiacute
143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h
my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu
jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg
jfrac34 uOHkH uQ fotilde h fotilde
jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla
jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=
Kkla i`oyd ioacutelrKh ild nuq
N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)
PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka
21
tu ksid jfrac34 uOHkH uQ fotilde h
fi suacuteh yels h
1 11 ksoiqk
25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak
uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1
by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj
fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama
lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml
pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh
u` ska th my oelafjk mszligEgrave idOkh llt yels h
fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt
yel
kB hkq fndaaUumliaudka kshh fotilde
22
wKqjla i`oyd
ujqhla i`oyd
fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq
fotilde
144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml
N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag
pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq
efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave
mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes
lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde
jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash
fi ye|skafotilde
16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--
fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd
fotilde jHdmash
23
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka
wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea
jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd
idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute
ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr
^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17
rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla
i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34
17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj
iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha
sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka
daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh
17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd
Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir
ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla
mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy
ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh
yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr
jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml
ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej
jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla
fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh
fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs
17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska
o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska
daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka
iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk
wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh
hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd
mszligudj (V)
mSvk
h (
P)
24
jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj
o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga
meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg
jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke
fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka
lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS
jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru
ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml
yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj
sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK
n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde
mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd
laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect
(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g
jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda
ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel
jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt
WIaKaj fotilde
daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o
WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel
fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg
jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml
fuh mltuq ioacutelrKfha wdfoaYfhka
fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH
ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk
nj wmg fmfka
fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh
pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we
tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj
hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h
mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq
wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt
jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect
jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia
PV mszligmQfrac34K
daauacutel
25
jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq
wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka
yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=
h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka
wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel
jdhq mszligmQfrac34K aajfhka wm ukh fotilde
151 jeka vrsquo jdaia ioacutelrKh
fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa
sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K
jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk
wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq
mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel
jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid
daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH
fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj
iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk
Egrave
bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka
kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka
mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka
igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash
iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg
fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh
mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde
1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj
ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh
by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK
fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde
gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq
mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde
fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg
iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq
msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect
moaOsfha mSvkh my mldYkfhka nd fohs
26
bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL
fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr
tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk
mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka
wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks
fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq
kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh
fi kej suacuteh yels h
fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh
fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql
nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia
flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha
wkafrac34--mszligjfrac34kh l yels fotilde
ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs
wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj
yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde
igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys
sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde
ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha
lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh
iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla
fi o yeisszligh yels ugraveu h
bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla
oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi
mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS
30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc
oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi
muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu
WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla
oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde
( )2
aP V b RTV
+ minus =
27
19 rEmh CO2 j ldm igyk
1 3 j =j - ioacutelrK idrdxYh
jdhq kshuh intildelrKhksh j mjsk
idOl
mszligmQfrac34K jdhq kshuh PV = nRT ke
fndhsa kshuh n iy T
pdaia kshuh V = kT n iy P
wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T
wKql pdl ioacutelrKh
idudkH fotilde h
jfrac34 uOHkH fotilde h
jfrac34 uOHkH fotilde h
fvdaagkaf a wdxYsl mSvk
kshuh
PA = xA PT
PT = PA + PB + PC
iiumlmSvHd idOlh jdhq ujq 1la i|yd
jeka vZjdaia ioacutelrKh
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
vii
mgqk
wOHCI ckrda=ntildehfa mKsuacutevhhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip iii
wOHCI=udfa mKsuacutevhhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip iv
uacuteIhudd lntildegqj helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip v
04 tallh - modfrac34fha jdhquh wjiadjhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip01-27
11 modfrac34fha wjiad =fkys wxY= ieleiau iy tajdfha ofrac34YSh CIK helliphelliphelliphelliphelliphellip02
12 jdhquh wjiadj helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip05
121 jdhq kshu
122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)
123 pdaia kshuh (WIaKajndashmszligud iiumlnkaOh)
124 wejdacircfrda kshuh (mudK-mszligud iiumlnkaOh)
125 ujqsl mszligudj (Vm)
126 ixhqla jdhq ioacutelrKh
13 fvdaagkafa wdxYsl mSvk kshuh helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip16
131 ujq Ndh wkqidrfhka wdxYsl mSvkh
14 jdhq msltsn`o pdl wKqljdoh helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip18
141 pdl wKqljdofha mszligmQfrac34K jdhqjla i|yd Wmlamk
142 pdl wKqljdofha ioacutelrKh
143 jfrac34 uOHkH uQ fotildeh iy uOHkH fotildeh
144 ueialafja-fndaaUumliaudka jHdmash
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh helliphelliphelliphelliphelliphellip23
151 jeka vrsquojdaia ioacutelrKh
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
05 tallh - Ylas uacuteoHdjhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip28-54
21 dm-ridhksl uacuteoHdfotilde yd dms uacuteoHdfotilde uQsl mo helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip29 211 moaOsh jgmsgdj yd iSudj 212 moaOs jfrac34
213 moaOshl =K
214 moaOshl wjiadj
215 tkaeamsh (H)
216 dmh
22 uacuteuacuteO dm-ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd helliphelliphelliphelliphelliphelliphellip34
iiumlu tkaeams uacutemfrac34hdi 221 dmodhl yd dmdjfYdaIl lshdjs
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh
23 oesi tkaeamsh fyja whksl ixfhdahl Wamdok tkaeamsh(helliphelliphelliphelliphelliphelliphelliphellip47 fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj ridhksl mslshdjl iiumlu helliphelliphelliphellip49
tkafgdms fjki siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
1
wkafrac34 h
1 1 modfrac34fha wjiad =fkys wxY= ieleiau
iy tajdfha ofrac34YSh CIK
1 2 jdhquh wjiadj
1 2 1 jdhq kshu
bull mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq
ioacutelrKh
bull mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ
Kkh lsIacuteiuml
1 2 2 fndhsa kshuh
(mSvk-mszligud iiumlnkaOh)
1 2 3 pdaia kshuh
(WIaKajndashmszligud iiumlnkaOh)
1 2 4 wej dacircfrda kshuh
(mudK-mszligud iiumlnkaOh)
1 2 5 ujqsl mszligudj (Vm)
1 2 6 ixhqla jdhq ioacutelrKh
1 3 fvdaagkaf a wdxYsl mSvk kshuh
1 3 1 ujq Nd h wkqidrfhka
wdxYsl mSvkh
1 4 jdhq msltsn`o pdl wKql jdoh
1 4 1 pdl wKql jdofha mszligmQfrac34K jdhqjla
i|yd Wmlamk
1 4 2 pdl wKql jdofha ioacutelrKh
1 4 3 jfrac34 uOHkH uQ fotilde h iy
uOHkH fotilde h
1 4 4 ueialafja--fndaaUumliaudka jHdmash
1 5 daauacutel jdhqjg eltfmk mszligEgrave
mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
1 5 1 jeka vrsquojdaia ioacutelrKh
1 5 2 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
1 modfrac34fha jdhquh
wjiadj
2
ye|skaugraveu
uacuteYajfha wes ishiquest oE iquacutefYaIS ridhksl wkkHdjlska hqla h modfrac34fha l=vdu wxY=j
mrudKqj nj wms oksuq irj oelajqjfyda ridhk uacuteoHdj hkq ldquomodfrac34h iy tys isyumljk
uacutemfrac34hdi msltsn|j wOHkhrdquo fi wfrac34 oelauacute h yel modfrac34h hkq wjldYhla wama
lr kakd ialkaOhla iys acutekEu fohla jk wr th oelsh yels yd weaSug yels
^mia ch wdsectamp fohla fi fuka u jdh jeks wmg fkdfmfkk fohla o uacuteh yel
ixhqsh yd =K mokiuml lr f k oslashjH ntildeYK uQoslashjH fuka u mrudKq iy wKq wdsect uacuteuacuteO
wdldr fuys sect y`yumlkd yels h ishiquestu oslashjH gtk oslashj iy jdhq fig wvqu rntildeka uQsl
wjiad =klska mejsh yels h gtkhl sect wxY= =ltska ne`oS tlsfklg lsUumlgqj lsishiuml
ksYaNtilde jHqyhlg ksYaNtilde yevhla iysj weisIacuteu ksid tajdg pkh ugravefiuml yelshdj wvq
h oslashjhl wxY= tlsfklg lsUumlgqj wea tlsfklg iadkShj bd Egraveka ne|S kes neuacuteka
ikaikaokdaulj gtkhl sect g jvd fotilde fhka pkh uacuteh yels h wxY= wr yumlr wkqj
oslashj yd gtkjg jvd jdhq fndfyda fjkia fotilde jdhqjlsect wxY= tlsfklska fjka ugrave wes yumlr
wxY=jl mudKhg ikaikaokdaulj uacuteYd ugraveu fya=fjka wxY=jg ksoyfia yeisIacuteug
bv we tneuacuteka jdhq wxY= wr wdlfrac34Yk n bd l=vd fyda fkd sksh yels riuml ugraveu
fya=fjka wmg jdhq wxY= fjka fjka j ielsh yels neuacuteka WIaKajh yd mSvkh u
mokiuml jQ iuyr lams myiqfjka mqfrdalkh llt yels fotilde
11 modfrac34fha mOdk wjiad =fkys wxY= ieleiau iy tajdfha ofrac34YSh CIK
wjldYfha bvla kakd ialkaOhla iys acutekE u fohla zmodfrac34hZ fi ye`Egravekauacuteh yels h
wmg plusmnlsh yels wska weash yels yfldlt fia u wm fkdolsk tfya yqiau kakd
jdh o oacuteg wha h mq`Ma jYfhka a l ishuml modfrac34h gtk oslashj yd jdhq hkqfjka
wjiad =klg jfrac34 SlrKh llt yels h ixhqsfhys fjkia ugraveulska fdrj modfrac34h fiuml
suacuteO wjiad wr tllska wfklg mszligjfrac34kh llt yels h ksoiqkla fi( oslashj wjiadfotilde
mjsk ch ra lsIacutefuka jdhq wjiadjg (yqudh) mszligjfrac34kh llt yels wr isisa
lsIacutefuka gtk wjiadjg ^whsiaamp ma llt yels h
gtk
^Wod( hlv weKhamp
iaOacuter yevhla yd
mszligudjla we
oslashj
^Wod( champ
iaOacuter yevhla
kes kuqa iaOacuter mszligudjla we
jdhq
^Wod( ySshiuml neAEligkamp
iaOacuter yevhla fyda
iaOacuter mszligudjla fyda ke
gtk
wxY= ^mrudKq wKq fyda whkamp
wr wdlfrac34IK n mn h
wxY= liumlmkh jk kuqa
eklska eklg
pkh fkd fotilde
oslashj
wxY= ^mrudKq wKq fyda whkamp
wr wdlfrac34IK n triuml
mn fkd fotilde wxY=jg hiuml
mudKhlg eklska eklg
pkh uacuteh yels h
jdhq
wxY= ^mrudKq wKq fyda whkamp
wr wdlfrac34IK n yumln h
wxY=jg eklska eklg
pkh uacuteh yels h
11 rEmh modfrac34fha suacuteO wjiad
wxY=j ieleiafuka yd psfhka modfrac34fha suacuteO wjiad tlsfklska fjkia fotilde
wkafrac34currenwxY= wr yumlr jdhq wjiadfotilde wecircl jk wr gtk wjiadfotilde sect th wju fotilde jdhq
wjiadjg idfmalaIj oslashj wjiadfotilde sect wxY= tlsfklg ioacutem jk wr th gtk wjiadfotilde
3
sect riuml tlsfklg ioacutem o fkd fotilde tneuacuteka luja j ixuacuteOdkh jQ wxY=uh rgdjla plusmnlsh
yelafla gtk wjiadfotilde muŒ oslashj yd jdhq wjiad foflys sect u wxY= ieliS weafa wyUq
fi h fuys msMhla fi oslashj wjiadfotilde wes wxY=jg idfmaalaIj jdhq wjiadfotilde
wes wxY=jg jvd fotilde fhka yd ksoyia fi pkh uacuteh yels h flfia jqj o gtkj
wes wxY=j psh liumlmkjg muKla iSud fotilde my 11 j =fjka plusmnlafjk mszligEgrave
modfrac34fha wxY=j ieleiau yd tys psh mszligudj yevh iiumlmSvHdj yd gtkajh jeks
ufyaalaI =Kj fjkialiumljg =vq fohs
1 1 j =j gtk oslashj yd jdhq j =Kj =Kdaul ixikaokh
=Kh gtk oslashj jdhq
yevh ksYaNtilde h wvx = n`yumlfkys
yevh kakd uqa
n`yumlfkys uq`M mszligudj
mqrd fkd mesfrhs
n`yumlfkys yevh
kakd wr
n`yumlfkys iuia
mszligudj wa lr kS
mszligudj ksYaNtilde h ksYaNtilde h wvx = n`yumlfkys
mszligudj wa lr kS
gtkajh (ρ) g cm-3 (293 K sect)
bylt w hka kS
Wod( hlv
(7 874 g cm-3)
rula bylt w hka
kS
Wod( ch
(0 997 g cm-3)
w hka mylt h
Wod( yhsvcka
(0 071g cm-3)
iiumlmSvHdj iiumlmSvkh lsIacuteu
bd yumlIalr h
iiumlmSvkh lsIacuteu bd
yumlIalr h
fnfyuacuteka iiumlmSvkh
llt yels h
igyk ( oslashj wvx = n`yumlfkys yevh kakd nj wm i`oyka lr wes wr tfia jkafka
ukaoehs issh hq= h idudkHfhka acutekE u jia=jla wkafrac34-wKql n jeks uacuteuacuteO jfrac34 fha
n u` ska tlg ne| nd kakd neuacuteka thg ksYaNtilde yevhla we icirclrhl wes fok o
c mudKhla ^mszligudjlaamp hiuml yevhla kafka mDIaAgravel wdsh ksid h oslashjh =lt mjsk
wkafrac34-wKql n ksid mDIaGh flltjffrac34 l=vd oslashj udjlhla wes fotilde icirclrfha igraveas u` ska
oslashjh u byltg aumljla wes flfrk wr mDIaAgravel wdshg jvd jeauml =reajc nh
u` ska myltg weoSula wes fotilde tuksid oslashjh byltska iu mDIaGhla iysj icirclrfha
yevh kS fufia jkafka fuu uacuteuacuteO jfrac34 fha ishuml nj nmEu ksid h flfia jqj
o mDIaAgravel wdsh =reajc nhg jvd mn jQjd kiuml cfha mDIaGh iu fkdjk
wr n`yumlfka yevh fkd kq we =reajc nhla keehs is=j fyda mDIaAgravel wdsh
fndfyda fihska bylt hhs mDIaGfha tla tla fldgilg u wfkla mDIaGh iu` yels riuml
ltx ugrave mejSug wjYH ksid tajd wr wes wdlfrac34IK wju lr ekSug fmfograve tneuacuteka
fok o mszligudjl wju mDIaAgravel lafIaMhla wes fyd`o u yevh jk f dadldr yevh
kS
ralsrSfuka fyda isiskfhka tla wjiadjl mjsk modfrac34h ja wjiadjlg mszligjfrac34kh
llt yels h WIaKajh jeauml lsIacutefiuml sect wxY=j pk fotilde h bylt hEua wxY= wr yumlr jeauml
ugraveua lrK fldg modfrac34j wjiadj fjkia fotilde ta wkqj WIaKajh jeauml lsIacutefiuml sect gtk
wjiadfotilde wes oslashjH oslashj wjiadjga oslashj wjiadfotilde wes oslashjH jdhq wjiadjga ma fotilde
WIaKajfha wvq ugraveua iu isyuml jkafka fuys uacutefdauhhs my 12 rEmfhka modfrac34h tys
wjiad wr wkafrac34-mszligjfrac34khg Ndck llt yels wdldrh fmkakqiuml flffrac34
4
12 rEmh modfrac34fha wjiad wr wkafrac34-mszligjfrac34kh
11 ksoiqk
wxY= jvda u ioacutem fi iamfrac34Y jkafka ugrave kuqa tajd wyUq fi weysIacute weafa modfrac34fha
ljr kiuml wjiadfotilde o
uacutei`yumlu oslashj wjiadj
11 j =jg wkqj wm modfrac34fha mOdk wjiad =fkys =K uacuteiar lrk uacuteg wxY=j ieliqu
yd pkh uQslj ild nd we uacutefYaIfhka u hiuml oslashjHhl wes wKq fyda mrudKqj
pkh ksid yg kakd Ylash dmc Ylash jk wr th oslashjHfha WIaKajhg wkqfdauj
iudkqmdsl fotilde tu` ska modfrac34fha wes wxY=j uOHkHh pdl Ylash uefkk neuacuteka
th wxY=j pkh fyda dmc psh i`oyd fya= fotilde
wkafrac34-wKql n u` ska wKq tlsfklg ltx ugrave mejSug fmfUk nj wm oekgua
okakd kuqa wKqj dmc Ylash u` ska wKq tlsfklska wEa ugraveug fmfograve ta wkqj
modfrac34fha mOdk wjiad =fkys mejSu wKqj wkafrac34-wKql n iy dmc Ylash
wr iu=sfhys msMhla fi ielsh yels h
wkafrac34-wKql wdlfrac34IK bd yumln jk uacuteg WIaKajh wvq lsIacutefuka dmc Ylash WIaKajhamp
wvq fkdllt fyda wKq oslashj fyda gtk fyda fi mejSug fkd fmfograve wKq tlsfklg
bd lt` ska wes uacuteg iy wkafrac34 - wKql n Wmszliguj wes uacuteg mjd iiumlmSvkh u` ska muKla
jdhq oslashj wjiadjg ma fkd fotilde flfia jqj o WIaKajh wvq lsIacuteu u` ska wKqj dmc
Ylash wvq jk uacuteg jdhq bd myiqfjka oslashj llt yels h fiuml yeisIacuteiuml my 1 3 rEmfhka
meyeEgraves llt yels h modfrac34fha mOdk wjiad =k flfrys wkafrac34-wKql nj yd dmc
Ylasfha msuacutereoaO nmEfiuml iajNdjh wmg tu` ska wjfndaO lr yels h
5
13 rEmh wkafrac34-wKql n yd dm Ylash wkqj modfrac34fha mOdk wjiad
=fkys yeisIacuteu
modfrac34fha mOdk wjiad =kla mejSug fya=j wm oekgua yodrd we oeka wm
modfrac34fha jdhquh yeisIacuteug fya= jk jdhq kshu iy jdhquh wjiAdj msltsn`o j yumlrga
ild nuq
12 jdhquh wjiadj
oeka wm idudkH WIaKaj mSvk aaj hgfa wes jdhquh wjiadfotilde mjsk oslashjHj
yeisIacuteu flfrys wjOdkh fhduq lruq
11 j =fotilde uacuteiar lr wes mszligEgrave jdhquh wjiadj my i`oyka fNsl =K wkqj uacuteiar
flffrac34
bull jdhq bd iiumlmSvH fotilde
bull jdhq ieu EgraveYdjlg u iudk whqszligka mSvkh wes lrhs
bull jdhqjg gtk iy oslashjjg jvd wvq gtkajhla we
bull jdhqj yevh iy mszligudj ksH fkd fotilde tajd wvx = Ndckfha yevh iy mszligudj
kS
bull jdhq lsis u hdkasl nmEulska fdrj iiumlmQfrac34Kfhka u iy iudkj tlsfkl
iuOtilde ntildeY fotilde
jdhqjl irdjhg fya= jkafka tu wKq wr mjsk n fkd ssbquoh yels ugraveuhs tajdfha
yeisIacuteu mIacutelaIKdaul wOHhkhkaf ka nd a msM u` ska fidhd kakd o fmdyuml jdhq kshujg (miqj idlEacutePd flffrac34iexcl) wkqj isyuml fotilde fiuml jdhq kshu hkq jdhqjl ueksh
yels =K wr mjsk iiumlnkaOd fotilde ueksh yels =K iuyrla jk mSvkh mszligudj
WIaKajh iy mudKh ^ujq fyda ialkaOhamp jeks tajd bd jeo a jkafka fiuml uacutepH
wr mjsk iiumlnkaOd jdhqjl mOdk wjiad (5 jk tallfha sect wfrac34 olajkq efiacuteiexcl) uacuteiar lrk ksid h tlsfkl yd ne`yumlKq fiuml uacutepHhka jdhq kshu iQ lsIacuteug uQsl
ugrave we
121 jdhq kshu
wm idlEacutePd lsIacuteug hk jdhq kshu uacuteoHdhka lsysm fokl= uacuteiska jdhqj fNsl =K
mokiumlj isyuml lrk o mIacutelaIKjska nd a msM fotilde mSvkh WIaKajh mszligudj iy
jdhq mudKh hk uacutepH wr mjsk iiumlnkaOd fuys sect ild nk wr tajd u` ska
6
modfrac34fha jdhquh wjiadj msltsn`o udkj jfrac34 hdg mfhdackja jk fdr=re rdYshla
mldY fotilde
mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq ioacutelrKh
jdhq wKq wr wkafrac34-wKql n fkdues nj Wmlamkh flffrac34 o tndivide jdhqjla mszligmQfrac34K
jdhqjla fi ye`Egravekafotilde tkiuml mszligmQfrac34K jdhqjl wKq wr wdlfrac34IK fyda uacutelfrac34IK fyda
n fkd mjS tfuka u jdhqj oud wes Ndckfha mszligudj iu` ieipoundfiuml sect jdhq wxY=jl
mszligudj fkdild yeszligh yels h
jdhqjl ksrfmalaI WIaKajh (T) mSvkh (P) mszligudj (V) iy oslashjH mudKh ^n ujqamp
jdhquh yeisIacuteu flfrys nmdk idOl fotilde P T V iy n wr iiumlnkaOdj my
mldYkfhka ksrEmKh flffrac34
fuh mszligmQfrac34K jdhq ioacutelrKh fyda mszligmQfrac34K jdhq kshuh fi oelafjk wr R hkq ieu
jdhqjlg u fmdyuml w hla wes jdhq kshh fotilde fok o acutekE u WIaKajhl sect yd
mSvkhl sect by iiumlnkaOdjg wkql+j yeisfrk acutekE u jdhqjla mszligmQfrac34K jdhqjla fi
y`yumlkajkq efiacute
fuu aaj hgfa oS mszligmQfrac34K jdhq ujq 1 la i|yd 0 degC sect yd 1 atm sect R kshfha w h
my wdldrhg Kkh l yel (0 degC sect yd 1 atm yssect mszligmqfrac34K jdhqjl 1 mol l mszligudj
22 414 dm3 fotilde)
mszligmQfrac34K jdhq ioacutelrKh by uacutepH yr wr wes iiumlnkaOdj jk nj wmg fmfkk
wr acutekE u jdhqjl wjiadj tuOtildeska uacuteiar flfrk ksid th wjiad ioacutelrKh fi
o ye|skafotilde
mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ Kkh lsIacuteiuml
mszligmQfrac34K jdhq ioacutelrKh u` ska wmg mszligudj WIaKajh mSvkh fyda ujq mudKh hk
tajdhska =kla sect wes uacuteg wfkla rdYsh ksfrac34Kh llt yels h jdhqjl ujq mudKh okakd
uacuteg tys ujqsl ialkaOh Nduacutefhka tys ialkaOh o Kkh llt yels h tfuka u
tu` ska jdhqjl gtkajh o ksfrac34Kh llt yels h mszligmQfrac34K jdhq kshfha w hg eltfmk
mszligEgrave wfkl=a rdYsj tall Nduacute lsIacuteu bd jeo a jk nj ul nd hq= h
idudkHfhka mSvkh atm Pa bar torr jeks tall jska mldY llt yels h tneuacuteka fiuml
eguml uacutei`oSfiuml sect my 1 2 j =fotilde sect wes mSvk tallj mszligjfrac34k Tng Wootilde jkq we
12 j =j mSvkh i`oyd jk tall
mSvk tallh Pa bar atm torr mmHg
1 Pa 1 N m-2 10-5 9 87 times 10-6 7 5 times 10-3
1 bar 100000 1bar 0 987 750 061 atm 101325 1 01325 1 atm 7601 torr mmHg 133 32 1 3332 times 10-3 1 3158 times 10-3 1 torr 1 mmHg
7
12 ksoiqk
jdhq isskavrhl mszligudj 0950 dm3 fotilde hiuml mSvkhla hgfa sect fiuml isskavrh oslashj
fmdfmakajska (C3H8) msIacute we isskavrh ysia jQ uacuteg jdhqf daSh mSvkh yd WIaKajh
hgfa sect tys fmdfmaka jdhqj hiuml mudKhla bsszlig fotilde
(i) wjg mszligirfha aaj 25degC iy 750 torr (1 torr = 133 52 Pa) kiuml isskavrh
ysiaj wes uacuteg tys bsszlig ugrave wes fmdfmaka jdhq ujq mudKh fldmuK o
(wNHkar mSvkh ndysr mSvkhg iudk uacuteg oS)
(ii) isskavrfha bsszlig ugrave wes fmdfmaka jdhq ialkaOh Kkh lrkak
(iii) isskavrfha bsszlig ugrave wes fmdfmaka jdhqfotilde gtkajh Kkh lrkak
uacutei`yumlu (i) mltuqj sect wes fdr=re iudfdapkh lrkak
WIaKajh T = (25 + 273) K = 298 K mSvkh P = 750 torr times 13332 Pa 1 torr = 99990 Pa mszligudj V = 0 950 dm3 = 0 950 times 10-3 m3
n fkdokakd moh fotilde
PV = nRT Nduacutefhka
(ii) fmdfmakays (C3H8) ujqsl ialkaOh = 44 g mol-1
fmdfmakays ialkaOh = 0 038 mol times 44 g mol-1 = 1 672 g
(iii) fmdfmakays gtkajh = ialkaOh mszligudj = = 1 76 g dm-3
by ksoiqk iel+ uacuteg mszligmQfrac34K jdhq kshuh uacuteuacuteO wdldrjska bEgraveszligma llt yels nj
fmkS hk wr my oelafjk mszligEgrave ir fjkia lsIacuteulska fok o jdhqjl ialkaOh
iy gtkajh fiuacuteh yels h
PV = nRT
P = RT
zwnjzwnj P = CRT
fuys zC Zhkq idkaoslashKhhs
j o PV = nRT iiumlnkaOdj my mszligEgrave o mldY llt yels h
PV = RT
fuys m hkq ialkaOh jk wr M hkq jdhqfotilde ujqsl ialkaOhhs
P = RT fi o suacuteh yels h
8
gtkajh (d) =
there4 P =
uacutefYaIs aaj hgfA fjka jdhq kshu jHqamkak lsIacutefiuml sect mszligmQfrac34K jdhq kshuh uQsl
moku fi lshd lrhs
122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)mdashksh WIaKajhla hgfa wes iaOacuter jdhq mudKhl (ialkaOhl) mSvkh jdhqfotilde mszligudjg
msfdauj uacutepkh fotilde (fyda iudkqmdsl) fotilde˜ fndhsa kshuh hkqfjka ye`Egravekafjk
fuh tfia kiuml lrk oafoa 17 jeks ishjfia sect WIaKajh ksh jQ aaj hgfa fjkia
jk mSvkha iu jdhqjl mszligudj uacutepkh jk wdldrh whsszligIa cdsl uacuteoHdhl= jQ
frdnUuml fndhsa (1627- 1691) uacuteiska wOHhkh lsIacutefuka miqj h tys Ksuh wdldrh
my oelafotilde
my plusmnlafjk mszligEgrave fndhsa kshuh jHqamkak lsIacuteu i`oyd mszligmQfrac34K jdhq kshuh fhdod
yelsh PV= nRT
jdhqfjys mudKh yd moaOsfhys WIaKajh kshj mjajd kakd oafoa kiuml nT =Ksh
kshhla fotilde R o kshhla jk neuacuteka nRT =Ksh o kshhla (k) fotilde
PV = k (kshhla)
tkiuml ksh WIaKajfha sect ksh jdhq mudKhl mSvkfhaa mszligudfotildea =Ksh kshhla
fotilde fuh fndhsa kshuh mldY lrk fjka wdldrhls
ksh T WIaKajhl wes ksh jdhq mudKhl mszligudj V1 o mSvkh P1 o kiuml yd th V2
mszligudjg yd P2 mSvkhg ma llt uacuteg fndhsa kshuhg wkqj
14 rEmh u` ska fndhsa kshufha idiumlmodhsl miadszligl ksrEmK folla fmkakqiuml flffrac34
14 rEmfha (a) u` ska ixikaokh i`oyd uacuteuacuteO WIaKajj sect PV = k miadr lr we
k w h WIaKajh u muKla r`od mjsk ksid fok o jdhq ialkaOhla i`oyd w`Egravek
o ieu jlhla i`oyd u k ys w h tlsfklg fjkia fotilde bylt WIaKajj sect mszligudfotilde
midrKh ksid plh byltg f dia wes nj ielsh hq= h tfuka u WIaKajh ksh
uacuteg jdhqfotilde mSvkh wvla jk uacuteg mszligudj fo =K jk nj ul nd hq= h
9
1 4 rEmh uacuteuacuteO ksh WIaKajj sect (a) mszligudj (V) iuOtilde (b) 1 V iuOtilde
mSvkfha fjkia ugraveu
14 (b) rEmh u` ska P g tosrsfhka ys miadrh ksrEmKh fotilde th uQ laIHh yryd hk
ir ffrac34Ldjls fndhsa uacuteiska lrk o mIacutelaIKjg wkqj nd kakd o fuu miadr
u` ska jdhqjg bylt iiumlmSvHdjla wes nj mudKdaulj fmkajd foa tkiuml fok o
jdhq ialkaOhla iiumlmSvkh llt uacuteg tl u mudKhlska wes wKq ixLHdj l=vd mszligudjla
=lt mesffrac34 fiuml wkqj bylt mSvkj sect jdhqj gtkajh jeauml fotilde
igyk fok o jdhqjl gtkajh d ialkaOh m o mszligudj v o jk uacuteg d = ioacutelrKfhka
fok nj wms oksuq tuksid ksh WIaKajfhasect
hkqfjka suacuteh yels h
1 3 ksoiqk
ksh WIaKajhla hgfa wes okakd jdhq ujq mudKhl mszligudj fo =K llt uacuteg
mSvkfha isyuml jk fjkia ugraveu Kkh lrkak
uacutei`yumlu V1 =V V2 = 2V P1 = P P2 = fndhsa kshuh fhsectfuka P1V1 = P2V2
P times V = P2 times 2VP2 = P 2 there4kj mSvkh uqa mSvkfhka wvla fotilde
10
1 4 ksoiqk
ldur WIaKajfha sect neumlkhla yhsvcka jdhqj okakd mudKhlska mqrjd we jdhqf daSh
mSvkfha sect (100 kPa) tu jdhq mudKh 2 50 dm3 l mszligudjla kS tu WIaKajfha sect u
we=lt mSvkh 20 kPa ugraveug neumlkfha mszligudj fldmuK uacuteh llt hq= o
uacutei`yumlu P1 = 100 kPa P2 = 20 kPa V1 = 2 5 dm3 V2 = fndhsa kshuh fhsectfuka P1V1 = P2V2
100 kPa times 2 5 dm3 = 20 kPa times V2 there4V2 = 12 5 dm3 neumlkfha mszligudj 12 5 dm3 olajd jeauml llt hq= h
123 pdaia kshuh (WIaKaj-mszligud iiumlnkaOh)cdlaia pdaia iy fcdaIma f a-umliela hk uacuteoHdhkaf a yeoEIacuteiuml u ska fmkajd sect wes mszligEgrave
ksh mSvkhl sect fok o ksH jdhq mudKhl ^ialkaOhamp mszligudj WIaKajha iu`
jeauml jk wr isisa lsIacuteua iu` wvq fotilde tfuka u WIaKajfhA isyuml jk ieu fiaishia
wxYlhl fjkila mdid ^jeauml ugraveu fyda wvq ugraveuamp mszligudj 0degC sect jdhqfotilde wdriumlNl mszligudfjka idOlhlska fjkia jk nj ^jeauml ugraveu fyda wvq ugraveuamp fidhd f k we
0 degC sect iy t degC ys sect jdhqfotilde mszligudj msltsfjltska V0 iy Vt hhs Wmlamkh lruq tuacuteg
fuu aajfha sect WIaKajh i`oyd kj mszligudKhla wfrac34 olajd we tuacuteg tu mszligudKhg
wkqj
t degC i`oyd Tt = 273 15 + t uOtildeska nd fok wr
0 degC i`oyd T0 = 273 15 uOtildeska nd fohs
fuu kj WIaKaj mszligudKh flauacuteka WIaKaj mszligudKh (K) fyja ksrfmalaI WIaKaj
mszligudKh fi ye`Egravekafotilde ndash 273 15 degC (0 K) hkak dm sl Y+kHh fi wfrac34 oelafjk
wr th ffioaOdkaslj lt` d uacuteh yels wju WIaKajh fotilde
fmdyumlfotilde a uacuteg ksh mSvkfha sect (V1 T1) isg (V2 T2) olajd isyuml jk fjkila i`oyd
11
tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg
wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde
jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys
WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg
yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h
PV = nRTV = nRT P
ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde
zwnjzwnjzwnjzwnjV prop T fyda V = kT
pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka
WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd
Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect
ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh
lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34
15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde
uacutepkh
12
1 5 ksoiqk
ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml
jk WIaKaj fjki Kkh lrkak
uacutei`yumlu
T1 = T V1 = V V2 = 3V T2 =
T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh
wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h
hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi
efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg
lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr
kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde
1 6 ksoiqk
23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde
tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki
Kkh lrkak
uacutei`yumlu
T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =
jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka
V2 = 2 03 dm3
mszligudfotilde isyumljk fjki = 0 03 dm3
124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=
jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj
lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla
hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)
fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h
13
jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda
kshh (NA fyda L) fi ye|skafotilde
my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka
wjfndaO lr yels h
fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl
u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud
follg by iiumlnkaOdj fhsectfuka
P iy T ksh uacuteg sect (R iy NA kshhka fotilde )
irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud
=lt iudk wKq ixLdjla wvx= fotilde (V α N)
by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd
mszligmQfrac34K jdhq ioacutelrKh nd yels h
by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka
k = R jQ uacuteg
P V = n R T
14
125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka
fi wmg suacuteh yels h
iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd
mszligudj (Vm) tl u w hla uacuteh hq= ksid th
fi Kkh llt yels h
tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u
mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34
bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu
aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj
22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi
ksrEmKh flffrac34
bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde
fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde
igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde
V = k n = k (m M) tneuacuteka M = k (m V) = k d
1 7 ksoiqk
298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud
iudk nj fmkajkak
uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe
VHe = nHeRTHe PHe
VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3
15
PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =
PNeVNe = nNeRTNe
VNe = nNeRTNe PNe
VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa
VNe = 24 4 dm3
tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq
wa lr kakd mszligud iudk fotilde
126 ixhqla jdhq kshuh
jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj
tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka
T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla
fi suacuteh yels h
fuh ixhqla jdhq kshuh fi ye|skafotilde
1 8 ksoiqk
25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o
uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh
P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3
T1 = 25 + 273 = 298 K
V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =
P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa
16
13 fvdaagkaf a wdxYsl mSvk kshuh
fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm
yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk
wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml
ishuml jdhq odhl fotilde
jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj
wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde
ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla
iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs
fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh
fi yeEgravekafotilde
A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska
PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde
my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka
jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha
we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh
PT hehs o isuq
PV = nRT
A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )
B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )
jdhq ntildeYKh i`oyd nT = PTV RT
iy nT = nA + nB
tu ksid PTV RT = (PAV RT) + (PBV RT)
iq`M llt uacuteg PT = PA + PB
fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl
131 ujq Nd h wkqidrfhka wdxYsl mSvkh
T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq
ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde
fvdaagkaf a kshuhg wkqj PT = PA + PB
PA iy PB mldYk fjk fjk u PT jska fnsectfuka
17
tu ksid
fi suacuteh yels h
hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk
fotilde
1 9 ksoiqk
(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla
tla jdhqfotilde wdxYsl mSvkh Kkh lrkak
(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd
lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq
ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak
uacutei`yumlu
18
fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK
u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd
fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj
tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla
fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re
uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq
irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq
efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj
u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk
nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja
ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj
mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=
jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes
lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect
tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh
wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K
jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl
1 10 ksoiqk
my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs
iskak
2KClO3(s) rarr2KCl(s) + 3O2(g)
27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute
27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh
Kkh lrkak
uacutei`yumlu
fvdaagkaf a kshuhg wkqj
Piuia = PTlaiscka + Pch
PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa
mszligmQfrac34K jdhq ioacutelrKh fhsectfuka
14 jdhq msltsn`o pdl wKqljdoh
by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(
fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks
mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla
nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka
uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml
jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh
llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad
fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd
fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj
yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde
19
141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde
wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd
uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr
wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS
wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh
u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka
gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska
jdhqj bylt iiumlmSvHdj meyeEgraves fotilde
bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu
jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO
wKqjg uacuteuacuteO fotilde mjS
fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg
ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash
jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk
ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde
bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS
fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq
wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj
fuu ska mldY flffrac34
fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh
mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt
uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka
jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr
iiumlnkaOdjh my ioacutelrKfhka nd foa
jyumlrga my oelafjk lreKq plusmnlauacuteh yels h
bull jdhq wxY= tlsfklska iajdhaj yeisffrac34
jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska
iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda
fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj
wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml
Wmlamkfhka meyeEgraves fotilde
bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla
u` ska mSvkhla wes fotilde
fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect
ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl
isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug
20
fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml
jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq
ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj
jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml
fotilde
142 pdl wKqljdofha ioacutelrKh
my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla
fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34
by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes
wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka
wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34
uOHkH fotilde h fi wfrac34 olajkq efiacute
143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h
my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu
jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg
jfrac34 uOHkH uQ fotilde h fotilde
jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla
jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=
Kkla i`oyd ioacutelrKh ild nuq
N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)
PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka
21
tu ksid jfrac34 uOHkH uQ fotilde h
fi suacuteh yels h
1 11 ksoiqk
25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak
uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1
by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj
fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama
lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml
pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh
u` ska th my oelafjk mszligEgrave idOkh llt yels h
fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt
yel
kB hkq fndaaUumliaudka kshh fotilde
22
wKqjla i`oyd
ujqhla i`oyd
fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq
fotilde
144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml
N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag
pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq
efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave
mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes
lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde
jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash
fi ye|skafotilde
16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--
fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd
fotilde jHdmash
23
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka
wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea
jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd
idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute
ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr
^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17
rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla
i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34
17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj
iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha
sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka
daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh
17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd
Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir
ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla
mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy
ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh
yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr
jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml
ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej
jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla
fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh
fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs
17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska
o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska
daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka
iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk
wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh
hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd
mszligudj (V)
mSvk
h (
P)
24
jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj
o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga
meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg
jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke
fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka
lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS
jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru
ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml
yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj
sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK
n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde
mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd
laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect
(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g
jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda
ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel
jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt
WIaKaj fotilde
daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o
WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel
fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg
jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml
fuh mltuq ioacutelrKfha wdfoaYfhka
fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH
ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk
nj wmg fmfka
fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh
pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we
tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj
hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h
mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq
wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt
jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect
jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia
PV mszligmQfrac34K
daauacutel
25
jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq
wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka
yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=
h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka
wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel
jdhq mszligmQfrac34K aajfhka wm ukh fotilde
151 jeka vrsquo jdaia ioacutelrKh
fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa
sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K
jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk
wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq
mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel
jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid
daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH
fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj
iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk
Egrave
bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka
kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka
mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka
igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash
iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg
fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh
mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde
1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj
ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh
by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK
fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde
gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq
mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde
fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg
iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq
msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect
moaOsfha mSvkh my mldYkfhka nd fohs
26
bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL
fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr
tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk
mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka
wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks
fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq
kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh
fi kej suacuteh yels h
fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh
fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql
nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia
flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha
wkafrac34--mszligjfrac34kh l yels fotilde
ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs
wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj
yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde
igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys
sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde
ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha
lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh
iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla
fi o yeisszligh yels ugraveu h
bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla
oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi
mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS
30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc
oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi
muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu
WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla
oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde
( )2
aP V b RTV
+ minus =
27
19 rEmh CO2 j ldm igyk
1 3 j =j - ioacutelrK idrdxYh
jdhq kshuh intildelrKhksh j mjsk
idOl
mszligmQfrac34K jdhq kshuh PV = nRT ke
fndhsa kshuh n iy T
pdaia kshuh V = kT n iy P
wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T
wKql pdl ioacutelrKh
idudkH fotilde h
jfrac34 uOHkH fotilde h
jfrac34 uOHkH fotilde h
fvdaagkaf a wdxYsl mSvk
kshuh
PA = xA PT
PT = PA + PB + PC
iiumlmSvHd idOlh jdhq ujq 1la i|yd
jeka vZjdaia ioacutelrKh
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
1
wkafrac34 h
1 1 modfrac34fha wjiad =fkys wxY= ieleiau
iy tajdfha ofrac34YSh CIK
1 2 jdhquh wjiadj
1 2 1 jdhq kshu
bull mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq
ioacutelrKh
bull mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ
Kkh lsIacuteiuml
1 2 2 fndhsa kshuh
(mSvk-mszligud iiumlnkaOh)
1 2 3 pdaia kshuh
(WIaKajndashmszligud iiumlnkaOh)
1 2 4 wej dacircfrda kshuh
(mudK-mszligud iiumlnkaOh)
1 2 5 ujqsl mszligudj (Vm)
1 2 6 ixhqla jdhq ioacutelrKh
1 3 fvdaagkaf a wdxYsl mSvk kshuh
1 3 1 ujq Nd h wkqidrfhka
wdxYsl mSvkh
1 4 jdhq msltsn`o pdl wKql jdoh
1 4 1 pdl wKql jdofha mszligmQfrac34K jdhqjla
i|yd Wmlamk
1 4 2 pdl wKql jdofha ioacutelrKh
1 4 3 jfrac34 uOHkH uQ fotilde h iy
uOHkH fotilde h
1 4 4 ueialafja--fndaaUumliaudka jHdmash
1 5 daauacutel jdhqjg eltfmk mszligEgrave
mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
1 5 1 jeka vrsquojdaia ioacutelrKh
1 5 2 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
1 modfrac34fha jdhquh
wjiadj
2
ye|skaugraveu
uacuteYajfha wes ishiquest oE iquacutefYaIS ridhksl wkkHdjlska hqla h modfrac34fha l=vdu wxY=j
mrudKqj nj wms oksuq irj oelajqjfyda ridhk uacuteoHdj hkq ldquomodfrac34h iy tys isyumljk
uacutemfrac34hdi msltsn|j wOHkhrdquo fi wfrac34 oelauacute h yel modfrac34h hkq wjldYhla wama
lr kakd ialkaOhla iys acutekEu fohla jk wr th oelsh yels yd weaSug yels
^mia ch wdsectamp fohla fi fuka u jdh jeks wmg fkdfmfkk fohla o uacuteh yel
ixhqsh yd =K mokiuml lr f k oslashjH ntildeYK uQoslashjH fuka u mrudKq iy wKq wdsect uacuteuacuteO
wdldr fuys sect y`yumlkd yels h ishiquestu oslashjH gtk oslashj iy jdhq fig wvqu rntildeka uQsl
wjiad =klska mejsh yels h gtkhl sect wxY= =ltska ne`oS tlsfklg lsUumlgqj lsishiuml
ksYaNtilde jHqyhlg ksYaNtilde yevhla iysj weisIacuteu ksid tajdg pkh ugravefiuml yelshdj wvq
h oslashjhl wxY= tlsfklg lsUumlgqj wea tlsfklg iadkShj bd Egraveka ne|S kes neuacuteka
ikaikaokdaulj gtkhl sect g jvd fotilde fhka pkh uacuteh yels h wxY= wr yumlr wkqj
oslashj yd gtkjg jvd jdhq fndfyda fjkia fotilde jdhqjlsect wxY= tlsfklska fjka ugrave wes yumlr
wxY=jl mudKhg ikaikaokdaulj uacuteYd ugraveu fya=fjka wxY=jg ksoyfia yeisIacuteug
bv we tneuacuteka jdhq wxY= wr wdlfrac34Yk n bd l=vd fyda fkd sksh yels riuml ugraveu
fya=fjka wmg jdhq wxY= fjka fjka j ielsh yels neuacuteka WIaKajh yd mSvkh u
mokiuml jQ iuyr lams myiqfjka mqfrdalkh llt yels fotilde
11 modfrac34fha mOdk wjiad =fkys wxY= ieleiau iy tajdfha ofrac34YSh CIK
wjldYfha bvla kakd ialkaOhla iys acutekE u fohla zmodfrac34hZ fi ye`Egravekauacuteh yels h
wmg plusmnlsh yels wska weash yels yfldlt fia u wm fkdolsk tfya yqiau kakd
jdh o oacuteg wha h mq`Ma jYfhka a l ishuml modfrac34h gtk oslashj yd jdhq hkqfjka
wjiad =klg jfrac34 SlrKh llt yels h ixhqsfhys fjkia ugraveulska fdrj modfrac34h fiuml
suacuteO wjiad wr tllska wfklg mszligjfrac34kh llt yels h ksoiqkla fi( oslashj wjiadfotilde
mjsk ch ra lsIacutefuka jdhq wjiadjg (yqudh) mszligjfrac34kh llt yels wr isisa
lsIacutefuka gtk wjiadjg ^whsiaamp ma llt yels h
gtk
^Wod( hlv weKhamp
iaOacuter yevhla yd
mszligudjla we
oslashj
^Wod( champ
iaOacuter yevhla
kes kuqa iaOacuter mszligudjla we
jdhq
^Wod( ySshiuml neAEligkamp
iaOacuter yevhla fyda
iaOacuter mszligudjla fyda ke
gtk
wxY= ^mrudKq wKq fyda whkamp
wr wdlfrac34IK n mn h
wxY= liumlmkh jk kuqa
eklska eklg
pkh fkd fotilde
oslashj
wxY= ^mrudKq wKq fyda whkamp
wr wdlfrac34IK n triuml
mn fkd fotilde wxY=jg hiuml
mudKhlg eklska eklg
pkh uacuteh yels h
jdhq
wxY= ^mrudKq wKq fyda whkamp
wr wdlfrac34IK n yumln h
wxY=jg eklska eklg
pkh uacuteh yels h
11 rEmh modfrac34fha suacuteO wjiad
wxY=j ieleiafuka yd psfhka modfrac34fha suacuteO wjiad tlsfklska fjkia fotilde
wkafrac34currenwxY= wr yumlr jdhq wjiadfotilde wecircl jk wr gtk wjiadfotilde sect th wju fotilde jdhq
wjiadjg idfmalaIj oslashj wjiadfotilde sect wxY= tlsfklg ioacutem jk wr th gtk wjiadfotilde
3
sect riuml tlsfklg ioacutem o fkd fotilde tneuacuteka luja j ixuacuteOdkh jQ wxY=uh rgdjla plusmnlsh
yelafla gtk wjiadfotilde muŒ oslashj yd jdhq wjiad foflys sect u wxY= ieliS weafa wyUq
fi h fuys msMhla fi oslashj wjiadfotilde wes wxY=jg idfmaalaIj jdhq wjiadfotilde
wes wxY=jg jvd fotilde fhka yd ksoyia fi pkh uacuteh yels h flfia jqj o gtkj
wes wxY=j psh liumlmkjg muKla iSud fotilde my 11 j =fjka plusmnlafjk mszligEgrave
modfrac34fha wxY=j ieleiau yd tys psh mszligudj yevh iiumlmSvHdj yd gtkajh jeks
ufyaalaI =Kj fjkialiumljg =vq fohs
1 1 j =j gtk oslashj yd jdhq j =Kj =Kdaul ixikaokh
=Kh gtk oslashj jdhq
yevh ksYaNtilde h wvx = n`yumlfkys
yevh kakd uqa
n`yumlfkys uq`M mszligudj
mqrd fkd mesfrhs
n`yumlfkys yevh
kakd wr
n`yumlfkys iuia
mszligudj wa lr kS
mszligudj ksYaNtilde h ksYaNtilde h wvx = n`yumlfkys
mszligudj wa lr kS
gtkajh (ρ) g cm-3 (293 K sect)
bylt w hka kS
Wod( hlv
(7 874 g cm-3)
rula bylt w hka
kS
Wod( ch
(0 997 g cm-3)
w hka mylt h
Wod( yhsvcka
(0 071g cm-3)
iiumlmSvHdj iiumlmSvkh lsIacuteu
bd yumlIalr h
iiumlmSvkh lsIacuteu bd
yumlIalr h
fnfyuacuteka iiumlmSvkh
llt yels h
igyk ( oslashj wvx = n`yumlfkys yevh kakd nj wm i`oyka lr wes wr tfia jkafka
ukaoehs issh hq= h idudkHfhka acutekE u jia=jla wkafrac34-wKql n jeks uacuteuacuteO jfrac34 fha
n u` ska tlg ne| nd kakd neuacuteka thg ksYaNtilde yevhla we icirclrhl wes fok o
c mudKhla ^mszligudjlaamp hiuml yevhla kafka mDIaAgravel wdsh ksid h oslashjh =lt mjsk
wkafrac34-wKql n ksid mDIaGh flltjffrac34 l=vd oslashj udjlhla wes fotilde icirclrfha igraveas u` ska
oslashjh u byltg aumljla wes flfrk wr mDIaAgravel wdshg jvd jeauml =reajc nh
u` ska myltg weoSula wes fotilde tuksid oslashjh byltska iu mDIaGhla iysj icirclrfha
yevh kS fufia jkafka fuu uacuteuacuteO jfrac34 fha ishuml nj nmEu ksid h flfia jqj
o mDIaAgravel wdsh =reajc nhg jvd mn jQjd kiuml cfha mDIaGh iu fkdjk
wr n`yumlfka yevh fkd kq we =reajc nhla keehs is=j fyda mDIaAgravel wdsh
fndfyda fihska bylt hhs mDIaGfha tla tla fldgilg u wfkla mDIaGh iu` yels riuml
ltx ugrave mejSug wjYH ksid tajd wr wes wdlfrac34IK wju lr ekSug fmfograve tneuacuteka
fok o mszligudjl wju mDIaAgravel lafIaMhla wes fyd`o u yevh jk f dadldr yevh
kS
ralsrSfuka fyda isiskfhka tla wjiadjl mjsk modfrac34h ja wjiadjlg mszligjfrac34kh
llt yels h WIaKajh jeauml lsIacutefiuml sect wxY=j pk fotilde h bylt hEua wxY= wr yumlr jeauml
ugraveua lrK fldg modfrac34j wjiadj fjkia fotilde ta wkqj WIaKajh jeauml lsIacutefiuml sect gtk
wjiadfotilde wes oslashjH oslashj wjiadjga oslashj wjiadfotilde wes oslashjH jdhq wjiadjga ma fotilde
WIaKajfha wvq ugraveua iu isyuml jkafka fuys uacutefdauhhs my 12 rEmfhka modfrac34h tys
wjiad wr wkafrac34-mszligjfrac34khg Ndck llt yels wdldrh fmkakqiuml flffrac34
4
12 rEmh modfrac34fha wjiad wr wkafrac34-mszligjfrac34kh
11 ksoiqk
wxY= jvda u ioacutem fi iamfrac34Y jkafka ugrave kuqa tajd wyUq fi weysIacute weafa modfrac34fha
ljr kiuml wjiadfotilde o
uacutei`yumlu oslashj wjiadj
11 j =jg wkqj wm modfrac34fha mOdk wjiad =fkys =K uacuteiar lrk uacuteg wxY=j ieliqu
yd pkh uQslj ild nd we uacutefYaIfhka u hiuml oslashjHhl wes wKq fyda mrudKqj
pkh ksid yg kakd Ylash dmc Ylash jk wr th oslashjHfha WIaKajhg wkqfdauj
iudkqmdsl fotilde tu` ska modfrac34fha wes wxY=j uOHkHh pdl Ylash uefkk neuacuteka
th wxY=j pkh fyda dmc psh i`oyd fya= fotilde
wkafrac34-wKql n u` ska wKq tlsfklg ltx ugrave mejSug fmfUk nj wm oekgua
okakd kuqa wKqj dmc Ylash u` ska wKq tlsfklska wEa ugraveug fmfograve ta wkqj
modfrac34fha mOdk wjiad =fkys mejSu wKqj wkafrac34-wKql n iy dmc Ylash
wr iu=sfhys msMhla fi ielsh yels h
wkafrac34-wKql wdlfrac34IK bd yumln jk uacuteg WIaKajh wvq lsIacutefuka dmc Ylash WIaKajhamp
wvq fkdllt fyda wKq oslashj fyda gtk fyda fi mejSug fkd fmfograve wKq tlsfklg
bd lt` ska wes uacuteg iy wkafrac34 - wKql n Wmszliguj wes uacuteg mjd iiumlmSvkh u` ska muKla
jdhq oslashj wjiadjg ma fkd fotilde flfia jqj o WIaKajh wvq lsIacuteu u` ska wKqj dmc
Ylash wvq jk uacuteg jdhq bd myiqfjka oslashj llt yels h fiuml yeisIacuteiuml my 1 3 rEmfhka
meyeEgraves llt yels h modfrac34fha mOdk wjiad =k flfrys wkafrac34-wKql nj yd dmc
Ylasfha msuacutereoaO nmEfiuml iajNdjh wmg tu` ska wjfndaO lr yels h
5
13 rEmh wkafrac34-wKql n yd dm Ylash wkqj modfrac34fha mOdk wjiad
=fkys yeisIacuteu
modfrac34fha mOdk wjiad =kla mejSug fya=j wm oekgua yodrd we oeka wm
modfrac34fha jdhquh yeisIacuteug fya= jk jdhq kshu iy jdhquh wjiAdj msltsn`o j yumlrga
ild nuq
12 jdhquh wjiadj
oeka wm idudkH WIaKaj mSvk aaj hgfa wes jdhquh wjiadfotilde mjsk oslashjHj
yeisIacuteu flfrys wjOdkh fhduq lruq
11 j =fotilde uacuteiar lr wes mszligEgrave jdhquh wjiadj my i`oyka fNsl =K wkqj uacuteiar
flffrac34
bull jdhq bd iiumlmSvH fotilde
bull jdhq ieu EgraveYdjlg u iudk whqszligka mSvkh wes lrhs
bull jdhqjg gtk iy oslashjjg jvd wvq gtkajhla we
bull jdhqj yevh iy mszligudj ksH fkd fotilde tajd wvx = Ndckfha yevh iy mszligudj
kS
bull jdhq lsis u hdkasl nmEulska fdrj iiumlmQfrac34Kfhka u iy iudkj tlsfkl
iuOtilde ntildeY fotilde
jdhqjl irdjhg fya= jkafka tu wKq wr mjsk n fkd ssbquoh yels ugraveuhs tajdfha
yeisIacuteu mIacutelaIKdaul wOHhkhkaf ka nd a msM u` ska fidhd kakd o fmdyuml jdhq kshujg (miqj idlEacutePd flffrac34iexcl) wkqj isyuml fotilde fiuml jdhq kshu hkq jdhqjl ueksh
yels =K wr mjsk iiumlnkaOd fotilde ueksh yels =K iuyrla jk mSvkh mszligudj
WIaKajh iy mudKh ^ujq fyda ialkaOhamp jeks tajd bd jeo a jkafka fiuml uacutepH
wr mjsk iiumlnkaOd jdhqjl mOdk wjiad (5 jk tallfha sect wfrac34 olajkq efiacuteiexcl) uacuteiar lrk ksid h tlsfkl yd ne`yumlKq fiuml uacutepHhka jdhq kshu iQ lsIacuteug uQsl
ugrave we
121 jdhq kshu
wm idlEacutePd lsIacuteug hk jdhq kshu uacuteoHdhka lsysm fokl= uacuteiska jdhqj fNsl =K
mokiumlj isyuml lrk o mIacutelaIKjska nd a msM fotilde mSvkh WIaKajh mszligudj iy
jdhq mudKh hk uacutepH wr mjsk iiumlnkaOd fuys sect ild nk wr tajd u` ska
6
modfrac34fha jdhquh wjiadj msltsn`o udkj jfrac34 hdg mfhdackja jk fdr=re rdYshla
mldY fotilde
mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq ioacutelrKh
jdhq wKq wr wkafrac34-wKql n fkdues nj Wmlamkh flffrac34 o tndivide jdhqjla mszligmQfrac34K
jdhqjla fi ye`Egravekafotilde tkiuml mszligmQfrac34K jdhqjl wKq wr wdlfrac34IK fyda uacutelfrac34IK fyda
n fkd mjS tfuka u jdhqj oud wes Ndckfha mszligudj iu` ieipoundfiuml sect jdhq wxY=jl
mszligudj fkdild yeszligh yels h
jdhqjl ksrfmalaI WIaKajh (T) mSvkh (P) mszligudj (V) iy oslashjH mudKh ^n ujqamp
jdhquh yeisIacuteu flfrys nmdk idOl fotilde P T V iy n wr iiumlnkaOdj my
mldYkfhka ksrEmKh flffrac34
fuh mszligmQfrac34K jdhq ioacutelrKh fyda mszligmQfrac34K jdhq kshuh fi oelafjk wr R hkq ieu
jdhqjlg u fmdyuml w hla wes jdhq kshh fotilde fok o acutekE u WIaKajhl sect yd
mSvkhl sect by iiumlnkaOdjg wkql+j yeisfrk acutekE u jdhqjla mszligmQfrac34K jdhqjla fi
y`yumlkajkq efiacute
fuu aaj hgfa oS mszligmQfrac34K jdhq ujq 1 la i|yd 0 degC sect yd 1 atm sect R kshfha w h
my wdldrhg Kkh l yel (0 degC sect yd 1 atm yssect mszligmqfrac34K jdhqjl 1 mol l mszligudj
22 414 dm3 fotilde)
mszligmQfrac34K jdhq ioacutelrKh by uacutepH yr wr wes iiumlnkaOdj jk nj wmg fmfkk
wr acutekE u jdhqjl wjiadj tuOtildeska uacuteiar flfrk ksid th wjiad ioacutelrKh fi
o ye|skafotilde
mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ Kkh lsIacuteiuml
mszligmQfrac34K jdhq ioacutelrKh u` ska wmg mszligudj WIaKajh mSvkh fyda ujq mudKh hk
tajdhska =kla sect wes uacuteg wfkla rdYsh ksfrac34Kh llt yels h jdhqjl ujq mudKh okakd
uacuteg tys ujqsl ialkaOh Nduacutefhka tys ialkaOh o Kkh llt yels h tfuka u
tu` ska jdhqjl gtkajh o ksfrac34Kh llt yels h mszligmQfrac34K jdhq kshfha w hg eltfmk
mszligEgrave wfkl=a rdYsj tall Nduacute lsIacuteu bd jeo a jk nj ul nd hq= h
idudkHfhka mSvkh atm Pa bar torr jeks tall jska mldY llt yels h tneuacuteka fiuml
eguml uacutei`oSfiuml sect my 1 2 j =fotilde sect wes mSvk tallj mszligjfrac34k Tng Wootilde jkq we
12 j =j mSvkh i`oyd jk tall
mSvk tallh Pa bar atm torr mmHg
1 Pa 1 N m-2 10-5 9 87 times 10-6 7 5 times 10-3
1 bar 100000 1bar 0 987 750 061 atm 101325 1 01325 1 atm 7601 torr mmHg 133 32 1 3332 times 10-3 1 3158 times 10-3 1 torr 1 mmHg
7
12 ksoiqk
jdhq isskavrhl mszligudj 0950 dm3 fotilde hiuml mSvkhla hgfa sect fiuml isskavrh oslashj
fmdfmakajska (C3H8) msIacute we isskavrh ysia jQ uacuteg jdhqf daSh mSvkh yd WIaKajh
hgfa sect tys fmdfmaka jdhqj hiuml mudKhla bsszlig fotilde
(i) wjg mszligirfha aaj 25degC iy 750 torr (1 torr = 133 52 Pa) kiuml isskavrh
ysiaj wes uacuteg tys bsszlig ugrave wes fmdfmaka jdhq ujq mudKh fldmuK o
(wNHkar mSvkh ndysr mSvkhg iudk uacuteg oS)
(ii) isskavrfha bsszlig ugrave wes fmdfmaka jdhq ialkaOh Kkh lrkak
(iii) isskavrfha bsszlig ugrave wes fmdfmaka jdhqfotilde gtkajh Kkh lrkak
uacutei`yumlu (i) mltuqj sect wes fdr=re iudfdapkh lrkak
WIaKajh T = (25 + 273) K = 298 K mSvkh P = 750 torr times 13332 Pa 1 torr = 99990 Pa mszligudj V = 0 950 dm3 = 0 950 times 10-3 m3
n fkdokakd moh fotilde
PV = nRT Nduacutefhka
(ii) fmdfmakays (C3H8) ujqsl ialkaOh = 44 g mol-1
fmdfmakays ialkaOh = 0 038 mol times 44 g mol-1 = 1 672 g
(iii) fmdfmakays gtkajh = ialkaOh mszligudj = = 1 76 g dm-3
by ksoiqk iel+ uacuteg mszligmQfrac34K jdhq kshuh uacuteuacuteO wdldrjska bEgraveszligma llt yels nj
fmkS hk wr my oelafjk mszligEgrave ir fjkia lsIacuteulska fok o jdhqjl ialkaOh
iy gtkajh fiuacuteh yels h
PV = nRT
P = RT
zwnjzwnj P = CRT
fuys zC Zhkq idkaoslashKhhs
j o PV = nRT iiumlnkaOdj my mszligEgrave o mldY llt yels h
PV = RT
fuys m hkq ialkaOh jk wr M hkq jdhqfotilde ujqsl ialkaOhhs
P = RT fi o suacuteh yels h
8
gtkajh (d) =
there4 P =
uacutefYaIs aaj hgfA fjka jdhq kshu jHqamkak lsIacutefiuml sect mszligmQfrac34K jdhq kshuh uQsl
moku fi lshd lrhs
122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)mdashksh WIaKajhla hgfa wes iaOacuter jdhq mudKhl (ialkaOhl) mSvkh jdhqfotilde mszligudjg
msfdauj uacutepkh fotilde (fyda iudkqmdsl) fotilde˜ fndhsa kshuh hkqfjka ye`Egravekafjk
fuh tfia kiuml lrk oafoa 17 jeks ishjfia sect WIaKajh ksh jQ aaj hgfa fjkia
jk mSvkha iu jdhqjl mszligudj uacutepkh jk wdldrh whsszligIa cdsl uacuteoHdhl= jQ
frdnUuml fndhsa (1627- 1691) uacuteiska wOHhkh lsIacutefuka miqj h tys Ksuh wdldrh
my oelafotilde
my plusmnlafjk mszligEgrave fndhsa kshuh jHqamkak lsIacuteu i`oyd mszligmQfrac34K jdhq kshuh fhdod
yelsh PV= nRT
jdhqfjys mudKh yd moaOsfhys WIaKajh kshj mjajd kakd oafoa kiuml nT =Ksh
kshhla fotilde R o kshhla jk neuacuteka nRT =Ksh o kshhla (k) fotilde
PV = k (kshhla)
tkiuml ksh WIaKajfha sect ksh jdhq mudKhl mSvkfhaa mszligudfotildea =Ksh kshhla
fotilde fuh fndhsa kshuh mldY lrk fjka wdldrhls
ksh T WIaKajhl wes ksh jdhq mudKhl mszligudj V1 o mSvkh P1 o kiuml yd th V2
mszligudjg yd P2 mSvkhg ma llt uacuteg fndhsa kshuhg wkqj
14 rEmh u` ska fndhsa kshufha idiumlmodhsl miadszligl ksrEmK folla fmkakqiuml flffrac34
14 rEmfha (a) u` ska ixikaokh i`oyd uacuteuacuteO WIaKajj sect PV = k miadr lr we
k w h WIaKajh u muKla r`od mjsk ksid fok o jdhq ialkaOhla i`oyd w`Egravek
o ieu jlhla i`oyd u k ys w h tlsfklg fjkia fotilde bylt WIaKajj sect mszligudfotilde
midrKh ksid plh byltg f dia wes nj ielsh hq= h tfuka u WIaKajh ksh
uacuteg jdhqfotilde mSvkh wvla jk uacuteg mszligudj fo =K jk nj ul nd hq= h
9
1 4 rEmh uacuteuacuteO ksh WIaKajj sect (a) mszligudj (V) iuOtilde (b) 1 V iuOtilde
mSvkfha fjkia ugraveu
14 (b) rEmh u` ska P g tosrsfhka ys miadrh ksrEmKh fotilde th uQ laIHh yryd hk
ir ffrac34Ldjls fndhsa uacuteiska lrk o mIacutelaIKjg wkqj nd kakd o fuu miadr
u` ska jdhqjg bylt iiumlmSvHdjla wes nj mudKdaulj fmkajd foa tkiuml fok o
jdhq ialkaOhla iiumlmSvkh llt uacuteg tl u mudKhlska wes wKq ixLHdj l=vd mszligudjla
=lt mesffrac34 fiuml wkqj bylt mSvkj sect jdhqj gtkajh jeauml fotilde
igyk fok o jdhqjl gtkajh d ialkaOh m o mszligudj v o jk uacuteg d = ioacutelrKfhka
fok nj wms oksuq tuksid ksh WIaKajfhasect
hkqfjka suacuteh yels h
1 3 ksoiqk
ksh WIaKajhla hgfa wes okakd jdhq ujq mudKhl mszligudj fo =K llt uacuteg
mSvkfha isyuml jk fjkia ugraveu Kkh lrkak
uacutei`yumlu V1 =V V2 = 2V P1 = P P2 = fndhsa kshuh fhsectfuka P1V1 = P2V2
P times V = P2 times 2VP2 = P 2 there4kj mSvkh uqa mSvkfhka wvla fotilde
10
1 4 ksoiqk
ldur WIaKajfha sect neumlkhla yhsvcka jdhqj okakd mudKhlska mqrjd we jdhqf daSh
mSvkfha sect (100 kPa) tu jdhq mudKh 2 50 dm3 l mszligudjla kS tu WIaKajfha sect u
we=lt mSvkh 20 kPa ugraveug neumlkfha mszligudj fldmuK uacuteh llt hq= o
uacutei`yumlu P1 = 100 kPa P2 = 20 kPa V1 = 2 5 dm3 V2 = fndhsa kshuh fhsectfuka P1V1 = P2V2
100 kPa times 2 5 dm3 = 20 kPa times V2 there4V2 = 12 5 dm3 neumlkfha mszligudj 12 5 dm3 olajd jeauml llt hq= h
123 pdaia kshuh (WIaKaj-mszligud iiumlnkaOh)cdlaia pdaia iy fcdaIma f a-umliela hk uacuteoHdhkaf a yeoEIacuteiuml u ska fmkajd sect wes mszligEgrave
ksh mSvkhl sect fok o ksH jdhq mudKhl ^ialkaOhamp mszligudj WIaKajha iu`
jeauml jk wr isisa lsIacuteua iu` wvq fotilde tfuka u WIaKajfhA isyuml jk ieu fiaishia
wxYlhl fjkila mdid ^jeauml ugraveu fyda wvq ugraveuamp mszligudj 0degC sect jdhqfotilde wdriumlNl mszligudfjka idOlhlska fjkia jk nj ^jeauml ugraveu fyda wvq ugraveuamp fidhd f k we
0 degC sect iy t degC ys sect jdhqfotilde mszligudj msltsfjltska V0 iy Vt hhs Wmlamkh lruq tuacuteg
fuu aajfha sect WIaKajh i`oyd kj mszligudKhla wfrac34 olajd we tuacuteg tu mszligudKhg
wkqj
t degC i`oyd Tt = 273 15 + t uOtildeska nd fok wr
0 degC i`oyd T0 = 273 15 uOtildeska nd fohs
fuu kj WIaKaj mszligudKh flauacuteka WIaKaj mszligudKh (K) fyja ksrfmalaI WIaKaj
mszligudKh fi ye`Egravekafotilde ndash 273 15 degC (0 K) hkak dm sl Y+kHh fi wfrac34 oelafjk
wr th ffioaOdkaslj lt` d uacuteh yels wju WIaKajh fotilde
fmdyumlfotilde a uacuteg ksh mSvkfha sect (V1 T1) isg (V2 T2) olajd isyuml jk fjkila i`oyd
11
tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg
wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde
jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys
WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg
yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h
PV = nRTV = nRT P
ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde
zwnjzwnjzwnjzwnjV prop T fyda V = kT
pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka
WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd
Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect
ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh
lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34
15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde
uacutepkh
12
1 5 ksoiqk
ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml
jk WIaKaj fjki Kkh lrkak
uacutei`yumlu
T1 = T V1 = V V2 = 3V T2 =
T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh
wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h
hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi
efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg
lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr
kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde
1 6 ksoiqk
23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde
tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki
Kkh lrkak
uacutei`yumlu
T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =
jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka
V2 = 2 03 dm3
mszligudfotilde isyumljk fjki = 0 03 dm3
124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=
jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj
lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla
hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)
fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h
13
jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda
kshh (NA fyda L) fi ye|skafotilde
my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka
wjfndaO lr yels h
fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl
u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud
follg by iiumlnkaOdj fhsectfuka
P iy T ksh uacuteg sect (R iy NA kshhka fotilde )
irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud
=lt iudk wKq ixLdjla wvx= fotilde (V α N)
by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd
mszligmQfrac34K jdhq ioacutelrKh nd yels h
by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka
k = R jQ uacuteg
P V = n R T
14
125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka
fi wmg suacuteh yels h
iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd
mszligudj (Vm) tl u w hla uacuteh hq= ksid th
fi Kkh llt yels h
tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u
mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34
bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu
aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj
22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi
ksrEmKh flffrac34
bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde
fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde
igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde
V = k n = k (m M) tneuacuteka M = k (m V) = k d
1 7 ksoiqk
298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud
iudk nj fmkajkak
uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe
VHe = nHeRTHe PHe
VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3
15
PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =
PNeVNe = nNeRTNe
VNe = nNeRTNe PNe
VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa
VNe = 24 4 dm3
tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq
wa lr kakd mszligud iudk fotilde
126 ixhqla jdhq kshuh
jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj
tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka
T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla
fi suacuteh yels h
fuh ixhqla jdhq kshuh fi ye|skafotilde
1 8 ksoiqk
25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o
uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh
P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3
T1 = 25 + 273 = 298 K
V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =
P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa
16
13 fvdaagkaf a wdxYsl mSvk kshuh
fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm
yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk
wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml
ishuml jdhq odhl fotilde
jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj
wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde
ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla
iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs
fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh
fi yeEgravekafotilde
A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska
PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde
my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka
jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha
we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh
PT hehs o isuq
PV = nRT
A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )
B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )
jdhq ntildeYKh i`oyd nT = PTV RT
iy nT = nA + nB
tu ksid PTV RT = (PAV RT) + (PBV RT)
iq`M llt uacuteg PT = PA + PB
fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl
131 ujq Nd h wkqidrfhka wdxYsl mSvkh
T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq
ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde
fvdaagkaf a kshuhg wkqj PT = PA + PB
PA iy PB mldYk fjk fjk u PT jska fnsectfuka
17
tu ksid
fi suacuteh yels h
hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk
fotilde
1 9 ksoiqk
(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla
tla jdhqfotilde wdxYsl mSvkh Kkh lrkak
(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd
lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq
ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak
uacutei`yumlu
18
fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK
u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd
fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj
tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla
fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re
uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq
irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq
efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj
u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk
nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja
ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj
mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=
jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes
lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect
tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh
wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K
jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl
1 10 ksoiqk
my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs
iskak
2KClO3(s) rarr2KCl(s) + 3O2(g)
27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute
27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh
Kkh lrkak
uacutei`yumlu
fvdaagkaf a kshuhg wkqj
Piuia = PTlaiscka + Pch
PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa
mszligmQfrac34K jdhq ioacutelrKh fhsectfuka
14 jdhq msltsn`o pdl wKqljdoh
by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(
fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks
mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla
nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka
uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml
jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh
llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad
fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd
fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj
yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde
19
141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde
wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd
uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr
wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS
wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh
u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka
gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska
jdhqj bylt iiumlmSvHdj meyeEgraves fotilde
bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu
jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO
wKqjg uacuteuacuteO fotilde mjS
fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg
ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash
jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk
ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde
bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS
fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq
wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj
fuu ska mldY flffrac34
fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh
mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt
uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka
jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr
iiumlnkaOdjh my ioacutelrKfhka nd foa
jyumlrga my oelafjk lreKq plusmnlauacuteh yels h
bull jdhq wxY= tlsfklska iajdhaj yeisffrac34
jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska
iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda
fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj
wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml
Wmlamkfhka meyeEgraves fotilde
bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla
u` ska mSvkhla wes fotilde
fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect
ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl
isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug
20
fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml
jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq
ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj
jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml
fotilde
142 pdl wKqljdofha ioacutelrKh
my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla
fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34
by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes
wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka
wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34
uOHkH fotilde h fi wfrac34 olajkq efiacute
143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h
my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu
jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg
jfrac34 uOHkH uQ fotilde h fotilde
jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla
jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=
Kkla i`oyd ioacutelrKh ild nuq
N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)
PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka
21
tu ksid jfrac34 uOHkH uQ fotilde h
fi suacuteh yels h
1 11 ksoiqk
25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak
uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1
by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj
fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama
lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml
pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh
u` ska th my oelafjk mszligEgrave idOkh llt yels h
fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt
yel
kB hkq fndaaUumliaudka kshh fotilde
22
wKqjla i`oyd
ujqhla i`oyd
fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq
fotilde
144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml
N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag
pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq
efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave
mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes
lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde
jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash
fi ye|skafotilde
16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--
fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd
fotilde jHdmash
23
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka
wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea
jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd
idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute
ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr
^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17
rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla
i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34
17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj
iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha
sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka
daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh
17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd
Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir
ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla
mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy
ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh
yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr
jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml
ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej
jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla
fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh
fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs
17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska
o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska
daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka
iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk
wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh
hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd
mszligudj (V)
mSvk
h (
P)
24
jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj
o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga
meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg
jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke
fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka
lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS
jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru
ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml
yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj
sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK
n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde
mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd
laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect
(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g
jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda
ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel
jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt
WIaKaj fotilde
daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o
WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel
fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg
jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml
fuh mltuq ioacutelrKfha wdfoaYfhka
fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH
ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk
nj wmg fmfka
fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh
pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we
tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj
hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h
mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq
wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt
jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect
jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia
PV mszligmQfrac34K
daauacutel
25
jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq
wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka
yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=
h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka
wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel
jdhq mszligmQfrac34K aajfhka wm ukh fotilde
151 jeka vrsquo jdaia ioacutelrKh
fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa
sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K
jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk
wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq
mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel
jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid
daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH
fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj
iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk
Egrave
bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka
kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka
mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka
igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash
iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg
fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh
mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde
1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj
ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh
by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK
fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde
gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq
mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde
fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg
iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq
msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect
moaOsfha mSvkh my mldYkfhka nd fohs
26
bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL
fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr
tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk
mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka
wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks
fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq
kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh
fi kej suacuteh yels h
fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh
fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql
nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia
flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha
wkafrac34--mszligjfrac34kh l yels fotilde
ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs
wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj
yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde
igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys
sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde
ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha
lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh
iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla
fi o yeisszligh yels ugraveu h
bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla
oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi
mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS
30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc
oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi
muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu
WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla
oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde
( )2
aP V b RTV
+ minus =
27
19 rEmh CO2 j ldm igyk
1 3 j =j - ioacutelrK idrdxYh
jdhq kshuh intildelrKhksh j mjsk
idOl
mszligmQfrac34K jdhq kshuh PV = nRT ke
fndhsa kshuh n iy T
pdaia kshuh V = kT n iy P
wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T
wKql pdl ioacutelrKh
idudkH fotilde h
jfrac34 uOHkH fotilde h
jfrac34 uOHkH fotilde h
fvdaagkaf a wdxYsl mSvk
kshuh
PA = xA PT
PT = PA + PB + PC
iiumlmSvHd idOlh jdhq ujq 1la i|yd
jeka vZjdaia ioacutelrKh
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
2
ye|skaugraveu
uacuteYajfha wes ishiquest oE iquacutefYaIS ridhksl wkkHdjlska hqla h modfrac34fha l=vdu wxY=j
mrudKqj nj wms oksuq irj oelajqjfyda ridhk uacuteoHdj hkq ldquomodfrac34h iy tys isyumljk
uacutemfrac34hdi msltsn|j wOHkhrdquo fi wfrac34 oelauacute h yel modfrac34h hkq wjldYhla wama
lr kakd ialkaOhla iys acutekEu fohla jk wr th oelsh yels yd weaSug yels
^mia ch wdsectamp fohla fi fuka u jdh jeks wmg fkdfmfkk fohla o uacuteh yel
ixhqsh yd =K mokiuml lr f k oslashjH ntildeYK uQoslashjH fuka u mrudKq iy wKq wdsect uacuteuacuteO
wdldr fuys sect y`yumlkd yels h ishiquestu oslashjH gtk oslashj iy jdhq fig wvqu rntildeka uQsl
wjiad =klska mejsh yels h gtkhl sect wxY= =ltska ne`oS tlsfklg lsUumlgqj lsishiuml
ksYaNtilde jHqyhlg ksYaNtilde yevhla iysj weisIacuteu ksid tajdg pkh ugravefiuml yelshdj wvq
h oslashjhl wxY= tlsfklg lsUumlgqj wea tlsfklg iadkShj bd Egraveka ne|S kes neuacuteka
ikaikaokdaulj gtkhl sect g jvd fotilde fhka pkh uacuteh yels h wxY= wr yumlr wkqj
oslashj yd gtkjg jvd jdhq fndfyda fjkia fotilde jdhqjlsect wxY= tlsfklska fjka ugrave wes yumlr
wxY=jl mudKhg ikaikaokdaulj uacuteYd ugraveu fya=fjka wxY=jg ksoyfia yeisIacuteug
bv we tneuacuteka jdhq wxY= wr wdlfrac34Yk n bd l=vd fyda fkd sksh yels riuml ugraveu
fya=fjka wmg jdhq wxY= fjka fjka j ielsh yels neuacuteka WIaKajh yd mSvkh u
mokiuml jQ iuyr lams myiqfjka mqfrdalkh llt yels fotilde
11 modfrac34fha mOdk wjiad =fkys wxY= ieleiau iy tajdfha ofrac34YSh CIK
wjldYfha bvla kakd ialkaOhla iys acutekE u fohla zmodfrac34hZ fi ye`Egravekauacuteh yels h
wmg plusmnlsh yels wska weash yels yfldlt fia u wm fkdolsk tfya yqiau kakd
jdh o oacuteg wha h mq`Ma jYfhka a l ishuml modfrac34h gtk oslashj yd jdhq hkqfjka
wjiad =klg jfrac34 SlrKh llt yels h ixhqsfhys fjkia ugraveulska fdrj modfrac34h fiuml
suacuteO wjiad wr tllska wfklg mszligjfrac34kh llt yels h ksoiqkla fi( oslashj wjiadfotilde
mjsk ch ra lsIacutefuka jdhq wjiadjg (yqudh) mszligjfrac34kh llt yels wr isisa
lsIacutefuka gtk wjiadjg ^whsiaamp ma llt yels h
gtk
^Wod( hlv weKhamp
iaOacuter yevhla yd
mszligudjla we
oslashj
^Wod( champ
iaOacuter yevhla
kes kuqa iaOacuter mszligudjla we
jdhq
^Wod( ySshiuml neAEligkamp
iaOacuter yevhla fyda
iaOacuter mszligudjla fyda ke
gtk
wxY= ^mrudKq wKq fyda whkamp
wr wdlfrac34IK n mn h
wxY= liumlmkh jk kuqa
eklska eklg
pkh fkd fotilde
oslashj
wxY= ^mrudKq wKq fyda whkamp
wr wdlfrac34IK n triuml
mn fkd fotilde wxY=jg hiuml
mudKhlg eklska eklg
pkh uacuteh yels h
jdhq
wxY= ^mrudKq wKq fyda whkamp
wr wdlfrac34IK n yumln h
wxY=jg eklska eklg
pkh uacuteh yels h
11 rEmh modfrac34fha suacuteO wjiad
wxY=j ieleiafuka yd psfhka modfrac34fha suacuteO wjiad tlsfklska fjkia fotilde
wkafrac34currenwxY= wr yumlr jdhq wjiadfotilde wecircl jk wr gtk wjiadfotilde sect th wju fotilde jdhq
wjiadjg idfmalaIj oslashj wjiadfotilde sect wxY= tlsfklg ioacutem jk wr th gtk wjiadfotilde
3
sect riuml tlsfklg ioacutem o fkd fotilde tneuacuteka luja j ixuacuteOdkh jQ wxY=uh rgdjla plusmnlsh
yelafla gtk wjiadfotilde muŒ oslashj yd jdhq wjiad foflys sect u wxY= ieliS weafa wyUq
fi h fuys msMhla fi oslashj wjiadfotilde wes wxY=jg idfmaalaIj jdhq wjiadfotilde
wes wxY=jg jvd fotilde fhka yd ksoyia fi pkh uacuteh yels h flfia jqj o gtkj
wes wxY=j psh liumlmkjg muKla iSud fotilde my 11 j =fjka plusmnlafjk mszligEgrave
modfrac34fha wxY=j ieleiau yd tys psh mszligudj yevh iiumlmSvHdj yd gtkajh jeks
ufyaalaI =Kj fjkialiumljg =vq fohs
1 1 j =j gtk oslashj yd jdhq j =Kj =Kdaul ixikaokh
=Kh gtk oslashj jdhq
yevh ksYaNtilde h wvx = n`yumlfkys
yevh kakd uqa
n`yumlfkys uq`M mszligudj
mqrd fkd mesfrhs
n`yumlfkys yevh
kakd wr
n`yumlfkys iuia
mszligudj wa lr kS
mszligudj ksYaNtilde h ksYaNtilde h wvx = n`yumlfkys
mszligudj wa lr kS
gtkajh (ρ) g cm-3 (293 K sect)
bylt w hka kS
Wod( hlv
(7 874 g cm-3)
rula bylt w hka
kS
Wod( ch
(0 997 g cm-3)
w hka mylt h
Wod( yhsvcka
(0 071g cm-3)
iiumlmSvHdj iiumlmSvkh lsIacuteu
bd yumlIalr h
iiumlmSvkh lsIacuteu bd
yumlIalr h
fnfyuacuteka iiumlmSvkh
llt yels h
igyk ( oslashj wvx = n`yumlfkys yevh kakd nj wm i`oyka lr wes wr tfia jkafka
ukaoehs issh hq= h idudkHfhka acutekE u jia=jla wkafrac34-wKql n jeks uacuteuacuteO jfrac34 fha
n u` ska tlg ne| nd kakd neuacuteka thg ksYaNtilde yevhla we icirclrhl wes fok o
c mudKhla ^mszligudjlaamp hiuml yevhla kafka mDIaAgravel wdsh ksid h oslashjh =lt mjsk
wkafrac34-wKql n ksid mDIaGh flltjffrac34 l=vd oslashj udjlhla wes fotilde icirclrfha igraveas u` ska
oslashjh u byltg aumljla wes flfrk wr mDIaAgravel wdshg jvd jeauml =reajc nh
u` ska myltg weoSula wes fotilde tuksid oslashjh byltska iu mDIaGhla iysj icirclrfha
yevh kS fufia jkafka fuu uacuteuacuteO jfrac34 fha ishuml nj nmEu ksid h flfia jqj
o mDIaAgravel wdsh =reajc nhg jvd mn jQjd kiuml cfha mDIaGh iu fkdjk
wr n`yumlfka yevh fkd kq we =reajc nhla keehs is=j fyda mDIaAgravel wdsh
fndfyda fihska bylt hhs mDIaGfha tla tla fldgilg u wfkla mDIaGh iu` yels riuml
ltx ugrave mejSug wjYH ksid tajd wr wes wdlfrac34IK wju lr ekSug fmfograve tneuacuteka
fok o mszligudjl wju mDIaAgravel lafIaMhla wes fyd`o u yevh jk f dadldr yevh
kS
ralsrSfuka fyda isiskfhka tla wjiadjl mjsk modfrac34h ja wjiadjlg mszligjfrac34kh
llt yels h WIaKajh jeauml lsIacutefiuml sect wxY=j pk fotilde h bylt hEua wxY= wr yumlr jeauml
ugraveua lrK fldg modfrac34j wjiadj fjkia fotilde ta wkqj WIaKajh jeauml lsIacutefiuml sect gtk
wjiadfotilde wes oslashjH oslashj wjiadjga oslashj wjiadfotilde wes oslashjH jdhq wjiadjga ma fotilde
WIaKajfha wvq ugraveua iu isyuml jkafka fuys uacutefdauhhs my 12 rEmfhka modfrac34h tys
wjiad wr wkafrac34-mszligjfrac34khg Ndck llt yels wdldrh fmkakqiuml flffrac34
4
12 rEmh modfrac34fha wjiad wr wkafrac34-mszligjfrac34kh
11 ksoiqk
wxY= jvda u ioacutem fi iamfrac34Y jkafka ugrave kuqa tajd wyUq fi weysIacute weafa modfrac34fha
ljr kiuml wjiadfotilde o
uacutei`yumlu oslashj wjiadj
11 j =jg wkqj wm modfrac34fha mOdk wjiad =fkys =K uacuteiar lrk uacuteg wxY=j ieliqu
yd pkh uQslj ild nd we uacutefYaIfhka u hiuml oslashjHhl wes wKq fyda mrudKqj
pkh ksid yg kakd Ylash dmc Ylash jk wr th oslashjHfha WIaKajhg wkqfdauj
iudkqmdsl fotilde tu` ska modfrac34fha wes wxY=j uOHkHh pdl Ylash uefkk neuacuteka
th wxY=j pkh fyda dmc psh i`oyd fya= fotilde
wkafrac34-wKql n u` ska wKq tlsfklg ltx ugrave mejSug fmfUk nj wm oekgua
okakd kuqa wKqj dmc Ylash u` ska wKq tlsfklska wEa ugraveug fmfograve ta wkqj
modfrac34fha mOdk wjiad =fkys mejSu wKqj wkafrac34-wKql n iy dmc Ylash
wr iu=sfhys msMhla fi ielsh yels h
wkafrac34-wKql wdlfrac34IK bd yumln jk uacuteg WIaKajh wvq lsIacutefuka dmc Ylash WIaKajhamp
wvq fkdllt fyda wKq oslashj fyda gtk fyda fi mejSug fkd fmfograve wKq tlsfklg
bd lt` ska wes uacuteg iy wkafrac34 - wKql n Wmszliguj wes uacuteg mjd iiumlmSvkh u` ska muKla
jdhq oslashj wjiadjg ma fkd fotilde flfia jqj o WIaKajh wvq lsIacuteu u` ska wKqj dmc
Ylash wvq jk uacuteg jdhq bd myiqfjka oslashj llt yels h fiuml yeisIacuteiuml my 1 3 rEmfhka
meyeEgraves llt yels h modfrac34fha mOdk wjiad =k flfrys wkafrac34-wKql nj yd dmc
Ylasfha msuacutereoaO nmEfiuml iajNdjh wmg tu` ska wjfndaO lr yels h
5
13 rEmh wkafrac34-wKql n yd dm Ylash wkqj modfrac34fha mOdk wjiad
=fkys yeisIacuteu
modfrac34fha mOdk wjiad =kla mejSug fya=j wm oekgua yodrd we oeka wm
modfrac34fha jdhquh yeisIacuteug fya= jk jdhq kshu iy jdhquh wjiAdj msltsn`o j yumlrga
ild nuq
12 jdhquh wjiadj
oeka wm idudkH WIaKaj mSvk aaj hgfa wes jdhquh wjiadfotilde mjsk oslashjHj
yeisIacuteu flfrys wjOdkh fhduq lruq
11 j =fotilde uacuteiar lr wes mszligEgrave jdhquh wjiadj my i`oyka fNsl =K wkqj uacuteiar
flffrac34
bull jdhq bd iiumlmSvH fotilde
bull jdhq ieu EgraveYdjlg u iudk whqszligka mSvkh wes lrhs
bull jdhqjg gtk iy oslashjjg jvd wvq gtkajhla we
bull jdhqj yevh iy mszligudj ksH fkd fotilde tajd wvx = Ndckfha yevh iy mszligudj
kS
bull jdhq lsis u hdkasl nmEulska fdrj iiumlmQfrac34Kfhka u iy iudkj tlsfkl
iuOtilde ntildeY fotilde
jdhqjl irdjhg fya= jkafka tu wKq wr mjsk n fkd ssbquoh yels ugraveuhs tajdfha
yeisIacuteu mIacutelaIKdaul wOHhkhkaf ka nd a msM u` ska fidhd kakd o fmdyuml jdhq kshujg (miqj idlEacutePd flffrac34iexcl) wkqj isyuml fotilde fiuml jdhq kshu hkq jdhqjl ueksh
yels =K wr mjsk iiumlnkaOd fotilde ueksh yels =K iuyrla jk mSvkh mszligudj
WIaKajh iy mudKh ^ujq fyda ialkaOhamp jeks tajd bd jeo a jkafka fiuml uacutepH
wr mjsk iiumlnkaOd jdhqjl mOdk wjiad (5 jk tallfha sect wfrac34 olajkq efiacuteiexcl) uacuteiar lrk ksid h tlsfkl yd ne`yumlKq fiuml uacutepHhka jdhq kshu iQ lsIacuteug uQsl
ugrave we
121 jdhq kshu
wm idlEacutePd lsIacuteug hk jdhq kshu uacuteoHdhka lsysm fokl= uacuteiska jdhqj fNsl =K
mokiumlj isyuml lrk o mIacutelaIKjska nd a msM fotilde mSvkh WIaKajh mszligudj iy
jdhq mudKh hk uacutepH wr mjsk iiumlnkaOd fuys sect ild nk wr tajd u` ska
6
modfrac34fha jdhquh wjiadj msltsn`o udkj jfrac34 hdg mfhdackja jk fdr=re rdYshla
mldY fotilde
mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq ioacutelrKh
jdhq wKq wr wkafrac34-wKql n fkdues nj Wmlamkh flffrac34 o tndivide jdhqjla mszligmQfrac34K
jdhqjla fi ye`Egravekafotilde tkiuml mszligmQfrac34K jdhqjl wKq wr wdlfrac34IK fyda uacutelfrac34IK fyda
n fkd mjS tfuka u jdhqj oud wes Ndckfha mszligudj iu` ieipoundfiuml sect jdhq wxY=jl
mszligudj fkdild yeszligh yels h
jdhqjl ksrfmalaI WIaKajh (T) mSvkh (P) mszligudj (V) iy oslashjH mudKh ^n ujqamp
jdhquh yeisIacuteu flfrys nmdk idOl fotilde P T V iy n wr iiumlnkaOdj my
mldYkfhka ksrEmKh flffrac34
fuh mszligmQfrac34K jdhq ioacutelrKh fyda mszligmQfrac34K jdhq kshuh fi oelafjk wr R hkq ieu
jdhqjlg u fmdyuml w hla wes jdhq kshh fotilde fok o acutekE u WIaKajhl sect yd
mSvkhl sect by iiumlnkaOdjg wkql+j yeisfrk acutekE u jdhqjla mszligmQfrac34K jdhqjla fi
y`yumlkajkq efiacute
fuu aaj hgfa oS mszligmQfrac34K jdhq ujq 1 la i|yd 0 degC sect yd 1 atm sect R kshfha w h
my wdldrhg Kkh l yel (0 degC sect yd 1 atm yssect mszligmqfrac34K jdhqjl 1 mol l mszligudj
22 414 dm3 fotilde)
mszligmQfrac34K jdhq ioacutelrKh by uacutepH yr wr wes iiumlnkaOdj jk nj wmg fmfkk
wr acutekE u jdhqjl wjiadj tuOtildeska uacuteiar flfrk ksid th wjiad ioacutelrKh fi
o ye|skafotilde
mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ Kkh lsIacuteiuml
mszligmQfrac34K jdhq ioacutelrKh u` ska wmg mszligudj WIaKajh mSvkh fyda ujq mudKh hk
tajdhska =kla sect wes uacuteg wfkla rdYsh ksfrac34Kh llt yels h jdhqjl ujq mudKh okakd
uacuteg tys ujqsl ialkaOh Nduacutefhka tys ialkaOh o Kkh llt yels h tfuka u
tu` ska jdhqjl gtkajh o ksfrac34Kh llt yels h mszligmQfrac34K jdhq kshfha w hg eltfmk
mszligEgrave wfkl=a rdYsj tall Nduacute lsIacuteu bd jeo a jk nj ul nd hq= h
idudkHfhka mSvkh atm Pa bar torr jeks tall jska mldY llt yels h tneuacuteka fiuml
eguml uacutei`oSfiuml sect my 1 2 j =fotilde sect wes mSvk tallj mszligjfrac34k Tng Wootilde jkq we
12 j =j mSvkh i`oyd jk tall
mSvk tallh Pa bar atm torr mmHg
1 Pa 1 N m-2 10-5 9 87 times 10-6 7 5 times 10-3
1 bar 100000 1bar 0 987 750 061 atm 101325 1 01325 1 atm 7601 torr mmHg 133 32 1 3332 times 10-3 1 3158 times 10-3 1 torr 1 mmHg
7
12 ksoiqk
jdhq isskavrhl mszligudj 0950 dm3 fotilde hiuml mSvkhla hgfa sect fiuml isskavrh oslashj
fmdfmakajska (C3H8) msIacute we isskavrh ysia jQ uacuteg jdhqf daSh mSvkh yd WIaKajh
hgfa sect tys fmdfmaka jdhqj hiuml mudKhla bsszlig fotilde
(i) wjg mszligirfha aaj 25degC iy 750 torr (1 torr = 133 52 Pa) kiuml isskavrh
ysiaj wes uacuteg tys bsszlig ugrave wes fmdfmaka jdhq ujq mudKh fldmuK o
(wNHkar mSvkh ndysr mSvkhg iudk uacuteg oS)
(ii) isskavrfha bsszlig ugrave wes fmdfmaka jdhq ialkaOh Kkh lrkak
(iii) isskavrfha bsszlig ugrave wes fmdfmaka jdhqfotilde gtkajh Kkh lrkak
uacutei`yumlu (i) mltuqj sect wes fdr=re iudfdapkh lrkak
WIaKajh T = (25 + 273) K = 298 K mSvkh P = 750 torr times 13332 Pa 1 torr = 99990 Pa mszligudj V = 0 950 dm3 = 0 950 times 10-3 m3
n fkdokakd moh fotilde
PV = nRT Nduacutefhka
(ii) fmdfmakays (C3H8) ujqsl ialkaOh = 44 g mol-1
fmdfmakays ialkaOh = 0 038 mol times 44 g mol-1 = 1 672 g
(iii) fmdfmakays gtkajh = ialkaOh mszligudj = = 1 76 g dm-3
by ksoiqk iel+ uacuteg mszligmQfrac34K jdhq kshuh uacuteuacuteO wdldrjska bEgraveszligma llt yels nj
fmkS hk wr my oelafjk mszligEgrave ir fjkia lsIacuteulska fok o jdhqjl ialkaOh
iy gtkajh fiuacuteh yels h
PV = nRT
P = RT
zwnjzwnj P = CRT
fuys zC Zhkq idkaoslashKhhs
j o PV = nRT iiumlnkaOdj my mszligEgrave o mldY llt yels h
PV = RT
fuys m hkq ialkaOh jk wr M hkq jdhqfotilde ujqsl ialkaOhhs
P = RT fi o suacuteh yels h
8
gtkajh (d) =
there4 P =
uacutefYaIs aaj hgfA fjka jdhq kshu jHqamkak lsIacutefiuml sect mszligmQfrac34K jdhq kshuh uQsl
moku fi lshd lrhs
122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)mdashksh WIaKajhla hgfa wes iaOacuter jdhq mudKhl (ialkaOhl) mSvkh jdhqfotilde mszligudjg
msfdauj uacutepkh fotilde (fyda iudkqmdsl) fotilde˜ fndhsa kshuh hkqfjka ye`Egravekafjk
fuh tfia kiuml lrk oafoa 17 jeks ishjfia sect WIaKajh ksh jQ aaj hgfa fjkia
jk mSvkha iu jdhqjl mszligudj uacutepkh jk wdldrh whsszligIa cdsl uacuteoHdhl= jQ
frdnUuml fndhsa (1627- 1691) uacuteiska wOHhkh lsIacutefuka miqj h tys Ksuh wdldrh
my oelafotilde
my plusmnlafjk mszligEgrave fndhsa kshuh jHqamkak lsIacuteu i`oyd mszligmQfrac34K jdhq kshuh fhdod
yelsh PV= nRT
jdhqfjys mudKh yd moaOsfhys WIaKajh kshj mjajd kakd oafoa kiuml nT =Ksh
kshhla fotilde R o kshhla jk neuacuteka nRT =Ksh o kshhla (k) fotilde
PV = k (kshhla)
tkiuml ksh WIaKajfha sect ksh jdhq mudKhl mSvkfhaa mszligudfotildea =Ksh kshhla
fotilde fuh fndhsa kshuh mldY lrk fjka wdldrhls
ksh T WIaKajhl wes ksh jdhq mudKhl mszligudj V1 o mSvkh P1 o kiuml yd th V2
mszligudjg yd P2 mSvkhg ma llt uacuteg fndhsa kshuhg wkqj
14 rEmh u` ska fndhsa kshufha idiumlmodhsl miadszligl ksrEmK folla fmkakqiuml flffrac34
14 rEmfha (a) u` ska ixikaokh i`oyd uacuteuacuteO WIaKajj sect PV = k miadr lr we
k w h WIaKajh u muKla r`od mjsk ksid fok o jdhq ialkaOhla i`oyd w`Egravek
o ieu jlhla i`oyd u k ys w h tlsfklg fjkia fotilde bylt WIaKajj sect mszligudfotilde
midrKh ksid plh byltg f dia wes nj ielsh hq= h tfuka u WIaKajh ksh
uacuteg jdhqfotilde mSvkh wvla jk uacuteg mszligudj fo =K jk nj ul nd hq= h
9
1 4 rEmh uacuteuacuteO ksh WIaKajj sect (a) mszligudj (V) iuOtilde (b) 1 V iuOtilde
mSvkfha fjkia ugraveu
14 (b) rEmh u` ska P g tosrsfhka ys miadrh ksrEmKh fotilde th uQ laIHh yryd hk
ir ffrac34Ldjls fndhsa uacuteiska lrk o mIacutelaIKjg wkqj nd kakd o fuu miadr
u` ska jdhqjg bylt iiumlmSvHdjla wes nj mudKdaulj fmkajd foa tkiuml fok o
jdhq ialkaOhla iiumlmSvkh llt uacuteg tl u mudKhlska wes wKq ixLHdj l=vd mszligudjla
=lt mesffrac34 fiuml wkqj bylt mSvkj sect jdhqj gtkajh jeauml fotilde
igyk fok o jdhqjl gtkajh d ialkaOh m o mszligudj v o jk uacuteg d = ioacutelrKfhka
fok nj wms oksuq tuksid ksh WIaKajfhasect
hkqfjka suacuteh yels h
1 3 ksoiqk
ksh WIaKajhla hgfa wes okakd jdhq ujq mudKhl mszligudj fo =K llt uacuteg
mSvkfha isyuml jk fjkia ugraveu Kkh lrkak
uacutei`yumlu V1 =V V2 = 2V P1 = P P2 = fndhsa kshuh fhsectfuka P1V1 = P2V2
P times V = P2 times 2VP2 = P 2 there4kj mSvkh uqa mSvkfhka wvla fotilde
10
1 4 ksoiqk
ldur WIaKajfha sect neumlkhla yhsvcka jdhqj okakd mudKhlska mqrjd we jdhqf daSh
mSvkfha sect (100 kPa) tu jdhq mudKh 2 50 dm3 l mszligudjla kS tu WIaKajfha sect u
we=lt mSvkh 20 kPa ugraveug neumlkfha mszligudj fldmuK uacuteh llt hq= o
uacutei`yumlu P1 = 100 kPa P2 = 20 kPa V1 = 2 5 dm3 V2 = fndhsa kshuh fhsectfuka P1V1 = P2V2
100 kPa times 2 5 dm3 = 20 kPa times V2 there4V2 = 12 5 dm3 neumlkfha mszligudj 12 5 dm3 olajd jeauml llt hq= h
123 pdaia kshuh (WIaKaj-mszligud iiumlnkaOh)cdlaia pdaia iy fcdaIma f a-umliela hk uacuteoHdhkaf a yeoEIacuteiuml u ska fmkajd sect wes mszligEgrave
ksh mSvkhl sect fok o ksH jdhq mudKhl ^ialkaOhamp mszligudj WIaKajha iu`
jeauml jk wr isisa lsIacuteua iu` wvq fotilde tfuka u WIaKajfhA isyuml jk ieu fiaishia
wxYlhl fjkila mdid ^jeauml ugraveu fyda wvq ugraveuamp mszligudj 0degC sect jdhqfotilde wdriumlNl mszligudfjka idOlhlska fjkia jk nj ^jeauml ugraveu fyda wvq ugraveuamp fidhd f k we
0 degC sect iy t degC ys sect jdhqfotilde mszligudj msltsfjltska V0 iy Vt hhs Wmlamkh lruq tuacuteg
fuu aajfha sect WIaKajh i`oyd kj mszligudKhla wfrac34 olajd we tuacuteg tu mszligudKhg
wkqj
t degC i`oyd Tt = 273 15 + t uOtildeska nd fok wr
0 degC i`oyd T0 = 273 15 uOtildeska nd fohs
fuu kj WIaKaj mszligudKh flauacuteka WIaKaj mszligudKh (K) fyja ksrfmalaI WIaKaj
mszligudKh fi ye`Egravekafotilde ndash 273 15 degC (0 K) hkak dm sl Y+kHh fi wfrac34 oelafjk
wr th ffioaOdkaslj lt` d uacuteh yels wju WIaKajh fotilde
fmdyumlfotilde a uacuteg ksh mSvkfha sect (V1 T1) isg (V2 T2) olajd isyuml jk fjkila i`oyd
11
tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg
wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde
jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys
WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg
yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h
PV = nRTV = nRT P
ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde
zwnjzwnjzwnjzwnjV prop T fyda V = kT
pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka
WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd
Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect
ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh
lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34
15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde
uacutepkh
12
1 5 ksoiqk
ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml
jk WIaKaj fjki Kkh lrkak
uacutei`yumlu
T1 = T V1 = V V2 = 3V T2 =
T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh
wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h
hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi
efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg
lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr
kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde
1 6 ksoiqk
23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde
tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki
Kkh lrkak
uacutei`yumlu
T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =
jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka
V2 = 2 03 dm3
mszligudfotilde isyumljk fjki = 0 03 dm3
124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=
jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj
lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla
hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)
fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h
13
jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda
kshh (NA fyda L) fi ye|skafotilde
my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka
wjfndaO lr yels h
fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl
u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud
follg by iiumlnkaOdj fhsectfuka
P iy T ksh uacuteg sect (R iy NA kshhka fotilde )
irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud
=lt iudk wKq ixLdjla wvx= fotilde (V α N)
by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd
mszligmQfrac34K jdhq ioacutelrKh nd yels h
by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka
k = R jQ uacuteg
P V = n R T
14
125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka
fi wmg suacuteh yels h
iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd
mszligudj (Vm) tl u w hla uacuteh hq= ksid th
fi Kkh llt yels h
tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u
mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34
bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu
aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj
22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi
ksrEmKh flffrac34
bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde
fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde
igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde
V = k n = k (m M) tneuacuteka M = k (m V) = k d
1 7 ksoiqk
298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud
iudk nj fmkajkak
uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe
VHe = nHeRTHe PHe
VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3
15
PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =
PNeVNe = nNeRTNe
VNe = nNeRTNe PNe
VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa
VNe = 24 4 dm3
tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq
wa lr kakd mszligud iudk fotilde
126 ixhqla jdhq kshuh
jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj
tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka
T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla
fi suacuteh yels h
fuh ixhqla jdhq kshuh fi ye|skafotilde
1 8 ksoiqk
25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o
uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh
P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3
T1 = 25 + 273 = 298 K
V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =
P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa
16
13 fvdaagkaf a wdxYsl mSvk kshuh
fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm
yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk
wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml
ishuml jdhq odhl fotilde
jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj
wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde
ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla
iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs
fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh
fi yeEgravekafotilde
A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska
PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde
my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka
jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha
we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh
PT hehs o isuq
PV = nRT
A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )
B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )
jdhq ntildeYKh i`oyd nT = PTV RT
iy nT = nA + nB
tu ksid PTV RT = (PAV RT) + (PBV RT)
iq`M llt uacuteg PT = PA + PB
fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl
131 ujq Nd h wkqidrfhka wdxYsl mSvkh
T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq
ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde
fvdaagkaf a kshuhg wkqj PT = PA + PB
PA iy PB mldYk fjk fjk u PT jska fnsectfuka
17
tu ksid
fi suacuteh yels h
hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk
fotilde
1 9 ksoiqk
(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla
tla jdhqfotilde wdxYsl mSvkh Kkh lrkak
(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd
lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq
ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak
uacutei`yumlu
18
fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK
u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd
fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj
tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla
fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re
uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq
irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq
efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj
u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk
nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja
ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj
mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=
jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes
lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect
tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh
wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K
jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl
1 10 ksoiqk
my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs
iskak
2KClO3(s) rarr2KCl(s) + 3O2(g)
27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute
27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh
Kkh lrkak
uacutei`yumlu
fvdaagkaf a kshuhg wkqj
Piuia = PTlaiscka + Pch
PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa
mszligmQfrac34K jdhq ioacutelrKh fhsectfuka
14 jdhq msltsn`o pdl wKqljdoh
by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(
fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks
mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla
nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka
uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml
jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh
llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad
fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd
fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj
yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde
19
141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde
wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd
uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr
wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS
wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh
u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka
gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska
jdhqj bylt iiumlmSvHdj meyeEgraves fotilde
bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu
jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO
wKqjg uacuteuacuteO fotilde mjS
fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg
ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash
jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk
ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde
bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS
fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq
wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj
fuu ska mldY flffrac34
fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh
mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt
uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka
jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr
iiumlnkaOdjh my ioacutelrKfhka nd foa
jyumlrga my oelafjk lreKq plusmnlauacuteh yels h
bull jdhq wxY= tlsfklska iajdhaj yeisffrac34
jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska
iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda
fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj
wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml
Wmlamkfhka meyeEgraves fotilde
bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla
u` ska mSvkhla wes fotilde
fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect
ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl
isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug
20
fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml
jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq
ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj
jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml
fotilde
142 pdl wKqljdofha ioacutelrKh
my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla
fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34
by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes
wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka
wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34
uOHkH fotilde h fi wfrac34 olajkq efiacute
143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h
my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu
jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg
jfrac34 uOHkH uQ fotilde h fotilde
jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla
jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=
Kkla i`oyd ioacutelrKh ild nuq
N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)
PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka
21
tu ksid jfrac34 uOHkH uQ fotilde h
fi suacuteh yels h
1 11 ksoiqk
25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak
uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1
by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj
fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama
lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml
pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh
u` ska th my oelafjk mszligEgrave idOkh llt yels h
fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt
yel
kB hkq fndaaUumliaudka kshh fotilde
22
wKqjla i`oyd
ujqhla i`oyd
fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq
fotilde
144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml
N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag
pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq
efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave
mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes
lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde
jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash
fi ye|skafotilde
16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--
fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd
fotilde jHdmash
23
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka
wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea
jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd
idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute
ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr
^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17
rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla
i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34
17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj
iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha
sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka
daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh
17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd
Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir
ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla
mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy
ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh
yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr
jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml
ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej
jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla
fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh
fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs
17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska
o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska
daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka
iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk
wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh
hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd
mszligudj (V)
mSvk
h (
P)
24
jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj
o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga
meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg
jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke
fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka
lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS
jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru
ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml
yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj
sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK
n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde
mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd
laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect
(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g
jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda
ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel
jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt
WIaKaj fotilde
daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o
WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel
fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg
jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml
fuh mltuq ioacutelrKfha wdfoaYfhka
fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH
ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk
nj wmg fmfka
fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh
pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we
tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj
hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h
mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq
wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt
jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect
jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia
PV mszligmQfrac34K
daauacutel
25
jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq
wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka
yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=
h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka
wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel
jdhq mszligmQfrac34K aajfhka wm ukh fotilde
151 jeka vrsquo jdaia ioacutelrKh
fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa
sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K
jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk
wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq
mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel
jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid
daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH
fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj
iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk
Egrave
bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka
kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka
mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka
igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash
iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg
fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh
mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde
1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj
ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh
by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK
fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde
gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq
mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde
fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg
iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq
msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect
moaOsfha mSvkh my mldYkfhka nd fohs
26
bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL
fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr
tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk
mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka
wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks
fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq
kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh
fi kej suacuteh yels h
fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh
fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql
nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia
flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha
wkafrac34--mszligjfrac34kh l yels fotilde
ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs
wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj
yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde
igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys
sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde
ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha
lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh
iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla
fi o yeisszligh yels ugraveu h
bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla
oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi
mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS
30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc
oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi
muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu
WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla
oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde
( )2
aP V b RTV
+ minus =
27
19 rEmh CO2 j ldm igyk
1 3 j =j - ioacutelrK idrdxYh
jdhq kshuh intildelrKhksh j mjsk
idOl
mszligmQfrac34K jdhq kshuh PV = nRT ke
fndhsa kshuh n iy T
pdaia kshuh V = kT n iy P
wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T
wKql pdl ioacutelrKh
idudkH fotilde h
jfrac34 uOHkH fotilde h
jfrac34 uOHkH fotilde h
fvdaagkaf a wdxYsl mSvk
kshuh
PA = xA PT
PT = PA + PB + PC
iiumlmSvHd idOlh jdhq ujq 1la i|yd
jeka vZjdaia ioacutelrKh
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
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Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
3
sect riuml tlsfklg ioacutem o fkd fotilde tneuacuteka luja j ixuacuteOdkh jQ wxY=uh rgdjla plusmnlsh
yelafla gtk wjiadfotilde muŒ oslashj yd jdhq wjiad foflys sect u wxY= ieliS weafa wyUq
fi h fuys msMhla fi oslashj wjiadfotilde wes wxY=jg idfmaalaIj jdhq wjiadfotilde
wes wxY=jg jvd fotilde fhka yd ksoyia fi pkh uacuteh yels h flfia jqj o gtkj
wes wxY=j psh liumlmkjg muKla iSud fotilde my 11 j =fjka plusmnlafjk mszligEgrave
modfrac34fha wxY=j ieleiau yd tys psh mszligudj yevh iiumlmSvHdj yd gtkajh jeks
ufyaalaI =Kj fjkialiumljg =vq fohs
1 1 j =j gtk oslashj yd jdhq j =Kj =Kdaul ixikaokh
=Kh gtk oslashj jdhq
yevh ksYaNtilde h wvx = n`yumlfkys
yevh kakd uqa
n`yumlfkys uq`M mszligudj
mqrd fkd mesfrhs
n`yumlfkys yevh
kakd wr
n`yumlfkys iuia
mszligudj wa lr kS
mszligudj ksYaNtilde h ksYaNtilde h wvx = n`yumlfkys
mszligudj wa lr kS
gtkajh (ρ) g cm-3 (293 K sect)
bylt w hka kS
Wod( hlv
(7 874 g cm-3)
rula bylt w hka
kS
Wod( ch
(0 997 g cm-3)
w hka mylt h
Wod( yhsvcka
(0 071g cm-3)
iiumlmSvHdj iiumlmSvkh lsIacuteu
bd yumlIalr h
iiumlmSvkh lsIacuteu bd
yumlIalr h
fnfyuacuteka iiumlmSvkh
llt yels h
igyk ( oslashj wvx = n`yumlfkys yevh kakd nj wm i`oyka lr wes wr tfia jkafka
ukaoehs issh hq= h idudkHfhka acutekE u jia=jla wkafrac34-wKql n jeks uacuteuacuteO jfrac34 fha
n u` ska tlg ne| nd kakd neuacuteka thg ksYaNtilde yevhla we icirclrhl wes fok o
c mudKhla ^mszligudjlaamp hiuml yevhla kafka mDIaAgravel wdsh ksid h oslashjh =lt mjsk
wkafrac34-wKql n ksid mDIaGh flltjffrac34 l=vd oslashj udjlhla wes fotilde icirclrfha igraveas u` ska
oslashjh u byltg aumljla wes flfrk wr mDIaAgravel wdshg jvd jeauml =reajc nh
u` ska myltg weoSula wes fotilde tuksid oslashjh byltska iu mDIaGhla iysj icirclrfha
yevh kS fufia jkafka fuu uacuteuacuteO jfrac34 fha ishuml nj nmEu ksid h flfia jqj
o mDIaAgravel wdsh =reajc nhg jvd mn jQjd kiuml cfha mDIaGh iu fkdjk
wr n`yumlfka yevh fkd kq we =reajc nhla keehs is=j fyda mDIaAgravel wdsh
fndfyda fihska bylt hhs mDIaGfha tla tla fldgilg u wfkla mDIaGh iu` yels riuml
ltx ugrave mejSug wjYH ksid tajd wr wes wdlfrac34IK wju lr ekSug fmfograve tneuacuteka
fok o mszligudjl wju mDIaAgravel lafIaMhla wes fyd`o u yevh jk f dadldr yevh
kS
ralsrSfuka fyda isiskfhka tla wjiadjl mjsk modfrac34h ja wjiadjlg mszligjfrac34kh
llt yels h WIaKajh jeauml lsIacutefiuml sect wxY=j pk fotilde h bylt hEua wxY= wr yumlr jeauml
ugraveua lrK fldg modfrac34j wjiadj fjkia fotilde ta wkqj WIaKajh jeauml lsIacutefiuml sect gtk
wjiadfotilde wes oslashjH oslashj wjiadjga oslashj wjiadfotilde wes oslashjH jdhq wjiadjga ma fotilde
WIaKajfha wvq ugraveua iu isyuml jkafka fuys uacutefdauhhs my 12 rEmfhka modfrac34h tys
wjiad wr wkafrac34-mszligjfrac34khg Ndck llt yels wdldrh fmkakqiuml flffrac34
4
12 rEmh modfrac34fha wjiad wr wkafrac34-mszligjfrac34kh
11 ksoiqk
wxY= jvda u ioacutem fi iamfrac34Y jkafka ugrave kuqa tajd wyUq fi weysIacute weafa modfrac34fha
ljr kiuml wjiadfotilde o
uacutei`yumlu oslashj wjiadj
11 j =jg wkqj wm modfrac34fha mOdk wjiad =fkys =K uacuteiar lrk uacuteg wxY=j ieliqu
yd pkh uQslj ild nd we uacutefYaIfhka u hiuml oslashjHhl wes wKq fyda mrudKqj
pkh ksid yg kakd Ylash dmc Ylash jk wr th oslashjHfha WIaKajhg wkqfdauj
iudkqmdsl fotilde tu` ska modfrac34fha wes wxY=j uOHkHh pdl Ylash uefkk neuacuteka
th wxY=j pkh fyda dmc psh i`oyd fya= fotilde
wkafrac34-wKql n u` ska wKq tlsfklg ltx ugrave mejSug fmfUk nj wm oekgua
okakd kuqa wKqj dmc Ylash u` ska wKq tlsfklska wEa ugraveug fmfograve ta wkqj
modfrac34fha mOdk wjiad =fkys mejSu wKqj wkafrac34-wKql n iy dmc Ylash
wr iu=sfhys msMhla fi ielsh yels h
wkafrac34-wKql wdlfrac34IK bd yumln jk uacuteg WIaKajh wvq lsIacutefuka dmc Ylash WIaKajhamp
wvq fkdllt fyda wKq oslashj fyda gtk fyda fi mejSug fkd fmfograve wKq tlsfklg
bd lt` ska wes uacuteg iy wkafrac34 - wKql n Wmszliguj wes uacuteg mjd iiumlmSvkh u` ska muKla
jdhq oslashj wjiadjg ma fkd fotilde flfia jqj o WIaKajh wvq lsIacuteu u` ska wKqj dmc
Ylash wvq jk uacuteg jdhq bd myiqfjka oslashj llt yels h fiuml yeisIacuteiuml my 1 3 rEmfhka
meyeEgraves llt yels h modfrac34fha mOdk wjiad =k flfrys wkafrac34-wKql nj yd dmc
Ylasfha msuacutereoaO nmEfiuml iajNdjh wmg tu` ska wjfndaO lr yels h
5
13 rEmh wkafrac34-wKql n yd dm Ylash wkqj modfrac34fha mOdk wjiad
=fkys yeisIacuteu
modfrac34fha mOdk wjiad =kla mejSug fya=j wm oekgua yodrd we oeka wm
modfrac34fha jdhquh yeisIacuteug fya= jk jdhq kshu iy jdhquh wjiAdj msltsn`o j yumlrga
ild nuq
12 jdhquh wjiadj
oeka wm idudkH WIaKaj mSvk aaj hgfa wes jdhquh wjiadfotilde mjsk oslashjHj
yeisIacuteu flfrys wjOdkh fhduq lruq
11 j =fotilde uacuteiar lr wes mszligEgrave jdhquh wjiadj my i`oyka fNsl =K wkqj uacuteiar
flffrac34
bull jdhq bd iiumlmSvH fotilde
bull jdhq ieu EgraveYdjlg u iudk whqszligka mSvkh wes lrhs
bull jdhqjg gtk iy oslashjjg jvd wvq gtkajhla we
bull jdhqj yevh iy mszligudj ksH fkd fotilde tajd wvx = Ndckfha yevh iy mszligudj
kS
bull jdhq lsis u hdkasl nmEulska fdrj iiumlmQfrac34Kfhka u iy iudkj tlsfkl
iuOtilde ntildeY fotilde
jdhqjl irdjhg fya= jkafka tu wKq wr mjsk n fkd ssbquoh yels ugraveuhs tajdfha
yeisIacuteu mIacutelaIKdaul wOHhkhkaf ka nd a msM u` ska fidhd kakd o fmdyuml jdhq kshujg (miqj idlEacutePd flffrac34iexcl) wkqj isyuml fotilde fiuml jdhq kshu hkq jdhqjl ueksh
yels =K wr mjsk iiumlnkaOd fotilde ueksh yels =K iuyrla jk mSvkh mszligudj
WIaKajh iy mudKh ^ujq fyda ialkaOhamp jeks tajd bd jeo a jkafka fiuml uacutepH
wr mjsk iiumlnkaOd jdhqjl mOdk wjiad (5 jk tallfha sect wfrac34 olajkq efiacuteiexcl) uacuteiar lrk ksid h tlsfkl yd ne`yumlKq fiuml uacutepHhka jdhq kshu iQ lsIacuteug uQsl
ugrave we
121 jdhq kshu
wm idlEacutePd lsIacuteug hk jdhq kshu uacuteoHdhka lsysm fokl= uacuteiska jdhqj fNsl =K
mokiumlj isyuml lrk o mIacutelaIKjska nd a msM fotilde mSvkh WIaKajh mszligudj iy
jdhq mudKh hk uacutepH wr mjsk iiumlnkaOd fuys sect ild nk wr tajd u` ska
6
modfrac34fha jdhquh wjiadj msltsn`o udkj jfrac34 hdg mfhdackja jk fdr=re rdYshla
mldY fotilde
mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq ioacutelrKh
jdhq wKq wr wkafrac34-wKql n fkdues nj Wmlamkh flffrac34 o tndivide jdhqjla mszligmQfrac34K
jdhqjla fi ye`Egravekafotilde tkiuml mszligmQfrac34K jdhqjl wKq wr wdlfrac34IK fyda uacutelfrac34IK fyda
n fkd mjS tfuka u jdhqj oud wes Ndckfha mszligudj iu` ieipoundfiuml sect jdhq wxY=jl
mszligudj fkdild yeszligh yels h
jdhqjl ksrfmalaI WIaKajh (T) mSvkh (P) mszligudj (V) iy oslashjH mudKh ^n ujqamp
jdhquh yeisIacuteu flfrys nmdk idOl fotilde P T V iy n wr iiumlnkaOdj my
mldYkfhka ksrEmKh flffrac34
fuh mszligmQfrac34K jdhq ioacutelrKh fyda mszligmQfrac34K jdhq kshuh fi oelafjk wr R hkq ieu
jdhqjlg u fmdyuml w hla wes jdhq kshh fotilde fok o acutekE u WIaKajhl sect yd
mSvkhl sect by iiumlnkaOdjg wkql+j yeisfrk acutekE u jdhqjla mszligmQfrac34K jdhqjla fi
y`yumlkajkq efiacute
fuu aaj hgfa oS mszligmQfrac34K jdhq ujq 1 la i|yd 0 degC sect yd 1 atm sect R kshfha w h
my wdldrhg Kkh l yel (0 degC sect yd 1 atm yssect mszligmqfrac34K jdhqjl 1 mol l mszligudj
22 414 dm3 fotilde)
mszligmQfrac34K jdhq ioacutelrKh by uacutepH yr wr wes iiumlnkaOdj jk nj wmg fmfkk
wr acutekE u jdhqjl wjiadj tuOtildeska uacuteiar flfrk ksid th wjiad ioacutelrKh fi
o ye|skafotilde
mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ Kkh lsIacuteiuml
mszligmQfrac34K jdhq ioacutelrKh u` ska wmg mszligudj WIaKajh mSvkh fyda ujq mudKh hk
tajdhska =kla sect wes uacuteg wfkla rdYsh ksfrac34Kh llt yels h jdhqjl ujq mudKh okakd
uacuteg tys ujqsl ialkaOh Nduacutefhka tys ialkaOh o Kkh llt yels h tfuka u
tu` ska jdhqjl gtkajh o ksfrac34Kh llt yels h mszligmQfrac34K jdhq kshfha w hg eltfmk
mszligEgrave wfkl=a rdYsj tall Nduacute lsIacuteu bd jeo a jk nj ul nd hq= h
idudkHfhka mSvkh atm Pa bar torr jeks tall jska mldY llt yels h tneuacuteka fiuml
eguml uacutei`oSfiuml sect my 1 2 j =fotilde sect wes mSvk tallj mszligjfrac34k Tng Wootilde jkq we
12 j =j mSvkh i`oyd jk tall
mSvk tallh Pa bar atm torr mmHg
1 Pa 1 N m-2 10-5 9 87 times 10-6 7 5 times 10-3
1 bar 100000 1bar 0 987 750 061 atm 101325 1 01325 1 atm 7601 torr mmHg 133 32 1 3332 times 10-3 1 3158 times 10-3 1 torr 1 mmHg
7
12 ksoiqk
jdhq isskavrhl mszligudj 0950 dm3 fotilde hiuml mSvkhla hgfa sect fiuml isskavrh oslashj
fmdfmakajska (C3H8) msIacute we isskavrh ysia jQ uacuteg jdhqf daSh mSvkh yd WIaKajh
hgfa sect tys fmdfmaka jdhqj hiuml mudKhla bsszlig fotilde
(i) wjg mszligirfha aaj 25degC iy 750 torr (1 torr = 133 52 Pa) kiuml isskavrh
ysiaj wes uacuteg tys bsszlig ugrave wes fmdfmaka jdhq ujq mudKh fldmuK o
(wNHkar mSvkh ndysr mSvkhg iudk uacuteg oS)
(ii) isskavrfha bsszlig ugrave wes fmdfmaka jdhq ialkaOh Kkh lrkak
(iii) isskavrfha bsszlig ugrave wes fmdfmaka jdhqfotilde gtkajh Kkh lrkak
uacutei`yumlu (i) mltuqj sect wes fdr=re iudfdapkh lrkak
WIaKajh T = (25 + 273) K = 298 K mSvkh P = 750 torr times 13332 Pa 1 torr = 99990 Pa mszligudj V = 0 950 dm3 = 0 950 times 10-3 m3
n fkdokakd moh fotilde
PV = nRT Nduacutefhka
(ii) fmdfmakays (C3H8) ujqsl ialkaOh = 44 g mol-1
fmdfmakays ialkaOh = 0 038 mol times 44 g mol-1 = 1 672 g
(iii) fmdfmakays gtkajh = ialkaOh mszligudj = = 1 76 g dm-3
by ksoiqk iel+ uacuteg mszligmQfrac34K jdhq kshuh uacuteuacuteO wdldrjska bEgraveszligma llt yels nj
fmkS hk wr my oelafjk mszligEgrave ir fjkia lsIacuteulska fok o jdhqjl ialkaOh
iy gtkajh fiuacuteh yels h
PV = nRT
P = RT
zwnjzwnj P = CRT
fuys zC Zhkq idkaoslashKhhs
j o PV = nRT iiumlnkaOdj my mszligEgrave o mldY llt yels h
PV = RT
fuys m hkq ialkaOh jk wr M hkq jdhqfotilde ujqsl ialkaOhhs
P = RT fi o suacuteh yels h
8
gtkajh (d) =
there4 P =
uacutefYaIs aaj hgfA fjka jdhq kshu jHqamkak lsIacutefiuml sect mszligmQfrac34K jdhq kshuh uQsl
moku fi lshd lrhs
122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)mdashksh WIaKajhla hgfa wes iaOacuter jdhq mudKhl (ialkaOhl) mSvkh jdhqfotilde mszligudjg
msfdauj uacutepkh fotilde (fyda iudkqmdsl) fotilde˜ fndhsa kshuh hkqfjka ye`Egravekafjk
fuh tfia kiuml lrk oafoa 17 jeks ishjfia sect WIaKajh ksh jQ aaj hgfa fjkia
jk mSvkha iu jdhqjl mszligudj uacutepkh jk wdldrh whsszligIa cdsl uacuteoHdhl= jQ
frdnUuml fndhsa (1627- 1691) uacuteiska wOHhkh lsIacutefuka miqj h tys Ksuh wdldrh
my oelafotilde
my plusmnlafjk mszligEgrave fndhsa kshuh jHqamkak lsIacuteu i`oyd mszligmQfrac34K jdhq kshuh fhdod
yelsh PV= nRT
jdhqfjys mudKh yd moaOsfhys WIaKajh kshj mjajd kakd oafoa kiuml nT =Ksh
kshhla fotilde R o kshhla jk neuacuteka nRT =Ksh o kshhla (k) fotilde
PV = k (kshhla)
tkiuml ksh WIaKajfha sect ksh jdhq mudKhl mSvkfhaa mszligudfotildea =Ksh kshhla
fotilde fuh fndhsa kshuh mldY lrk fjka wdldrhls
ksh T WIaKajhl wes ksh jdhq mudKhl mszligudj V1 o mSvkh P1 o kiuml yd th V2
mszligudjg yd P2 mSvkhg ma llt uacuteg fndhsa kshuhg wkqj
14 rEmh u` ska fndhsa kshufha idiumlmodhsl miadszligl ksrEmK folla fmkakqiuml flffrac34
14 rEmfha (a) u` ska ixikaokh i`oyd uacuteuacuteO WIaKajj sect PV = k miadr lr we
k w h WIaKajh u muKla r`od mjsk ksid fok o jdhq ialkaOhla i`oyd w`Egravek
o ieu jlhla i`oyd u k ys w h tlsfklg fjkia fotilde bylt WIaKajj sect mszligudfotilde
midrKh ksid plh byltg f dia wes nj ielsh hq= h tfuka u WIaKajh ksh
uacuteg jdhqfotilde mSvkh wvla jk uacuteg mszligudj fo =K jk nj ul nd hq= h
9
1 4 rEmh uacuteuacuteO ksh WIaKajj sect (a) mszligudj (V) iuOtilde (b) 1 V iuOtilde
mSvkfha fjkia ugraveu
14 (b) rEmh u` ska P g tosrsfhka ys miadrh ksrEmKh fotilde th uQ laIHh yryd hk
ir ffrac34Ldjls fndhsa uacuteiska lrk o mIacutelaIKjg wkqj nd kakd o fuu miadr
u` ska jdhqjg bylt iiumlmSvHdjla wes nj mudKdaulj fmkajd foa tkiuml fok o
jdhq ialkaOhla iiumlmSvkh llt uacuteg tl u mudKhlska wes wKq ixLHdj l=vd mszligudjla
=lt mesffrac34 fiuml wkqj bylt mSvkj sect jdhqj gtkajh jeauml fotilde
igyk fok o jdhqjl gtkajh d ialkaOh m o mszligudj v o jk uacuteg d = ioacutelrKfhka
fok nj wms oksuq tuksid ksh WIaKajfhasect
hkqfjka suacuteh yels h
1 3 ksoiqk
ksh WIaKajhla hgfa wes okakd jdhq ujq mudKhl mszligudj fo =K llt uacuteg
mSvkfha isyuml jk fjkia ugraveu Kkh lrkak
uacutei`yumlu V1 =V V2 = 2V P1 = P P2 = fndhsa kshuh fhsectfuka P1V1 = P2V2
P times V = P2 times 2VP2 = P 2 there4kj mSvkh uqa mSvkfhka wvla fotilde
10
1 4 ksoiqk
ldur WIaKajfha sect neumlkhla yhsvcka jdhqj okakd mudKhlska mqrjd we jdhqf daSh
mSvkfha sect (100 kPa) tu jdhq mudKh 2 50 dm3 l mszligudjla kS tu WIaKajfha sect u
we=lt mSvkh 20 kPa ugraveug neumlkfha mszligudj fldmuK uacuteh llt hq= o
uacutei`yumlu P1 = 100 kPa P2 = 20 kPa V1 = 2 5 dm3 V2 = fndhsa kshuh fhsectfuka P1V1 = P2V2
100 kPa times 2 5 dm3 = 20 kPa times V2 there4V2 = 12 5 dm3 neumlkfha mszligudj 12 5 dm3 olajd jeauml llt hq= h
123 pdaia kshuh (WIaKaj-mszligud iiumlnkaOh)cdlaia pdaia iy fcdaIma f a-umliela hk uacuteoHdhkaf a yeoEIacuteiuml u ska fmkajd sect wes mszligEgrave
ksh mSvkhl sect fok o ksH jdhq mudKhl ^ialkaOhamp mszligudj WIaKajha iu`
jeauml jk wr isisa lsIacuteua iu` wvq fotilde tfuka u WIaKajfhA isyuml jk ieu fiaishia
wxYlhl fjkila mdid ^jeauml ugraveu fyda wvq ugraveuamp mszligudj 0degC sect jdhqfotilde wdriumlNl mszligudfjka idOlhlska fjkia jk nj ^jeauml ugraveu fyda wvq ugraveuamp fidhd f k we
0 degC sect iy t degC ys sect jdhqfotilde mszligudj msltsfjltska V0 iy Vt hhs Wmlamkh lruq tuacuteg
fuu aajfha sect WIaKajh i`oyd kj mszligudKhla wfrac34 olajd we tuacuteg tu mszligudKhg
wkqj
t degC i`oyd Tt = 273 15 + t uOtildeska nd fok wr
0 degC i`oyd T0 = 273 15 uOtildeska nd fohs
fuu kj WIaKaj mszligudKh flauacuteka WIaKaj mszligudKh (K) fyja ksrfmalaI WIaKaj
mszligudKh fi ye`Egravekafotilde ndash 273 15 degC (0 K) hkak dm sl Y+kHh fi wfrac34 oelafjk
wr th ffioaOdkaslj lt` d uacuteh yels wju WIaKajh fotilde
fmdyumlfotilde a uacuteg ksh mSvkfha sect (V1 T1) isg (V2 T2) olajd isyuml jk fjkila i`oyd
11
tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg
wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde
jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys
WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg
yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h
PV = nRTV = nRT P
ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde
zwnjzwnjzwnjzwnjV prop T fyda V = kT
pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka
WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd
Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect
ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh
lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34
15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde
uacutepkh
12
1 5 ksoiqk
ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml
jk WIaKaj fjki Kkh lrkak
uacutei`yumlu
T1 = T V1 = V V2 = 3V T2 =
T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh
wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h
hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi
efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg
lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr
kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde
1 6 ksoiqk
23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde
tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki
Kkh lrkak
uacutei`yumlu
T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =
jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka
V2 = 2 03 dm3
mszligudfotilde isyumljk fjki = 0 03 dm3
124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=
jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj
lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla
hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)
fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h
13
jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda
kshh (NA fyda L) fi ye|skafotilde
my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka
wjfndaO lr yels h
fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl
u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud
follg by iiumlnkaOdj fhsectfuka
P iy T ksh uacuteg sect (R iy NA kshhka fotilde )
irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud
=lt iudk wKq ixLdjla wvx= fotilde (V α N)
by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd
mszligmQfrac34K jdhq ioacutelrKh nd yels h
by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka
k = R jQ uacuteg
P V = n R T
14
125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka
fi wmg suacuteh yels h
iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd
mszligudj (Vm) tl u w hla uacuteh hq= ksid th
fi Kkh llt yels h
tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u
mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34
bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu
aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj
22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi
ksrEmKh flffrac34
bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde
fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde
igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde
V = k n = k (m M) tneuacuteka M = k (m V) = k d
1 7 ksoiqk
298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud
iudk nj fmkajkak
uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe
VHe = nHeRTHe PHe
VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3
15
PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =
PNeVNe = nNeRTNe
VNe = nNeRTNe PNe
VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa
VNe = 24 4 dm3
tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq
wa lr kakd mszligud iudk fotilde
126 ixhqla jdhq kshuh
jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj
tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka
T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla
fi suacuteh yels h
fuh ixhqla jdhq kshuh fi ye|skafotilde
1 8 ksoiqk
25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o
uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh
P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3
T1 = 25 + 273 = 298 K
V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =
P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa
16
13 fvdaagkaf a wdxYsl mSvk kshuh
fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm
yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk
wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml
ishuml jdhq odhl fotilde
jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj
wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde
ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla
iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs
fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh
fi yeEgravekafotilde
A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska
PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde
my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka
jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha
we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh
PT hehs o isuq
PV = nRT
A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )
B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )
jdhq ntildeYKh i`oyd nT = PTV RT
iy nT = nA + nB
tu ksid PTV RT = (PAV RT) + (PBV RT)
iq`M llt uacuteg PT = PA + PB
fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl
131 ujq Nd h wkqidrfhka wdxYsl mSvkh
T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq
ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde
fvdaagkaf a kshuhg wkqj PT = PA + PB
PA iy PB mldYk fjk fjk u PT jska fnsectfuka
17
tu ksid
fi suacuteh yels h
hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk
fotilde
1 9 ksoiqk
(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla
tla jdhqfotilde wdxYsl mSvkh Kkh lrkak
(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd
lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq
ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak
uacutei`yumlu
18
fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK
u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd
fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj
tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla
fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re
uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq
irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq
efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj
u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk
nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja
ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj
mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=
jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes
lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect
tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh
wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K
jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl
1 10 ksoiqk
my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs
iskak
2KClO3(s) rarr2KCl(s) + 3O2(g)
27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute
27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh
Kkh lrkak
uacutei`yumlu
fvdaagkaf a kshuhg wkqj
Piuia = PTlaiscka + Pch
PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa
mszligmQfrac34K jdhq ioacutelrKh fhsectfuka
14 jdhq msltsn`o pdl wKqljdoh
by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(
fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks
mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla
nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka
uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml
jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh
llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad
fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd
fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj
yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde
19
141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde
wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd
uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr
wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS
wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh
u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka
gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska
jdhqj bylt iiumlmSvHdj meyeEgraves fotilde
bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu
jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO
wKqjg uacuteuacuteO fotilde mjS
fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg
ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash
jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk
ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde
bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS
fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq
wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj
fuu ska mldY flffrac34
fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh
mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt
uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka
jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr
iiumlnkaOdjh my ioacutelrKfhka nd foa
jyumlrga my oelafjk lreKq plusmnlauacuteh yels h
bull jdhq wxY= tlsfklska iajdhaj yeisffrac34
jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska
iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda
fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj
wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml
Wmlamkfhka meyeEgraves fotilde
bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla
u` ska mSvkhla wes fotilde
fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect
ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl
isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug
20
fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml
jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq
ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj
jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml
fotilde
142 pdl wKqljdofha ioacutelrKh
my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla
fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34
by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes
wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka
wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34
uOHkH fotilde h fi wfrac34 olajkq efiacute
143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h
my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu
jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg
jfrac34 uOHkH uQ fotilde h fotilde
jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla
jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=
Kkla i`oyd ioacutelrKh ild nuq
N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)
PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka
21
tu ksid jfrac34 uOHkH uQ fotilde h
fi suacuteh yels h
1 11 ksoiqk
25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak
uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1
by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj
fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama
lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml
pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh
u` ska th my oelafjk mszligEgrave idOkh llt yels h
fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt
yel
kB hkq fndaaUumliaudka kshh fotilde
22
wKqjla i`oyd
ujqhla i`oyd
fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq
fotilde
144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml
N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag
pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq
efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave
mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes
lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde
jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash
fi ye|skafotilde
16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--
fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd
fotilde jHdmash
23
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka
wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea
jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd
idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute
ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr
^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17
rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla
i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34
17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj
iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha
sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka
daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh
17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd
Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir
ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla
mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy
ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh
yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr
jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml
ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej
jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla
fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh
fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs
17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska
o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska
daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka
iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk
wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh
hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd
mszligudj (V)
mSvk
h (
P)
24
jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj
o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga
meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg
jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke
fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka
lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS
jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru
ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml
yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj
sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK
n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde
mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd
laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect
(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g
jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda
ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel
jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt
WIaKaj fotilde
daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o
WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel
fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg
jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml
fuh mltuq ioacutelrKfha wdfoaYfhka
fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH
ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk
nj wmg fmfka
fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh
pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we
tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj
hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h
mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq
wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt
jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect
jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia
PV mszligmQfrac34K
daauacutel
25
jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq
wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka
yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=
h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka
wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel
jdhq mszligmQfrac34K aajfhka wm ukh fotilde
151 jeka vrsquo jdaia ioacutelrKh
fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa
sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K
jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk
wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq
mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel
jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid
daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH
fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj
iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk
Egrave
bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka
kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka
mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka
igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash
iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg
fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh
mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde
1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj
ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh
by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK
fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde
gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq
mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde
fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg
iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq
msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect
moaOsfha mSvkh my mldYkfhka nd fohs
26
bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL
fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr
tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk
mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka
wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks
fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq
kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh
fi kej suacuteh yels h
fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh
fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql
nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia
flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha
wkafrac34--mszligjfrac34kh l yels fotilde
ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs
wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj
yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde
igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys
sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde
ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha
lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh
iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla
fi o yeisszligh yels ugraveu h
bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla
oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi
mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS
30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc
oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi
muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu
WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla
oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde
( )2
aP V b RTV
+ minus =
27
19 rEmh CO2 j ldm igyk
1 3 j =j - ioacutelrK idrdxYh
jdhq kshuh intildelrKhksh j mjsk
idOl
mszligmQfrac34K jdhq kshuh PV = nRT ke
fndhsa kshuh n iy T
pdaia kshuh V = kT n iy P
wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T
wKql pdl ioacutelrKh
idudkH fotilde h
jfrac34 uOHkH fotilde h
jfrac34 uOHkH fotilde h
fvdaagkaf a wdxYsl mSvk
kshuh
PA = xA PT
PT = PA + PB + PC
iiumlmSvHd idOlh jdhq ujq 1la i|yd
jeka vZjdaia ioacutelrKh
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
4
12 rEmh modfrac34fha wjiad wr wkafrac34-mszligjfrac34kh
11 ksoiqk
wxY= jvda u ioacutem fi iamfrac34Y jkafka ugrave kuqa tajd wyUq fi weysIacute weafa modfrac34fha
ljr kiuml wjiadfotilde o
uacutei`yumlu oslashj wjiadj
11 j =jg wkqj wm modfrac34fha mOdk wjiad =fkys =K uacuteiar lrk uacuteg wxY=j ieliqu
yd pkh uQslj ild nd we uacutefYaIfhka u hiuml oslashjHhl wes wKq fyda mrudKqj
pkh ksid yg kakd Ylash dmc Ylash jk wr th oslashjHfha WIaKajhg wkqfdauj
iudkqmdsl fotilde tu` ska modfrac34fha wes wxY=j uOHkHh pdl Ylash uefkk neuacuteka
th wxY=j pkh fyda dmc psh i`oyd fya= fotilde
wkafrac34-wKql n u` ska wKq tlsfklg ltx ugrave mejSug fmfUk nj wm oekgua
okakd kuqa wKqj dmc Ylash u` ska wKq tlsfklska wEa ugraveug fmfograve ta wkqj
modfrac34fha mOdk wjiad =fkys mejSu wKqj wkafrac34-wKql n iy dmc Ylash
wr iu=sfhys msMhla fi ielsh yels h
wkafrac34-wKql wdlfrac34IK bd yumln jk uacuteg WIaKajh wvq lsIacutefuka dmc Ylash WIaKajhamp
wvq fkdllt fyda wKq oslashj fyda gtk fyda fi mejSug fkd fmfograve wKq tlsfklg
bd lt` ska wes uacuteg iy wkafrac34 - wKql n Wmszliguj wes uacuteg mjd iiumlmSvkh u` ska muKla
jdhq oslashj wjiadjg ma fkd fotilde flfia jqj o WIaKajh wvq lsIacuteu u` ska wKqj dmc
Ylash wvq jk uacuteg jdhq bd myiqfjka oslashj llt yels h fiuml yeisIacuteiuml my 1 3 rEmfhka
meyeEgraves llt yels h modfrac34fha mOdk wjiad =k flfrys wkafrac34-wKql nj yd dmc
Ylasfha msuacutereoaO nmEfiuml iajNdjh wmg tu` ska wjfndaO lr yels h
5
13 rEmh wkafrac34-wKql n yd dm Ylash wkqj modfrac34fha mOdk wjiad
=fkys yeisIacuteu
modfrac34fha mOdk wjiad =kla mejSug fya=j wm oekgua yodrd we oeka wm
modfrac34fha jdhquh yeisIacuteug fya= jk jdhq kshu iy jdhquh wjiAdj msltsn`o j yumlrga
ild nuq
12 jdhquh wjiadj
oeka wm idudkH WIaKaj mSvk aaj hgfa wes jdhquh wjiadfotilde mjsk oslashjHj
yeisIacuteu flfrys wjOdkh fhduq lruq
11 j =fotilde uacuteiar lr wes mszligEgrave jdhquh wjiadj my i`oyka fNsl =K wkqj uacuteiar
flffrac34
bull jdhq bd iiumlmSvH fotilde
bull jdhq ieu EgraveYdjlg u iudk whqszligka mSvkh wes lrhs
bull jdhqjg gtk iy oslashjjg jvd wvq gtkajhla we
bull jdhqj yevh iy mszligudj ksH fkd fotilde tajd wvx = Ndckfha yevh iy mszligudj
kS
bull jdhq lsis u hdkasl nmEulska fdrj iiumlmQfrac34Kfhka u iy iudkj tlsfkl
iuOtilde ntildeY fotilde
jdhqjl irdjhg fya= jkafka tu wKq wr mjsk n fkd ssbquoh yels ugraveuhs tajdfha
yeisIacuteu mIacutelaIKdaul wOHhkhkaf ka nd a msM u` ska fidhd kakd o fmdyuml jdhq kshujg (miqj idlEacutePd flffrac34iexcl) wkqj isyuml fotilde fiuml jdhq kshu hkq jdhqjl ueksh
yels =K wr mjsk iiumlnkaOd fotilde ueksh yels =K iuyrla jk mSvkh mszligudj
WIaKajh iy mudKh ^ujq fyda ialkaOhamp jeks tajd bd jeo a jkafka fiuml uacutepH
wr mjsk iiumlnkaOd jdhqjl mOdk wjiad (5 jk tallfha sect wfrac34 olajkq efiacuteiexcl) uacuteiar lrk ksid h tlsfkl yd ne`yumlKq fiuml uacutepHhka jdhq kshu iQ lsIacuteug uQsl
ugrave we
121 jdhq kshu
wm idlEacutePd lsIacuteug hk jdhq kshu uacuteoHdhka lsysm fokl= uacuteiska jdhqj fNsl =K
mokiumlj isyuml lrk o mIacutelaIKjska nd a msM fotilde mSvkh WIaKajh mszligudj iy
jdhq mudKh hk uacutepH wr mjsk iiumlnkaOd fuys sect ild nk wr tajd u` ska
6
modfrac34fha jdhquh wjiadj msltsn`o udkj jfrac34 hdg mfhdackja jk fdr=re rdYshla
mldY fotilde
mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq ioacutelrKh
jdhq wKq wr wkafrac34-wKql n fkdues nj Wmlamkh flffrac34 o tndivide jdhqjla mszligmQfrac34K
jdhqjla fi ye`Egravekafotilde tkiuml mszligmQfrac34K jdhqjl wKq wr wdlfrac34IK fyda uacutelfrac34IK fyda
n fkd mjS tfuka u jdhqj oud wes Ndckfha mszligudj iu` ieipoundfiuml sect jdhq wxY=jl
mszligudj fkdild yeszligh yels h
jdhqjl ksrfmalaI WIaKajh (T) mSvkh (P) mszligudj (V) iy oslashjH mudKh ^n ujqamp
jdhquh yeisIacuteu flfrys nmdk idOl fotilde P T V iy n wr iiumlnkaOdj my
mldYkfhka ksrEmKh flffrac34
fuh mszligmQfrac34K jdhq ioacutelrKh fyda mszligmQfrac34K jdhq kshuh fi oelafjk wr R hkq ieu
jdhqjlg u fmdyuml w hla wes jdhq kshh fotilde fok o acutekE u WIaKajhl sect yd
mSvkhl sect by iiumlnkaOdjg wkql+j yeisfrk acutekE u jdhqjla mszligmQfrac34K jdhqjla fi
y`yumlkajkq efiacute
fuu aaj hgfa oS mszligmQfrac34K jdhq ujq 1 la i|yd 0 degC sect yd 1 atm sect R kshfha w h
my wdldrhg Kkh l yel (0 degC sect yd 1 atm yssect mszligmqfrac34K jdhqjl 1 mol l mszligudj
22 414 dm3 fotilde)
mszligmQfrac34K jdhq ioacutelrKh by uacutepH yr wr wes iiumlnkaOdj jk nj wmg fmfkk
wr acutekE u jdhqjl wjiadj tuOtildeska uacuteiar flfrk ksid th wjiad ioacutelrKh fi
o ye|skafotilde
mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ Kkh lsIacuteiuml
mszligmQfrac34K jdhq ioacutelrKh u` ska wmg mszligudj WIaKajh mSvkh fyda ujq mudKh hk
tajdhska =kla sect wes uacuteg wfkla rdYsh ksfrac34Kh llt yels h jdhqjl ujq mudKh okakd
uacuteg tys ujqsl ialkaOh Nduacutefhka tys ialkaOh o Kkh llt yels h tfuka u
tu` ska jdhqjl gtkajh o ksfrac34Kh llt yels h mszligmQfrac34K jdhq kshfha w hg eltfmk
mszligEgrave wfkl=a rdYsj tall Nduacute lsIacuteu bd jeo a jk nj ul nd hq= h
idudkHfhka mSvkh atm Pa bar torr jeks tall jska mldY llt yels h tneuacuteka fiuml
eguml uacutei`oSfiuml sect my 1 2 j =fotilde sect wes mSvk tallj mszligjfrac34k Tng Wootilde jkq we
12 j =j mSvkh i`oyd jk tall
mSvk tallh Pa bar atm torr mmHg
1 Pa 1 N m-2 10-5 9 87 times 10-6 7 5 times 10-3
1 bar 100000 1bar 0 987 750 061 atm 101325 1 01325 1 atm 7601 torr mmHg 133 32 1 3332 times 10-3 1 3158 times 10-3 1 torr 1 mmHg
7
12 ksoiqk
jdhq isskavrhl mszligudj 0950 dm3 fotilde hiuml mSvkhla hgfa sect fiuml isskavrh oslashj
fmdfmakajska (C3H8) msIacute we isskavrh ysia jQ uacuteg jdhqf daSh mSvkh yd WIaKajh
hgfa sect tys fmdfmaka jdhqj hiuml mudKhla bsszlig fotilde
(i) wjg mszligirfha aaj 25degC iy 750 torr (1 torr = 133 52 Pa) kiuml isskavrh
ysiaj wes uacuteg tys bsszlig ugrave wes fmdfmaka jdhq ujq mudKh fldmuK o
(wNHkar mSvkh ndysr mSvkhg iudk uacuteg oS)
(ii) isskavrfha bsszlig ugrave wes fmdfmaka jdhq ialkaOh Kkh lrkak
(iii) isskavrfha bsszlig ugrave wes fmdfmaka jdhqfotilde gtkajh Kkh lrkak
uacutei`yumlu (i) mltuqj sect wes fdr=re iudfdapkh lrkak
WIaKajh T = (25 + 273) K = 298 K mSvkh P = 750 torr times 13332 Pa 1 torr = 99990 Pa mszligudj V = 0 950 dm3 = 0 950 times 10-3 m3
n fkdokakd moh fotilde
PV = nRT Nduacutefhka
(ii) fmdfmakays (C3H8) ujqsl ialkaOh = 44 g mol-1
fmdfmakays ialkaOh = 0 038 mol times 44 g mol-1 = 1 672 g
(iii) fmdfmakays gtkajh = ialkaOh mszligudj = = 1 76 g dm-3
by ksoiqk iel+ uacuteg mszligmQfrac34K jdhq kshuh uacuteuacuteO wdldrjska bEgraveszligma llt yels nj
fmkS hk wr my oelafjk mszligEgrave ir fjkia lsIacuteulska fok o jdhqjl ialkaOh
iy gtkajh fiuacuteh yels h
PV = nRT
P = RT
zwnjzwnj P = CRT
fuys zC Zhkq idkaoslashKhhs
j o PV = nRT iiumlnkaOdj my mszligEgrave o mldY llt yels h
PV = RT
fuys m hkq ialkaOh jk wr M hkq jdhqfotilde ujqsl ialkaOhhs
P = RT fi o suacuteh yels h
8
gtkajh (d) =
there4 P =
uacutefYaIs aaj hgfA fjka jdhq kshu jHqamkak lsIacutefiuml sect mszligmQfrac34K jdhq kshuh uQsl
moku fi lshd lrhs
122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)mdashksh WIaKajhla hgfa wes iaOacuter jdhq mudKhl (ialkaOhl) mSvkh jdhqfotilde mszligudjg
msfdauj uacutepkh fotilde (fyda iudkqmdsl) fotilde˜ fndhsa kshuh hkqfjka ye`Egravekafjk
fuh tfia kiuml lrk oafoa 17 jeks ishjfia sect WIaKajh ksh jQ aaj hgfa fjkia
jk mSvkha iu jdhqjl mszligudj uacutepkh jk wdldrh whsszligIa cdsl uacuteoHdhl= jQ
frdnUuml fndhsa (1627- 1691) uacuteiska wOHhkh lsIacutefuka miqj h tys Ksuh wdldrh
my oelafotilde
my plusmnlafjk mszligEgrave fndhsa kshuh jHqamkak lsIacuteu i`oyd mszligmQfrac34K jdhq kshuh fhdod
yelsh PV= nRT
jdhqfjys mudKh yd moaOsfhys WIaKajh kshj mjajd kakd oafoa kiuml nT =Ksh
kshhla fotilde R o kshhla jk neuacuteka nRT =Ksh o kshhla (k) fotilde
PV = k (kshhla)
tkiuml ksh WIaKajfha sect ksh jdhq mudKhl mSvkfhaa mszligudfotildea =Ksh kshhla
fotilde fuh fndhsa kshuh mldY lrk fjka wdldrhls
ksh T WIaKajhl wes ksh jdhq mudKhl mszligudj V1 o mSvkh P1 o kiuml yd th V2
mszligudjg yd P2 mSvkhg ma llt uacuteg fndhsa kshuhg wkqj
14 rEmh u` ska fndhsa kshufha idiumlmodhsl miadszligl ksrEmK folla fmkakqiuml flffrac34
14 rEmfha (a) u` ska ixikaokh i`oyd uacuteuacuteO WIaKajj sect PV = k miadr lr we
k w h WIaKajh u muKla r`od mjsk ksid fok o jdhq ialkaOhla i`oyd w`Egravek
o ieu jlhla i`oyd u k ys w h tlsfklg fjkia fotilde bylt WIaKajj sect mszligudfotilde
midrKh ksid plh byltg f dia wes nj ielsh hq= h tfuka u WIaKajh ksh
uacuteg jdhqfotilde mSvkh wvla jk uacuteg mszligudj fo =K jk nj ul nd hq= h
9
1 4 rEmh uacuteuacuteO ksh WIaKajj sect (a) mszligudj (V) iuOtilde (b) 1 V iuOtilde
mSvkfha fjkia ugraveu
14 (b) rEmh u` ska P g tosrsfhka ys miadrh ksrEmKh fotilde th uQ laIHh yryd hk
ir ffrac34Ldjls fndhsa uacuteiska lrk o mIacutelaIKjg wkqj nd kakd o fuu miadr
u` ska jdhqjg bylt iiumlmSvHdjla wes nj mudKdaulj fmkajd foa tkiuml fok o
jdhq ialkaOhla iiumlmSvkh llt uacuteg tl u mudKhlska wes wKq ixLHdj l=vd mszligudjla
=lt mesffrac34 fiuml wkqj bylt mSvkj sect jdhqj gtkajh jeauml fotilde
igyk fok o jdhqjl gtkajh d ialkaOh m o mszligudj v o jk uacuteg d = ioacutelrKfhka
fok nj wms oksuq tuksid ksh WIaKajfhasect
hkqfjka suacuteh yels h
1 3 ksoiqk
ksh WIaKajhla hgfa wes okakd jdhq ujq mudKhl mszligudj fo =K llt uacuteg
mSvkfha isyuml jk fjkia ugraveu Kkh lrkak
uacutei`yumlu V1 =V V2 = 2V P1 = P P2 = fndhsa kshuh fhsectfuka P1V1 = P2V2
P times V = P2 times 2VP2 = P 2 there4kj mSvkh uqa mSvkfhka wvla fotilde
10
1 4 ksoiqk
ldur WIaKajfha sect neumlkhla yhsvcka jdhqj okakd mudKhlska mqrjd we jdhqf daSh
mSvkfha sect (100 kPa) tu jdhq mudKh 2 50 dm3 l mszligudjla kS tu WIaKajfha sect u
we=lt mSvkh 20 kPa ugraveug neumlkfha mszligudj fldmuK uacuteh llt hq= o
uacutei`yumlu P1 = 100 kPa P2 = 20 kPa V1 = 2 5 dm3 V2 = fndhsa kshuh fhsectfuka P1V1 = P2V2
100 kPa times 2 5 dm3 = 20 kPa times V2 there4V2 = 12 5 dm3 neumlkfha mszligudj 12 5 dm3 olajd jeauml llt hq= h
123 pdaia kshuh (WIaKaj-mszligud iiumlnkaOh)cdlaia pdaia iy fcdaIma f a-umliela hk uacuteoHdhkaf a yeoEIacuteiuml u ska fmkajd sect wes mszligEgrave
ksh mSvkhl sect fok o ksH jdhq mudKhl ^ialkaOhamp mszligudj WIaKajha iu`
jeauml jk wr isisa lsIacuteua iu` wvq fotilde tfuka u WIaKajfhA isyuml jk ieu fiaishia
wxYlhl fjkila mdid ^jeauml ugraveu fyda wvq ugraveuamp mszligudj 0degC sect jdhqfotilde wdriumlNl mszligudfjka idOlhlska fjkia jk nj ^jeauml ugraveu fyda wvq ugraveuamp fidhd f k we
0 degC sect iy t degC ys sect jdhqfotilde mszligudj msltsfjltska V0 iy Vt hhs Wmlamkh lruq tuacuteg
fuu aajfha sect WIaKajh i`oyd kj mszligudKhla wfrac34 olajd we tuacuteg tu mszligudKhg
wkqj
t degC i`oyd Tt = 273 15 + t uOtildeska nd fok wr
0 degC i`oyd T0 = 273 15 uOtildeska nd fohs
fuu kj WIaKaj mszligudKh flauacuteka WIaKaj mszligudKh (K) fyja ksrfmalaI WIaKaj
mszligudKh fi ye`Egravekafotilde ndash 273 15 degC (0 K) hkak dm sl Y+kHh fi wfrac34 oelafjk
wr th ffioaOdkaslj lt` d uacuteh yels wju WIaKajh fotilde
fmdyumlfotilde a uacuteg ksh mSvkfha sect (V1 T1) isg (V2 T2) olajd isyuml jk fjkila i`oyd
11
tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg
wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde
jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys
WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg
yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h
PV = nRTV = nRT P
ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde
zwnjzwnjzwnjzwnjV prop T fyda V = kT
pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka
WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd
Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect
ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh
lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34
15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde
uacutepkh
12
1 5 ksoiqk
ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml
jk WIaKaj fjki Kkh lrkak
uacutei`yumlu
T1 = T V1 = V V2 = 3V T2 =
T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh
wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h
hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi
efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg
lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr
kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde
1 6 ksoiqk
23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde
tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki
Kkh lrkak
uacutei`yumlu
T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =
jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka
V2 = 2 03 dm3
mszligudfotilde isyumljk fjki = 0 03 dm3
124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=
jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj
lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla
hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)
fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h
13
jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda
kshh (NA fyda L) fi ye|skafotilde
my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka
wjfndaO lr yels h
fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl
u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud
follg by iiumlnkaOdj fhsectfuka
P iy T ksh uacuteg sect (R iy NA kshhka fotilde )
irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud
=lt iudk wKq ixLdjla wvx= fotilde (V α N)
by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd
mszligmQfrac34K jdhq ioacutelrKh nd yels h
by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka
k = R jQ uacuteg
P V = n R T
14
125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka
fi wmg suacuteh yels h
iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd
mszligudj (Vm) tl u w hla uacuteh hq= ksid th
fi Kkh llt yels h
tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u
mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34
bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu
aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj
22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi
ksrEmKh flffrac34
bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde
fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde
igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde
V = k n = k (m M) tneuacuteka M = k (m V) = k d
1 7 ksoiqk
298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud
iudk nj fmkajkak
uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe
VHe = nHeRTHe PHe
VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3
15
PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =
PNeVNe = nNeRTNe
VNe = nNeRTNe PNe
VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa
VNe = 24 4 dm3
tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq
wa lr kakd mszligud iudk fotilde
126 ixhqla jdhq kshuh
jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj
tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka
T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla
fi suacuteh yels h
fuh ixhqla jdhq kshuh fi ye|skafotilde
1 8 ksoiqk
25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o
uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh
P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3
T1 = 25 + 273 = 298 K
V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =
P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa
16
13 fvdaagkaf a wdxYsl mSvk kshuh
fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm
yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk
wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml
ishuml jdhq odhl fotilde
jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj
wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde
ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla
iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs
fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh
fi yeEgravekafotilde
A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska
PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde
my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka
jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha
we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh
PT hehs o isuq
PV = nRT
A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )
B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )
jdhq ntildeYKh i`oyd nT = PTV RT
iy nT = nA + nB
tu ksid PTV RT = (PAV RT) + (PBV RT)
iq`M llt uacuteg PT = PA + PB
fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl
131 ujq Nd h wkqidrfhka wdxYsl mSvkh
T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq
ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde
fvdaagkaf a kshuhg wkqj PT = PA + PB
PA iy PB mldYk fjk fjk u PT jska fnsectfuka
17
tu ksid
fi suacuteh yels h
hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk
fotilde
1 9 ksoiqk
(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla
tla jdhqfotilde wdxYsl mSvkh Kkh lrkak
(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd
lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq
ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak
uacutei`yumlu
18
fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK
u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd
fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj
tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla
fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re
uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq
irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq
efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj
u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk
nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja
ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj
mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=
jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes
lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect
tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh
wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K
jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl
1 10 ksoiqk
my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs
iskak
2KClO3(s) rarr2KCl(s) + 3O2(g)
27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute
27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh
Kkh lrkak
uacutei`yumlu
fvdaagkaf a kshuhg wkqj
Piuia = PTlaiscka + Pch
PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa
mszligmQfrac34K jdhq ioacutelrKh fhsectfuka
14 jdhq msltsn`o pdl wKqljdoh
by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(
fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks
mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla
nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka
uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml
jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh
llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad
fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd
fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj
yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde
19
141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde
wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd
uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr
wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS
wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh
u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka
gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska
jdhqj bylt iiumlmSvHdj meyeEgraves fotilde
bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu
jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO
wKqjg uacuteuacuteO fotilde mjS
fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg
ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash
jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk
ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde
bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS
fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq
wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj
fuu ska mldY flffrac34
fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh
mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt
uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka
jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr
iiumlnkaOdjh my ioacutelrKfhka nd foa
jyumlrga my oelafjk lreKq plusmnlauacuteh yels h
bull jdhq wxY= tlsfklska iajdhaj yeisffrac34
jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska
iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda
fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj
wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml
Wmlamkfhka meyeEgraves fotilde
bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla
u` ska mSvkhla wes fotilde
fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect
ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl
isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug
20
fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml
jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq
ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj
jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml
fotilde
142 pdl wKqljdofha ioacutelrKh
my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla
fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34
by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes
wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka
wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34
uOHkH fotilde h fi wfrac34 olajkq efiacute
143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h
my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu
jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg
jfrac34 uOHkH uQ fotilde h fotilde
jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla
jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=
Kkla i`oyd ioacutelrKh ild nuq
N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)
PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka
21
tu ksid jfrac34 uOHkH uQ fotilde h
fi suacuteh yels h
1 11 ksoiqk
25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak
uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1
by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj
fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama
lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml
pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh
u` ska th my oelafjk mszligEgrave idOkh llt yels h
fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt
yel
kB hkq fndaaUumliaudka kshh fotilde
22
wKqjla i`oyd
ujqhla i`oyd
fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq
fotilde
144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml
N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag
pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq
efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave
mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes
lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde
jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash
fi ye|skafotilde
16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--
fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd
fotilde jHdmash
23
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka
wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea
jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd
idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute
ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr
^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17
rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla
i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34
17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj
iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha
sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka
daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh
17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd
Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir
ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla
mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy
ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh
yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr
jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml
ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej
jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla
fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh
fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs
17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska
o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska
daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka
iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk
wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh
hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd
mszligudj (V)
mSvk
h (
P)
24
jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj
o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga
meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg
jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke
fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka
lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS
jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru
ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml
yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj
sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK
n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde
mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd
laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect
(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g
jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda
ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel
jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt
WIaKaj fotilde
daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o
WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel
fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg
jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml
fuh mltuq ioacutelrKfha wdfoaYfhka
fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH
ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk
nj wmg fmfka
fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh
pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we
tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj
hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h
mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq
wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt
jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect
jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia
PV mszligmQfrac34K
daauacutel
25
jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq
wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka
yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=
h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka
wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel
jdhq mszligmQfrac34K aajfhka wm ukh fotilde
151 jeka vrsquo jdaia ioacutelrKh
fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa
sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K
jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk
wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq
mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel
jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid
daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH
fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj
iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk
Egrave
bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka
kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka
mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka
igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash
iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg
fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh
mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde
1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj
ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh
by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK
fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde
gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq
mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde
fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg
iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq
msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect
moaOsfha mSvkh my mldYkfhka nd fohs
26
bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL
fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr
tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk
mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka
wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks
fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq
kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh
fi kej suacuteh yels h
fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh
fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql
nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia
flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha
wkafrac34--mszligjfrac34kh l yels fotilde
ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs
wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj
yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde
igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys
sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde
ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha
lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh
iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla
fi o yeisszligh yels ugraveu h
bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla
oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi
mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS
30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc
oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi
muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu
WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla
oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde
( )2
aP V b RTV
+ minus =
27
19 rEmh CO2 j ldm igyk
1 3 j =j - ioacutelrK idrdxYh
jdhq kshuh intildelrKhksh j mjsk
idOl
mszligmQfrac34K jdhq kshuh PV = nRT ke
fndhsa kshuh n iy T
pdaia kshuh V = kT n iy P
wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T
wKql pdl ioacutelrKh
idudkH fotilde h
jfrac34 uOHkH fotilde h
jfrac34 uOHkH fotilde h
fvdaagkaf a wdxYsl mSvk
kshuh
PA = xA PT
PT = PA + PB + PC
iiumlmSvHd idOlh jdhq ujq 1la i|yd
jeka vZjdaia ioacutelrKh
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
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Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
5
13 rEmh wkafrac34-wKql n yd dm Ylash wkqj modfrac34fha mOdk wjiad
=fkys yeisIacuteu
modfrac34fha mOdk wjiad =kla mejSug fya=j wm oekgua yodrd we oeka wm
modfrac34fha jdhquh yeisIacuteug fya= jk jdhq kshu iy jdhquh wjiAdj msltsn`o j yumlrga
ild nuq
12 jdhquh wjiadj
oeka wm idudkH WIaKaj mSvk aaj hgfa wes jdhquh wjiadfotilde mjsk oslashjHj
yeisIacuteu flfrys wjOdkh fhduq lruq
11 j =fotilde uacuteiar lr wes mszligEgrave jdhquh wjiadj my i`oyka fNsl =K wkqj uacuteiar
flffrac34
bull jdhq bd iiumlmSvH fotilde
bull jdhq ieu EgraveYdjlg u iudk whqszligka mSvkh wes lrhs
bull jdhqjg gtk iy oslashjjg jvd wvq gtkajhla we
bull jdhqj yevh iy mszligudj ksH fkd fotilde tajd wvx = Ndckfha yevh iy mszligudj
kS
bull jdhq lsis u hdkasl nmEulska fdrj iiumlmQfrac34Kfhka u iy iudkj tlsfkl
iuOtilde ntildeY fotilde
jdhqjl irdjhg fya= jkafka tu wKq wr mjsk n fkd ssbquoh yels ugraveuhs tajdfha
yeisIacuteu mIacutelaIKdaul wOHhkhkaf ka nd a msM u` ska fidhd kakd o fmdyuml jdhq kshujg (miqj idlEacutePd flffrac34iexcl) wkqj isyuml fotilde fiuml jdhq kshu hkq jdhqjl ueksh
yels =K wr mjsk iiumlnkaOd fotilde ueksh yels =K iuyrla jk mSvkh mszligudj
WIaKajh iy mudKh ^ujq fyda ialkaOhamp jeks tajd bd jeo a jkafka fiuml uacutepH
wr mjsk iiumlnkaOd jdhqjl mOdk wjiad (5 jk tallfha sect wfrac34 olajkq efiacuteiexcl) uacuteiar lrk ksid h tlsfkl yd ne`yumlKq fiuml uacutepHhka jdhq kshu iQ lsIacuteug uQsl
ugrave we
121 jdhq kshu
wm idlEacutePd lsIacuteug hk jdhq kshu uacuteoHdhka lsysm fokl= uacuteiska jdhqj fNsl =K
mokiumlj isyuml lrk o mIacutelaIKjska nd a msM fotilde mSvkh WIaKajh mszligudj iy
jdhq mudKh hk uacutepH wr mjsk iiumlnkaOd fuys sect ild nk wr tajd u` ska
6
modfrac34fha jdhquh wjiadj msltsn`o udkj jfrac34 hdg mfhdackja jk fdr=re rdYshla
mldY fotilde
mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq ioacutelrKh
jdhq wKq wr wkafrac34-wKql n fkdues nj Wmlamkh flffrac34 o tndivide jdhqjla mszligmQfrac34K
jdhqjla fi ye`Egravekafotilde tkiuml mszligmQfrac34K jdhqjl wKq wr wdlfrac34IK fyda uacutelfrac34IK fyda
n fkd mjS tfuka u jdhqj oud wes Ndckfha mszligudj iu` ieipoundfiuml sect jdhq wxY=jl
mszligudj fkdild yeszligh yels h
jdhqjl ksrfmalaI WIaKajh (T) mSvkh (P) mszligudj (V) iy oslashjH mudKh ^n ujqamp
jdhquh yeisIacuteu flfrys nmdk idOl fotilde P T V iy n wr iiumlnkaOdj my
mldYkfhka ksrEmKh flffrac34
fuh mszligmQfrac34K jdhq ioacutelrKh fyda mszligmQfrac34K jdhq kshuh fi oelafjk wr R hkq ieu
jdhqjlg u fmdyuml w hla wes jdhq kshh fotilde fok o acutekE u WIaKajhl sect yd
mSvkhl sect by iiumlnkaOdjg wkql+j yeisfrk acutekE u jdhqjla mszligmQfrac34K jdhqjla fi
y`yumlkajkq efiacute
fuu aaj hgfa oS mszligmQfrac34K jdhq ujq 1 la i|yd 0 degC sect yd 1 atm sect R kshfha w h
my wdldrhg Kkh l yel (0 degC sect yd 1 atm yssect mszligmqfrac34K jdhqjl 1 mol l mszligudj
22 414 dm3 fotilde)
mszligmQfrac34K jdhq ioacutelrKh by uacutepH yr wr wes iiumlnkaOdj jk nj wmg fmfkk
wr acutekE u jdhqjl wjiadj tuOtildeska uacuteiar flfrk ksid th wjiad ioacutelrKh fi
o ye|skafotilde
mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ Kkh lsIacuteiuml
mszligmQfrac34K jdhq ioacutelrKh u` ska wmg mszligudj WIaKajh mSvkh fyda ujq mudKh hk
tajdhska =kla sect wes uacuteg wfkla rdYsh ksfrac34Kh llt yels h jdhqjl ujq mudKh okakd
uacuteg tys ujqsl ialkaOh Nduacutefhka tys ialkaOh o Kkh llt yels h tfuka u
tu` ska jdhqjl gtkajh o ksfrac34Kh llt yels h mszligmQfrac34K jdhq kshfha w hg eltfmk
mszligEgrave wfkl=a rdYsj tall Nduacute lsIacuteu bd jeo a jk nj ul nd hq= h
idudkHfhka mSvkh atm Pa bar torr jeks tall jska mldY llt yels h tneuacuteka fiuml
eguml uacutei`oSfiuml sect my 1 2 j =fotilde sect wes mSvk tallj mszligjfrac34k Tng Wootilde jkq we
12 j =j mSvkh i`oyd jk tall
mSvk tallh Pa bar atm torr mmHg
1 Pa 1 N m-2 10-5 9 87 times 10-6 7 5 times 10-3
1 bar 100000 1bar 0 987 750 061 atm 101325 1 01325 1 atm 7601 torr mmHg 133 32 1 3332 times 10-3 1 3158 times 10-3 1 torr 1 mmHg
7
12 ksoiqk
jdhq isskavrhl mszligudj 0950 dm3 fotilde hiuml mSvkhla hgfa sect fiuml isskavrh oslashj
fmdfmakajska (C3H8) msIacute we isskavrh ysia jQ uacuteg jdhqf daSh mSvkh yd WIaKajh
hgfa sect tys fmdfmaka jdhqj hiuml mudKhla bsszlig fotilde
(i) wjg mszligirfha aaj 25degC iy 750 torr (1 torr = 133 52 Pa) kiuml isskavrh
ysiaj wes uacuteg tys bsszlig ugrave wes fmdfmaka jdhq ujq mudKh fldmuK o
(wNHkar mSvkh ndysr mSvkhg iudk uacuteg oS)
(ii) isskavrfha bsszlig ugrave wes fmdfmaka jdhq ialkaOh Kkh lrkak
(iii) isskavrfha bsszlig ugrave wes fmdfmaka jdhqfotilde gtkajh Kkh lrkak
uacutei`yumlu (i) mltuqj sect wes fdr=re iudfdapkh lrkak
WIaKajh T = (25 + 273) K = 298 K mSvkh P = 750 torr times 13332 Pa 1 torr = 99990 Pa mszligudj V = 0 950 dm3 = 0 950 times 10-3 m3
n fkdokakd moh fotilde
PV = nRT Nduacutefhka
(ii) fmdfmakays (C3H8) ujqsl ialkaOh = 44 g mol-1
fmdfmakays ialkaOh = 0 038 mol times 44 g mol-1 = 1 672 g
(iii) fmdfmakays gtkajh = ialkaOh mszligudj = = 1 76 g dm-3
by ksoiqk iel+ uacuteg mszligmQfrac34K jdhq kshuh uacuteuacuteO wdldrjska bEgraveszligma llt yels nj
fmkS hk wr my oelafjk mszligEgrave ir fjkia lsIacuteulska fok o jdhqjl ialkaOh
iy gtkajh fiuacuteh yels h
PV = nRT
P = RT
zwnjzwnj P = CRT
fuys zC Zhkq idkaoslashKhhs
j o PV = nRT iiumlnkaOdj my mszligEgrave o mldY llt yels h
PV = RT
fuys m hkq ialkaOh jk wr M hkq jdhqfotilde ujqsl ialkaOhhs
P = RT fi o suacuteh yels h
8
gtkajh (d) =
there4 P =
uacutefYaIs aaj hgfA fjka jdhq kshu jHqamkak lsIacutefiuml sect mszligmQfrac34K jdhq kshuh uQsl
moku fi lshd lrhs
122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)mdashksh WIaKajhla hgfa wes iaOacuter jdhq mudKhl (ialkaOhl) mSvkh jdhqfotilde mszligudjg
msfdauj uacutepkh fotilde (fyda iudkqmdsl) fotilde˜ fndhsa kshuh hkqfjka ye`Egravekafjk
fuh tfia kiuml lrk oafoa 17 jeks ishjfia sect WIaKajh ksh jQ aaj hgfa fjkia
jk mSvkha iu jdhqjl mszligudj uacutepkh jk wdldrh whsszligIa cdsl uacuteoHdhl= jQ
frdnUuml fndhsa (1627- 1691) uacuteiska wOHhkh lsIacutefuka miqj h tys Ksuh wdldrh
my oelafotilde
my plusmnlafjk mszligEgrave fndhsa kshuh jHqamkak lsIacuteu i`oyd mszligmQfrac34K jdhq kshuh fhdod
yelsh PV= nRT
jdhqfjys mudKh yd moaOsfhys WIaKajh kshj mjajd kakd oafoa kiuml nT =Ksh
kshhla fotilde R o kshhla jk neuacuteka nRT =Ksh o kshhla (k) fotilde
PV = k (kshhla)
tkiuml ksh WIaKajfha sect ksh jdhq mudKhl mSvkfhaa mszligudfotildea =Ksh kshhla
fotilde fuh fndhsa kshuh mldY lrk fjka wdldrhls
ksh T WIaKajhl wes ksh jdhq mudKhl mszligudj V1 o mSvkh P1 o kiuml yd th V2
mszligudjg yd P2 mSvkhg ma llt uacuteg fndhsa kshuhg wkqj
14 rEmh u` ska fndhsa kshufha idiumlmodhsl miadszligl ksrEmK folla fmkakqiuml flffrac34
14 rEmfha (a) u` ska ixikaokh i`oyd uacuteuacuteO WIaKajj sect PV = k miadr lr we
k w h WIaKajh u muKla r`od mjsk ksid fok o jdhq ialkaOhla i`oyd w`Egravek
o ieu jlhla i`oyd u k ys w h tlsfklg fjkia fotilde bylt WIaKajj sect mszligudfotilde
midrKh ksid plh byltg f dia wes nj ielsh hq= h tfuka u WIaKajh ksh
uacuteg jdhqfotilde mSvkh wvla jk uacuteg mszligudj fo =K jk nj ul nd hq= h
9
1 4 rEmh uacuteuacuteO ksh WIaKajj sect (a) mszligudj (V) iuOtilde (b) 1 V iuOtilde
mSvkfha fjkia ugraveu
14 (b) rEmh u` ska P g tosrsfhka ys miadrh ksrEmKh fotilde th uQ laIHh yryd hk
ir ffrac34Ldjls fndhsa uacuteiska lrk o mIacutelaIKjg wkqj nd kakd o fuu miadr
u` ska jdhqjg bylt iiumlmSvHdjla wes nj mudKdaulj fmkajd foa tkiuml fok o
jdhq ialkaOhla iiumlmSvkh llt uacuteg tl u mudKhlska wes wKq ixLHdj l=vd mszligudjla
=lt mesffrac34 fiuml wkqj bylt mSvkj sect jdhqj gtkajh jeauml fotilde
igyk fok o jdhqjl gtkajh d ialkaOh m o mszligudj v o jk uacuteg d = ioacutelrKfhka
fok nj wms oksuq tuksid ksh WIaKajfhasect
hkqfjka suacuteh yels h
1 3 ksoiqk
ksh WIaKajhla hgfa wes okakd jdhq ujq mudKhl mszligudj fo =K llt uacuteg
mSvkfha isyuml jk fjkia ugraveu Kkh lrkak
uacutei`yumlu V1 =V V2 = 2V P1 = P P2 = fndhsa kshuh fhsectfuka P1V1 = P2V2
P times V = P2 times 2VP2 = P 2 there4kj mSvkh uqa mSvkfhka wvla fotilde
10
1 4 ksoiqk
ldur WIaKajfha sect neumlkhla yhsvcka jdhqj okakd mudKhlska mqrjd we jdhqf daSh
mSvkfha sect (100 kPa) tu jdhq mudKh 2 50 dm3 l mszligudjla kS tu WIaKajfha sect u
we=lt mSvkh 20 kPa ugraveug neumlkfha mszligudj fldmuK uacuteh llt hq= o
uacutei`yumlu P1 = 100 kPa P2 = 20 kPa V1 = 2 5 dm3 V2 = fndhsa kshuh fhsectfuka P1V1 = P2V2
100 kPa times 2 5 dm3 = 20 kPa times V2 there4V2 = 12 5 dm3 neumlkfha mszligudj 12 5 dm3 olajd jeauml llt hq= h
123 pdaia kshuh (WIaKaj-mszligud iiumlnkaOh)cdlaia pdaia iy fcdaIma f a-umliela hk uacuteoHdhkaf a yeoEIacuteiuml u ska fmkajd sect wes mszligEgrave
ksh mSvkhl sect fok o ksH jdhq mudKhl ^ialkaOhamp mszligudj WIaKajha iu`
jeauml jk wr isisa lsIacuteua iu` wvq fotilde tfuka u WIaKajfhA isyuml jk ieu fiaishia
wxYlhl fjkila mdid ^jeauml ugraveu fyda wvq ugraveuamp mszligudj 0degC sect jdhqfotilde wdriumlNl mszligudfjka idOlhlska fjkia jk nj ^jeauml ugraveu fyda wvq ugraveuamp fidhd f k we
0 degC sect iy t degC ys sect jdhqfotilde mszligudj msltsfjltska V0 iy Vt hhs Wmlamkh lruq tuacuteg
fuu aajfha sect WIaKajh i`oyd kj mszligudKhla wfrac34 olajd we tuacuteg tu mszligudKhg
wkqj
t degC i`oyd Tt = 273 15 + t uOtildeska nd fok wr
0 degC i`oyd T0 = 273 15 uOtildeska nd fohs
fuu kj WIaKaj mszligudKh flauacuteka WIaKaj mszligudKh (K) fyja ksrfmalaI WIaKaj
mszligudKh fi ye`Egravekafotilde ndash 273 15 degC (0 K) hkak dm sl Y+kHh fi wfrac34 oelafjk
wr th ffioaOdkaslj lt` d uacuteh yels wju WIaKajh fotilde
fmdyumlfotilde a uacuteg ksh mSvkfha sect (V1 T1) isg (V2 T2) olajd isyuml jk fjkila i`oyd
11
tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg
wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde
jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys
WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg
yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h
PV = nRTV = nRT P
ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde
zwnjzwnjzwnjzwnjV prop T fyda V = kT
pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka
WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd
Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect
ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh
lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34
15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde
uacutepkh
12
1 5 ksoiqk
ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml
jk WIaKaj fjki Kkh lrkak
uacutei`yumlu
T1 = T V1 = V V2 = 3V T2 =
T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh
wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h
hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi
efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg
lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr
kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde
1 6 ksoiqk
23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde
tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki
Kkh lrkak
uacutei`yumlu
T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =
jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka
V2 = 2 03 dm3
mszligudfotilde isyumljk fjki = 0 03 dm3
124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=
jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj
lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla
hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)
fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h
13
jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda
kshh (NA fyda L) fi ye|skafotilde
my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka
wjfndaO lr yels h
fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl
u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud
follg by iiumlnkaOdj fhsectfuka
P iy T ksh uacuteg sect (R iy NA kshhka fotilde )
irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud
=lt iudk wKq ixLdjla wvx= fotilde (V α N)
by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd
mszligmQfrac34K jdhq ioacutelrKh nd yels h
by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka
k = R jQ uacuteg
P V = n R T
14
125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka
fi wmg suacuteh yels h
iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd
mszligudj (Vm) tl u w hla uacuteh hq= ksid th
fi Kkh llt yels h
tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u
mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34
bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu
aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj
22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi
ksrEmKh flffrac34
bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde
fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde
igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde
V = k n = k (m M) tneuacuteka M = k (m V) = k d
1 7 ksoiqk
298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud
iudk nj fmkajkak
uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe
VHe = nHeRTHe PHe
VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3
15
PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =
PNeVNe = nNeRTNe
VNe = nNeRTNe PNe
VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa
VNe = 24 4 dm3
tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq
wa lr kakd mszligud iudk fotilde
126 ixhqla jdhq kshuh
jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj
tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka
T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla
fi suacuteh yels h
fuh ixhqla jdhq kshuh fi ye|skafotilde
1 8 ksoiqk
25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o
uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh
P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3
T1 = 25 + 273 = 298 K
V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =
P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa
16
13 fvdaagkaf a wdxYsl mSvk kshuh
fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm
yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk
wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml
ishuml jdhq odhl fotilde
jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj
wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde
ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla
iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs
fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh
fi yeEgravekafotilde
A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska
PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde
my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka
jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha
we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh
PT hehs o isuq
PV = nRT
A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )
B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )
jdhq ntildeYKh i`oyd nT = PTV RT
iy nT = nA + nB
tu ksid PTV RT = (PAV RT) + (PBV RT)
iq`M llt uacuteg PT = PA + PB
fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl
131 ujq Nd h wkqidrfhka wdxYsl mSvkh
T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq
ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde
fvdaagkaf a kshuhg wkqj PT = PA + PB
PA iy PB mldYk fjk fjk u PT jska fnsectfuka
17
tu ksid
fi suacuteh yels h
hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk
fotilde
1 9 ksoiqk
(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla
tla jdhqfotilde wdxYsl mSvkh Kkh lrkak
(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd
lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq
ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak
uacutei`yumlu
18
fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK
u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd
fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj
tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla
fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re
uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq
irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq
efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj
u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk
nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja
ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj
mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=
jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes
lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect
tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh
wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K
jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl
1 10 ksoiqk
my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs
iskak
2KClO3(s) rarr2KCl(s) + 3O2(g)
27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute
27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh
Kkh lrkak
uacutei`yumlu
fvdaagkaf a kshuhg wkqj
Piuia = PTlaiscka + Pch
PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa
mszligmQfrac34K jdhq ioacutelrKh fhsectfuka
14 jdhq msltsn`o pdl wKqljdoh
by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(
fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks
mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla
nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka
uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml
jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh
llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad
fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd
fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj
yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde
19
141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde
wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd
uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr
wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS
wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh
u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka
gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska
jdhqj bylt iiumlmSvHdj meyeEgraves fotilde
bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu
jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO
wKqjg uacuteuacuteO fotilde mjS
fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg
ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash
jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk
ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde
bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS
fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq
wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj
fuu ska mldY flffrac34
fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh
mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt
uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka
jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr
iiumlnkaOdjh my ioacutelrKfhka nd foa
jyumlrga my oelafjk lreKq plusmnlauacuteh yels h
bull jdhq wxY= tlsfklska iajdhaj yeisffrac34
jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska
iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda
fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj
wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml
Wmlamkfhka meyeEgraves fotilde
bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla
u` ska mSvkhla wes fotilde
fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect
ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl
isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug
20
fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml
jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq
ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj
jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml
fotilde
142 pdl wKqljdofha ioacutelrKh
my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla
fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34
by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes
wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka
wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34
uOHkH fotilde h fi wfrac34 olajkq efiacute
143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h
my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu
jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg
jfrac34 uOHkH uQ fotilde h fotilde
jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla
jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=
Kkla i`oyd ioacutelrKh ild nuq
N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)
PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka
21
tu ksid jfrac34 uOHkH uQ fotilde h
fi suacuteh yels h
1 11 ksoiqk
25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak
uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1
by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj
fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama
lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml
pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh
u` ska th my oelafjk mszligEgrave idOkh llt yels h
fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt
yel
kB hkq fndaaUumliaudka kshh fotilde
22
wKqjla i`oyd
ujqhla i`oyd
fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq
fotilde
144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml
N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag
pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq
efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave
mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes
lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde
jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash
fi ye|skafotilde
16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--
fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd
fotilde jHdmash
23
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka
wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea
jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd
idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute
ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr
^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17
rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla
i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34
17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj
iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha
sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka
daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh
17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd
Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir
ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla
mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy
ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh
yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr
jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml
ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej
jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla
fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh
fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs
17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska
o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska
daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka
iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk
wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh
hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd
mszligudj (V)
mSvk
h (
P)
24
jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj
o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga
meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg
jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke
fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka
lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS
jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru
ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml
yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj
sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK
n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde
mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd
laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect
(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g
jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda
ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel
jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt
WIaKaj fotilde
daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o
WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel
fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg
jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml
fuh mltuq ioacutelrKfha wdfoaYfhka
fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH
ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk
nj wmg fmfka
fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh
pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we
tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj
hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h
mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq
wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt
jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect
jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia
PV mszligmQfrac34K
daauacutel
25
jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq
wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka
yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=
h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka
wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel
jdhq mszligmQfrac34K aajfhka wm ukh fotilde
151 jeka vrsquo jdaia ioacutelrKh
fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa
sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K
jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk
wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq
mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel
jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid
daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH
fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj
iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk
Egrave
bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka
kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka
mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka
igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash
iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg
fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh
mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde
1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj
ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh
by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK
fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde
gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq
mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde
fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg
iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq
msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect
moaOsfha mSvkh my mldYkfhka nd fohs
26
bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL
fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr
tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk
mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka
wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks
fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq
kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh
fi kej suacuteh yels h
fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh
fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql
nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia
flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha
wkafrac34--mszligjfrac34kh l yels fotilde
ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs
wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj
yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde
igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys
sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde
ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha
lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh
iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla
fi o yeisszligh yels ugraveu h
bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla
oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi
mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS
30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc
oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi
muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu
WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla
oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde
( )2
aP V b RTV
+ minus =
27
19 rEmh CO2 j ldm igyk
1 3 j =j - ioacutelrK idrdxYh
jdhq kshuh intildelrKhksh j mjsk
idOl
mszligmQfrac34K jdhq kshuh PV = nRT ke
fndhsa kshuh n iy T
pdaia kshuh V = kT n iy P
wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T
wKql pdl ioacutelrKh
idudkH fotilde h
jfrac34 uOHkH fotilde h
jfrac34 uOHkH fotilde h
fvdaagkaf a wdxYsl mSvk
kshuh
PA = xA PT
PT = PA + PB + PC
iiumlmSvHd idOlh jdhq ujq 1la i|yd
jeka vZjdaia ioacutelrKh
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
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Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
6
modfrac34fha jdhquh wjiadj msltsn`o udkj jfrac34 hdg mfhdackja jk fdr=re rdYshla
mldY fotilde
mszligmQfrac34K jdhq iy mszligmQfrac34K jdhq ioacutelrKh
jdhq wKq wr wkafrac34-wKql n fkdues nj Wmlamkh flffrac34 o tndivide jdhqjla mszligmQfrac34K
jdhqjla fi ye`Egravekafotilde tkiuml mszligmQfrac34K jdhqjl wKq wr wdlfrac34IK fyda uacutelfrac34IK fyda
n fkd mjS tfuka u jdhqj oud wes Ndckfha mszligudj iu` ieipoundfiuml sect jdhq wxY=jl
mszligudj fkdild yeszligh yels h
jdhqjl ksrfmalaI WIaKajh (T) mSvkh (P) mszligudj (V) iy oslashjH mudKh ^n ujqamp
jdhquh yeisIacuteu flfrys nmdk idOl fotilde P T V iy n wr iiumlnkaOdj my
mldYkfhka ksrEmKh flffrac34
fuh mszligmQfrac34K jdhq ioacutelrKh fyda mszligmQfrac34K jdhq kshuh fi oelafjk wr R hkq ieu
jdhqjlg u fmdyuml w hla wes jdhq kshh fotilde fok o acutekE u WIaKajhl sect yd
mSvkhl sect by iiumlnkaOdjg wkql+j yeisfrk acutekE u jdhqjla mszligmQfrac34K jdhqjla fi
y`yumlkajkq efiacute
fuu aaj hgfa oS mszligmQfrac34K jdhq ujq 1 la i|yd 0 degC sect yd 1 atm sect R kshfha w h
my wdldrhg Kkh l yel (0 degC sect yd 1 atm yssect mszligmqfrac34K jdhqjl 1 mol l mszligudj
22 414 dm3 fotilde)
mszligmQfrac34K jdhq ioacutelrKh by uacutepH yr wr wes iiumlnkaOdj jk nj wmg fmfkk
wr acutekE u jdhqjl wjiadj tuOtildeska uacuteiar flfrk ksid th wjiad ioacutelrKh fi
o ye|skafotilde
mszligmQfrac34K jdhq ioacutelrKh mokiuml jQ Kkh lsIacuteiuml
mszligmQfrac34K jdhq ioacutelrKh u` ska wmg mszligudj WIaKajh mSvkh fyda ujq mudKh hk
tajdhska =kla sect wes uacuteg wfkla rdYsh ksfrac34Kh llt yels h jdhqjl ujq mudKh okakd
uacuteg tys ujqsl ialkaOh Nduacutefhka tys ialkaOh o Kkh llt yels h tfuka u
tu` ska jdhqjl gtkajh o ksfrac34Kh llt yels h mszligmQfrac34K jdhq kshfha w hg eltfmk
mszligEgrave wfkl=a rdYsj tall Nduacute lsIacuteu bd jeo a jk nj ul nd hq= h
idudkHfhka mSvkh atm Pa bar torr jeks tall jska mldY llt yels h tneuacuteka fiuml
eguml uacutei`oSfiuml sect my 1 2 j =fotilde sect wes mSvk tallj mszligjfrac34k Tng Wootilde jkq we
12 j =j mSvkh i`oyd jk tall
mSvk tallh Pa bar atm torr mmHg
1 Pa 1 N m-2 10-5 9 87 times 10-6 7 5 times 10-3
1 bar 100000 1bar 0 987 750 061 atm 101325 1 01325 1 atm 7601 torr mmHg 133 32 1 3332 times 10-3 1 3158 times 10-3 1 torr 1 mmHg
7
12 ksoiqk
jdhq isskavrhl mszligudj 0950 dm3 fotilde hiuml mSvkhla hgfa sect fiuml isskavrh oslashj
fmdfmakajska (C3H8) msIacute we isskavrh ysia jQ uacuteg jdhqf daSh mSvkh yd WIaKajh
hgfa sect tys fmdfmaka jdhqj hiuml mudKhla bsszlig fotilde
(i) wjg mszligirfha aaj 25degC iy 750 torr (1 torr = 133 52 Pa) kiuml isskavrh
ysiaj wes uacuteg tys bsszlig ugrave wes fmdfmaka jdhq ujq mudKh fldmuK o
(wNHkar mSvkh ndysr mSvkhg iudk uacuteg oS)
(ii) isskavrfha bsszlig ugrave wes fmdfmaka jdhq ialkaOh Kkh lrkak
(iii) isskavrfha bsszlig ugrave wes fmdfmaka jdhqfotilde gtkajh Kkh lrkak
uacutei`yumlu (i) mltuqj sect wes fdr=re iudfdapkh lrkak
WIaKajh T = (25 + 273) K = 298 K mSvkh P = 750 torr times 13332 Pa 1 torr = 99990 Pa mszligudj V = 0 950 dm3 = 0 950 times 10-3 m3
n fkdokakd moh fotilde
PV = nRT Nduacutefhka
(ii) fmdfmakays (C3H8) ujqsl ialkaOh = 44 g mol-1
fmdfmakays ialkaOh = 0 038 mol times 44 g mol-1 = 1 672 g
(iii) fmdfmakays gtkajh = ialkaOh mszligudj = = 1 76 g dm-3
by ksoiqk iel+ uacuteg mszligmQfrac34K jdhq kshuh uacuteuacuteO wdldrjska bEgraveszligma llt yels nj
fmkS hk wr my oelafjk mszligEgrave ir fjkia lsIacuteulska fok o jdhqjl ialkaOh
iy gtkajh fiuacuteh yels h
PV = nRT
P = RT
zwnjzwnj P = CRT
fuys zC Zhkq idkaoslashKhhs
j o PV = nRT iiumlnkaOdj my mszligEgrave o mldY llt yels h
PV = RT
fuys m hkq ialkaOh jk wr M hkq jdhqfotilde ujqsl ialkaOhhs
P = RT fi o suacuteh yels h
8
gtkajh (d) =
there4 P =
uacutefYaIs aaj hgfA fjka jdhq kshu jHqamkak lsIacutefiuml sect mszligmQfrac34K jdhq kshuh uQsl
moku fi lshd lrhs
122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)mdashksh WIaKajhla hgfa wes iaOacuter jdhq mudKhl (ialkaOhl) mSvkh jdhqfotilde mszligudjg
msfdauj uacutepkh fotilde (fyda iudkqmdsl) fotilde˜ fndhsa kshuh hkqfjka ye`Egravekafjk
fuh tfia kiuml lrk oafoa 17 jeks ishjfia sect WIaKajh ksh jQ aaj hgfa fjkia
jk mSvkha iu jdhqjl mszligudj uacutepkh jk wdldrh whsszligIa cdsl uacuteoHdhl= jQ
frdnUuml fndhsa (1627- 1691) uacuteiska wOHhkh lsIacutefuka miqj h tys Ksuh wdldrh
my oelafotilde
my plusmnlafjk mszligEgrave fndhsa kshuh jHqamkak lsIacuteu i`oyd mszligmQfrac34K jdhq kshuh fhdod
yelsh PV= nRT
jdhqfjys mudKh yd moaOsfhys WIaKajh kshj mjajd kakd oafoa kiuml nT =Ksh
kshhla fotilde R o kshhla jk neuacuteka nRT =Ksh o kshhla (k) fotilde
PV = k (kshhla)
tkiuml ksh WIaKajfha sect ksh jdhq mudKhl mSvkfhaa mszligudfotildea =Ksh kshhla
fotilde fuh fndhsa kshuh mldY lrk fjka wdldrhls
ksh T WIaKajhl wes ksh jdhq mudKhl mszligudj V1 o mSvkh P1 o kiuml yd th V2
mszligudjg yd P2 mSvkhg ma llt uacuteg fndhsa kshuhg wkqj
14 rEmh u` ska fndhsa kshufha idiumlmodhsl miadszligl ksrEmK folla fmkakqiuml flffrac34
14 rEmfha (a) u` ska ixikaokh i`oyd uacuteuacuteO WIaKajj sect PV = k miadr lr we
k w h WIaKajh u muKla r`od mjsk ksid fok o jdhq ialkaOhla i`oyd w`Egravek
o ieu jlhla i`oyd u k ys w h tlsfklg fjkia fotilde bylt WIaKajj sect mszligudfotilde
midrKh ksid plh byltg f dia wes nj ielsh hq= h tfuka u WIaKajh ksh
uacuteg jdhqfotilde mSvkh wvla jk uacuteg mszligudj fo =K jk nj ul nd hq= h
9
1 4 rEmh uacuteuacuteO ksh WIaKajj sect (a) mszligudj (V) iuOtilde (b) 1 V iuOtilde
mSvkfha fjkia ugraveu
14 (b) rEmh u` ska P g tosrsfhka ys miadrh ksrEmKh fotilde th uQ laIHh yryd hk
ir ffrac34Ldjls fndhsa uacuteiska lrk o mIacutelaIKjg wkqj nd kakd o fuu miadr
u` ska jdhqjg bylt iiumlmSvHdjla wes nj mudKdaulj fmkajd foa tkiuml fok o
jdhq ialkaOhla iiumlmSvkh llt uacuteg tl u mudKhlska wes wKq ixLHdj l=vd mszligudjla
=lt mesffrac34 fiuml wkqj bylt mSvkj sect jdhqj gtkajh jeauml fotilde
igyk fok o jdhqjl gtkajh d ialkaOh m o mszligudj v o jk uacuteg d = ioacutelrKfhka
fok nj wms oksuq tuksid ksh WIaKajfhasect
hkqfjka suacuteh yels h
1 3 ksoiqk
ksh WIaKajhla hgfa wes okakd jdhq ujq mudKhl mszligudj fo =K llt uacuteg
mSvkfha isyuml jk fjkia ugraveu Kkh lrkak
uacutei`yumlu V1 =V V2 = 2V P1 = P P2 = fndhsa kshuh fhsectfuka P1V1 = P2V2
P times V = P2 times 2VP2 = P 2 there4kj mSvkh uqa mSvkfhka wvla fotilde
10
1 4 ksoiqk
ldur WIaKajfha sect neumlkhla yhsvcka jdhqj okakd mudKhlska mqrjd we jdhqf daSh
mSvkfha sect (100 kPa) tu jdhq mudKh 2 50 dm3 l mszligudjla kS tu WIaKajfha sect u
we=lt mSvkh 20 kPa ugraveug neumlkfha mszligudj fldmuK uacuteh llt hq= o
uacutei`yumlu P1 = 100 kPa P2 = 20 kPa V1 = 2 5 dm3 V2 = fndhsa kshuh fhsectfuka P1V1 = P2V2
100 kPa times 2 5 dm3 = 20 kPa times V2 there4V2 = 12 5 dm3 neumlkfha mszligudj 12 5 dm3 olajd jeauml llt hq= h
123 pdaia kshuh (WIaKaj-mszligud iiumlnkaOh)cdlaia pdaia iy fcdaIma f a-umliela hk uacuteoHdhkaf a yeoEIacuteiuml u ska fmkajd sect wes mszligEgrave
ksh mSvkhl sect fok o ksH jdhq mudKhl ^ialkaOhamp mszligudj WIaKajha iu`
jeauml jk wr isisa lsIacuteua iu` wvq fotilde tfuka u WIaKajfhA isyuml jk ieu fiaishia
wxYlhl fjkila mdid ^jeauml ugraveu fyda wvq ugraveuamp mszligudj 0degC sect jdhqfotilde wdriumlNl mszligudfjka idOlhlska fjkia jk nj ^jeauml ugraveu fyda wvq ugraveuamp fidhd f k we
0 degC sect iy t degC ys sect jdhqfotilde mszligudj msltsfjltska V0 iy Vt hhs Wmlamkh lruq tuacuteg
fuu aajfha sect WIaKajh i`oyd kj mszligudKhla wfrac34 olajd we tuacuteg tu mszligudKhg
wkqj
t degC i`oyd Tt = 273 15 + t uOtildeska nd fok wr
0 degC i`oyd T0 = 273 15 uOtildeska nd fohs
fuu kj WIaKaj mszligudKh flauacuteka WIaKaj mszligudKh (K) fyja ksrfmalaI WIaKaj
mszligudKh fi ye`Egravekafotilde ndash 273 15 degC (0 K) hkak dm sl Y+kHh fi wfrac34 oelafjk
wr th ffioaOdkaslj lt` d uacuteh yels wju WIaKajh fotilde
fmdyumlfotilde a uacuteg ksh mSvkfha sect (V1 T1) isg (V2 T2) olajd isyuml jk fjkila i`oyd
11
tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg
wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde
jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys
WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg
yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h
PV = nRTV = nRT P
ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde
zwnjzwnjzwnjzwnjV prop T fyda V = kT
pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka
WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd
Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect
ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh
lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34
15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde
uacutepkh
12
1 5 ksoiqk
ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml
jk WIaKaj fjki Kkh lrkak
uacutei`yumlu
T1 = T V1 = V V2 = 3V T2 =
T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh
wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h
hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi
efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg
lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr
kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde
1 6 ksoiqk
23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde
tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki
Kkh lrkak
uacutei`yumlu
T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =
jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka
V2 = 2 03 dm3
mszligudfotilde isyumljk fjki = 0 03 dm3
124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=
jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj
lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla
hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)
fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h
13
jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda
kshh (NA fyda L) fi ye|skafotilde
my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka
wjfndaO lr yels h
fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl
u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud
follg by iiumlnkaOdj fhsectfuka
P iy T ksh uacuteg sect (R iy NA kshhka fotilde )
irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud
=lt iudk wKq ixLdjla wvx= fotilde (V α N)
by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd
mszligmQfrac34K jdhq ioacutelrKh nd yels h
by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka
k = R jQ uacuteg
P V = n R T
14
125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka
fi wmg suacuteh yels h
iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd
mszligudj (Vm) tl u w hla uacuteh hq= ksid th
fi Kkh llt yels h
tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u
mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34
bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu
aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj
22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi
ksrEmKh flffrac34
bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde
fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde
igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde
V = k n = k (m M) tneuacuteka M = k (m V) = k d
1 7 ksoiqk
298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud
iudk nj fmkajkak
uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe
VHe = nHeRTHe PHe
VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3
15
PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =
PNeVNe = nNeRTNe
VNe = nNeRTNe PNe
VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa
VNe = 24 4 dm3
tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq
wa lr kakd mszligud iudk fotilde
126 ixhqla jdhq kshuh
jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj
tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka
T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla
fi suacuteh yels h
fuh ixhqla jdhq kshuh fi ye|skafotilde
1 8 ksoiqk
25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o
uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh
P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3
T1 = 25 + 273 = 298 K
V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =
P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa
16
13 fvdaagkaf a wdxYsl mSvk kshuh
fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm
yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk
wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml
ishuml jdhq odhl fotilde
jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj
wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde
ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla
iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs
fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh
fi yeEgravekafotilde
A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska
PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde
my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka
jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha
we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh
PT hehs o isuq
PV = nRT
A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )
B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )
jdhq ntildeYKh i`oyd nT = PTV RT
iy nT = nA + nB
tu ksid PTV RT = (PAV RT) + (PBV RT)
iq`M llt uacuteg PT = PA + PB
fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl
131 ujq Nd h wkqidrfhka wdxYsl mSvkh
T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq
ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde
fvdaagkaf a kshuhg wkqj PT = PA + PB
PA iy PB mldYk fjk fjk u PT jska fnsectfuka
17
tu ksid
fi suacuteh yels h
hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk
fotilde
1 9 ksoiqk
(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla
tla jdhqfotilde wdxYsl mSvkh Kkh lrkak
(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd
lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq
ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak
uacutei`yumlu
18
fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK
u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd
fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj
tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla
fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re
uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq
irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq
efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj
u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk
nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja
ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj
mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=
jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes
lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect
tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh
wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K
jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl
1 10 ksoiqk
my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs
iskak
2KClO3(s) rarr2KCl(s) + 3O2(g)
27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute
27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh
Kkh lrkak
uacutei`yumlu
fvdaagkaf a kshuhg wkqj
Piuia = PTlaiscka + Pch
PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa
mszligmQfrac34K jdhq ioacutelrKh fhsectfuka
14 jdhq msltsn`o pdl wKqljdoh
by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(
fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks
mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla
nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka
uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml
jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh
llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad
fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd
fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj
yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde
19
141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde
wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd
uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr
wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS
wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh
u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka
gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska
jdhqj bylt iiumlmSvHdj meyeEgraves fotilde
bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu
jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO
wKqjg uacuteuacuteO fotilde mjS
fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg
ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash
jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk
ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde
bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS
fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq
wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj
fuu ska mldY flffrac34
fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh
mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt
uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka
jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr
iiumlnkaOdjh my ioacutelrKfhka nd foa
jyumlrga my oelafjk lreKq plusmnlauacuteh yels h
bull jdhq wxY= tlsfklska iajdhaj yeisffrac34
jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska
iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda
fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj
wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml
Wmlamkfhka meyeEgraves fotilde
bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla
u` ska mSvkhla wes fotilde
fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect
ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl
isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug
20
fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml
jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq
ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj
jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml
fotilde
142 pdl wKqljdofha ioacutelrKh
my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla
fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34
by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes
wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka
wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34
uOHkH fotilde h fi wfrac34 olajkq efiacute
143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h
my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu
jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg
jfrac34 uOHkH uQ fotilde h fotilde
jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla
jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=
Kkla i`oyd ioacutelrKh ild nuq
N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)
PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka
21
tu ksid jfrac34 uOHkH uQ fotilde h
fi suacuteh yels h
1 11 ksoiqk
25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak
uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1
by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj
fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama
lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml
pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh
u` ska th my oelafjk mszligEgrave idOkh llt yels h
fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt
yel
kB hkq fndaaUumliaudka kshh fotilde
22
wKqjla i`oyd
ujqhla i`oyd
fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq
fotilde
144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml
N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag
pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq
efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave
mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes
lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde
jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash
fi ye|skafotilde
16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--
fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd
fotilde jHdmash
23
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka
wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea
jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd
idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute
ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr
^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17
rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla
i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34
17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj
iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha
sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka
daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh
17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd
Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir
ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla
mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy
ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh
yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr
jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml
ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej
jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla
fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh
fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs
17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska
o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska
daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka
iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk
wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh
hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd
mszligudj (V)
mSvk
h (
P)
24
jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj
o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga
meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg
jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke
fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka
lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS
jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru
ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml
yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj
sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK
n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde
mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd
laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect
(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g
jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda
ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel
jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt
WIaKaj fotilde
daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o
WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel
fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg
jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml
fuh mltuq ioacutelrKfha wdfoaYfhka
fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH
ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk
nj wmg fmfka
fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh
pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we
tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj
hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h
mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq
wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt
jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect
jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia
PV mszligmQfrac34K
daauacutel
25
jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq
wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka
yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=
h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka
wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel
jdhq mszligmQfrac34K aajfhka wm ukh fotilde
151 jeka vrsquo jdaia ioacutelrKh
fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa
sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K
jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk
wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq
mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel
jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid
daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH
fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj
iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk
Egrave
bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka
kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka
mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka
igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash
iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg
fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh
mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde
1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj
ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh
by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK
fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde
gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq
mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde
fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg
iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq
msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect
moaOsfha mSvkh my mldYkfhka nd fohs
26
bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL
fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr
tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk
mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka
wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks
fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq
kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh
fi kej suacuteh yels h
fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh
fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql
nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia
flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha
wkafrac34--mszligjfrac34kh l yels fotilde
ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs
wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj
yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde
igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys
sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde
ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha
lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh
iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla
fi o yeisszligh yels ugraveu h
bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla
oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi
mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS
30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc
oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi
muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu
WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla
oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde
( )2
aP V b RTV
+ minus =
27
19 rEmh CO2 j ldm igyk
1 3 j =j - ioacutelrK idrdxYh
jdhq kshuh intildelrKhksh j mjsk
idOl
mszligmQfrac34K jdhq kshuh PV = nRT ke
fndhsa kshuh n iy T
pdaia kshuh V = kT n iy P
wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T
wKql pdl ioacutelrKh
idudkH fotilde h
jfrac34 uOHkH fotilde h
jfrac34 uOHkH fotilde h
fvdaagkaf a wdxYsl mSvk
kshuh
PA = xA PT
PT = PA + PB + PC
iiumlmSvHd idOlh jdhq ujq 1la i|yd
jeka vZjdaia ioacutelrKh
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
7
12 ksoiqk
jdhq isskavrhl mszligudj 0950 dm3 fotilde hiuml mSvkhla hgfa sect fiuml isskavrh oslashj
fmdfmakajska (C3H8) msIacute we isskavrh ysia jQ uacuteg jdhqf daSh mSvkh yd WIaKajh
hgfa sect tys fmdfmaka jdhqj hiuml mudKhla bsszlig fotilde
(i) wjg mszligirfha aaj 25degC iy 750 torr (1 torr = 133 52 Pa) kiuml isskavrh
ysiaj wes uacuteg tys bsszlig ugrave wes fmdfmaka jdhq ujq mudKh fldmuK o
(wNHkar mSvkh ndysr mSvkhg iudk uacuteg oS)
(ii) isskavrfha bsszlig ugrave wes fmdfmaka jdhq ialkaOh Kkh lrkak
(iii) isskavrfha bsszlig ugrave wes fmdfmaka jdhqfotilde gtkajh Kkh lrkak
uacutei`yumlu (i) mltuqj sect wes fdr=re iudfdapkh lrkak
WIaKajh T = (25 + 273) K = 298 K mSvkh P = 750 torr times 13332 Pa 1 torr = 99990 Pa mszligudj V = 0 950 dm3 = 0 950 times 10-3 m3
n fkdokakd moh fotilde
PV = nRT Nduacutefhka
(ii) fmdfmakays (C3H8) ujqsl ialkaOh = 44 g mol-1
fmdfmakays ialkaOh = 0 038 mol times 44 g mol-1 = 1 672 g
(iii) fmdfmakays gtkajh = ialkaOh mszligudj = = 1 76 g dm-3
by ksoiqk iel+ uacuteg mszligmQfrac34K jdhq kshuh uacuteuacuteO wdldrjska bEgraveszligma llt yels nj
fmkS hk wr my oelafjk mszligEgrave ir fjkia lsIacuteulska fok o jdhqjl ialkaOh
iy gtkajh fiuacuteh yels h
PV = nRT
P = RT
zwnjzwnj P = CRT
fuys zC Zhkq idkaoslashKhhs
j o PV = nRT iiumlnkaOdj my mszligEgrave o mldY llt yels h
PV = RT
fuys m hkq ialkaOh jk wr M hkq jdhqfotilde ujqsl ialkaOhhs
P = RT fi o suacuteh yels h
8
gtkajh (d) =
there4 P =
uacutefYaIs aaj hgfA fjka jdhq kshu jHqamkak lsIacutefiuml sect mszligmQfrac34K jdhq kshuh uQsl
moku fi lshd lrhs
122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)mdashksh WIaKajhla hgfa wes iaOacuter jdhq mudKhl (ialkaOhl) mSvkh jdhqfotilde mszligudjg
msfdauj uacutepkh fotilde (fyda iudkqmdsl) fotilde˜ fndhsa kshuh hkqfjka ye`Egravekafjk
fuh tfia kiuml lrk oafoa 17 jeks ishjfia sect WIaKajh ksh jQ aaj hgfa fjkia
jk mSvkha iu jdhqjl mszligudj uacutepkh jk wdldrh whsszligIa cdsl uacuteoHdhl= jQ
frdnUuml fndhsa (1627- 1691) uacuteiska wOHhkh lsIacutefuka miqj h tys Ksuh wdldrh
my oelafotilde
my plusmnlafjk mszligEgrave fndhsa kshuh jHqamkak lsIacuteu i`oyd mszligmQfrac34K jdhq kshuh fhdod
yelsh PV= nRT
jdhqfjys mudKh yd moaOsfhys WIaKajh kshj mjajd kakd oafoa kiuml nT =Ksh
kshhla fotilde R o kshhla jk neuacuteka nRT =Ksh o kshhla (k) fotilde
PV = k (kshhla)
tkiuml ksh WIaKajfha sect ksh jdhq mudKhl mSvkfhaa mszligudfotildea =Ksh kshhla
fotilde fuh fndhsa kshuh mldY lrk fjka wdldrhls
ksh T WIaKajhl wes ksh jdhq mudKhl mszligudj V1 o mSvkh P1 o kiuml yd th V2
mszligudjg yd P2 mSvkhg ma llt uacuteg fndhsa kshuhg wkqj
14 rEmh u` ska fndhsa kshufha idiumlmodhsl miadszligl ksrEmK folla fmkakqiuml flffrac34
14 rEmfha (a) u` ska ixikaokh i`oyd uacuteuacuteO WIaKajj sect PV = k miadr lr we
k w h WIaKajh u muKla r`od mjsk ksid fok o jdhq ialkaOhla i`oyd w`Egravek
o ieu jlhla i`oyd u k ys w h tlsfklg fjkia fotilde bylt WIaKajj sect mszligudfotilde
midrKh ksid plh byltg f dia wes nj ielsh hq= h tfuka u WIaKajh ksh
uacuteg jdhqfotilde mSvkh wvla jk uacuteg mszligudj fo =K jk nj ul nd hq= h
9
1 4 rEmh uacuteuacuteO ksh WIaKajj sect (a) mszligudj (V) iuOtilde (b) 1 V iuOtilde
mSvkfha fjkia ugraveu
14 (b) rEmh u` ska P g tosrsfhka ys miadrh ksrEmKh fotilde th uQ laIHh yryd hk
ir ffrac34Ldjls fndhsa uacuteiska lrk o mIacutelaIKjg wkqj nd kakd o fuu miadr
u` ska jdhqjg bylt iiumlmSvHdjla wes nj mudKdaulj fmkajd foa tkiuml fok o
jdhq ialkaOhla iiumlmSvkh llt uacuteg tl u mudKhlska wes wKq ixLHdj l=vd mszligudjla
=lt mesffrac34 fiuml wkqj bylt mSvkj sect jdhqj gtkajh jeauml fotilde
igyk fok o jdhqjl gtkajh d ialkaOh m o mszligudj v o jk uacuteg d = ioacutelrKfhka
fok nj wms oksuq tuksid ksh WIaKajfhasect
hkqfjka suacuteh yels h
1 3 ksoiqk
ksh WIaKajhla hgfa wes okakd jdhq ujq mudKhl mszligudj fo =K llt uacuteg
mSvkfha isyuml jk fjkia ugraveu Kkh lrkak
uacutei`yumlu V1 =V V2 = 2V P1 = P P2 = fndhsa kshuh fhsectfuka P1V1 = P2V2
P times V = P2 times 2VP2 = P 2 there4kj mSvkh uqa mSvkfhka wvla fotilde
10
1 4 ksoiqk
ldur WIaKajfha sect neumlkhla yhsvcka jdhqj okakd mudKhlska mqrjd we jdhqf daSh
mSvkfha sect (100 kPa) tu jdhq mudKh 2 50 dm3 l mszligudjla kS tu WIaKajfha sect u
we=lt mSvkh 20 kPa ugraveug neumlkfha mszligudj fldmuK uacuteh llt hq= o
uacutei`yumlu P1 = 100 kPa P2 = 20 kPa V1 = 2 5 dm3 V2 = fndhsa kshuh fhsectfuka P1V1 = P2V2
100 kPa times 2 5 dm3 = 20 kPa times V2 there4V2 = 12 5 dm3 neumlkfha mszligudj 12 5 dm3 olajd jeauml llt hq= h
123 pdaia kshuh (WIaKaj-mszligud iiumlnkaOh)cdlaia pdaia iy fcdaIma f a-umliela hk uacuteoHdhkaf a yeoEIacuteiuml u ska fmkajd sect wes mszligEgrave
ksh mSvkhl sect fok o ksH jdhq mudKhl ^ialkaOhamp mszligudj WIaKajha iu`
jeauml jk wr isisa lsIacuteua iu` wvq fotilde tfuka u WIaKajfhA isyuml jk ieu fiaishia
wxYlhl fjkila mdid ^jeauml ugraveu fyda wvq ugraveuamp mszligudj 0degC sect jdhqfotilde wdriumlNl mszligudfjka idOlhlska fjkia jk nj ^jeauml ugraveu fyda wvq ugraveuamp fidhd f k we
0 degC sect iy t degC ys sect jdhqfotilde mszligudj msltsfjltska V0 iy Vt hhs Wmlamkh lruq tuacuteg
fuu aajfha sect WIaKajh i`oyd kj mszligudKhla wfrac34 olajd we tuacuteg tu mszligudKhg
wkqj
t degC i`oyd Tt = 273 15 + t uOtildeska nd fok wr
0 degC i`oyd T0 = 273 15 uOtildeska nd fohs
fuu kj WIaKaj mszligudKh flauacuteka WIaKaj mszligudKh (K) fyja ksrfmalaI WIaKaj
mszligudKh fi ye`Egravekafotilde ndash 273 15 degC (0 K) hkak dm sl Y+kHh fi wfrac34 oelafjk
wr th ffioaOdkaslj lt` d uacuteh yels wju WIaKajh fotilde
fmdyumlfotilde a uacuteg ksh mSvkfha sect (V1 T1) isg (V2 T2) olajd isyuml jk fjkila i`oyd
11
tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg
wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde
jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys
WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg
yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h
PV = nRTV = nRT P
ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde
zwnjzwnjzwnjzwnjV prop T fyda V = kT
pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka
WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd
Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect
ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh
lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34
15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde
uacutepkh
12
1 5 ksoiqk
ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml
jk WIaKaj fjki Kkh lrkak
uacutei`yumlu
T1 = T V1 = V V2 = 3V T2 =
T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh
wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h
hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi
efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg
lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr
kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde
1 6 ksoiqk
23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde
tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki
Kkh lrkak
uacutei`yumlu
T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =
jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka
V2 = 2 03 dm3
mszligudfotilde isyumljk fjki = 0 03 dm3
124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=
jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj
lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla
hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)
fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h
13
jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda
kshh (NA fyda L) fi ye|skafotilde
my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka
wjfndaO lr yels h
fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl
u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud
follg by iiumlnkaOdj fhsectfuka
P iy T ksh uacuteg sect (R iy NA kshhka fotilde )
irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud
=lt iudk wKq ixLdjla wvx= fotilde (V α N)
by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd
mszligmQfrac34K jdhq ioacutelrKh nd yels h
by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka
k = R jQ uacuteg
P V = n R T
14
125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka
fi wmg suacuteh yels h
iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd
mszligudj (Vm) tl u w hla uacuteh hq= ksid th
fi Kkh llt yels h
tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u
mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34
bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu
aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj
22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi
ksrEmKh flffrac34
bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde
fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde
igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde
V = k n = k (m M) tneuacuteka M = k (m V) = k d
1 7 ksoiqk
298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud
iudk nj fmkajkak
uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe
VHe = nHeRTHe PHe
VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3
15
PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =
PNeVNe = nNeRTNe
VNe = nNeRTNe PNe
VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa
VNe = 24 4 dm3
tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq
wa lr kakd mszligud iudk fotilde
126 ixhqla jdhq kshuh
jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj
tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka
T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla
fi suacuteh yels h
fuh ixhqla jdhq kshuh fi ye|skafotilde
1 8 ksoiqk
25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o
uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh
P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3
T1 = 25 + 273 = 298 K
V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =
P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa
16
13 fvdaagkaf a wdxYsl mSvk kshuh
fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm
yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk
wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml
ishuml jdhq odhl fotilde
jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj
wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde
ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla
iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs
fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh
fi yeEgravekafotilde
A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska
PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde
my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka
jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha
we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh
PT hehs o isuq
PV = nRT
A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )
B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )
jdhq ntildeYKh i`oyd nT = PTV RT
iy nT = nA + nB
tu ksid PTV RT = (PAV RT) + (PBV RT)
iq`M llt uacuteg PT = PA + PB
fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl
131 ujq Nd h wkqidrfhka wdxYsl mSvkh
T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq
ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde
fvdaagkaf a kshuhg wkqj PT = PA + PB
PA iy PB mldYk fjk fjk u PT jska fnsectfuka
17
tu ksid
fi suacuteh yels h
hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk
fotilde
1 9 ksoiqk
(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla
tla jdhqfotilde wdxYsl mSvkh Kkh lrkak
(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd
lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq
ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak
uacutei`yumlu
18
fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK
u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd
fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj
tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla
fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re
uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq
irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq
efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj
u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk
nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja
ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj
mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=
jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes
lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect
tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh
wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K
jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl
1 10 ksoiqk
my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs
iskak
2KClO3(s) rarr2KCl(s) + 3O2(g)
27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute
27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh
Kkh lrkak
uacutei`yumlu
fvdaagkaf a kshuhg wkqj
Piuia = PTlaiscka + Pch
PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa
mszligmQfrac34K jdhq ioacutelrKh fhsectfuka
14 jdhq msltsn`o pdl wKqljdoh
by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(
fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks
mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla
nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka
uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml
jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh
llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad
fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd
fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj
yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde
19
141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde
wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd
uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr
wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS
wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh
u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka
gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska
jdhqj bylt iiumlmSvHdj meyeEgraves fotilde
bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu
jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO
wKqjg uacuteuacuteO fotilde mjS
fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg
ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash
jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk
ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde
bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS
fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq
wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj
fuu ska mldY flffrac34
fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh
mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt
uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka
jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr
iiumlnkaOdjh my ioacutelrKfhka nd foa
jyumlrga my oelafjk lreKq plusmnlauacuteh yels h
bull jdhq wxY= tlsfklska iajdhaj yeisffrac34
jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska
iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda
fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj
wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml
Wmlamkfhka meyeEgraves fotilde
bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla
u` ska mSvkhla wes fotilde
fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect
ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl
isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug
20
fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml
jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq
ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj
jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml
fotilde
142 pdl wKqljdofha ioacutelrKh
my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla
fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34
by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes
wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka
wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34
uOHkH fotilde h fi wfrac34 olajkq efiacute
143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h
my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu
jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg
jfrac34 uOHkH uQ fotilde h fotilde
jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla
jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=
Kkla i`oyd ioacutelrKh ild nuq
N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)
PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka
21
tu ksid jfrac34 uOHkH uQ fotilde h
fi suacuteh yels h
1 11 ksoiqk
25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak
uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1
by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj
fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama
lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml
pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh
u` ska th my oelafjk mszligEgrave idOkh llt yels h
fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt
yel
kB hkq fndaaUumliaudka kshh fotilde
22
wKqjla i`oyd
ujqhla i`oyd
fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq
fotilde
144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml
N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag
pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq
efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave
mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes
lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde
jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash
fi ye|skafotilde
16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--
fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd
fotilde jHdmash
23
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka
wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea
jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd
idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute
ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr
^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17
rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla
i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34
17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj
iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha
sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka
daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh
17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd
Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir
ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla
mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy
ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh
yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr
jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml
ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej
jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla
fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh
fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs
17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska
o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska
daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka
iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk
wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh
hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd
mszligudj (V)
mSvk
h (
P)
24
jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj
o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga
meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg
jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke
fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka
lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS
jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru
ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml
yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj
sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK
n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde
mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd
laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect
(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g
jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda
ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel
jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt
WIaKaj fotilde
daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o
WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel
fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg
jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml
fuh mltuq ioacutelrKfha wdfoaYfhka
fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH
ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk
nj wmg fmfka
fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh
pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we
tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj
hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h
mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq
wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt
jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect
jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia
PV mszligmQfrac34K
daauacutel
25
jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq
wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka
yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=
h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka
wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel
jdhq mszligmQfrac34K aajfhka wm ukh fotilde
151 jeka vrsquo jdaia ioacutelrKh
fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa
sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K
jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk
wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq
mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel
jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid
daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH
fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj
iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk
Egrave
bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka
kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka
mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka
igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash
iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg
fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh
mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde
1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj
ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh
by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK
fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde
gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq
mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde
fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg
iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq
msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect
moaOsfha mSvkh my mldYkfhka nd fohs
26
bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL
fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr
tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk
mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka
wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks
fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq
kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh
fi kej suacuteh yels h
fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh
fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql
nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia
flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha
wkafrac34--mszligjfrac34kh l yels fotilde
ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs
wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj
yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde
igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys
sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde
ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha
lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh
iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla
fi o yeisszligh yels ugraveu h
bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla
oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi
mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS
30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc
oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi
muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu
WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla
oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde
( )2
aP V b RTV
+ minus =
27
19 rEmh CO2 j ldm igyk
1 3 j =j - ioacutelrK idrdxYh
jdhq kshuh intildelrKhksh j mjsk
idOl
mszligmQfrac34K jdhq kshuh PV = nRT ke
fndhsa kshuh n iy T
pdaia kshuh V = kT n iy P
wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T
wKql pdl ioacutelrKh
idudkH fotilde h
jfrac34 uOHkH fotilde h
jfrac34 uOHkH fotilde h
fvdaagkaf a wdxYsl mSvk
kshuh
PA = xA PT
PT = PA + PB + PC
iiumlmSvHd idOlh jdhq ujq 1la i|yd
jeka vZjdaia ioacutelrKh
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
8
gtkajh (d) =
there4 P =
uacutefYaIs aaj hgfA fjka jdhq kshu jHqamkak lsIacutefiuml sect mszligmQfrac34K jdhq kshuh uQsl
moku fi lshd lrhs
122 fndhsa kshuh (mSvk-mszligud iiumlnkaOh)mdashksh WIaKajhla hgfa wes iaOacuter jdhq mudKhl (ialkaOhl) mSvkh jdhqfotilde mszligudjg
msfdauj uacutepkh fotilde (fyda iudkqmdsl) fotilde˜ fndhsa kshuh hkqfjka ye`Egravekafjk
fuh tfia kiuml lrk oafoa 17 jeks ishjfia sect WIaKajh ksh jQ aaj hgfa fjkia
jk mSvkha iu jdhqjl mszligudj uacutepkh jk wdldrh whsszligIa cdsl uacuteoHdhl= jQ
frdnUuml fndhsa (1627- 1691) uacuteiska wOHhkh lsIacutefuka miqj h tys Ksuh wdldrh
my oelafotilde
my plusmnlafjk mszligEgrave fndhsa kshuh jHqamkak lsIacuteu i`oyd mszligmQfrac34K jdhq kshuh fhdod
yelsh PV= nRT
jdhqfjys mudKh yd moaOsfhys WIaKajh kshj mjajd kakd oafoa kiuml nT =Ksh
kshhla fotilde R o kshhla jk neuacuteka nRT =Ksh o kshhla (k) fotilde
PV = k (kshhla)
tkiuml ksh WIaKajfha sect ksh jdhq mudKhl mSvkfhaa mszligudfotildea =Ksh kshhla
fotilde fuh fndhsa kshuh mldY lrk fjka wdldrhls
ksh T WIaKajhl wes ksh jdhq mudKhl mszligudj V1 o mSvkh P1 o kiuml yd th V2
mszligudjg yd P2 mSvkhg ma llt uacuteg fndhsa kshuhg wkqj
14 rEmh u` ska fndhsa kshufha idiumlmodhsl miadszligl ksrEmK folla fmkakqiuml flffrac34
14 rEmfha (a) u` ska ixikaokh i`oyd uacuteuacuteO WIaKajj sect PV = k miadr lr we
k w h WIaKajh u muKla r`od mjsk ksid fok o jdhq ialkaOhla i`oyd w`Egravek
o ieu jlhla i`oyd u k ys w h tlsfklg fjkia fotilde bylt WIaKajj sect mszligudfotilde
midrKh ksid plh byltg f dia wes nj ielsh hq= h tfuka u WIaKajh ksh
uacuteg jdhqfotilde mSvkh wvla jk uacuteg mszligudj fo =K jk nj ul nd hq= h
9
1 4 rEmh uacuteuacuteO ksh WIaKajj sect (a) mszligudj (V) iuOtilde (b) 1 V iuOtilde
mSvkfha fjkia ugraveu
14 (b) rEmh u` ska P g tosrsfhka ys miadrh ksrEmKh fotilde th uQ laIHh yryd hk
ir ffrac34Ldjls fndhsa uacuteiska lrk o mIacutelaIKjg wkqj nd kakd o fuu miadr
u` ska jdhqjg bylt iiumlmSvHdjla wes nj mudKdaulj fmkajd foa tkiuml fok o
jdhq ialkaOhla iiumlmSvkh llt uacuteg tl u mudKhlska wes wKq ixLHdj l=vd mszligudjla
=lt mesffrac34 fiuml wkqj bylt mSvkj sect jdhqj gtkajh jeauml fotilde
igyk fok o jdhqjl gtkajh d ialkaOh m o mszligudj v o jk uacuteg d = ioacutelrKfhka
fok nj wms oksuq tuksid ksh WIaKajfhasect
hkqfjka suacuteh yels h
1 3 ksoiqk
ksh WIaKajhla hgfa wes okakd jdhq ujq mudKhl mszligudj fo =K llt uacuteg
mSvkfha isyuml jk fjkia ugraveu Kkh lrkak
uacutei`yumlu V1 =V V2 = 2V P1 = P P2 = fndhsa kshuh fhsectfuka P1V1 = P2V2
P times V = P2 times 2VP2 = P 2 there4kj mSvkh uqa mSvkfhka wvla fotilde
10
1 4 ksoiqk
ldur WIaKajfha sect neumlkhla yhsvcka jdhqj okakd mudKhlska mqrjd we jdhqf daSh
mSvkfha sect (100 kPa) tu jdhq mudKh 2 50 dm3 l mszligudjla kS tu WIaKajfha sect u
we=lt mSvkh 20 kPa ugraveug neumlkfha mszligudj fldmuK uacuteh llt hq= o
uacutei`yumlu P1 = 100 kPa P2 = 20 kPa V1 = 2 5 dm3 V2 = fndhsa kshuh fhsectfuka P1V1 = P2V2
100 kPa times 2 5 dm3 = 20 kPa times V2 there4V2 = 12 5 dm3 neumlkfha mszligudj 12 5 dm3 olajd jeauml llt hq= h
123 pdaia kshuh (WIaKaj-mszligud iiumlnkaOh)cdlaia pdaia iy fcdaIma f a-umliela hk uacuteoHdhkaf a yeoEIacuteiuml u ska fmkajd sect wes mszligEgrave
ksh mSvkhl sect fok o ksH jdhq mudKhl ^ialkaOhamp mszligudj WIaKajha iu`
jeauml jk wr isisa lsIacuteua iu` wvq fotilde tfuka u WIaKajfhA isyuml jk ieu fiaishia
wxYlhl fjkila mdid ^jeauml ugraveu fyda wvq ugraveuamp mszligudj 0degC sect jdhqfotilde wdriumlNl mszligudfjka idOlhlska fjkia jk nj ^jeauml ugraveu fyda wvq ugraveuamp fidhd f k we
0 degC sect iy t degC ys sect jdhqfotilde mszligudj msltsfjltska V0 iy Vt hhs Wmlamkh lruq tuacuteg
fuu aajfha sect WIaKajh i`oyd kj mszligudKhla wfrac34 olajd we tuacuteg tu mszligudKhg
wkqj
t degC i`oyd Tt = 273 15 + t uOtildeska nd fok wr
0 degC i`oyd T0 = 273 15 uOtildeska nd fohs
fuu kj WIaKaj mszligudKh flauacuteka WIaKaj mszligudKh (K) fyja ksrfmalaI WIaKaj
mszligudKh fi ye`Egravekafotilde ndash 273 15 degC (0 K) hkak dm sl Y+kHh fi wfrac34 oelafjk
wr th ffioaOdkaslj lt` d uacuteh yels wju WIaKajh fotilde
fmdyumlfotilde a uacuteg ksh mSvkfha sect (V1 T1) isg (V2 T2) olajd isyuml jk fjkila i`oyd
11
tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg
wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde
jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys
WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg
yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h
PV = nRTV = nRT P
ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde
zwnjzwnjzwnjzwnjV prop T fyda V = kT
pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka
WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd
Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect
ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh
lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34
15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde
uacutepkh
12
1 5 ksoiqk
ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml
jk WIaKaj fjki Kkh lrkak
uacutei`yumlu
T1 = T V1 = V V2 = 3V T2 =
T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh
wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h
hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi
efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg
lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr
kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde
1 6 ksoiqk
23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde
tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki
Kkh lrkak
uacutei`yumlu
T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =
jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka
V2 = 2 03 dm3
mszligudfotilde isyumljk fjki = 0 03 dm3
124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=
jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj
lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla
hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)
fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h
13
jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda
kshh (NA fyda L) fi ye|skafotilde
my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka
wjfndaO lr yels h
fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl
u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud
follg by iiumlnkaOdj fhsectfuka
P iy T ksh uacuteg sect (R iy NA kshhka fotilde )
irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud
=lt iudk wKq ixLdjla wvx= fotilde (V α N)
by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd
mszligmQfrac34K jdhq ioacutelrKh nd yels h
by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka
k = R jQ uacuteg
P V = n R T
14
125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka
fi wmg suacuteh yels h
iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd
mszligudj (Vm) tl u w hla uacuteh hq= ksid th
fi Kkh llt yels h
tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u
mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34
bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu
aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj
22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi
ksrEmKh flffrac34
bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde
fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde
igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde
V = k n = k (m M) tneuacuteka M = k (m V) = k d
1 7 ksoiqk
298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud
iudk nj fmkajkak
uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe
VHe = nHeRTHe PHe
VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3
15
PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =
PNeVNe = nNeRTNe
VNe = nNeRTNe PNe
VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa
VNe = 24 4 dm3
tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq
wa lr kakd mszligud iudk fotilde
126 ixhqla jdhq kshuh
jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj
tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka
T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla
fi suacuteh yels h
fuh ixhqla jdhq kshuh fi ye|skafotilde
1 8 ksoiqk
25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o
uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh
P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3
T1 = 25 + 273 = 298 K
V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =
P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa
16
13 fvdaagkaf a wdxYsl mSvk kshuh
fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm
yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk
wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml
ishuml jdhq odhl fotilde
jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj
wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde
ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla
iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs
fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh
fi yeEgravekafotilde
A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska
PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde
my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka
jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha
we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh
PT hehs o isuq
PV = nRT
A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )
B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )
jdhq ntildeYKh i`oyd nT = PTV RT
iy nT = nA + nB
tu ksid PTV RT = (PAV RT) + (PBV RT)
iq`M llt uacuteg PT = PA + PB
fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl
131 ujq Nd h wkqidrfhka wdxYsl mSvkh
T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq
ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde
fvdaagkaf a kshuhg wkqj PT = PA + PB
PA iy PB mldYk fjk fjk u PT jska fnsectfuka
17
tu ksid
fi suacuteh yels h
hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk
fotilde
1 9 ksoiqk
(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla
tla jdhqfotilde wdxYsl mSvkh Kkh lrkak
(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd
lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq
ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak
uacutei`yumlu
18
fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK
u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd
fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj
tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla
fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re
uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq
irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq
efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj
u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk
nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja
ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj
mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=
jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes
lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect
tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh
wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K
jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl
1 10 ksoiqk
my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs
iskak
2KClO3(s) rarr2KCl(s) + 3O2(g)
27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute
27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh
Kkh lrkak
uacutei`yumlu
fvdaagkaf a kshuhg wkqj
Piuia = PTlaiscka + Pch
PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa
mszligmQfrac34K jdhq ioacutelrKh fhsectfuka
14 jdhq msltsn`o pdl wKqljdoh
by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(
fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks
mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla
nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka
uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml
jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh
llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad
fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd
fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj
yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde
19
141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde
wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd
uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr
wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS
wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh
u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka
gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska
jdhqj bylt iiumlmSvHdj meyeEgraves fotilde
bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu
jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO
wKqjg uacuteuacuteO fotilde mjS
fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg
ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash
jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk
ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde
bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS
fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq
wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj
fuu ska mldY flffrac34
fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh
mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt
uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka
jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr
iiumlnkaOdjh my ioacutelrKfhka nd foa
jyumlrga my oelafjk lreKq plusmnlauacuteh yels h
bull jdhq wxY= tlsfklska iajdhaj yeisffrac34
jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska
iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda
fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj
wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml
Wmlamkfhka meyeEgraves fotilde
bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla
u` ska mSvkhla wes fotilde
fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect
ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl
isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug
20
fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml
jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq
ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj
jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml
fotilde
142 pdl wKqljdofha ioacutelrKh
my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla
fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34
by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes
wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka
wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34
uOHkH fotilde h fi wfrac34 olajkq efiacute
143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h
my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu
jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg
jfrac34 uOHkH uQ fotilde h fotilde
jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla
jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=
Kkla i`oyd ioacutelrKh ild nuq
N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)
PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka
21
tu ksid jfrac34 uOHkH uQ fotilde h
fi suacuteh yels h
1 11 ksoiqk
25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak
uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1
by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj
fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama
lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml
pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh
u` ska th my oelafjk mszligEgrave idOkh llt yels h
fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt
yel
kB hkq fndaaUumliaudka kshh fotilde
22
wKqjla i`oyd
ujqhla i`oyd
fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq
fotilde
144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml
N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag
pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq
efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave
mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes
lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde
jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash
fi ye|skafotilde
16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--
fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd
fotilde jHdmash
23
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka
wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea
jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd
idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute
ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr
^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17
rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla
i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34
17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj
iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha
sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka
daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh
17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd
Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir
ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla
mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy
ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh
yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr
jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml
ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej
jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla
fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh
fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs
17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska
o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska
daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka
iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk
wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh
hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd
mszligudj (V)
mSvk
h (
P)
24
jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj
o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga
meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg
jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke
fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka
lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS
jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru
ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml
yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj
sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK
n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde
mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd
laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect
(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g
jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda
ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel
jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt
WIaKaj fotilde
daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o
WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel
fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg
jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml
fuh mltuq ioacutelrKfha wdfoaYfhka
fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH
ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk
nj wmg fmfka
fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh
pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we
tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj
hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h
mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq
wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt
jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect
jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia
PV mszligmQfrac34K
daauacutel
25
jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq
wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka
yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=
h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka
wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel
jdhq mszligmQfrac34K aajfhka wm ukh fotilde
151 jeka vrsquo jdaia ioacutelrKh
fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa
sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K
jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk
wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq
mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel
jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid
daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH
fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj
iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk
Egrave
bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka
kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka
mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka
igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash
iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg
fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh
mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde
1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj
ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh
by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK
fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde
gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq
mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde
fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg
iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq
msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect
moaOsfha mSvkh my mldYkfhka nd fohs
26
bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL
fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr
tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk
mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka
wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks
fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq
kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh
fi kej suacuteh yels h
fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh
fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql
nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia
flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha
wkafrac34--mszligjfrac34kh l yels fotilde
ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs
wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj
yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde
igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys
sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde
ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha
lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh
iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla
fi o yeisszligh yels ugraveu h
bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla
oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi
mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS
30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc
oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi
muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu
WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla
oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde
( )2
aP V b RTV
+ minus =
27
19 rEmh CO2 j ldm igyk
1 3 j =j - ioacutelrK idrdxYh
jdhq kshuh intildelrKhksh j mjsk
idOl
mszligmQfrac34K jdhq kshuh PV = nRT ke
fndhsa kshuh n iy T
pdaia kshuh V = kT n iy P
wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T
wKql pdl ioacutelrKh
idudkH fotilde h
jfrac34 uOHkH fotilde h
jfrac34 uOHkH fotilde h
fvdaagkaf a wdxYsl mSvk
kshuh
PA = xA PT
PT = PA + PB + PC
iiumlmSvHd idOlh jdhq ujq 1la i|yd
jeka vZjdaia ioacutelrKh
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
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iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
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Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
9
1 4 rEmh uacuteuacuteO ksh WIaKajj sect (a) mszligudj (V) iuOtilde (b) 1 V iuOtilde
mSvkfha fjkia ugraveu
14 (b) rEmh u` ska P g tosrsfhka ys miadrh ksrEmKh fotilde th uQ laIHh yryd hk
ir ffrac34Ldjls fndhsa uacuteiska lrk o mIacutelaIKjg wkqj nd kakd o fuu miadr
u` ska jdhqjg bylt iiumlmSvHdjla wes nj mudKdaulj fmkajd foa tkiuml fok o
jdhq ialkaOhla iiumlmSvkh llt uacuteg tl u mudKhlska wes wKq ixLHdj l=vd mszligudjla
=lt mesffrac34 fiuml wkqj bylt mSvkj sect jdhqj gtkajh jeauml fotilde
igyk fok o jdhqjl gtkajh d ialkaOh m o mszligudj v o jk uacuteg d = ioacutelrKfhka
fok nj wms oksuq tuksid ksh WIaKajfhasect
hkqfjka suacuteh yels h
1 3 ksoiqk
ksh WIaKajhla hgfa wes okakd jdhq ujq mudKhl mszligudj fo =K llt uacuteg
mSvkfha isyuml jk fjkia ugraveu Kkh lrkak
uacutei`yumlu V1 =V V2 = 2V P1 = P P2 = fndhsa kshuh fhsectfuka P1V1 = P2V2
P times V = P2 times 2VP2 = P 2 there4kj mSvkh uqa mSvkfhka wvla fotilde
10
1 4 ksoiqk
ldur WIaKajfha sect neumlkhla yhsvcka jdhqj okakd mudKhlska mqrjd we jdhqf daSh
mSvkfha sect (100 kPa) tu jdhq mudKh 2 50 dm3 l mszligudjla kS tu WIaKajfha sect u
we=lt mSvkh 20 kPa ugraveug neumlkfha mszligudj fldmuK uacuteh llt hq= o
uacutei`yumlu P1 = 100 kPa P2 = 20 kPa V1 = 2 5 dm3 V2 = fndhsa kshuh fhsectfuka P1V1 = P2V2
100 kPa times 2 5 dm3 = 20 kPa times V2 there4V2 = 12 5 dm3 neumlkfha mszligudj 12 5 dm3 olajd jeauml llt hq= h
123 pdaia kshuh (WIaKaj-mszligud iiumlnkaOh)cdlaia pdaia iy fcdaIma f a-umliela hk uacuteoHdhkaf a yeoEIacuteiuml u ska fmkajd sect wes mszligEgrave
ksh mSvkhl sect fok o ksH jdhq mudKhl ^ialkaOhamp mszligudj WIaKajha iu`
jeauml jk wr isisa lsIacuteua iu` wvq fotilde tfuka u WIaKajfhA isyuml jk ieu fiaishia
wxYlhl fjkila mdid ^jeauml ugraveu fyda wvq ugraveuamp mszligudj 0degC sect jdhqfotilde wdriumlNl mszligudfjka idOlhlska fjkia jk nj ^jeauml ugraveu fyda wvq ugraveuamp fidhd f k we
0 degC sect iy t degC ys sect jdhqfotilde mszligudj msltsfjltska V0 iy Vt hhs Wmlamkh lruq tuacuteg
fuu aajfha sect WIaKajh i`oyd kj mszligudKhla wfrac34 olajd we tuacuteg tu mszligudKhg
wkqj
t degC i`oyd Tt = 273 15 + t uOtildeska nd fok wr
0 degC i`oyd T0 = 273 15 uOtildeska nd fohs
fuu kj WIaKaj mszligudKh flauacuteka WIaKaj mszligudKh (K) fyja ksrfmalaI WIaKaj
mszligudKh fi ye`Egravekafotilde ndash 273 15 degC (0 K) hkak dm sl Y+kHh fi wfrac34 oelafjk
wr th ffioaOdkaslj lt` d uacuteh yels wju WIaKajh fotilde
fmdyumlfotilde a uacuteg ksh mSvkfha sect (V1 T1) isg (V2 T2) olajd isyuml jk fjkila i`oyd
11
tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg
wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde
jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys
WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg
yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h
PV = nRTV = nRT P
ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde
zwnjzwnjzwnjzwnjV prop T fyda V = kT
pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka
WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd
Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect
ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh
lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34
15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde
uacutepkh
12
1 5 ksoiqk
ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml
jk WIaKaj fjki Kkh lrkak
uacutei`yumlu
T1 = T V1 = V V2 = 3V T2 =
T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh
wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h
hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi
efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg
lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr
kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde
1 6 ksoiqk
23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde
tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki
Kkh lrkak
uacutei`yumlu
T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =
jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka
V2 = 2 03 dm3
mszligudfotilde isyumljk fjki = 0 03 dm3
124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=
jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj
lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla
hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)
fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h
13
jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda
kshh (NA fyda L) fi ye|skafotilde
my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka
wjfndaO lr yels h
fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl
u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud
follg by iiumlnkaOdj fhsectfuka
P iy T ksh uacuteg sect (R iy NA kshhka fotilde )
irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud
=lt iudk wKq ixLdjla wvx= fotilde (V α N)
by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd
mszligmQfrac34K jdhq ioacutelrKh nd yels h
by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka
k = R jQ uacuteg
P V = n R T
14
125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka
fi wmg suacuteh yels h
iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd
mszligudj (Vm) tl u w hla uacuteh hq= ksid th
fi Kkh llt yels h
tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u
mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34
bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu
aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj
22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi
ksrEmKh flffrac34
bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde
fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde
igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde
V = k n = k (m M) tneuacuteka M = k (m V) = k d
1 7 ksoiqk
298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud
iudk nj fmkajkak
uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe
VHe = nHeRTHe PHe
VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3
15
PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =
PNeVNe = nNeRTNe
VNe = nNeRTNe PNe
VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa
VNe = 24 4 dm3
tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq
wa lr kakd mszligud iudk fotilde
126 ixhqla jdhq kshuh
jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj
tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka
T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla
fi suacuteh yels h
fuh ixhqla jdhq kshuh fi ye|skafotilde
1 8 ksoiqk
25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o
uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh
P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3
T1 = 25 + 273 = 298 K
V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =
P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa
16
13 fvdaagkaf a wdxYsl mSvk kshuh
fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm
yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk
wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml
ishuml jdhq odhl fotilde
jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj
wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde
ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla
iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs
fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh
fi yeEgravekafotilde
A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska
PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde
my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka
jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha
we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh
PT hehs o isuq
PV = nRT
A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )
B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )
jdhq ntildeYKh i`oyd nT = PTV RT
iy nT = nA + nB
tu ksid PTV RT = (PAV RT) + (PBV RT)
iq`M llt uacuteg PT = PA + PB
fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl
131 ujq Nd h wkqidrfhka wdxYsl mSvkh
T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq
ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde
fvdaagkaf a kshuhg wkqj PT = PA + PB
PA iy PB mldYk fjk fjk u PT jska fnsectfuka
17
tu ksid
fi suacuteh yels h
hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk
fotilde
1 9 ksoiqk
(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla
tla jdhqfotilde wdxYsl mSvkh Kkh lrkak
(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd
lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq
ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak
uacutei`yumlu
18
fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK
u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd
fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj
tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla
fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re
uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq
irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq
efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj
u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk
nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja
ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj
mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=
jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes
lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect
tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh
wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K
jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl
1 10 ksoiqk
my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs
iskak
2KClO3(s) rarr2KCl(s) + 3O2(g)
27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute
27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh
Kkh lrkak
uacutei`yumlu
fvdaagkaf a kshuhg wkqj
Piuia = PTlaiscka + Pch
PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa
mszligmQfrac34K jdhq ioacutelrKh fhsectfuka
14 jdhq msltsn`o pdl wKqljdoh
by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(
fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks
mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla
nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka
uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml
jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh
llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad
fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd
fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj
yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde
19
141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde
wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd
uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr
wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS
wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh
u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka
gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska
jdhqj bylt iiumlmSvHdj meyeEgraves fotilde
bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu
jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO
wKqjg uacuteuacuteO fotilde mjS
fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg
ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash
jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk
ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde
bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS
fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq
wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj
fuu ska mldY flffrac34
fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh
mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt
uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka
jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr
iiumlnkaOdjh my ioacutelrKfhka nd foa
jyumlrga my oelafjk lreKq plusmnlauacuteh yels h
bull jdhq wxY= tlsfklska iajdhaj yeisffrac34
jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska
iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda
fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj
wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml
Wmlamkfhka meyeEgraves fotilde
bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla
u` ska mSvkhla wes fotilde
fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect
ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl
isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug
20
fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml
jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq
ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj
jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml
fotilde
142 pdl wKqljdofha ioacutelrKh
my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla
fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34
by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes
wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka
wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34
uOHkH fotilde h fi wfrac34 olajkq efiacute
143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h
my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu
jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg
jfrac34 uOHkH uQ fotilde h fotilde
jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla
jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=
Kkla i`oyd ioacutelrKh ild nuq
N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)
PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka
21
tu ksid jfrac34 uOHkH uQ fotilde h
fi suacuteh yels h
1 11 ksoiqk
25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak
uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1
by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj
fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama
lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml
pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh
u` ska th my oelafjk mszligEgrave idOkh llt yels h
fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt
yel
kB hkq fndaaUumliaudka kshh fotilde
22
wKqjla i`oyd
ujqhla i`oyd
fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq
fotilde
144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml
N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag
pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq
efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave
mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes
lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde
jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash
fi ye|skafotilde
16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--
fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd
fotilde jHdmash
23
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka
wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea
jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd
idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute
ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr
^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17
rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla
i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34
17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj
iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha
sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka
daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh
17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd
Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir
ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla
mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy
ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh
yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr
jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml
ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej
jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla
fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh
fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs
17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska
o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska
daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka
iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk
wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh
hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd
mszligudj (V)
mSvk
h (
P)
24
jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj
o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga
meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg
jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke
fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka
lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS
jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru
ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml
yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj
sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK
n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde
mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd
laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect
(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g
jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda
ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel
jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt
WIaKaj fotilde
daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o
WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel
fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg
jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml
fuh mltuq ioacutelrKfha wdfoaYfhka
fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH
ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk
nj wmg fmfka
fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh
pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we
tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj
hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h
mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq
wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt
jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect
jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia
PV mszligmQfrac34K
daauacutel
25
jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq
wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka
yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=
h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka
wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel
jdhq mszligmQfrac34K aajfhka wm ukh fotilde
151 jeka vrsquo jdaia ioacutelrKh
fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa
sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K
jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk
wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq
mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel
jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid
daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH
fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj
iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk
Egrave
bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka
kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka
mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka
igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash
iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg
fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh
mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde
1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj
ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh
by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK
fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde
gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq
mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde
fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg
iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq
msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect
moaOsfha mSvkh my mldYkfhka nd fohs
26
bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL
fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr
tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk
mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka
wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks
fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq
kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh
fi kej suacuteh yels h
fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh
fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql
nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia
flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha
wkafrac34--mszligjfrac34kh l yels fotilde
ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs
wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj
yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde
igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys
sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde
ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha
lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh
iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla
fi o yeisszligh yels ugraveu h
bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla
oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi
mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS
30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc
oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi
muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu
WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla
oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde
( )2
aP V b RTV
+ minus =
27
19 rEmh CO2 j ldm igyk
1 3 j =j - ioacutelrK idrdxYh
jdhq kshuh intildelrKhksh j mjsk
idOl
mszligmQfrac34K jdhq kshuh PV = nRT ke
fndhsa kshuh n iy T
pdaia kshuh V = kT n iy P
wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T
wKql pdl ioacutelrKh
idudkH fotilde h
jfrac34 uOHkH fotilde h
jfrac34 uOHkH fotilde h
fvdaagkaf a wdxYsl mSvk
kshuh
PA = xA PT
PT = PA + PB + PC
iiumlmSvHd idOlh jdhq ujq 1la i|yd
jeka vZjdaia ioacutelrKh
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
10
1 4 ksoiqk
ldur WIaKajfha sect neumlkhla yhsvcka jdhqj okakd mudKhlska mqrjd we jdhqf daSh
mSvkfha sect (100 kPa) tu jdhq mudKh 2 50 dm3 l mszligudjla kS tu WIaKajfha sect u
we=lt mSvkh 20 kPa ugraveug neumlkfha mszligudj fldmuK uacuteh llt hq= o
uacutei`yumlu P1 = 100 kPa P2 = 20 kPa V1 = 2 5 dm3 V2 = fndhsa kshuh fhsectfuka P1V1 = P2V2
100 kPa times 2 5 dm3 = 20 kPa times V2 there4V2 = 12 5 dm3 neumlkfha mszligudj 12 5 dm3 olajd jeauml llt hq= h
123 pdaia kshuh (WIaKaj-mszligud iiumlnkaOh)cdlaia pdaia iy fcdaIma f a-umliela hk uacuteoHdhkaf a yeoEIacuteiuml u ska fmkajd sect wes mszligEgrave
ksh mSvkhl sect fok o ksH jdhq mudKhl ^ialkaOhamp mszligudj WIaKajha iu`
jeauml jk wr isisa lsIacuteua iu` wvq fotilde tfuka u WIaKajfhA isyuml jk ieu fiaishia
wxYlhl fjkila mdid ^jeauml ugraveu fyda wvq ugraveuamp mszligudj 0degC sect jdhqfotilde wdriumlNl mszligudfjka idOlhlska fjkia jk nj ^jeauml ugraveu fyda wvq ugraveuamp fidhd f k we
0 degC sect iy t degC ys sect jdhqfotilde mszligudj msltsfjltska V0 iy Vt hhs Wmlamkh lruq tuacuteg
fuu aajfha sect WIaKajh i`oyd kj mszligudKhla wfrac34 olajd we tuacuteg tu mszligudKhg
wkqj
t degC i`oyd Tt = 273 15 + t uOtildeska nd fok wr
0 degC i`oyd T0 = 273 15 uOtildeska nd fohs
fuu kj WIaKaj mszligudKh flauacuteka WIaKaj mszligudKh (K) fyja ksrfmalaI WIaKaj
mszligudKh fi ye`Egravekafotilde ndash 273 15 degC (0 K) hkak dm sl Y+kHh fi wfrac34 oelafjk
wr th ffioaOdkaslj lt` d uacuteh yels wju WIaKajh fotilde
fmdyumlfotilde a uacuteg ksh mSvkfha sect (V1 T1) isg (V2 T2) olajd isyuml jk fjkila i`oyd
11
tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg
wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde
jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys
WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg
yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h
PV = nRTV = nRT P
ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde
zwnjzwnjzwnjzwnjV prop T fyda V = kT
pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka
WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd
Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect
ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh
lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34
15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde
uacutepkh
12
1 5 ksoiqk
ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml
jk WIaKaj fjki Kkh lrkak
uacutei`yumlu
T1 = T V1 = V V2 = 3V T2 =
T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh
wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h
hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi
efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg
lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr
kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde
1 6 ksoiqk
23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde
tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki
Kkh lrkak
uacutei`yumlu
T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =
jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka
V2 = 2 03 dm3
mszligudfotilde isyumljk fjki = 0 03 dm3
124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=
jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj
lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla
hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)
fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h
13
jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda
kshh (NA fyda L) fi ye|skafotilde
my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka
wjfndaO lr yels h
fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl
u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud
follg by iiumlnkaOdj fhsectfuka
P iy T ksh uacuteg sect (R iy NA kshhka fotilde )
irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud
=lt iudk wKq ixLdjla wvx= fotilde (V α N)
by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd
mszligmQfrac34K jdhq ioacutelrKh nd yels h
by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka
k = R jQ uacuteg
P V = n R T
14
125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka
fi wmg suacuteh yels h
iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd
mszligudj (Vm) tl u w hla uacuteh hq= ksid th
fi Kkh llt yels h
tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u
mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34
bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu
aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj
22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi
ksrEmKh flffrac34
bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde
fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde
igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde
V = k n = k (m M) tneuacuteka M = k (m V) = k d
1 7 ksoiqk
298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud
iudk nj fmkajkak
uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe
VHe = nHeRTHe PHe
VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3
15
PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =
PNeVNe = nNeRTNe
VNe = nNeRTNe PNe
VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa
VNe = 24 4 dm3
tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq
wa lr kakd mszligud iudk fotilde
126 ixhqla jdhq kshuh
jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj
tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka
T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla
fi suacuteh yels h
fuh ixhqla jdhq kshuh fi ye|skafotilde
1 8 ksoiqk
25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o
uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh
P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3
T1 = 25 + 273 = 298 K
V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =
P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa
16
13 fvdaagkaf a wdxYsl mSvk kshuh
fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm
yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk
wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml
ishuml jdhq odhl fotilde
jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj
wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde
ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla
iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs
fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh
fi yeEgravekafotilde
A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska
PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde
my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka
jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha
we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh
PT hehs o isuq
PV = nRT
A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )
B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )
jdhq ntildeYKh i`oyd nT = PTV RT
iy nT = nA + nB
tu ksid PTV RT = (PAV RT) + (PBV RT)
iq`M llt uacuteg PT = PA + PB
fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl
131 ujq Nd h wkqidrfhka wdxYsl mSvkh
T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq
ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde
fvdaagkaf a kshuhg wkqj PT = PA + PB
PA iy PB mldYk fjk fjk u PT jska fnsectfuka
17
tu ksid
fi suacuteh yels h
hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk
fotilde
1 9 ksoiqk
(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla
tla jdhqfotilde wdxYsl mSvkh Kkh lrkak
(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd
lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq
ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak
uacutei`yumlu
18
fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK
u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd
fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj
tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla
fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re
uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq
irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq
efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj
u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk
nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja
ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj
mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=
jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes
lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect
tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh
wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K
jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl
1 10 ksoiqk
my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs
iskak
2KClO3(s) rarr2KCl(s) + 3O2(g)
27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute
27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh
Kkh lrkak
uacutei`yumlu
fvdaagkaf a kshuhg wkqj
Piuia = PTlaiscka + Pch
PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa
mszligmQfrac34K jdhq ioacutelrKh fhsectfuka
14 jdhq msltsn`o pdl wKqljdoh
by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(
fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks
mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla
nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka
uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml
jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh
llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad
fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd
fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj
yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde
19
141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde
wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd
uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr
wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS
wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh
u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka
gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska
jdhqj bylt iiumlmSvHdj meyeEgraves fotilde
bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu
jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO
wKqjg uacuteuacuteO fotilde mjS
fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg
ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash
jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk
ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde
bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS
fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq
wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj
fuu ska mldY flffrac34
fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh
mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt
uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka
jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr
iiumlnkaOdjh my ioacutelrKfhka nd foa
jyumlrga my oelafjk lreKq plusmnlauacuteh yels h
bull jdhq wxY= tlsfklska iajdhaj yeisffrac34
jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska
iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda
fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj
wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml
Wmlamkfhka meyeEgraves fotilde
bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla
u` ska mSvkhla wes fotilde
fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect
ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl
isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug
20
fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml
jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq
ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj
jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml
fotilde
142 pdl wKqljdofha ioacutelrKh
my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla
fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34
by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes
wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka
wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34
uOHkH fotilde h fi wfrac34 olajkq efiacute
143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h
my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu
jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg
jfrac34 uOHkH uQ fotilde h fotilde
jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla
jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=
Kkla i`oyd ioacutelrKh ild nuq
N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)
PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka
21
tu ksid jfrac34 uOHkH uQ fotilde h
fi suacuteh yels h
1 11 ksoiqk
25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak
uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1
by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj
fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama
lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml
pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh
u` ska th my oelafjk mszligEgrave idOkh llt yels h
fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt
yel
kB hkq fndaaUumliaudka kshh fotilde
22
wKqjla i`oyd
ujqhla i`oyd
fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq
fotilde
144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml
N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag
pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq
efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave
mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes
lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde
jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash
fi ye|skafotilde
16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--
fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd
fotilde jHdmash
23
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka
wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea
jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd
idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute
ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr
^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17
rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla
i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34
17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj
iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha
sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka
daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh
17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd
Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir
ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla
mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy
ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh
yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr
jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml
ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej
jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla
fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh
fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs
17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska
o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska
daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka
iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk
wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh
hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd
mszligudj (V)
mSvk
h (
P)
24
jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj
o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga
meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg
jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke
fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka
lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS
jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru
ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml
yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj
sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK
n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde
mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd
laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect
(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g
jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda
ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel
jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt
WIaKaj fotilde
daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o
WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel
fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg
jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml
fuh mltuq ioacutelrKfha wdfoaYfhka
fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH
ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk
nj wmg fmfka
fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh
pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we
tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj
hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h
mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq
wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt
jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect
jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia
PV mszligmQfrac34K
daauacutel
25
jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq
wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka
yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=
h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka
wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel
jdhq mszligmQfrac34K aajfhka wm ukh fotilde
151 jeka vrsquo jdaia ioacutelrKh
fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa
sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K
jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk
wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq
mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel
jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid
daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH
fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj
iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk
Egrave
bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka
kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka
mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka
igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash
iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg
fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh
mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde
1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj
ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh
by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK
fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde
gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq
mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde
fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg
iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq
msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect
moaOsfha mSvkh my mldYkfhka nd fohs
26
bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL
fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr
tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk
mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka
wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks
fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq
kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh
fi kej suacuteh yels h
fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh
fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql
nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia
flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha
wkafrac34--mszligjfrac34kh l yels fotilde
ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs
wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj
yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde
igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys
sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde
ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha
lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh
iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla
fi o yeisszligh yels ugraveu h
bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla
oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi
mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS
30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc
oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi
muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu
WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla
oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde
( )2
aP V b RTV
+ minus =
27
19 rEmh CO2 j ldm igyk
1 3 j =j - ioacutelrK idrdxYh
jdhq kshuh intildelrKhksh j mjsk
idOl
mszligmQfrac34K jdhq kshuh PV = nRT ke
fndhsa kshuh n iy T
pdaia kshuh V = kT n iy P
wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T
wKql pdl ioacutelrKh
idudkH fotilde h
jfrac34 uOHkH fotilde h
jfrac34 uOHkH fotilde h
fvdaagkaf a wdxYsl mSvk
kshuh
PA = xA PT
PT = PA + PB + PC
iiumlmSvHd idOlh jdhq ujq 1la i|yd
jeka vZjdaia ioacutelrKh
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
11
tuksidzzksh mSvkhla hgfa sect ksh jdhq mudKhl mszligudj ksrfmalaI WIaKajhg
wkqfdauj iudkqmdsl fotildeZZ fuh pdaia kshuh fi ye`Egravekafotilde
jyumlrga ksh jdhq mudKhl mSvkh kshj mjajd a uacuteg tys mszligudj flfrys
WIaKajh nmdk wdldrh wOHhkh lsIacuteu i`oyd mszligmQfrac34K jdhq ioacutelrKh Nduacutehg
yels h mszligmQfrac34K jdhq ioacutelrKh my plusmnlafjk mszligEgrave msixuacuteOdkh llt yels h
PV = nRTV = nRT P
ksh jdhq ialkaOhl mSvkh ksh kiuml nR P kshhla fotilde
zwnjzwnjzwnjzwnjV prop T fyda V = kT
pdaia kshuhg wkqj ishiquest jdhq i`oyd fok o acutekE u mSvkhl sect mszligudjg tosszligfhka
WIaKajh (degC jska) wr miadrh ir ffrac34Ldjla jk wr th Y+kH mszligudjla olajd
Egravela llt uacuteg ieu ffrac34Ldjlg u WIaKaj wlaIh - 273 15 degC sect yuq fotilde uacuteuacuteO mSvkjsect
ffrac34Ldj nEjqu uacuteuacuteO jk kuqa Y+kH mszligudfotilde sect ieu ffrac34Ldjla u WIaKaj wlaIh
lmkqfha - 273 15 degC sect fyda 0 K sect nj 15 rEmfhka fmkakqiuml flffrac34
15 rEmh uacuteuacuteO ksh mSvkj sect WIaKajh iuOtilde jdhqjl mszligudfotilde
uacutepkh
12
1 5 ksoiqk
ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml
jk WIaKaj fjki Kkh lrkak
uacutei`yumlu
T1 = T V1 = V V2 = 3V T2 =
T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh
wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h
hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi
efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg
lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr
kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde
1 6 ksoiqk
23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde
tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki
Kkh lrkak
uacutei`yumlu
T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =
jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka
V2 = 2 03 dm3
mszligudfotilde isyumljk fjki = 0 03 dm3
124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=
jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj
lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla
hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)
fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h
13
jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda
kshh (NA fyda L) fi ye|skafotilde
my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka
wjfndaO lr yels h
fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl
u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud
follg by iiumlnkaOdj fhsectfuka
P iy T ksh uacuteg sect (R iy NA kshhka fotilde )
irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud
=lt iudk wKq ixLdjla wvx= fotilde (V α N)
by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd
mszligmQfrac34K jdhq ioacutelrKh nd yels h
by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka
k = R jQ uacuteg
P V = n R T
14
125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka
fi wmg suacuteh yels h
iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd
mszligudj (Vm) tl u w hla uacuteh hq= ksid th
fi Kkh llt yels h
tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u
mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34
bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu
aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj
22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi
ksrEmKh flffrac34
bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde
fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde
igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde
V = k n = k (m M) tneuacuteka M = k (m V) = k d
1 7 ksoiqk
298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud
iudk nj fmkajkak
uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe
VHe = nHeRTHe PHe
VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3
15
PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =
PNeVNe = nNeRTNe
VNe = nNeRTNe PNe
VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa
VNe = 24 4 dm3
tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq
wa lr kakd mszligud iudk fotilde
126 ixhqla jdhq kshuh
jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj
tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka
T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla
fi suacuteh yels h
fuh ixhqla jdhq kshuh fi ye|skafotilde
1 8 ksoiqk
25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o
uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh
P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3
T1 = 25 + 273 = 298 K
V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =
P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa
16
13 fvdaagkaf a wdxYsl mSvk kshuh
fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm
yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk
wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml
ishuml jdhq odhl fotilde
jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj
wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde
ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla
iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs
fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh
fi yeEgravekafotilde
A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska
PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde
my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka
jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha
we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh
PT hehs o isuq
PV = nRT
A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )
B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )
jdhq ntildeYKh i`oyd nT = PTV RT
iy nT = nA + nB
tu ksid PTV RT = (PAV RT) + (PBV RT)
iq`M llt uacuteg PT = PA + PB
fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl
131 ujq Nd h wkqidrfhka wdxYsl mSvkh
T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq
ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde
fvdaagkaf a kshuhg wkqj PT = PA + PB
PA iy PB mldYk fjk fjk u PT jska fnsectfuka
17
tu ksid
fi suacuteh yels h
hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk
fotilde
1 9 ksoiqk
(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla
tla jdhqfotilde wdxYsl mSvkh Kkh lrkak
(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd
lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq
ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak
uacutei`yumlu
18
fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK
u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd
fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj
tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla
fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re
uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq
irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq
efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj
u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk
nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja
ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj
mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=
jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes
lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect
tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh
wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K
jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl
1 10 ksoiqk
my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs
iskak
2KClO3(s) rarr2KCl(s) + 3O2(g)
27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute
27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh
Kkh lrkak
uacutei`yumlu
fvdaagkaf a kshuhg wkqj
Piuia = PTlaiscka + Pch
PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa
mszligmQfrac34K jdhq ioacutelrKh fhsectfuka
14 jdhq msltsn`o pdl wKqljdoh
by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(
fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks
mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla
nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka
uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml
jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh
llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad
fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd
fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj
yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde
19
141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde
wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd
uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr
wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS
wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh
u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka
gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska
jdhqj bylt iiumlmSvHdj meyeEgraves fotilde
bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu
jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO
wKqjg uacuteuacuteO fotilde mjS
fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg
ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash
jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk
ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde
bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS
fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq
wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj
fuu ska mldY flffrac34
fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh
mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt
uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka
jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr
iiumlnkaOdjh my ioacutelrKfhka nd foa
jyumlrga my oelafjk lreKq plusmnlauacuteh yels h
bull jdhq wxY= tlsfklska iajdhaj yeisffrac34
jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska
iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda
fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj
wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml
Wmlamkfhka meyeEgraves fotilde
bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla
u` ska mSvkhla wes fotilde
fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect
ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl
isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug
20
fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml
jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq
ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj
jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml
fotilde
142 pdl wKqljdofha ioacutelrKh
my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla
fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34
by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes
wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka
wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34
uOHkH fotilde h fi wfrac34 olajkq efiacute
143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h
my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu
jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg
jfrac34 uOHkH uQ fotilde h fotilde
jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla
jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=
Kkla i`oyd ioacutelrKh ild nuq
N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)
PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka
21
tu ksid jfrac34 uOHkH uQ fotilde h
fi suacuteh yels h
1 11 ksoiqk
25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak
uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1
by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj
fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama
lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml
pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh
u` ska th my oelafjk mszligEgrave idOkh llt yels h
fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt
yel
kB hkq fndaaUumliaudka kshh fotilde
22
wKqjla i`oyd
ujqhla i`oyd
fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq
fotilde
144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml
N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag
pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq
efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave
mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes
lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde
jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash
fi ye|skafotilde
16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--
fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd
fotilde jHdmash
23
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka
wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea
jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd
idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute
ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr
^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17
rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla
i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34
17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj
iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha
sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka
daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh
17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd
Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir
ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla
mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy
ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh
yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr
jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml
ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej
jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla
fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh
fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs
17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska
o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska
daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka
iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk
wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh
hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd
mszligudj (V)
mSvk
h (
P)
24
jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj
o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga
meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg
jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke
fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka
lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS
jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru
ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml
yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj
sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK
n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde
mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd
laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect
(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g
jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda
ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel
jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt
WIaKaj fotilde
daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o
WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel
fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg
jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml
fuh mltuq ioacutelrKfha wdfoaYfhka
fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH
ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk
nj wmg fmfka
fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh
pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we
tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj
hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h
mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq
wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt
jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect
jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia
PV mszligmQfrac34K
daauacutel
25
jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq
wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka
yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=
h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka
wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel
jdhq mszligmQfrac34K aajfhka wm ukh fotilde
151 jeka vrsquo jdaia ioacutelrKh
fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa
sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K
jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk
wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq
mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel
jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid
daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH
fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj
iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk
Egrave
bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka
kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka
mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka
igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash
iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg
fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh
mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde
1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj
ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh
by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK
fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde
gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq
mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde
fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg
iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq
msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect
moaOsfha mSvkh my mldYkfhka nd fohs
26
bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL
fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr
tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk
mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka
wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks
fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq
kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh
fi kej suacuteh yels h
fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh
fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql
nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia
flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha
wkafrac34--mszligjfrac34kh l yels fotilde
ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs
wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj
yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde
igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys
sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde
ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha
lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh
iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla
fi o yeisszligh yels ugraveu h
bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla
oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi
mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS
30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc
oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi
muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu
WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla
oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde
( )2
aP V b RTV
+ minus =
27
19 rEmh CO2 j ldm igyk
1 3 j =j - ioacutelrK idrdxYh
jdhq kshuh intildelrKhksh j mjsk
idOl
mszligmQfrac34K jdhq kshuh PV = nRT ke
fndhsa kshuh n iy T
pdaia kshuh V = kT n iy P
wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T
wKql pdl ioacutelrKh
idudkH fotilde h
jfrac34 uOHkH fotilde h
jfrac34 uOHkH fotilde h
fvdaagkaf a wdxYsl mSvk
kshuh
PA = xA PT
PT = PA + PB + PC
iiumlmSvHd idOlh jdhq ujq 1la i|yd
jeka vZjdaia ioacutelrKh
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
12
1 5 ksoiqk
ksh mSvkhla hgfa wes okakd jdhq ujq mudKhl mszligudj f =K llt uacuteg tys isyuml
jk WIaKaj fjki Kkh lrkak
uacutei`yumlu
T1 = T V1 = V V2 = 3V T2 =
T2 = 3Tmszligudj flauacuteka WIaKajhg wkqfdauj iudkqmdsl jk neuacuteka kj WIaKajh
wdriumlNl w h fuka =ka =Khla jk nj flltska u ksudkh llt yels h
hk ioacutelrKh ild t = -273 15 wdfoaY llt uacuteg mszligudj Y+kH fi
efiacute tys fareu tuacuteg jdhqj fkdmjsk nj h ta wkqj acutekE u jdhqjla fiuml WIaKajhg
lt` d ugraveug fmr oslashj jk nj wmg wjfndaO lr yels h jdhq Y+kH mszligudjla wa lr
kafka hehs issh yels wju Wmlams WIaKajh ksrfmalaI Y=kHh fi ye`Egravekafotilde
1 6 ksoiqk
23 degC sect neumlkhla yhsvcka jdhqj hiuml mudKhlska msrjQ uacuteg tys mszligudj 2 0 dm3 fotilde
tu mSvkfha sect u WIaKajh 27 degC olajd jeauml llt uacuteg jdhqfotilde mszligudfotilde isyuml jk fjki
Kkh lrkak
uacutei`yumlu
T1 = 23 + 273 = 296 K T2 = 27 + 273= 300 K V1 = 2 0 dm3 V2 =
jdhqfotilde mSvkh yd mudKh ksh neuacuteka pdaia kshuh fhsectfuka
V2 = 2 03 dm3
mszligudfotilde isyumljk fjki = 0 03 dm3
124 wej dacircfrda kshuh (mudK-mszligud iiumlnkaOh)fndhsa iy pdaia kshu jeauml EgravehqKq lsIacutefuka a ixlaIsmah 1811 sect bds cdsl uacuteoHdhl=
jQ wufoda wej dacircfrda uacuteiska jdhqj ujq mudKh iy jdhqj mszligudj iiumlnkaO lr kj
lamshla jk wej dacircfrda kshuh bEgraveszligma lrk Egrave tkiuml tl u WIaKajhla yd mSvkhla
hgfa wes iudk jdhq mszligudj iudk ujqq ixLHdjla we hkakh (wej dacircfrda kshuh)
fiuml wkqj V prop n fyda V = k n wej dacircfrda kshuh fi suacuteh yels h
13
jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda
kshh (NA fyda L) fi ye|skafotilde
my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka
wjfndaO lr yels h
fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl
u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud
follg by iiumlnkaOdj fhsectfuka
P iy T ksh uacuteg sect (R iy NA kshhka fotilde )
irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud
=lt iudk wKq ixLdjla wvx= fotilde (V α N)
by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd
mszligmQfrac34K jdhq ioacutelrKh nd yels h
by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka
k = R jQ uacuteg
P V = n R T
14
125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka
fi wmg suacuteh yels h
iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd
mszligudj (Vm) tl u w hla uacuteh hq= ksid th
fi Kkh llt yels h
tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u
mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34
bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu
aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj
22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi
ksrEmKh flffrac34
bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde
fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde
igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde
V = k n = k (m M) tneuacuteka M = k (m V) = k d
1 7 ksoiqk
298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud
iudk nj fmkajkak
uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe
VHe = nHeRTHe PHe
VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3
15
PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =
PNeVNe = nNeRTNe
VNe = nNeRTNe PNe
VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa
VNe = 24 4 dm3
tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq
wa lr kakd mszligud iudk fotilde
126 ixhqla jdhq kshuh
jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj
tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka
T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla
fi suacuteh yels h
fuh ixhqla jdhq kshuh fi ye|skafotilde
1 8 ksoiqk
25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o
uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh
P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3
T1 = 25 + 273 = 298 K
V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =
P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa
16
13 fvdaagkaf a wdxYsl mSvk kshuh
fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm
yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk
wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml
ishuml jdhq odhl fotilde
jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj
wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde
ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla
iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs
fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh
fi yeEgravekafotilde
A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska
PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde
my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka
jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha
we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh
PT hehs o isuq
PV = nRT
A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )
B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )
jdhq ntildeYKh i`oyd nT = PTV RT
iy nT = nA + nB
tu ksid PTV RT = (PAV RT) + (PBV RT)
iq`M llt uacuteg PT = PA + PB
fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl
131 ujq Nd h wkqidrfhka wdxYsl mSvkh
T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq
ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde
fvdaagkaf a kshuhg wkqj PT = PA + PB
PA iy PB mldYk fjk fjk u PT jska fnsectfuka
17
tu ksid
fi suacuteh yels h
hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk
fotilde
1 9 ksoiqk
(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla
tla jdhqfotilde wdxYsl mSvkh Kkh lrkak
(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd
lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq
ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak
uacutei`yumlu
18
fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK
u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd
fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj
tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla
fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re
uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq
irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq
efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj
u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk
nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja
ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj
mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=
jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes
lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect
tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh
wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K
jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl
1 10 ksoiqk
my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs
iskak
2KClO3(s) rarr2KCl(s) + 3O2(g)
27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute
27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh
Kkh lrkak
uacutei`yumlu
fvdaagkaf a kshuhg wkqj
Piuia = PTlaiscka + Pch
PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa
mszligmQfrac34K jdhq ioacutelrKh fhsectfuka
14 jdhq msltsn`o pdl wKqljdoh
by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(
fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks
mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla
nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka
uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml
jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh
llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad
fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd
fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj
yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde
19
141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde
wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd
uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr
wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS
wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh
u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka
gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska
jdhqj bylt iiumlmSvHdj meyeEgraves fotilde
bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu
jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO
wKqjg uacuteuacuteO fotilde mjS
fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg
ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash
jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk
ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde
bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS
fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq
wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj
fuu ska mldY flffrac34
fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh
mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt
uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka
jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr
iiumlnkaOdjh my ioacutelrKfhka nd foa
jyumlrga my oelafjk lreKq plusmnlauacuteh yels h
bull jdhq wxY= tlsfklska iajdhaj yeisffrac34
jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska
iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda
fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj
wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml
Wmlamkfhka meyeEgraves fotilde
bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla
u` ska mSvkhla wes fotilde
fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect
ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl
isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug
20
fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml
jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq
ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj
jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml
fotilde
142 pdl wKqljdofha ioacutelrKh
my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla
fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34
by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes
wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka
wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34
uOHkH fotilde h fi wfrac34 olajkq efiacute
143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h
my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu
jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg
jfrac34 uOHkH uQ fotilde h fotilde
jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla
jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=
Kkla i`oyd ioacutelrKh ild nuq
N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)
PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka
21
tu ksid jfrac34 uOHkH uQ fotilde h
fi suacuteh yels h
1 11 ksoiqk
25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak
uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1
by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj
fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama
lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml
pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh
u` ska th my oelafjk mszligEgrave idOkh llt yels h
fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt
yel
kB hkq fndaaUumliaudka kshh fotilde
22
wKqjla i`oyd
ujqhla i`oyd
fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq
fotilde
144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml
N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag
pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq
efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave
mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes
lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde
jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash
fi ye|skafotilde
16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--
fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd
fotilde jHdmash
23
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka
wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea
jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd
idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute
ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr
^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17
rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla
i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34
17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj
iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha
sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka
daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh
17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd
Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir
ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla
mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy
ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh
yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr
jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml
ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej
jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla
fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh
fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs
17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska
o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska
daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka
iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk
wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh
hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd
mszligudj (V)
mSvk
h (
P)
24
jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj
o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga
meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg
jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke
fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka
lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS
jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru
ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml
yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj
sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK
n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde
mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd
laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect
(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g
jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda
ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel
jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt
WIaKaj fotilde
daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o
WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel
fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg
jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml
fuh mltuq ioacutelrKfha wdfoaYfhka
fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH
ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk
nj wmg fmfka
fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh
pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we
tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj
hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h
mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq
wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt
jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect
jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia
PV mszligmQfrac34K
daauacutel
25
jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq
wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka
yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=
h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka
wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel
jdhq mszligmQfrac34K aajfhka wm ukh fotilde
151 jeka vrsquo jdaia ioacutelrKh
fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa
sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K
jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk
wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq
mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel
jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid
daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH
fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj
iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk
Egrave
bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka
kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka
mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka
igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash
iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg
fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh
mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde
1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj
ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh
by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK
fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde
gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq
mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde
fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg
iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq
msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect
moaOsfha mSvkh my mldYkfhka nd fohs
26
bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL
fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr
tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk
mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka
wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks
fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq
kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh
fi kej suacuteh yels h
fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh
fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql
nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia
flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha
wkafrac34--mszligjfrac34kh l yels fotilde
ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs
wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj
yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde
igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys
sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde
ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha
lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh
iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla
fi o yeisszligh yels ugraveu h
bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla
oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi
mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS
30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc
oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi
muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu
WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla
oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde
( )2
aP V b RTV
+ minus =
27
19 rEmh CO2 j ldm igyk
1 3 j =j - ioacutelrK idrdxYh
jdhq kshuh intildelrKhksh j mjsk
idOl
mszligmQfrac34K jdhq kshuh PV = nRT ke
fndhsa kshuh n iy T
pdaia kshuh V = kT n iy P
wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T
wKql pdl ioacutelrKh
idudkH fotilde h
jfrac34 uOHkH fotilde h
jfrac34 uOHkH fotilde h
fvdaagkaf a wdxYsl mSvk
kshuh
PA = xA PT
PT = PA + PB + PC
iiumlmSvHd idOlh jdhq ujq 1la i|yd
jeka vZjdaia ioacutelrKh
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
13
jdhq ujqhl wes wKq Kk 6 022 times 1023 fi ksfrac34Kh lr wes wr th wej dacircfrda
kshh (NA fyda L) fi ye|skafotilde
my oelafjk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh uOtildeska wej dacircfrda kshuh myiqfjka
wjfndaO lr yels h
fuys N yd NA hkq msltsfjltska jdhqfotilde wes wKq ixLHdj iy wej dacircfrda kshh fotilde tl
u WIaKajhla yd tlu mSvkhla hgfa wes P iy Q kiuml jQ jdhq foll iudk mszligud
follg by iiumlnkaOdj fhsectfuka
P iy T ksh uacuteg sect (R iy NA kshhka fotilde )
irj oelajqjfyda ksh WIaKajhla iy mSvkhla hgfa wes jdhqj iudk mszligud
=lt iudk wKq ixLdjla wvx= fotilde (V α N)
by idlEacutePd lrk o jdhq kshu fhdod ksntildeka fok o jdhq mszligudjla (V) i`oyd
mszligmQfrac34K jdhq ioacutelrKh nd yels h
by (1) (2) iy (3) ioacutelrK =ku imqrdk tlu ioacutelrKh jkafka
k = R jQ uacuteg
P V = n R T
14
125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka
fi wmg suacuteh yels h
iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd
mszligudj (Vm) tl u w hla uacuteh hq= ksid th
fi Kkh llt yels h
tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u
mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34
bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu
aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj
22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi
ksrEmKh flffrac34
bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde
fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde
igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde
V = k n = k (m M) tneuacuteka M = k (m V) = k d
1 7 ksoiqk
298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud
iudk nj fmkajkak
uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe
VHe = nHeRTHe PHe
VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3
15
PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =
PNeVNe = nNeRTNe
VNe = nNeRTNe PNe
VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa
VNe = 24 4 dm3
tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq
wa lr kakd mszligud iudk fotilde
126 ixhqla jdhq kshuh
jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj
tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka
T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla
fi suacuteh yels h
fuh ixhqla jdhq kshuh fi ye|skafotilde
1 8 ksoiqk
25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o
uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh
P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3
T1 = 25 + 273 = 298 K
V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =
P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa
16
13 fvdaagkaf a wdxYsl mSvk kshuh
fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm
yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk
wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml
ishuml jdhq odhl fotilde
jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj
wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde
ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla
iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs
fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh
fi yeEgravekafotilde
A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska
PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde
my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka
jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha
we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh
PT hehs o isuq
PV = nRT
A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )
B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )
jdhq ntildeYKh i`oyd nT = PTV RT
iy nT = nA + nB
tu ksid PTV RT = (PAV RT) + (PBV RT)
iq`M llt uacuteg PT = PA + PB
fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl
131 ujq Nd h wkqidrfhka wdxYsl mSvkh
T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq
ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde
fvdaagkaf a kshuhg wkqj PT = PA + PB
PA iy PB mldYk fjk fjk u PT jska fnsectfuka
17
tu ksid
fi suacuteh yels h
hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk
fotilde
1 9 ksoiqk
(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla
tla jdhqfotilde wdxYsl mSvkh Kkh lrkak
(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd
lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq
ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak
uacutei`yumlu
18
fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK
u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd
fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj
tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla
fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re
uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq
irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq
efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj
u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk
nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja
ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj
mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=
jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes
lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect
tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh
wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K
jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl
1 10 ksoiqk
my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs
iskak
2KClO3(s) rarr2KCl(s) + 3O2(g)
27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute
27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh
Kkh lrkak
uacutei`yumlu
fvdaagkaf a kshuhg wkqj
Piuia = PTlaiscka + Pch
PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa
mszligmQfrac34K jdhq ioacutelrKh fhsectfuka
14 jdhq msltsn`o pdl wKqljdoh
by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(
fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks
mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla
nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka
uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml
jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh
llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad
fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd
fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj
yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde
19
141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde
wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd
uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr
wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS
wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh
u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka
gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska
jdhqj bylt iiumlmSvHdj meyeEgraves fotilde
bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu
jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO
wKqjg uacuteuacuteO fotilde mjS
fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg
ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash
jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk
ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde
bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS
fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq
wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj
fuu ska mldY flffrac34
fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh
mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt
uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka
jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr
iiumlnkaOdjh my ioacutelrKfhka nd foa
jyumlrga my oelafjk lreKq plusmnlauacuteh yels h
bull jdhq wxY= tlsfklska iajdhaj yeisffrac34
jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska
iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda
fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj
wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml
Wmlamkfhka meyeEgraves fotilde
bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla
u` ska mSvkhla wes fotilde
fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect
ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl
isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug
20
fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml
jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq
ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj
jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml
fotilde
142 pdl wKqljdofha ioacutelrKh
my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla
fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34
by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes
wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka
wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34
uOHkH fotilde h fi wfrac34 olajkq efiacute
143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h
my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu
jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg
jfrac34 uOHkH uQ fotilde h fotilde
jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla
jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=
Kkla i`oyd ioacutelrKh ild nuq
N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)
PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka
21
tu ksid jfrac34 uOHkH uQ fotilde h
fi suacuteh yels h
1 11 ksoiqk
25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak
uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1
by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj
fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama
lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml
pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh
u` ska th my oelafjk mszligEgrave idOkh llt yels h
fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt
yel
kB hkq fndaaUumliaudka kshh fotilde
22
wKqjla i`oyd
ujqhla i`oyd
fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq
fotilde
144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml
N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag
pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq
efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave
mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes
lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde
jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash
fi ye|skafotilde
16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--
fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd
fotilde jHdmash
23
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka
wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea
jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd
idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute
ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr
^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17
rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla
i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34
17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj
iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha
sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka
daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh
17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd
Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir
ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla
mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy
ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh
yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr
jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml
ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej
jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla
fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh
fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs
17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska
o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska
daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka
iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk
wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh
hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd
mszligudj (V)
mSvk
h (
P)
24
jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj
o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga
meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg
jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke
fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka
lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS
jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru
ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml
yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj
sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK
n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde
mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd
laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect
(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g
jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda
ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel
jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt
WIaKaj fotilde
daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o
WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel
fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg
jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml
fuh mltuq ioacutelrKfha wdfoaYfhka
fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH
ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk
nj wmg fmfka
fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh
pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we
tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj
hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h
mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq
wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt
jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect
jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia
PV mszligmQfrac34K
daauacutel
25
jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq
wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka
yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=
h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka
wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel
jdhq mszligmQfrac34K aajfhka wm ukh fotilde
151 jeka vrsquo jdaia ioacutelrKh
fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa
sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K
jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk
wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq
mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel
jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid
daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH
fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj
iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk
Egrave
bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka
kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka
mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka
igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash
iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg
fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh
mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde
1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj
ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh
by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK
fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde
gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq
mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde
fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg
iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq
msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect
moaOsfha mSvkh my mldYkfhka nd fohs
26
bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL
fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr
tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk
mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka
wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks
fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq
kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh
fi kej suacuteh yels h
fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh
fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql
nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia
flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha
wkafrac34--mszligjfrac34kh l yels fotilde
ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs
wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj
yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde
igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys
sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde
ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha
lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh
iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla
fi o yeisszligh yels ugraveu h
bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla
oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi
mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS
30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc
oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi
muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu
WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla
oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde
( )2
aP V b RTV
+ minus =
27
19 rEmh CO2 j ldm igyk
1 3 j =j - ioacutelrK idrdxYh
jdhq kshuh intildelrKhksh j mjsk
idOl
mszligmQfrac34K jdhq kshuh PV = nRT ke
fndhsa kshuh n iy T
pdaia kshuh V = kT n iy P
wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T
wKql pdl ioacutelrKh
idudkH fotilde h
jfrac34 uOHkH fotilde h
jfrac34 uOHkH fotilde h
fvdaagkaf a wdxYsl mSvk
kshuh
PA = xA PT
PT = PA + PB + PC
iiumlmSvHd idOlh jdhq ujq 1la i|yd
jeka vZjdaia ioacutelrKh
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
14
125 ujqsl mszligudj (Vm)jdhqjl mszligudj ujq mudKhg wkqfdauj iudkqmdsl jk neuacuteka
fi wmg suacuteh yels h
iudk WIaKaj yd mSvk aaj hgfa sect acutekE u jdhqjl ujq tlla wa lr kakd
mszligudj (Vm) tl u w hla uacuteh hq= ksid th
fi Kkh llt yels h
tu ksid WIaKajfha sect iy iiumlu mSvkfha sect acutekE u jdhqjl ujqsl mszligudj Vm tl u
mszligudjla uacuteh hq= h iiumlu w h i`oyd aaj l=l folla Nduacute flffrac34
bull mltuq aaj wkqj WIaKajh 0 degC ^273 15 K) iy iiumlu mSvkh 1 atm (101325 Pa) fotilde fuu iiumlu
aajh hgfa mszligmQfrac34K jdhqjla fydA mszligmQfrac34K jdhq ixfhdackhl ujqsl mszligudj
22 414 dm3 mol-1 fotilde fuu aaj hgfa sect jdhqjl ujqsl mszligudj Vθm fi
ksrEmKh flffrac34
bull fojk aaj wkqj iadksl WIaKajh 25 degC (298 15 K) iy iiumlu mSvkh 1atm (101325Pa) fotilde
fuys sect jdhqjl ujqsl mszligudfotilde w h 24 790 dm3 mol-1 fotilde
igyk ( wej dacircfrda kshuhg wkqj jdhqjl ujqsl ialkaOh (M) tys gtkajhg (d) wkqfdauj iudkqmdsl fotilde
V = k n = k (m M) tneuacuteka M = k (m V) = k d
1 7 ksoiqk
298 K WIaKajfha sect yd 1 atm mSvkfha sect He jdhqfotilde iy Ne jdhqfotilde ujqsl mszligud
iudk nj fmkajkak
uacutei`yumlu PHe = 1 atm = 101325 Pa THe = 298 K nHe = 1 00 mol VHe = PHeVHe = nHeRTHe
VHe = nHeRTHe PHe
VHe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa = 24 4 dm3
15
PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =
PNeVNe = nNeRTNe
VNe = nNeRTNe PNe
VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa
VNe = 24 4 dm3
tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq
wa lr kakd mszligud iudk fotilde
126 ixhqla jdhq kshuh
jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj
tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka
T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla
fi suacuteh yels h
fuh ixhqla jdhq kshuh fi ye|skafotilde
1 8 ksoiqk
25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o
uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh
P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3
T1 = 25 + 273 = 298 K
V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =
P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa
16
13 fvdaagkaf a wdxYsl mSvk kshuh
fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm
yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk
wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml
ishuml jdhq odhl fotilde
jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj
wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde
ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla
iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs
fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh
fi yeEgravekafotilde
A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska
PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde
my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka
jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha
we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh
PT hehs o isuq
PV = nRT
A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )
B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )
jdhq ntildeYKh i`oyd nT = PTV RT
iy nT = nA + nB
tu ksid PTV RT = (PAV RT) + (PBV RT)
iq`M llt uacuteg PT = PA + PB
fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl
131 ujq Nd h wkqidrfhka wdxYsl mSvkh
T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq
ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde
fvdaagkaf a kshuhg wkqj PT = PA + PB
PA iy PB mldYk fjk fjk u PT jska fnsectfuka
17
tu ksid
fi suacuteh yels h
hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk
fotilde
1 9 ksoiqk
(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla
tla jdhqfotilde wdxYsl mSvkh Kkh lrkak
(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd
lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq
ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak
uacutei`yumlu
18
fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK
u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd
fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj
tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla
fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re
uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq
irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq
efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj
u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk
nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja
ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj
mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=
jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes
lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect
tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh
wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K
jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl
1 10 ksoiqk
my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs
iskak
2KClO3(s) rarr2KCl(s) + 3O2(g)
27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute
27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh
Kkh lrkak
uacutei`yumlu
fvdaagkaf a kshuhg wkqj
Piuia = PTlaiscka + Pch
PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa
mszligmQfrac34K jdhq ioacutelrKh fhsectfuka
14 jdhq msltsn`o pdl wKqljdoh
by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(
fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks
mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla
nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka
uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml
jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh
llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad
fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd
fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj
yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde
19
141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde
wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd
uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr
wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS
wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh
u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka
gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska
jdhqj bylt iiumlmSvHdj meyeEgraves fotilde
bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu
jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO
wKqjg uacuteuacuteO fotilde mjS
fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg
ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash
jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk
ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde
bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS
fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq
wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj
fuu ska mldY flffrac34
fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh
mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt
uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka
jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr
iiumlnkaOdjh my ioacutelrKfhka nd foa
jyumlrga my oelafjk lreKq plusmnlauacuteh yels h
bull jdhq wxY= tlsfklska iajdhaj yeisffrac34
jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska
iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda
fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj
wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml
Wmlamkfhka meyeEgraves fotilde
bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla
u` ska mSvkhla wes fotilde
fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect
ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl
isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug
20
fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml
jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq
ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj
jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml
fotilde
142 pdl wKqljdofha ioacutelrKh
my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla
fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34
by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes
wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka
wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34
uOHkH fotilde h fi wfrac34 olajkq efiacute
143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h
my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu
jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg
jfrac34 uOHkH uQ fotilde h fotilde
jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla
jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=
Kkla i`oyd ioacutelrKh ild nuq
N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)
PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka
21
tu ksid jfrac34 uOHkH uQ fotilde h
fi suacuteh yels h
1 11 ksoiqk
25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak
uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1
by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj
fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama
lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml
pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh
u` ska th my oelafjk mszligEgrave idOkh llt yels h
fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt
yel
kB hkq fndaaUumliaudka kshh fotilde
22
wKqjla i`oyd
ujqhla i`oyd
fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq
fotilde
144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml
N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag
pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq
efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave
mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes
lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde
jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash
fi ye|skafotilde
16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--
fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd
fotilde jHdmash
23
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka
wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea
jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd
idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute
ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr
^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17
rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla
i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34
17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj
iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha
sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka
daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh
17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd
Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir
ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla
mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy
ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh
yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr
jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml
ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej
jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla
fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh
fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs
17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska
o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska
daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka
iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk
wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh
hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd
mszligudj (V)
mSvk
h (
P)
24
jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj
o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga
meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg
jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke
fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka
lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS
jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru
ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml
yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj
sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK
n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde
mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd
laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect
(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g
jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda
ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel
jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt
WIaKaj fotilde
daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o
WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel
fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg
jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml
fuh mltuq ioacutelrKfha wdfoaYfhka
fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH
ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk
nj wmg fmfka
fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh
pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we
tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj
hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h
mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq
wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt
jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect
jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia
PV mszligmQfrac34K
daauacutel
25
jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq
wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka
yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=
h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka
wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel
jdhq mszligmQfrac34K aajfhka wm ukh fotilde
151 jeka vrsquo jdaia ioacutelrKh
fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa
sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K
jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk
wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq
mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel
jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid
daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH
fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj
iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk
Egrave
bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka
kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka
mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka
igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash
iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg
fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh
mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde
1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj
ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh
by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK
fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde
gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq
mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde
fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg
iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq
msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect
moaOsfha mSvkh my mldYkfhka nd fohs
26
bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL
fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr
tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk
mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka
wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks
fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq
kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh
fi kej suacuteh yels h
fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh
fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql
nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia
flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha
wkafrac34--mszligjfrac34kh l yels fotilde
ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs
wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj
yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde
igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys
sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde
ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha
lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh
iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla
fi o yeisszligh yels ugraveu h
bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla
oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi
mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS
30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc
oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi
muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu
WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla
oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde
( )2
aP V b RTV
+ minus =
27
19 rEmh CO2 j ldm igyk
1 3 j =j - ioacutelrK idrdxYh
jdhq kshuh intildelrKhksh j mjsk
idOl
mszligmQfrac34K jdhq kshuh PV = nRT ke
fndhsa kshuh n iy T
pdaia kshuh V = kT n iy P
wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T
wKql pdl ioacutelrKh
idudkH fotilde h
jfrac34 uOHkH fotilde h
jfrac34 uOHkH fotilde h
fvdaagkaf a wdxYsl mSvk
kshuh
PA = xA PT
PT = PA + PB + PC
iiumlmSvHd idOlh jdhq ujq 1la i|yd
jeka vZjdaia ioacutelrKh
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
15
PNe = 1 atm = 101325 Pa TNe = 298 K nNe = 1 00 mol VNe =
PNeVNe = nNeRTNe
VNe = nNeRTNe PNe
VNe = (1 mol times 8 314 J K-1mol-1 times 298 K) 101325 Pa
VNe = 24 4 dm3
tkiuml tl u WIaKajfha sect iy mSvkfha sect jdhq ujq mudK iudk kiuml uacuteuacuteO jdhq
wa lr kakd mszligud iudk fotilde
126 ixhqla jdhq kshuh
jdhq mudKh ujqjska uekak uacuteg ishuml jdhq mSvkh mszligudj yd WIaKajhg wkqnoaOj
tl u wdldrhlg yeisffrac34 ksH jdhq mudKhl WIaKajh mSvkh yd mszligudj wdEgrave rdYSka
T1 P1 V1 isg T2 P2 V2 olajd fjkia lrk uacuteg mszligmQfrac34K jdhq ioacutelrKh u wkqmdhla
fi suacuteh yels h
fuh ixhqla jdhq kshuh fi ye|skafotilde
1 8 ksoiqk
25 degC sect iy 760 mm Hg mSvkhl sect fok o jdhq mudKhl mszligudj 600 cm3 fotilde 10 degC sect tys mszligudj 650 cm3 jk uacuteg tys mSvkh l=ula fotilde o
uacutei`yumlu (T1 V1 P1) isg (T2 V2 P2) olajd wmg suacuteh yelsh
P1 = 760 mm Hg = 1 atm = 101325 Pa V1= 600 cm3 = 0 600 dm3
T1 = 25 + 273 = 298 K
V2 = 650 cm3 = 0 650 dm3 T2 = 10 + 273 = 283 K P2 =
P2 = 666 2 mmHg = 88823 Pa = 88 823 kPa
16
13 fvdaagkaf a wdxYsl mSvk kshuh
fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm
yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk
wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml
ishuml jdhq odhl fotilde
jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj
wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde
ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla
iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs
fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh
fi yeEgravekafotilde
A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska
PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde
my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka
jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha
we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh
PT hehs o isuq
PV = nRT
A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )
B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )
jdhq ntildeYKh i`oyd nT = PTV RT
iy nT = nA + nB
tu ksid PTV RT = (PAV RT) + (PBV RT)
iq`M llt uacuteg PT = PA + PB
fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl
131 ujq Nd h wkqidrfhka wdxYsl mSvkh
T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq
ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde
fvdaagkaf a kshuhg wkqj PT = PA + PB
PA iy PB mldYk fjk fjk u PT jska fnsectfuka
17
tu ksid
fi suacuteh yels h
hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk
fotilde
1 9 ksoiqk
(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla
tla jdhqfotilde wdxYsl mSvkh Kkh lrkak
(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd
lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq
ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak
uacutei`yumlu
18
fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK
u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd
fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj
tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla
fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re
uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq
irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq
efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj
u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk
nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja
ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj
mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=
jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes
lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect
tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh
wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K
jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl
1 10 ksoiqk
my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs
iskak
2KClO3(s) rarr2KCl(s) + 3O2(g)
27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute
27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh
Kkh lrkak
uacutei`yumlu
fvdaagkaf a kshuhg wkqj
Piuia = PTlaiscka + Pch
PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa
mszligmQfrac34K jdhq ioacutelrKh fhsectfuka
14 jdhq msltsn`o pdl wKqljdoh
by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(
fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks
mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla
nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka
uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml
jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh
llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad
fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd
fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj
yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde
19
141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde
wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd
uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr
wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS
wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh
u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka
gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska
jdhqj bylt iiumlmSvHdj meyeEgraves fotilde
bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu
jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO
wKqjg uacuteuacuteO fotilde mjS
fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg
ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash
jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk
ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde
bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS
fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq
wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj
fuu ska mldY flffrac34
fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh
mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt
uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka
jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr
iiumlnkaOdjh my ioacutelrKfhka nd foa
jyumlrga my oelafjk lreKq plusmnlauacuteh yels h
bull jdhq wxY= tlsfklska iajdhaj yeisffrac34
jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska
iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda
fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj
wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml
Wmlamkfhka meyeEgraves fotilde
bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla
u` ska mSvkhla wes fotilde
fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect
ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl
isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug
20
fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml
jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq
ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj
jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml
fotilde
142 pdl wKqljdofha ioacutelrKh
my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla
fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34
by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes
wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka
wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34
uOHkH fotilde h fi wfrac34 olajkq efiacute
143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h
my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu
jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg
jfrac34 uOHkH uQ fotilde h fotilde
jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla
jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=
Kkla i`oyd ioacutelrKh ild nuq
N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)
PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka
21
tu ksid jfrac34 uOHkH uQ fotilde h
fi suacuteh yels h
1 11 ksoiqk
25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak
uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1
by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj
fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama
lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml
pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh
u` ska th my oelafjk mszligEgrave idOkh llt yels h
fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt
yel
kB hkq fndaaUumliaudka kshh fotilde
22
wKqjla i`oyd
ujqhla i`oyd
fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq
fotilde
144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml
N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag
pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq
efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave
mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes
lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde
jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash
fi ye|skafotilde
16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--
fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd
fotilde jHdmash
23
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka
wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea
jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd
idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute
ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr
^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17
rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla
i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34
17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj
iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha
sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka
daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh
17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd
Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir
ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla
mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy
ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh
yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr
jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml
ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej
jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla
fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh
fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs
17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska
o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska
daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka
iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk
wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh
hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd
mszligudj (V)
mSvk
h (
P)
24
jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj
o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga
meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg
jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke
fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka
lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS
jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru
ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml
yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj
sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK
n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde
mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd
laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect
(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g
jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda
ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel
jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt
WIaKaj fotilde
daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o
WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel
fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg
jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml
fuh mltuq ioacutelrKfha wdfoaYfhka
fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH
ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk
nj wmg fmfka
fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh
pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we
tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj
hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h
mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq
wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt
jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect
jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia
PV mszligmQfrac34K
daauacutel
25
jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq
wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka
yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=
h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka
wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel
jdhq mszligmQfrac34K aajfhka wm ukh fotilde
151 jeka vrsquo jdaia ioacutelrKh
fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa
sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K
jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk
wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq
mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel
jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid
daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH
fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj
iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk
Egrave
bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka
kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka
mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka
igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash
iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg
fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh
mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde
1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj
ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh
by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK
fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde
gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq
mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde
fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg
iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq
msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect
moaOsfha mSvkh my mldYkfhka nd fohs
26
bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL
fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr
tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk
mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka
wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks
fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq
kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh
fi kej suacuteh yels h
fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh
fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql
nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia
flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha
wkafrac34--mszligjfrac34kh l yels fotilde
ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs
wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj
yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde
igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys
sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde
ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha
lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh
iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla
fi o yeisszligh yels ugraveu h
bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla
oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi
mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS
30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc
oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi
muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu
WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla
oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde
( )2
aP V b RTV
+ minus =
27
19 rEmh CO2 j ldm igyk
1 3 j =j - ioacutelrK idrdxYh
jdhq kshuh intildelrKhksh j mjsk
idOl
mszligmQfrac34K jdhq kshuh PV = nRT ke
fndhsa kshuh n iy T
pdaia kshuh V = kT n iy P
wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T
wKql pdl ioacutelrKh
idudkH fotilde h
jfrac34 uOHkH fotilde h
jfrac34 uOHkH fotilde h
fvdaagkaf a wdxYsl mSvk
kshuh
PA = xA PT
PT = PA + PB + PC
iiumlmSvHd idOlh jdhq ujq 1la i|yd
jeka vZjdaia ioacutelrKh
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
16
13 fvdaagkaf a wdxYsl mSvk kshuh
fndfyda mdfhda sl Nduacutej sect wmg yuq jkafka ks jdhqjla fkdj jdhq ntildeYK h wm
yqiau kakd jdfha mOdk ixrpl fi khsgcka yd Tlaiscka hk jdhq we=lta jk
wr wam jYfhka mjakd fjka jdhq o Kkdjla fotilde uq`M jdhqf daSh mSvkhg fiuml
ishuml jdhq odhl fotilde
jdhq ntildeYKh wa lr kakd mszligudj lsishiuml ixgtaacute jdhqjla uacuteiska tu WIaKajfhasectu ksj
wama lr a lays bka fhfok mSvkh tu jdhqfotilde wdxYsl mSvkh hkqfjka ye`Egravekafotilde
ta wkqj ridhksl jYfhka tlsfkl iu` mslshd fkdlrk jdhq lsysmhl ntildeYKhla
iluq fuys uq`M mSvkh ixgtaacute jdhqj wdxYsl mSvkj ftlHhg iudk fotilde hhs
fvdaagka f a Wm yKfhka bEgraveszligma lrk sect fuh fvdaagkaf a wdxYsl mSvk kshuh
fi yeEgravekafotilde
A B iy C hk jdhqjska iukauacute jdhq ntildeYKhl tu jdhqj wdxYsl mSvk msltsfjltska
PA PB iy PC kiuml ksh WIaKajfhasect iy ksh mszligudfotildesect jdhq ntildeYKfha uq`M mSvkh PT my plusmnlafjk ioacutelrKfhka oelafotilde
my plusmnlafjk mszligEgrave fvdaagkaf a wdxYsl mSvk kshuh mszligmQfrac34K jdhq ioacutelrKfhka
jHqamkak llt yels h A iy B hk jdhq foflka hqa jdhq ntildeYKhla iluq ntildeYKfha
we=lta A iy B jdhqj ujq mudK msltsfjltska nA iy nB hehs o ntildeYKfha uq`M mSvkh
PT hehs o isuq
PV = nRT
A jdhqj i`oyd nA = PAV RT (A jdhqfjys wdxYsl mSvkh PA fotilde )
B jdhqj i`oyd nB= PBV RT (B jdhqfjys wdxYsl mSvkh PB fotilde )
jdhq ntildeYKh i`oyd nT = PTV RT
iy nT = nA + nB
tu ksid PTV RT = (PAV RT) + (PBV RT)
iq`M llt uacuteg PT = PA + PB
fuh fvdaagkaf a wdxYsl mSvk kshuhhsiexcl
131 ujq Nd h wkqidrfhka wdxYsl mSvkh
T hk WIaKajfha sect mszligudj V jk uqiquest mSvkh PT jk n`yumlkl A jdhq ujq nA o B jdhq
ujq nB o wvx = jk wr tajdfha wdxYsl mSvk msltsfjltska PA iy PB fotilde
fvdaagkaf a kshuhg wkqj PT = PA + PB
PA iy PB mldYk fjk fjk u PT jska fnsectfuka
17
tu ksid
fi suacuteh yels h
hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk
fotilde
1 9 ksoiqk
(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla
tla jdhqfotilde wdxYsl mSvkh Kkh lrkak
(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd
lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq
ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak
uacutei`yumlu
18
fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK
u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd
fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj
tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla
fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re
uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq
irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq
efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj
u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk
nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja
ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj
mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=
jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes
lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect
tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh
wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K
jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl
1 10 ksoiqk
my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs
iskak
2KClO3(s) rarr2KCl(s) + 3O2(g)
27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute
27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh
Kkh lrkak
uacutei`yumlu
fvdaagkaf a kshuhg wkqj
Piuia = PTlaiscka + Pch
PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa
mszligmQfrac34K jdhq ioacutelrKh fhsectfuka
14 jdhq msltsn`o pdl wKqljdoh
by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(
fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks
mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla
nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka
uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml
jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh
llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad
fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd
fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj
yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde
19
141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde
wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd
uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr
wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS
wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh
u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka
gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska
jdhqj bylt iiumlmSvHdj meyeEgraves fotilde
bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu
jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO
wKqjg uacuteuacuteO fotilde mjS
fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg
ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash
jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk
ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde
bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS
fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq
wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj
fuu ska mldY flffrac34
fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh
mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt
uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka
jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr
iiumlnkaOdjh my ioacutelrKfhka nd foa
jyumlrga my oelafjk lreKq plusmnlauacuteh yels h
bull jdhq wxY= tlsfklska iajdhaj yeisffrac34
jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska
iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda
fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj
wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml
Wmlamkfhka meyeEgraves fotilde
bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla
u` ska mSvkhla wes fotilde
fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect
ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl
isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug
20
fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml
jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq
ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj
jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml
fotilde
142 pdl wKqljdofha ioacutelrKh
my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla
fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34
by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes
wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka
wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34
uOHkH fotilde h fi wfrac34 olajkq efiacute
143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h
my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu
jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg
jfrac34 uOHkH uQ fotilde h fotilde
jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla
jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=
Kkla i`oyd ioacutelrKh ild nuq
N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)
PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka
21
tu ksid jfrac34 uOHkH uQ fotilde h
fi suacuteh yels h
1 11 ksoiqk
25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak
uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1
by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj
fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama
lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml
pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh
u` ska th my oelafjk mszligEgrave idOkh llt yels h
fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt
yel
kB hkq fndaaUumliaudka kshh fotilde
22
wKqjla i`oyd
ujqhla i`oyd
fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq
fotilde
144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml
N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag
pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq
efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave
mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes
lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde
jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash
fi ye|skafotilde
16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--
fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd
fotilde jHdmash
23
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka
wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea
jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd
idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute
ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr
^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17
rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla
i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34
17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj
iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha
sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka
daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh
17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd
Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir
ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla
mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy
ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh
yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr
jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml
ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej
jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla
fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh
fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs
17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska
o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska
daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka
iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk
wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh
hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd
mszligudj (V)
mSvk
h (
P)
24
jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj
o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga
meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg
jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke
fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka
lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS
jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru
ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml
yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj
sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK
n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde
mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd
laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect
(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g
jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda
ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel
jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt
WIaKaj fotilde
daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o
WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel
fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg
jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml
fuh mltuq ioacutelrKfha wdfoaYfhka
fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH
ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk
nj wmg fmfka
fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh
pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we
tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj
hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h
mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq
wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt
jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect
jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia
PV mszligmQfrac34K
daauacutel
25
jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq
wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka
yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=
h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka
wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel
jdhq mszligmQfrac34K aajfhka wm ukh fotilde
151 jeka vrsquo jdaia ioacutelrKh
fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa
sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K
jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk
wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq
mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel
jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid
daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH
fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj
iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk
Egrave
bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka
kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka
mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka
igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash
iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg
fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh
mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde
1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj
ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh
by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK
fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde
gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq
mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde
fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg
iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq
msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect
moaOsfha mSvkh my mldYkfhka nd fohs
26
bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL
fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr
tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk
mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka
wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks
fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq
kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh
fi kej suacuteh yels h
fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh
fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql
nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia
flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha
wkafrac34--mszligjfrac34kh l yels fotilde
ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs
wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj
yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde
igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys
sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde
ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha
lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh
iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla
fi o yeisszligh yels ugraveu h
bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla
oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi
mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS
30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc
oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi
muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu
WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla
oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde
( )2
aP V b RTV
+ minus =
27
19 rEmh CO2 j ldm igyk
1 3 j =j - ioacutelrK idrdxYh
jdhq kshuh intildelrKhksh j mjsk
idOl
mszligmQfrac34K jdhq kshuh PV = nRT ke
fndhsa kshuh n iy T
pdaia kshuh V = kT n iy P
wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T
wKql pdl ioacutelrKh
idudkH fotilde h
jfrac34 uOHkH fotilde h
jfrac34 uOHkH fotilde h
fvdaagkaf a wdxYsl mSvk
kshuh
PA = xA PT
PT = PA + PB + PC
iiumlmSvHd idOlh jdhq ujq 1la i|yd
jeka vZjdaia ioacutelrKh
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
17
tu ksid
fi suacuteh yels h
hiuml jdhquh mfNaohl wdxYsl mSvkh tys ujq Nd fhAA uqiquest mSvkfhaa =Kshg iudk
fotilde
1 9 ksoiqk
(i) jdhq ntildeYKhl khsgcka (N2) jdhqj 0 8 mol o Tlaiscka (O2) jdhqj 0 2 mol o wvx = h tlard WIaKajhl sect jdhq ntildeYKfha uq`M mSvkh 1 00 atm kiuml tla
tla jdhqfotilde wdxYsl mSvkh Kkh lrkak
(ii) n`yumlk ra lr ksh WIaKajhl nd a uacuteg N2 jdhqj O2 jdhqj iu` mslshd
lr NO2 jdhqj idohs iu=sdfotilde sect n`yumlfkys N2 jdhq ujq 07la o O2 jdhq
ujq 015la o NO2 jdhq ujq 01la o we tuacuteg N2 jdhqfjys wdxYsl mSvkh 0 88 atm kiuml O2 yd NO2 jdhqj wdxYsl mSvkh Kkh lrkak
uacutei`yumlu
18
fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK
u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd
fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj
tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla
fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re
uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq
irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq
efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj
u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk
nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja
ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj
mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=
jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes
lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect
tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh
wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K
jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl
1 10 ksoiqk
my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs
iskak
2KClO3(s) rarr2KCl(s) + 3O2(g)
27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute
27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh
Kkh lrkak
uacutei`yumlu
fvdaagkaf a kshuhg wkqj
Piuia = PTlaiscka + Pch
PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa
mszligmQfrac34K jdhq ioacutelrKh fhsectfuka
14 jdhq msltsn`o pdl wKqljdoh
by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(
fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks
mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla
nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka
uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml
jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh
llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad
fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd
fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj
yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde
19
141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde
wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd
uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr
wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS
wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh
u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka
gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska
jdhqj bylt iiumlmSvHdj meyeEgraves fotilde
bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu
jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO
wKqjg uacuteuacuteO fotilde mjS
fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg
ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash
jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk
ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde
bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS
fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq
wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj
fuu ska mldY flffrac34
fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh
mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt
uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka
jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr
iiumlnkaOdjh my ioacutelrKfhka nd foa
jyumlrga my oelafjk lreKq plusmnlauacuteh yels h
bull jdhq wxY= tlsfklska iajdhaj yeisffrac34
jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska
iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda
fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj
wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml
Wmlamkfhka meyeEgraves fotilde
bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla
u` ska mSvkhla wes fotilde
fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect
ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl
isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug
20
fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml
jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq
ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj
jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml
fotilde
142 pdl wKqljdofha ioacutelrKh
my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla
fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34
by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes
wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka
wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34
uOHkH fotilde h fi wfrac34 olajkq efiacute
143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h
my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu
jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg
jfrac34 uOHkH uQ fotilde h fotilde
jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla
jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=
Kkla i`oyd ioacutelrKh ild nuq
N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)
PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka
21
tu ksid jfrac34 uOHkH uQ fotilde h
fi suacuteh yels h
1 11 ksoiqk
25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak
uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1
by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj
fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama
lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml
pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh
u` ska th my oelafjk mszligEgrave idOkh llt yels h
fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt
yel
kB hkq fndaaUumliaudka kshh fotilde
22
wKqjla i`oyd
ujqhla i`oyd
fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq
fotilde
144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml
N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag
pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq
efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave
mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes
lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde
jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash
fi ye|skafotilde
16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--
fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd
fotilde jHdmash
23
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka
wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea
jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd
idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute
ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr
^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17
rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla
i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34
17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj
iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha
sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka
daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh
17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd
Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir
ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla
mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy
ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh
yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr
jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml
ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej
jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla
fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh
fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs
17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska
o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska
daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka
iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk
wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh
hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd
mszligudj (V)
mSvk
h (
P)
24
jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj
o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga
meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg
jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke
fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka
lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS
jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru
ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml
yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj
sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK
n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde
mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd
laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect
(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g
jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda
ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel
jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt
WIaKaj fotilde
daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o
WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel
fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg
jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml
fuh mltuq ioacutelrKfha wdfoaYfhka
fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH
ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk
nj wmg fmfka
fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh
pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we
tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj
hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h
mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq
wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt
jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect
jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia
PV mszligmQfrac34K
daauacutel
25
jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq
wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka
yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=
h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka
wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel
jdhq mszligmQfrac34K aajfhka wm ukh fotilde
151 jeka vrsquo jdaia ioacutelrKh
fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa
sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K
jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk
wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq
mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel
jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid
daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH
fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj
iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk
Egrave
bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka
kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka
mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka
igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash
iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg
fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh
mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde
1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj
ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh
by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK
fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde
gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq
mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde
fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg
iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq
msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect
moaOsfha mSvkh my mldYkfhka nd fohs
26
bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL
fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr
tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk
mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka
wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks
fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq
kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh
fi kej suacuteh yels h
fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh
fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql
nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia
flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha
wkafrac34--mszligjfrac34kh l yels fotilde
ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs
wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj
yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde
igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys
sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde
ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha
lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh
iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla
fi o yeisszligh yels ugraveu h
bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla
oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi
mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS
30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc
oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi
muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu
WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla
oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde
( )2
aP V b RTV
+ minus =
27
19 rEmh CO2 j ldm igyk
1 3 j =j - ioacutelrK idrdxYh
jdhq kshuh intildelrKhksh j mjsk
idOl
mszligmQfrac34K jdhq kshuh PV = nRT ke
fndhsa kshuh n iy T
pdaia kshuh V = kT n iy P
wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T
wKql pdl ioacutelrKh
idudkH fotilde h
jfrac34 uOHkH fotilde h
jfrac34 uOHkH fotilde h
fvdaagkaf a wdxYsl mSvk
kshuh
PA = xA PT
PT = PA + PB + PC
iiumlmSvHd idOlh jdhq ujq 1la i|yd
jeka vZjdaia ioacutelrKh
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
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Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
18
fvdaagkaf a kshuh msltsn`o oekqug wkqj jdhq ntildeYKhlg o ixY=oaO jdhqj laIK
u wes nja fok o ishuml jdhq mszligmQfrac34K jdhq nja ridhkslj tlsfkl yd mslshd
fkdlrk nja ielsag hq= h flfia jqj o jdhq wvx = mslshdj sect mdfhda slj
tajd tla ia lr kakd wdldrfha sect o fjka jdhqjla wumlska tl= uacuteh yel ksoiqkla
fi ridhksl mslshdjl sect idudkHfhka jdhqjla ia lr kq nkafka cfha haacutel=re
uacuteiadmkfhks fiuml lufha sect c foslashdaKsldjla =lt haacutel=rej enQ cfhka mqrjk o jdhq
irdjla =g khla yryd jdhqjla nqnqkh lsIacutefuka ndividek =lt jdhqj tla ia lr kq
efiacute tneuacuteka jdhq nqnqiquest klth yryd ch wvx = fndah =ltg uka lrkqfha jdhqj
u` ska ch auml lrntildeka ch bja jk wdldrhg h fuys sect jdhqj cfha Egraveh fkdjk
nj iy ch iu` mslshd fkdlrk nj Wmlamkh lrkq efiacute flfia fja
ixY=oaO wjiadfjys mjsk jdhqjla wmg nd fkdyel fuys sect ia lr kakd jdhqj
mslshdfotilde sect iefok jdhqfotilde iy jdIamsNjkh u` ska iEfok c jdIam iajamhla o wvx=
jdhq ntildeYKhla fotilde jdhqfotilde wvx = jk c jdIam mudKh u` ska tu WIaKajfha sect wes
lrk mSvkh cfhaa ikaDma jdIam mSvkh fi ye`Egravekafotilde tneuacuteka hiuml WIaKajhl sect
tla ia lr kakd jdhqfjys mSvkh ksfrac34Kh lsIacutefiuml sect uqiquest mSvkfhka cfha jdIam mSvkh
wvq llt hq= h tuacuteg efnk jdhqfotilde wdxYsl mSvkh tys mszligudj iy WIaKajh mszligmQfrac34K
jdhq ioacutelrKhg fhsectfuka tla ia lr a jdhq ujq mudKh Kkh llt yels h 1 10 ksoiqk u` ska fuh oelafotildeiexcl
1 10 ksoiqk
my mslshdjg wkqj KClO3(s) ra lsIacutefuka Tlaiscka jdhqj msltsfh lrkafka hehs
iskak
2KClO3(s) rarr2KCl(s) + 3O2(g)
27 degC iy 760 torr ys sect O2 jdhqj 1 50 dm3la ch yryd tl= lr kq efiacute
27 degC oS cfha ikaDma jdIam mSvkh 26 7 torr fotilde ieyumlK O2 jdhq ujq mudKh
Kkh lrkak
uacutei`yumlu
fvdaagkaf a kshuhg wkqj
Piuia = PTlaiscka + Pch
PTlaiscka = Piuia - Pch = (760 ndash 26 7) torr = 733 3 torr = 97764 Pa
mszligmQfrac34K jdhq ioacutelrKh fhsectfuka
14 jdhq msltsn`o pdl wKqljdoh
by fldgiaj sect wms mIacutelaIKdaul oa u mokiuml jQ jdhq iiumlnkaO kshu ^ksoiqka(
fndhsa kshuh pdaia kshuh jeks kshuamp wOHhkh lr wjfndaOh nd afuq tjeks
mIacutelaIK u` ska uacuteuacuteO aaj hgfa sect jdhq moaOs yeisfrk wdldrh msltsn`o wjfndaOhla
nd yels h mIacutelaIK u` ska tu ksIacutelaIK nd a o jdhq moaOs tfi yeisfrkafka
uka o hkak wm oek hq= h ksoiqkla fi jdhqjla iiumlmSvkh llt uacuteg mSvkh jeauml
jk nj jdhq kshu wdOdrfhka wmg mqfrdalkh llt yels kuqa jdhqjla iiumlmSvkh
llt uacuteg wKql uUumlgntildeka thg l=ula isyuml fotilde o hkak wm oek hq= h fujeks wjiad
fyda mjsk eguml meyeEgraves lsIacuteu i`oyd ffioaOdkasl wdlDshla wjYH neuacuteka wmg jvd
fyd`o wjfndaOhla nd ekSug Wojq jk isoaOdkahla wjYH fotilde wKql uUumlgntildeka jdhqj
yeisIacuteu meyeEgraves lsIacuteug fhdod kakd tu isoaOdkah zpdl wKqljdohZ fi ye`Egravekafotilde
19
141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde
wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd
uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr
wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS
wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh
u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka
gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska
jdhqj bylt iiumlmSvHdj meyeEgraves fotilde
bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu
jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO
wKqjg uacuteuacuteO fotilde mjS
fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg
ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash
jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk
ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde
bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS
fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq
wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj
fuu ska mldY flffrac34
fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh
mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt
uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka
jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr
iiumlnkaOdjh my ioacutelrKfhka nd foa
jyumlrga my oelafjk lreKq plusmnlauacuteh yels h
bull jdhq wxY= tlsfklska iajdhaj yeisffrac34
jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska
iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda
fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj
wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml
Wmlamkfhka meyeEgraves fotilde
bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla
u` ska mSvkhla wes fotilde
fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect
ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl
isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug
20
fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml
jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq
ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj
jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml
fotilde
142 pdl wKqljdofha ioacutelrKh
my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla
fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34
by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes
wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka
wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34
uOHkH fotilde h fi wfrac34 olajkq efiacute
143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h
my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu
jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg
jfrac34 uOHkH uQ fotilde h fotilde
jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla
jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=
Kkla i`oyd ioacutelrKh ild nuq
N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)
PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka
21
tu ksid jfrac34 uOHkH uQ fotilde h
fi suacuteh yels h
1 11 ksoiqk
25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak
uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1
by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj
fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama
lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml
pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh
u` ska th my oelafjk mszligEgrave idOkh llt yels h
fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt
yel
kB hkq fndaaUumliaudka kshh fotilde
22
wKqjla i`oyd
ujqhla i`oyd
fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq
fotilde
144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml
N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag
pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq
efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave
mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes
lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde
jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash
fi ye|skafotilde
16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--
fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd
fotilde jHdmash
23
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka
wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea
jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd
idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute
ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr
^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17
rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla
i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34
17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj
iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha
sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka
daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh
17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd
Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir
ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla
mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy
ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh
yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr
jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml
ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej
jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla
fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh
fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs
17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska
o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska
daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka
iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk
wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh
hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd
mszligudj (V)
mSvk
h (
P)
24
jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj
o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga
meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg
jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke
fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka
lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS
jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru
ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml
yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj
sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK
n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde
mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd
laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect
(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g
jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda
ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel
jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt
WIaKaj fotilde
daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o
WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel
fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg
jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml
fuh mltuq ioacutelrKfha wdfoaYfhka
fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH
ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk
nj wmg fmfka
fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh
pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we
tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj
hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h
mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq
wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt
jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect
jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia
PV mszligmQfrac34K
daauacutel
25
jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq
wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka
yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=
h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka
wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel
jdhq mszligmQfrac34K aajfhka wm ukh fotilde
151 jeka vrsquo jdaia ioacutelrKh
fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa
sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K
jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk
wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq
mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel
jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid
daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH
fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj
iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk
Egrave
bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka
kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka
mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka
igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash
iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg
fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh
mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde
1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj
ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh
by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK
fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde
gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq
mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde
fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg
iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq
msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect
moaOsfha mSvkh my mldYkfhka nd fohs
26
bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL
fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr
tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk
mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka
wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks
fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq
kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh
fi kej suacuteh yels h
fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh
fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql
nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia
flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha
wkafrac34--mszligjfrac34kh l yels fotilde
ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs
wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj
yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde
igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys
sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde
ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha
lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh
iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla
fi o yeisszligh yels ugraveu h
bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla
oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi
mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS
30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc
oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi
muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu
WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla
oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde
( )2
aP V b RTV
+ minus =
27
19 rEmh CO2 j ldm igyk
1 3 j =j - ioacutelrK idrdxYh
jdhq kshuh intildelrKhksh j mjsk
idOl
mszligmQfrac34K jdhq kshuh PV = nRT ke
fndhsa kshuh n iy T
pdaia kshuh V = kT n iy P
wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T
wKql pdl ioacutelrKh
idudkH fotilde h
jfrac34 uOHkH fotilde h
jfrac34 uOHkH fotilde h
fvdaagkaf a wdxYsl mSvk
kshuh
PA = xA PT
PT = PA + PB + PC
iiumlmSvHd idOlh jdhq ujq 1la i|yd
jeka vZjdaia ioacutelrKh
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
19
141 mszligmQfrac34K jdhqjla i|yd pdl wKql jdofha Wmlamk bull mqiquestaj me=reKq bd l=vd wxY= rdYshlska ^wKq fyda mrudKqamp jdhqjla iukauacute fotilde
wxY= mqiquesta mrdihl mesIacute wes neuacuteka wxY=jl iH mszligudj jdhqj wa lr kakd
uqiquest mszligudjg idfmalaIj bd l=vd h ke fyda wxY=j iH mszligudj tajd wr
wes ysia wjldYhg idfmalaIj fkdild yeszligh yels h bd lt` ska wxY= ieliS
wes gtkhlg fyda oslashjhlg jvd jdhqjl mszligudj bd uacuteYd jk nj fiuml Wmlamkh
u` ska ksjerEgravej mqfrdalkh llt yels h jdhq wxY= bd mqiquestaj mesIacute wes neuacuteka
gtkjg iy oslashjjg idfmalaIj jdhqjg wvq gtkaj we fiuml Wmlamkh u` ska
jdhqj bylt iiumlmSvHdj meyeEgraves fotilde
bull jdhq wKq tlsfkl iu` fyda Ndckfha igraveas iu` ixgtUumlgkh jk =re ieu
jdhq wKqjla u wyUq fi ^yels ieu EgraveYdjlg uamp ir ffrac34Ccedilhj pkh fotilde uacuteuacuteO
wKqjg uacuteuacuteO fotilde mjS
fiuml ixgtUumlgk mQfrac34K mHia fotilde tkiuml tla jdhq wKqjl Ylash fjka wKqjlg
ixluKh ugraveu iy tla tla wKqfotilde Ylash fjkia ugraveu isyuml uacuteh yels jqj o uqiquest Ylash
jeauml ugraveula fyda wvq ugraveula isyuml fkd fotilde jdhq wKq Ndckfha igraveas iu` isyuml lrk
ixgtUumlgk fya=fjka Ndckh =lt mSvkhla wes fotilde
bull jdhq wKqj uOHkH pdl Ylash ksrfmalaI WIaKajh u muKla r`od mjS
fok o jdhqjl pdl Ylash (KE) my ioacutelrKfhka mldY jk neuacuteka jdhq
wxY=jlg ^mrudKq fyda wKqamp thg wkkH jQ ialkaOhla yd fotilde hla wes nj
fuu ska mldY flffrac34
fuys m hkq jdhq wxY=fotilde ialkaOh jk wr v hkq mfotilde h ^fyda fotilde hamp fotilde ksh
mszligudfotilde sect jdhqjla ra llt uacuteg mSvkh jeauml jk nj wm oksuq thg fya=j jdhqj ra llt
uacuteg wxY=j pdl Ylash jeauml ugrave tajd n`yumlfka igraveas iu` isyuml lrk ixgtUumlgk jeauml ugravefuka
jeauml mSvkhla wes lsIacuteuhs ta wkqj wxY= ujq tll pdl Ylash iy WIaKajh wr
iiumlnkaOdjh my ioacutelrKfhka nd foa
jyumlrga my oelafjk lreKq plusmnlauacuteh yels h
bull jdhq wxY= tlsfklska iajdhaj yeisffrac34
jdhq wxY= mqiquestaj mesIacute wes neuacuteka tajd ixgtUumlgkh fkdfotilde kiuml tlsfklska
iajdhaj pkh fotilde tkiuml jdhq wxY= wr wdlfrac34IK n fyda uacutelfrac34IK n fyda
fkdmjS fiuml Wmlamkfhka fvdaagkaf a wdxYsl mSvk kshuh o meyeEgraves jk nj
wmg fmfka tfukau jdhqjla iiumlmQfrac34Kfhka u n`yumlkl msIacute mjskafka wehs oehs fiuml
Wmlamkfhka meyeEgraves fotilde
bull jdhq wKq n`yumlfka igraveash iu` isyuml lrk ishuml ixgtUumlgkj tl=j ksid jdhqjla
u` ska mSvkhla wes fotilde
fiuml Wmlamkh u` ska fndhsa kshuh meyeEgraves fotilde tkiuml fok o WIaKajhl sect
ksH jdhq mudKhla i`oyd n`yumlfka mszligudj bd l=vd jk uacuteg tall lafIa Mhl
isyuml jk ixgtUumlgk ixLHdj jeauml fotilde l=vd mszligudjl sect jdhq wKqjla ixgtUumlgkh ugraveug
20
fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml
jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq
ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj
jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml
fotilde
142 pdl wKqljdofha ioacutelrKh
my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla
fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34
by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes
wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka
wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34
uOHkH fotilde h fi wfrac34 olajkq efiacute
143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h
my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu
jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg
jfrac34 uOHkH uQ fotilde h fotilde
jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla
jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=
Kkla i`oyd ioacutelrKh ild nuq
N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)
PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka
21
tu ksid jfrac34 uOHkH uQ fotilde h
fi suacuteh yels h
1 11 ksoiqk
25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak
uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1
by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj
fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama
lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml
pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh
u` ska th my oelafjk mszligEgrave idOkh llt yels h
fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt
yel
kB hkq fndaaUumliaudka kshh fotilde
22
wKqjla i`oyd
ujqhla i`oyd
fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq
fotilde
144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml
N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag
pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq
efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave
mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes
lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde
jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash
fi ye|skafotilde
16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--
fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd
fotilde jHdmash
23
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka
wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea
jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd
idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute
ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr
^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17
rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla
i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34
17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj
iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha
sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka
daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh
17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd
Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir
ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla
mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy
ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh
yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr
jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml
ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej
jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla
fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh
fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs
17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska
o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska
daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka
iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk
wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh
hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd
mszligudj (V)
mSvk
h (
P)
24
jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj
o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga
meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg
jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke
fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka
lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS
jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru
ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml
yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj
sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK
n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde
mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd
laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect
(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g
jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda
ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel
jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt
WIaKaj fotilde
daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o
WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel
fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg
jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml
fuh mltuq ioacutelrKfha wdfoaYfhka
fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH
ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk
nj wmg fmfka
fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh
pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we
tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj
hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h
mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq
wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt
jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect
jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia
PV mszligmQfrac34K
daauacutel
25
jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq
wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka
yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=
h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka
wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel
jdhq mszligmQfrac34K aajfhka wm ukh fotilde
151 jeka vrsquo jdaia ioacutelrKh
fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa
sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K
jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk
wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq
mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel
jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid
daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH
fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj
iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk
Egrave
bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka
kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka
mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka
igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash
iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg
fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh
mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde
1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj
ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh
by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK
fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde
gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq
mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde
fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg
iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq
msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect
moaOsfha mSvkh my mldYkfhka nd fohs
26
bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL
fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr
tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk
mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka
wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks
fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq
kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh
fi kej suacuteh yels h
fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh
fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql
nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia
flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha
wkafrac34--mszligjfrac34kh l yels fotilde
ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs
wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj
yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde
igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys
sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde
ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha
lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh
iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla
fi o yeisszligh yels ugraveu h
bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla
oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi
mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS
30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc
oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi
muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu
WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla
oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde
( )2
aP V b RTV
+ minus =
27
19 rEmh CO2 j ldm igyk
1 3 j =j - ioacutelrK idrdxYh
jdhq kshuh intildelrKhksh j mjsk
idOl
mszligmQfrac34K jdhq kshuh PV = nRT ke
fndhsa kshuh n iy T
pdaia kshuh V = kT n iy P
wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T
wKql pdl ioacutelrKh
idudkH fotilde h
jfrac34 uOHkH fotilde h
jfrac34 uOHkH fotilde h
fvdaagkaf a wdxYsl mSvk
kshuh
PA = xA PT
PT = PA + PB + PC
iiumlmSvHd idOlh jdhq ujq 1la i|yd
jeka vZjdaia ioacutelrKh
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
20
fmr uka llt hq= uOHkH yumlr mudKh wvq h tu ksid hiuml lsis lafIa Mhl isyuml
jk jeauml ixgtUumlgk mudKh jeauml mSvkhla wes lrhs fiuml Wmlamkh u` ska jdhq
ujq mudKh mSvkhg iudkqmdsl jk nj o mqfrdalkh fotilde jdhq wKq ixLHdj
jeauml jk uacuteg igraveas iu` isyuml jk ixgtUumlgk jdr Kk o jeauml jk ksid mSvkh jeauml
fotilde
142 pdl wKqljdofha ioacutelrKh
my sect wes ioacutelrKh pdl wKql jdofha ioacutelrKh fi iefla
fiuml mldYkfhka wKql psh weiqfrka ufyalaI =Khla jk mSvkh mldY flffrac34
by iiumlnkaOfha uacutefYaIajh jkafka mSvkh fok o WIaKajhl sect sect wes n`yumlkl wes
wKqj jfrac34 uOHkH fotilde hg iudkqmdsl jk njhs fiuml ioacutelrKhg wkqj fmkS hkafka
wKql fotilde h jeauml llt uacuteg n`yumlklg wes jk mSvkh o jeauml jk njhs hkq wKqj jfrac34
uOHkH fotilde h fi wfrac34 olajkq efiacute
143 jfrac34 uOHkH uQ fotilde h iy uOHkH fotilde h
my olajd wes mszligEgrave wKql fotilde h i`oyd wfrac34 oelaugraveu uacuteuacuteO wdldrfhka oek ekSu
jeo a fotilde ksh WIaKajfha sect ksH mszligudjla wes n`yumlkla =lt wvx =j wes wKq N ixLHdjla tlsfklg fjkia c1 c2helliphellip cN hk fotilde jska pkh jk uacuteg
jfrac34 uOHkH uQ fotilde h fotilde
jfrac34 uOHkH fotilde h WIaKajh u r`od mjsk nj fmkaugraveu i`oyd ioacutelrKhla
jHqamkak lsIacuteug pdl wKql ioacutelrKh fhdod yels h V mszligudjl wes N wxY=
Kkla i`oyd ioacutelrKh ild nuq
N = n NA ksid (NA hkq wej dacircfrda kshh jk wr n hkq ujq mudKhhs)
PV = nRT hk mszligmQfrac34K jdhq ioacutelrKh by ioacutelrKfha wdfoaYfhka
21
tu ksid jfrac34 uOHkH uQ fotilde h
fi suacuteh yels h
1 11 ksoiqk
25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak
uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1
by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj
fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama
lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml
pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh
u` ska th my oelafjk mszligEgrave idOkh llt yels h
fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt
yel
kB hkq fndaaUumliaudka kshh fotilde
22
wKqjla i`oyd
ujqhla i`oyd
fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq
fotilde
144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml
N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag
pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq
efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave
mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes
lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde
jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash
fi ye|skafotilde
16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--
fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd
fotilde jHdmash
23
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka
wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea
jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd
idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute
ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr
^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17
rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla
i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34
17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj
iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha
sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka
daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh
17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd
Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir
ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla
mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy
ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh
yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr
jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml
ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej
jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla
fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh
fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs
17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska
o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska
daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka
iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk
wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh
hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd
mszligudj (V)
mSvk
h (
P)
24
jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj
o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga
meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg
jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke
fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka
lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS
jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru
ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml
yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj
sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK
n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde
mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd
laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect
(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g
jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda
ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel
jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt
WIaKaj fotilde
daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o
WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel
fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg
jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml
fuh mltuq ioacutelrKfha wdfoaYfhka
fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH
ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk
nj wmg fmfka
fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh
pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we
tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj
hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h
mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq
wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt
jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect
jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia
PV mszligmQfrac34K
daauacutel
25
jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq
wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka
yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=
h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka
wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel
jdhq mszligmQfrac34K aajfhka wm ukh fotilde
151 jeka vrsquo jdaia ioacutelrKh
fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa
sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K
jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk
wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq
mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel
jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid
daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH
fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj
iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk
Egrave
bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka
kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka
mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka
igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash
iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg
fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh
mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde
1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj
ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh
by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK
fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde
gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq
mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde
fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg
iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq
msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect
moaOsfha mSvkh my mldYkfhka nd fohs
26
bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL
fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr
tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk
mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka
wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks
fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq
kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh
fi kej suacuteh yels h
fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh
fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql
nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia
flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha
wkafrac34--mszligjfrac34kh l yels fotilde
ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs
wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj
yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde
igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys
sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde
ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha
lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh
iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla
fi o yeisszligh yels ugraveu h
bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla
oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi
mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS
30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc
oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi
muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu
WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla
oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde
( )2
aP V b RTV
+ minus =
27
19 rEmh CO2 j ldm igyk
1 3 j =j - ioacutelrK idrdxYh
jdhq kshuh intildelrKhksh j mjsk
idOl
mszligmQfrac34K jdhq kshuh PV = nRT ke
fndhsa kshuh n iy T
pdaia kshuh V = kT n iy P
wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T
wKql pdl ioacutelrKh
idudkH fotilde h
jfrac34 uOHkH fotilde h
jfrac34 uOHkH fotilde h
fvdaagkaf a wdxYsl mSvk
kshuh
PA = xA PT
PT = PA + PB + PC
iiumlmSvHd idOlh jdhq ujq 1la i|yd
jeka vZjdaia ioacutelrKh
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
21
tu ksid jfrac34 uOHkH uQ fotilde h
fi suacuteh yels h
1 11 ksoiqk
25 degC oS H2 iy N2 jdhqj jfrac34 uOHkH uQ fotilde h Kkh lrkak
uacutei`yumlu T = 25 0C = 298 K M(H2) = 2 0 g mol-1 = 0 002 kg mol-1 M(N2) = 28 0 g mol-1 = 0 028 kg mol-1 R = 8 314 J K-1 mol-1
by ksoiqkg wkqj fok o WIaKajhl sect nszligka jeauml wKq fifuka pkh jk nj
fmfka thska ks ukh jkafka jeauml ialkaOhla iys wKq tl u pdl Ylashla wama
lr kq msKsi ieyeauml wKq fiska jeauml fotilde hla iysj pkh fkdjk nj h fiuml
pdl Ylash WIaKajhg Rcqj u iiumlnkaO jk wr pdl wKqljdofha ioacutelrKh
u` ska th my oelafjk mszligEgrave idOkh llt yels h
fiuml ioacutelrKh 2ka =K lr 2ka fnsectfuka miqj kej tu ioacutelrKh msixuacuteOdkh llt
yel
kB hkq fndaaUumliaudka kshh fotilde
22
wKqjla i`oyd
ujqhla i`oyd
fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq
fotilde
144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml
N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag
pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq
efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave
mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes
lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde
jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash
fi ye|skafotilde
16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--
fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd
fotilde jHdmash
23
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka
wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea
jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd
idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute
ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr
^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17
rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla
i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34
17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj
iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha
sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka
daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh
17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd
Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir
ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla
mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy
ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh
yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr
jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml
ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej
jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla
fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh
fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs
17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska
o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska
daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka
iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk
wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh
hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd
mszligudj (V)
mSvk
h (
P)
24
jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj
o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga
meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg
jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke
fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka
lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS
jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru
ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml
yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj
sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK
n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde
mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd
laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect
(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g
jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda
ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel
jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt
WIaKaj fotilde
daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o
WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel
fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg
jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml
fuh mltuq ioacutelrKfha wdfoaYfhka
fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH
ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk
nj wmg fmfka
fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh
pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we
tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj
hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h
mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq
wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt
jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect
jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia
PV mszligmQfrac34K
daauacutel
25
jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq
wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka
yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=
h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka
wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel
jdhq mszligmQfrac34K aajfhka wm ukh fotilde
151 jeka vrsquo jdaia ioacutelrKh
fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa
sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K
jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk
wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq
mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel
jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid
daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH
fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj
iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk
Egrave
bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka
kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka
mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka
igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash
iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg
fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh
mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde
1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj
ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh
by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK
fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde
gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq
mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde
fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg
iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq
msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect
moaOsfha mSvkh my mldYkfhka nd fohs
26
bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL
fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr
tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk
mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka
wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks
fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq
kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh
fi kej suacuteh yels h
fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh
fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql
nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia
flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha
wkafrac34--mszligjfrac34kh l yels fotilde
ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs
wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj
yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde
igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys
sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde
ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha
lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh
iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla
fi o yeisszligh yels ugraveu h
bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla
oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi
mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS
30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc
oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi
muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu
WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla
oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde
( )2
aP V b RTV
+ minus =
27
19 rEmh CO2 j ldm igyk
1 3 j =j - ioacutelrK idrdxYh
jdhq kshuh intildelrKhksh j mjsk
idOl
mszligmQfrac34K jdhq kshuh PV = nRT ke
fndhsa kshuh n iy T
pdaia kshuh V = kT n iy P
wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T
wKql pdl ioacutelrKh
idudkH fotilde h
jfrac34 uOHkH fotilde h
jfrac34 uOHkH fotilde h
fvdaagkaf a wdxYsl mSvk
kshuh
PA = xA PT
PT = PA + PB + PC
iiumlmSvHd idOlh jdhq ujq 1la i|yd
jeka vZjdaia ioacutelrKh
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
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iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
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iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
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Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
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sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
22
wKqjla i`oyd
ujqhla i`oyd
fuu ska jdhqjl pdl Ylash flauacuteka WIaKajh u muKla r`od mjsk nj Tmamq
fotilde
144 ueialafja-fndaaUumliaudka jHdmash by ksoiqkg wkqj N2 wKqfotilde fotilde h 515 m s-1 fi Kkh lr wes kuqa tu` ska ishuml
N2 wKq tu fotilde fhka pkh fotilde hehs woyia fkdflffrac34 (wKq ir ffrac34Ccedilh EgraveYdjkag
pkh jk neuacuteka pshg ffoYssl =K wes wr ta wkqj wKq j fotilde h mldY lrkq
efiacute) wKqj fotilde Y+kHfha isg idfmalaIj 515 m s-1g jvd jeauml w hla olajd jHdma ugrave
mjS thg fya=j tla tla wKq ixgtUumlgkh ugrave Ylash yqjudre lr ksntildeka uacuteuacuteO fotilde wes
lsIacuteuhs 16 rEmfha olajd wes mszligEgrave hiuml lsis fotilde hla iys wKq Nd hla fi fiuml fotilde
jHdmash fmkakqiuml llt yels h tjeks jHdmashla uelaiafja-fndaaUumliaudka fotilde jHdmash
fi ye|skafotilde
16 rEmh (a) uacuteuacuteO WIaKajj sect khsgcka jdhqj i`oyd uelaiafja--
fndaaUumliaudka fotilde jHdmash (b) 300 K sect jdhq =kla i`oyd
fotilde jHdmash
23
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka
wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea
jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd
idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute
ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr
^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17
rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla
i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34
17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj
iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha
sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka
daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh
17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd
Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir
ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla
mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy
ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh
yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr
jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml
ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej
jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla
fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh
fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs
17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska
o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska
daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka
iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk
wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh
hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd
mszligudj (V)
mSvk
h (
P)
24
jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj
o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga
meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg
jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke
fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka
lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS
jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru
ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml
yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj
sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK
n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde
mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd
laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect
(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g
jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda
ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel
jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt
WIaKaj fotilde
daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o
WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel
fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg
jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml
fuh mltuq ioacutelrKfha wdfoaYfhka
fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH
ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk
nj wmg fmfka
fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh
pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we
tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj
hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h
mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq
wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt
jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect
jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia
PV mszligmQfrac34K
daauacutel
25
jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq
wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka
yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=
h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka
wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel
jdhq mszligmQfrac34K aajfhka wm ukh fotilde
151 jeka vrsquo jdaia ioacutelrKh
fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa
sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K
jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk
wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq
mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel
jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid
daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH
fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj
iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk
Egrave
bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka
kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka
mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka
igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash
iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg
fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh
mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde
1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj
ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh
by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK
fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde
gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq
mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde
fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg
iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq
msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect
moaOsfha mSvkh my mldYkfhka nd fohs
26
bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL
fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr
tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk
mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka
wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks
fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq
kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh
fi kej suacuteh yels h
fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh
fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql
nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia
flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha
wkafrac34--mszligjfrac34kh l yels fotilde
ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs
wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj
yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde
igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys
sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde
ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha
lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh
iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla
fi o yeisszligh yels ugraveu h
bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla
oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi
mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS
30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc
oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi
muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu
WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla
oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde
( )2
aP V b RTV
+ minus =
27
19 rEmh CO2 j ldm igyk
1 3 j =j - ioacutelrK idrdxYh
jdhq kshuh intildelrKhksh j mjsk
idOl
mszligmQfrac34K jdhq kshuh PV = nRT ke
fndhsa kshuh n iy T
pdaia kshuh V = kT n iy P
wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T
wKql pdl ioacutelrKh
idudkH fotilde h
jfrac34 uOHkH fotilde h
jfrac34 uOHkH fotilde h
fvdaagkaf a wdxYsl mSvk
kshuh
PA = xA PT
PT = PA + PB + PC
iiumlmSvHd idOlh jdhq ujq 1la i|yd
jeka vZjdaia ioacutelrKh
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
23
15 daauacutel jdhqjg eltfmk mszligEgrave mszligmQfrac34K jdhq ioacutelrKh ixfYdaOkh
fok o WIaKajhl sect mszligmQfrac34K jdhq wKq ujqhla i`oyd PV = RT fi fyda fjka
wdldrhlska fi wmg suacuteh yels h daauacutel jdhqjla iel+ uacuteg th wea
jYfhka u mszligmQfrac34K yeisrefuka rula yumlrg fyda wm ukh fotilde hkak iiumlmSvHd
idOlh (ix =Klh) fi y`yumlkajk wr fiuml wm ukh uekSug th fhdod kq efiacute
ksoiqkla fi mszligmQfrac34K jdhqfotilde ujqhla iel+ uacuteg ksh WIaKajhl sect mSvkh iu` Z ys uacutepkh x wlaIhg (mSvk - wlaIh) iudkar ir ffrac34Ldjla fotilde PV kshhla jk wr
^fndhsa kshuhamp P g tEgraveszligfhka Z ys miadrh ishuml mSvk i`oyd ir ffrac34Ldjla fotilde 17
rEmfhka 273 K oS uacuteuacuteO jdhq i`oyd (a) miadrh uOtildeska o uacuteuacuteO WIaKajj sect tla jdhqjla
i`oyd (b) miadrh uOtildeska o fmkakqiuml flffrac34
17 rEmh mszligmQfrac34K jdhqjla iu` ixikaokh lrk uacuteg uacuteuacuteO jdhqj
iiumlmSvHd idOlh uacutepkh jk whqre (a) ksh WIaKajfha
sect mSvkh iu` Z uacutepkh jk whqre (a) =lt jQ l=vd rEmfhka
daauacutel yd mszligmQfrac34K jdhqjla i`oyd fndhsa kshufha jl (b) uacuteuacuteO WIaKajj sect CH4 jdhqfotilde mSvkh iu` Z ys uacutepkh
17 (a) rEmfha olajd wes miadrhg wkqj ksh WIaKajhl sect daauacutel jdhqjla i`oyd
Pg tEgraveszligfhka (P g tosszligfhka Z) wr miadrh x wlaIhg ^mSvkhamp iudkar ir
ffrac34Ldjla fkdjk nj wmg fmfka tkiuml mszligmQfrac34K yeisIacutefuka ielsh hq= wm ukhla
mjS uacuteuacuteO jfrac34 fha daauacutel jdhq i`oyd miadr jfrac34 folla eicirc we yhsacircrcka iy
ySshiuml i`oyd mSvkh jeauml jk uacuteg Z w h jeauml ugrave we fojk jfrac34 fha miadr oelsh
yelafla ldnka fudfkdlaihsacirc (CO) iy fufaka (CH4) jdhq i`oyd fotilde fiuml miadr
jsect mltuqj mszligmQfrac34K aajfhka RK wm ukhla fmkajk wr Z w h mSvkh jeauml
ugraveua iu` wvq ugrave jdhqjlg wdfotildeKsl wju wm ukhlg lt` d ugrave we Bg miq th kej
jeauml ugraveug mgka f k mszligmQfrac34K jdhq ffrac34Ldj lmntildeka tl Egrave g u jeauml ugrave Ok wm ukhla
fmkajhs ishuml aaj hgfa sect daauacutel jdhq iiumlmQfrac34Kfhka u mszligmQfrac34K jdhq ioacutelrKh
fkdmsltsmEgravek nj fiuml ksIacutelaIK u` ska wkdjrKh fjhs
17 (a) rEmfha = weo wes l=vd rEmfha oelafjk mSvkh iy mszligudj wr jlh u` ska
o fiuml mszligmQfrac34K aajfhka wm ukh ugraveu wjfndaO lr yels h tu jlh u` ska
daauacutel jdhqjla i`oyd mSvkh iy mszligud oa ffioaOdkaslj Kkh lrk o w hka
iuOtilde ixikaokh lr we th fndhsa kshuhg wodlt jlh ^mszligmQfrac34K jdhqjla i`oydamp jk
wr daauacutel jdhq mszligmQfrac34K yeisIacuteu olajhs kiuml tu jl fol tlsfkl yd iumd uacuteh
hq= nj wm oksuq bd bylt mSvkj sect uksk o mszligudj Kkh lrk o mszligudjg jvd
mszligudj (V)
mSvk
h (
P)
24
jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj
o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga
meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg
jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke
fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka
lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS
jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru
ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml
yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj
sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK
n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde
mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd
laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect
(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g
jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda
ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel
jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt
WIaKaj fotilde
daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o
WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel
fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg
jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml
fuh mltuq ioacutelrKfha wdfoaYfhka
fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH
ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk
nj wmg fmfka
fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh
pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we
tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj
hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h
mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq
wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt
jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect
jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia
PV mszligmQfrac34K
daauacutel
25
jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq
wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka
yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=
h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka
wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel
jdhq mszligmQfrac34K aajfhka wm ukh fotilde
151 jeka vrsquo jdaia ioacutelrKh
fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa
sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K
jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk
wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq
mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel
jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid
daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH
fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj
iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk
Egrave
bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka
kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka
mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka
igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash
iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg
fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh
mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde
1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj
ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh
by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK
fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde
gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq
mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde
fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg
iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq
msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect
moaOsfha mSvkh my mldYkfhka nd fohs
26
bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL
fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr
tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk
mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka
wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks
fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq
kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh
fi kej suacuteh yels h
fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh
fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql
nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia
flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha
wkafrac34--mszligjfrac34kh l yels fotilde
ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs
wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj
yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde
igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys
sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde
ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha
lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh
iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla
fi o yeisszligh yels ugraveu h
bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla
oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi
mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS
30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc
oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi
muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu
WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla
oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde
( )2
aP V b RTV
+ minus =
27
19 rEmh CO2 j ldm igyk
1 3 j =j - ioacutelrK idrdxYh
jdhq kshuh intildelrKhksh j mjsk
idOl
mszligmQfrac34K jdhq kshuh PV = nRT ke
fndhsa kshuh n iy T
pdaia kshuh V = kT n iy P
wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T
wKql pdl ioacutelrKh
idudkH fotilde h
jfrac34 uOHkH fotilde h
jfrac34 uOHkH fotilde h
fvdaagkaf a wdxYsl mSvk
kshuh
PA = xA PT
PT = PA + PB + PC
iiumlmSvHd idOlh jdhq ujq 1la i|yd
jeka vZjdaia ioacutelrKh
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
24
jeauml nj o wvq mSvkj sect uksk o iy Kkh lrk o mszligud tlsfklg ioacutem jk nj
o ntildeka meyeossj fmfka wvq mSvk aaj mszligmQfrac34K yeisIacuteug wdOdr jk nj ntildeka jyumlrga
meyeEgraves h jdhq wkafrac34 ugrave wes mszligudj bd uacuteYd kiuml n`yumlfka mszligudj iu` ii`ok uacuteg
jdhq wKqj mszligudj fkdild yeszligh yels h tuacuteg jdhq mszligmQfrac34K yeisIacuteu fmkajhs ke
fyda mSvkh bd wvq jk uacuteg dauacutel jdhqjl yeisIacuteu mszligmQfrac34K aajhg fnfyuacuteka
lt` d jk wr WIaKajh iy jdhqfotilde iajNdjh u th r`od mjS
jeauml mSvkhl sect jdhq wKq wjldYhla =lt frfmntildeka tla ia jQ uacuteg tajdfha mszligntilde ru
ksid wes jk wkafrac34-wKql wdlfrac34IK iy uacutelfrac34IK n u` ska o daauacutel jdhqjl fiuml
yeisIacuteu tkiuml Z w h 1g jvd l=vd ugraveu (Z lt 1) jyumlrga meyeEgraves llt yels h wvq mSvkj
sect kuqa jua mszligmQfrac34K yeisIacuteu fmkaugraveug jvd by mSvk j sect wkafrac34-wKql wdlfrac34IK
n fya=fjka ujqsl mszligudj wvq jk wr iiumlmSvHd idOlh 1 g jvd wvq (Z lt 1) fotilde
mudKja riuml jeauml mSvkj sect wKq tlsfklg ltx jk ksid jdhq wKqj mszligudj tajd
laIHhSh ialkaO fi yeisfrk aajhg idfmalaIj bylt fotilde bylt WIaKajj sect
(1 7 (b) rEmh) wkafrac34-wKql wdlfrac34IK n wvq ugrave PV =Ksh jeauml ugravefuka Z ys w h 1g
jvd jeauml fotilde (Z gt 1) flfia jqj o bylt WIaKajj sect mszligmQfrac34K aajhg rula fyda
ltx jk neuacuteka mszligmQfrac34K ffrac34Ldfjka wm ukh jk mudKh wvq fotilde tu ksid daauacutel
jdhqjla mszligmQfrac34K yeisIacuteu fmkaugraveu i`oyd jvd iqyumliq aaj jkafka bd wvq mSvk iy bylt
WIaKaj fotilde
daauacutel jdhqj fiuml yeisIacuteu mszligmQfrac34K jdhq iu` ixikaokh llt uacuteg fok o
WIaKajhl sect yd mSvkhl sect fiuml ujqsl mszligudfjys uacutepk iy iiumlmSvHd idOlh (Z) wr iiumlnkaOdj wjfndaO lr yels h daauacutel jdhqjl ujq tll mszligudj Vdaauacutel
fi o mszligmQfrac34K jdhqjl ujq tll mszligudj VmszligmQfrac34K fi o Wmlamkh llt uacuteg
jdhqj tu aaj hgfA sect u mszligmQfrac34Kj yeisffrac34 kiuml
fuh mltuq ioacutelrKfha wdfoaYfhka
fiuml wkqj iiumlmSvHd idOlh hkq fok o WIaKajhl sect iy mSvkhl sect jdhqjl iH
ujqsl mszligudja th mszligmQfrac34K fi yeisffrac34 kiuml tys ujqsl mszligudja wr wkqmdh jk
nj wmg fmfka
fiuml jfrac34 fhA mIacutelaIKjg wkqj ishuml aaj hgfa sect dauacutel jdhq fndhsa kshuh
pdaia kshuh iy wej dacircfrda kshuh iiumlmQfrac34Kfhka fkdmsltsmEgravek nj fidhd f k we
tu ksid jdhQka mszligmQfrac34K yeisIacutefuka wm ukh jkafka wehs o hkaka l=uk aaj
hgfa sect jdhq mszligmQfrac34K aajfhka wm ukh fotilde o hkaka wm wjfndaO lr hq= h
mltuq mYakh i`oyd wmg pdl wKqljdofha Wmlamk fhdod yels h tkiuml jdhq wKq
wr wdlfrac34IK n fkdmjsk nja jdhqj wkafrac34 n`yumlfka mszligudj iu` ii|k llt
jdhq wKqj mszligudj fkd sksh yels riuml l=vd nja Wmlamkh lrk sect
jdhq wKq wr wdlfrac34IK n fkdmjS kiuml jdhqjla lsisod oslashj llt fkdyels h flfia
PV mszligmQfrac34K
daauacutel
25
jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq
wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka
yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=
h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka
wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel
jdhq mszligmQfrac34K aajfhka wm ukh fotilde
151 jeka vrsquo jdaia ioacutelrKh
fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa
sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K
jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk
wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq
mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel
jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid
daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH
fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj
iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk
Egrave
bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka
kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka
mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka
igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash
iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg
fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh
mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde
1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj
ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh
by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK
fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde
gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq
mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde
fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg
iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq
msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect
moaOsfha mSvkh my mldYkfhka nd fohs
26
bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL
fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr
tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk
mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka
wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks
fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq
kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh
fi kej suacuteh yels h
fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh
fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql
nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia
flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha
wkafrac34--mszligjfrac34kh l yels fotilde
ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs
wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj
yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde
igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys
sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde
ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha
lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh
iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla
fi o yeisszligh yels ugraveu h
bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla
oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi
mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS
30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc
oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi
muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu
WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla
oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde
( )2
aP V b RTV
+ minus =
27
19 rEmh CO2 j ldm igyk
1 3 j =j - ioacutelrK idrdxYh
jdhq kshuh intildelrKhksh j mjsk
idOl
mszligmQfrac34K jdhq kshuh PV = nRT ke
fndhsa kshuh n iy T
pdaia kshuh V = kT n iy P
wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T
wKql pdl ioacutelrKh
idudkH fotilde h
jfrac34 uOHkH fotilde h
jfrac34 uOHkH fotilde h
fvdaagkaf a wdxYsl mSvk
kshuh
PA = xA PT
PT = PA + PB + PC
iiumlmSvHd idOlh jdhq ujq 1la i|yd
jeka vZjdaia ioacutelrKh
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
25
jqja isisa llt uacuteg iy iiumlmSvkh llt uacuteg jdhq oslashj llt yels nj wm okakd lreKls jdhq isisa llt uacuteg yd iiumlmSvkh llt uacuteg jdhq wKq tlsfklg ltx ugrave oslashj njg ma fotilde jdhq
wKqjl mszligudj fkd ssbquoh yels kiuml tuacuteg daauacutel jdhqjla i`oyd jk mSvkhg tEgraveszligfhka
yd mszligudj wr miadrh mszligmQfrac34K jdhqjla i`oyd jk miadrh iu` iumd uacuteh hq=
h (17 (a) rEmfhys we= jQ l=vd rEmh uOtildeska dauacutel jdhq mszligmQfrac34K aajfhka
wm ukh jk wdldrh wjfndaO lr yelsh) kuqa tfia isyuml fkdjk ksid daauacutel
jdhq mszligmQfrac34K aajfhka wm ukh fotilde
151 jeka vrsquo jdaia ioacutelrKh
fiuml fldgi wdriumlNfha sect P V T iy n hk ueksh yels uacutepH uacuteuacuteO aaj hgfa
sect jdhqj yeisIacuteu wjfndaO lr ekSug wjiad ioacutelrKh fi ye|skafjk mszligmQfrac34K
jdhq ioacutelrKh PV = nRT Nduacute lrk Egrave tu meyeEgraves lsIacuteiumlj sect wKq wr mjsk
wkafrac34lshd ksida jdhq wKqjl ielsh hq= riuml jk mszligudj ksida daauacutel jdhq
mszligmQfrac34K jdhq kshufhka wm ukh jk nj wjfndaO lr yels uacuteh tneuacuteka daauacutel
jdhqj ukskq nk mSvk yd mszligud mszligmQfrac34K jdhqjl tu w hkag iudk fkdjk ksid
daauacutel jdhqj yeisIacuteu uacuteiar lsIacuteug fjka wdldrhl wjiad ioacutelrKhla wjYH
fotilde acutekao cdsl fNsl uacuteoHdhl= jQ fEcirc atilde jeka vrsquo jdaia uacuteiska iH jdhqjl mszligudj
iy mSvkh mszligmQfrac34K jdhqjl mszligudj yd mSvkhg iiumlnkaO lrk my fhdackd isyuml lrk
Egrave
bylt mSvkj sect jdhq wKq tlsfklg bd ltx jk wr wKql wkafrac34 lshd wes ugraveug mgka
kS tneuacuteka bylt mSvkhl sect fiuml wkafrac34--wKql wdlfrac34IK n fya=fjka ^18 rEmfhka
mszligmQfrac34K jdhqjla iu` ixikaokh lr tu yeisIacuteu lgqigyka lr weamp jdhq wKq n`yumlfka
igraveash iu` eagravefiuml sect wfkla jdhq wKq uacuteiska wdmiq wEgravekq nk neuacuteka ndividefka igraveash
iu` bd Egraveka ixgtUumlgkh fkd fotilde ndividefka igraveash u wKq uOtildeska wes lrk mSvkhg
fuh nmdhs tneuacuteka tl u aaj hgfA sect daauacutel jdhqjla u` ska wes lrk mSvkh
mszligmQfrac34K jdhqjlska wes lrk mSvkhg jvd wvq fotilde
1 8 rEmh (a) mszligmQfrac34K jdhq wKqj (b) daauacutel jdhq wKqj
ixgtUumlgk ksid igraveash u wes jk nmEu ixikaokh
by rEmfha fmkajd sect wes mszligEgrave daauacutel jdhqjl mSvkh wvqugraveu wkafrac34-wKql wdlfrac34IK
fya=fjka isyuml fotilde hiuml lsis ldhl sect igraveash iu` wes jk ixgtUumlgk ixLHdj jdhqfotilde
gtkajhg iudkqmdsl fotilde tu ksid mSvkh i`oyd fhdokq nk fYdaOkh jdhq
mudKfhys jfrac34 hg iudkqmdsl jk wr mszligudfotilde jfrac34 hg msfdauj iudkqmdsl fotilde
fiuml ksid fYdaOkh fi suacuteh yels h fuys a hk kshh wdlfrac34IK nj w hg
iiumlnkaOdjla olajk wr WIaKajfhka yd mSvkfhka iajdha fotilde n yd V hkq
msltssfjltska jdhq ujq mudKh iy Ndckfha mszligudj fotilde tu ksid fiuml aaj hgfa sect
moaOsfha mSvkh my mldYkfhka nd fohs
26
bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL
fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr
tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk
mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka
wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks
fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq
kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh
fi kej suacuteh yels h
fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh
fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql
nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia
flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha
wkafrac34--mszligjfrac34kh l yels fotilde
ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs
wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj
yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde
igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys
sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde
ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha
lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh
iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla
fi o yeisszligh yels ugraveu h
bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla
oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi
mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS
30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc
oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi
muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu
WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla
oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde
( )2
aP V b RTV
+ minus =
27
19 rEmh CO2 j ldm igyk
1 3 j =j - ioacutelrK idrdxYh
jdhq kshuh intildelrKhksh j mjsk
idOl
mszligmQfrac34K jdhq kshuh PV = nRT ke
fndhsa kshuh n iy T
pdaia kshuh V = kT n iy P
wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T
wKql pdl ioacutelrKh
idudkH fotilde h
jfrac34 uOHkH fotilde h
jfrac34 uOHkH fotilde h
fvdaagkaf a wdxYsl mSvk
kshuh
PA = xA PT
PT = PA + PB + PC
iiumlmSvHd idOlh jdhq ujq 1la i|yd
jeka vZjdaia ioacutelrKh
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
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Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
26
bylt mSvkfha sect jdhq wKq tlsfklg ltx ugrave mjsk ksid wkafrac34-wKql uacutelfrac34IK jvd muqL
fotilde fiuml uacutelfrac34IK n nmEu wju lr ekSug wKq l=vd f da fi yeisfrk wr
tu` ska jdhq wKq ielsh hq= mszligudjla wa lr kS tuacuteg mszligmQfrac34K mszligudj ukskq nk
mszligudjg jvd wvq fotilde tfia jkafka V mszligudjl pkh ugraveug oeka ndOd wes jk neuacuteka
wKql psh isyuml jk iM mszligudj (V ndash nb) jk neuacuteks
fuys nb hkq wdikak jYfhka jdhq wKq wa lr kakd uqiquest mszligudj jk wr b hkq
kshhla fotilde ^ wKqjl mszligudjamp mSvkh iy mszligudj i`oyd fYdaOk fhyen uacuteg PV = nRT ioacutelrKh
fi kej suacuteh yels h
fuh jeka vrsquo jdaia ioacutelrKh fi ye|skafjk wr a iy b hkq jeka vrsquo jdaia ksh
fotilde wm tu ioacutelrKh dauacutel jdhq ujqhla i`oyd shQ uacuteg my oelafjk wdldr fotilde
152 wjecirc WIaKajh iy jdhq oslashj lsIacuteu
fiuml mszligEacutefthornoh wdriumlNfha sect hiuml fNsl wjiadjla mjajd ekSu i`oyd wkafrac34-wKql
nj uacuteYdajfhys jeo alu idlEacutePd lfltuq wkafrac34-wKql yumlr wjYH mszligEgrave fjkia
flfrk fia dmh iemhSfuka fyda isisa lsIacutefuka fyda fNsl wjiad wr modfrac34fha
wkafrac34--mszligjfrac34kh l yels fotilde
ksoiqkla fi( isisa lsIacutefuka iy iiumlmSvkh lsIacutefuka muKla jdhqjla oslashj llt yels hehs
wmg issh yel th hiumldla yumlrlg iH jqj o tajdfha ldm fjkig wkqj iH jdhqj
yeisIacuteu msltsn`o ja lreKq wmg wjYH fotilde
igyk fiuml msltssn`o jeauml uacuteiar iysj 12 jk tallfha sect idlEacutePd lrkq nk wr fuys
sect jdhq oslashj lsIacuteug wjYH aaj msltsn`o uQsl lreKq muKla idlEacutePd lsIacuteu jeo a fotilde
ksoiqkla fi( mSvkh WIaKajh iy mszligudj wr iiumlnkaOd msltsn`o fujeks wdldrfha
lreKq meyeEgraves lsszligug ldnka vfhdlaihsacirc (CO2) Nduacute llt yels h thg fya=j mSvkh
iy WIaKajh fjkia lsIacutefuka ldnka vfhdlaihsacircjg jdhqjla oslashjhla fuka u gtkhla
fi o yeisszligh yels ugraveu h
bylt WIaKaj mszligmQfrac34K aajhg yslr jk wr bd bylt mSvkj sect mjd jdhqjla
oslashj llt fkdyels h ldnkavfhdlaihsacirc iel= uacuteg bylt WIaKajj sect CO2 jdhqjlA fi
mjsk wr mSvkh 73 atmg jvd wvq llt uacuteg 30 98 degC (304 2 K) sect oslashj ugraveug mgka kS
30 98 degC WIaKajh CO2 ys wjecirc WIaKajh (Tc) fi ye`Egravekafotilde fuh ldnka vfhdlaihsacirc
oslashj fi mjsk Wmszligu WIaKajh jk wr Bg bylt WIaKajj sect th jdhqjla fi
muKla mjS fldriuml mSvkh jeauml llt o hiuml oslashjHhl jdIAmh oslashj llt fkdyels Wmszligu
WIaKajh tu oslashjHfha wjecirc WIaKajh fi wfrac34 oelafotilde wjecirc WIaKajfha sect jdIamhla
oslashj lsIacuteug wjYH mSvkh tu oslashjHfha wjecirc mSvkh fi ye`Egravekafotilde
( )2
aP V b RTV
+ minus =
27
19 rEmh CO2 j ldm igyk
1 3 j =j - ioacutelrK idrdxYh
jdhq kshuh intildelrKhksh j mjsk
idOl
mszligmQfrac34K jdhq kshuh PV = nRT ke
fndhsa kshuh n iy T
pdaia kshuh V = kT n iy P
wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T
wKql pdl ioacutelrKh
idudkH fotilde h
jfrac34 uOHkH fotilde h
jfrac34 uOHkH fotilde h
fvdaagkaf a wdxYsl mSvk
kshuh
PA = xA PT
PT = PA + PB + PC
iiumlmSvHd idOlh jdhq ujq 1la i|yd
jeka vZjdaia ioacutelrKh
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
27
19 rEmh CO2 j ldm igyk
1 3 j =j - ioacutelrK idrdxYh
jdhq kshuh intildelrKhksh j mjsk
idOl
mszligmQfrac34K jdhq kshuh PV = nRT ke
fndhsa kshuh n iy T
pdaia kshuh V = kT n iy P
wej dacircfrda kshuh VA = VB uacuteg NA = NB P iy T
wKql pdl ioacutelrKh
idudkH fotilde h
jfrac34 uOHkH fotilde h
jfrac34 uOHkH fotilde h
fvdaagkaf a wdxYsl mSvk
kshuh
PA = xA PT
PT = PA + PB + PC
iiumlmSvHd idOlh jdhq ujq 1la i|yd
jeka vZjdaia ioacutelrKh
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
28
wkafrac34 h
21 dm-ridhksl uacuteoHdfotilde yd
dms uacuteoHdfotilde uQsl mo
211 moaOsh jgmsgdj yd iSudj
212 moaOs jfrac34
bull uacutejD moaOs
bull ixjD moaOs
bull tals moaOs
bull iucdsh yd uacuteIucdSh moaOs
213 moaOshl =K
bull wkaugravelaISh =K
bull ufyalaI =K
bull uacuteas =K
bull gtgkd =K
214 moaOshl wjiadj
bull iajhxisoaO lshdjsh
bull iajhxisoaO fkdjk lshdjs
bull msjfrac34H lshdjsh
bull wmsjfrac34H lshdjsh
215 tkaeamsh (H)
216 dmh
bull uacuteYsIag dm Odszligdj iy dm
Odszligdj
22 uacuteuacuteO dm-ridhksl lshdjs$
mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
221 dmodhl yd dmdjfYdaIl lshdjs
bull iiumlu tkaeams uacutemfrac34hdi
222 dm-ridhksl ioacutelrK
223 tkaeams rEmigyka
224 tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
bull iiumlu Wamdok tkaeamsh ΔHθf
bull iiumlu oyk tkaeamsh ΔHθC
bull iiumlu nkaOk uacutegtgk tkaeamsh ΔHθD
bull iiumlu WodiSkslrK tkaeamsh ΔHθneu
bull iiumlu ioslashdjK tkaeamsh ΔHθsol
bull iiumlu ick tkaeamsh ΔHθhyd
bull iiumlu oslashdjK tkaeamsh ΔHθdissolution
bull iiumlu Wfrac34Ojmdk tkaeamsh ΔHθsub
bull iiumlu jdIamSlrK tkaeamsh ΔHθevap
bull iiumlu uacutehk tkaeamsh ΔHθfus
bull iiumlu mrudKqlrK tkaeamsh ΔHθat
bull iiumlu mltuq whkSlrK Ylas tkaeamsh ΔHθ
IE1
bull iiumlu bflafgdaklrK tkaeamsh ΔHθ
EG
whksl ixfhdahl iiumlu oesia
(uacutegtgk) tkaeamsh ΔHθL
225 jldldrfhka ΔH (ΔHdeg) ksfrac34Kh lsIacuteu ( fyia kshuh iiumlu mslshd tkaeams
23 oesia tkaeamsh fyja whksl
ixfhdahl Wamdok tkaeamsh (
fndaka-ydnfrac34 plh
24 ridhksl mslshdj iajhxisoaOdj
bull ridhksl mslshdjl iiumlu
tkafgdms fjki bull siacuteia fhdacH Ylash (G) yd
iajhxisoaOdj
2 Ylas uacuteoHdj
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
29
ye|skaugraveu
fuu tallfha sect dmh wdldrfhka mldYhg ma jk Ylas uacutemfrac34hdi msltsn`o yodrkq efiacute iEu ridhksl mslshdjl sect u mdfya dmh iajrEmfhka Ylash wjfYdaIKh ugraveula fyda
uacutefudapkh ugraveula isyuml fotilde fuyssect dm Ylash iy dmh wr fjki wjfndaO lr ekSu
jeo a h dmh hkq fjkia WIaKajjska hqa jia= folla wr dm Ylash yqjudre
ugraveuhs tneuacuteka wms ksrkarfhka WKqiqiuml jia=jl isg isisa jia=jla fj zdmh d
hEulaZ ek ld lruq zdmhZ hk moh ta jQ wdldrfhka a l bka Ylas yqjudrejla
woyia jk kuqyuml lsishiuml lshdjshla wdYs Ylas uacutemfrac34hdi uacuteiar lsIacutefiuml sect wms isszligla
fi zwjfYdaIKh jk dmhZ iy zuacutefudapkh jk dmhZ ek ld lruq dm-ridhk
uacuteoHdj hkq iiumlu wjiadjg wkqrEmj ridhksl mslshdj sect isyuml jk dm uacutemfrac34hdi
msltsn`o wOHhkhhs
fiuml mszligEacutefthornofha sect wms wKql uUumlgfiuml Ylas uacutemfrac34hdi yd Bg wkqrEmj moaOsj isyuml jk
fjkialiuml msltsn`o wOHhkh lruq fuys sect mltuqj dm--ridhkfha sect yuq jk uQsl moj
wfrac34 oelaugraveiuml o hq= jk wr dmodhl yd dmdjfYdaIl mslshdj sect ksmofjk iy
iemhsh hq= Ylas mudK wdYs l=Kq msltsn`oj o iuacutedkl uacuteh hq= h j o fuys sect uacuteuacuteO
ridhksl mslshd$ isoaecirc wdYs tkaeams uacutemfrac34hdi wfrac34 olajkq nk wr th iiumlu
wjiad lrd o jHdma flfrkq we WNtilde mszligEgrave ridhksl isoaecirc wdYs Kkh lsIacuteiuml
i`oyd dm ridhkfha uQsl kshuh ^fyia kshuhamp Wmfhda s lr ksuq wjidk jYfhka
tkafgdmsh tkaeamsh iy siacuteia ksoyia Ylash wr iiumlnkaOdj (ΔG = ΔH - TΔS) weiqfrka mslshdjla iajhxisoaO fi isyuml ugraveug wes keUqrej ek yodruq
2 1 dm-ridhk uacuteoHdfotilde yd dm s uacuteoHdfotilde uQsl mo
2 1 1 moaOsh jgmsgdj yd iSudj
dm--ridhk uacuteoHdfotilde uQsl ixlam yd kshu wfrac34 oelaugraveua yd meyeEgraves lsIacuteuga Nduacute
flfrk jeo a mo ksfrac34jpkh lsIacuteu yd wjfndaO lr ekSu mfhdackja h
bull moaOsh
fiiq uacuteYajfhka fjka fldg ksntildeka ielsag Ndck flfrk modfrac34fha fyda
uacuteYajfha acutekE u fldgila dm--ridhksl moaOshla fi wfrac34 oelafotilde ^irj lsj
fyda wOHhkhg Ndck jk jia=j moaOsh fi wfrac34 oelafotildeamp
bull jgmsgdj
moaOsfha fldgila fkdjkakd jQ tfya ta yd wkafrac34lshd llt yels uacuteYajfha fiiq
isha jgmsgdj fotilde ^irj lsj fyda moaOsfhka mszligndysr isha jgmsgdjhsamp
bull iSudj
moaOsh jgmsgdfjka fjka flfrk udhsuhs (WodyrK jYfhka madial=jl igraveas
iSudj fi ielsh yel)
2 1 rEmh moaOsh jgmsgdj yd iSudj maacutemdaacutel fi fmkakqiuml lsIacuteu
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
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Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
30
212 moaOs jfrac34
moaOsh yd jgmsgdj wr isyuml jk uacuteuacuteOdldr wkafrac34lshd$ lshdjs wkqj wdldr lsysmhl
moaOs wfrac34 oelauacuteh yels h
bull uacutejD moaOs
Ylash yd modfrac34h$ ialkaOh hk fol u jgmsgdj yd yqjudre lr yels
moaOshla uacutejD moaOshla fia ye`Egravekafotilde ksoiqkla fi cSh umlKq oslashdjKhla
wvx = uacutejD fndahla uacutejD moaOshls fuys tl u wjiadfotilde sect fyda fjk
fjk u fyda modfrac34h yd dmh jgmsgdfjka moaOshg tl= lsIacuteuga moaOsfhka
jgmsgdjg neyer lsIacuteuga yels h
bull ixjD moaOs
iSudj yryd Ylashg muKla yqjudre ugraveug bv fok tfya ialkaOhg ta yryd
yqjudre ugraveug bv fkdfok moaOshlg ixjD moaOshla hehs lshkq efiacute uqoslashd
nk o fndahl we=lta jk jdIamh iuOtilde iu=sdfotilde wes oslashjhla fiuml
i`oyd ksoiqka fotilde fndah ra lsIacutefuka fyda isisa lsIacutefuka fyda Bg Ylash tla
lsIacuteuga bka Ylash bja lsIacuteuga yels h tfya modfrac34h ^oslashjh fyda jdIamhamp
thg tla lsIacuteug fyda bka neyer lsIacuteug fyda fkdyels h
bull tals moaOs
Ylash yd modfrac34h hk folska tlla ja iSudj yryd yqjudre llt fkdyels moaOs
tals moaOs fotilde ksoiqkla fi( uqoslashd nd jik o mszligjdrl oslashjHjska ekqKq
igraveasjska hqa rsquofudia madial=jla tals moaOshla ksfhdackh lrhs
2 2 rEmh (a) uacutejD (b) ixjD (c) tals moaOsj maacutemdaacutel ksrEmKh
bull iucdSh yd uacuteIucdSh moaOs
moaOshl wvx = ishuml modfrac34j fNsl wjiadj taldldr kiuml tjekaklg
iucdSh moaOshla hehs lshkq efiacute jdhq ntildeYKhla yd mQfrac34K fi ntildeYjk oslashjjska
hqa ntildeYKhla oacuteg ksoiqka fotilde
moaOshl wvx = ishuml modfrac34 ixgtglj fNsl wjiadj taldldr fkdfotilde
kiuml tjekaklg uacuteIucdSh moaOshla hehs lshkq efiacute wntildeY oslashj gtkhla iuOtilde
iamfrac34Yj wes wntildeY oslashjhla gtkhla iuOtilde iamfrac34Yj wes jdhqjla wvx = moaOs fiuml
i|yd ksoiqka fotilde
2 1 3 moaOshl =K
bull wkaugravelaISh =K
moaOshla mrudKql fyda wKql mszligudKhl wea kiuml th wkauacutelaISh moaOshls
tkiuml ixjD ndividekla jeks lsishiuml moaOshl we=lta mrudKqj wKqj pdl
Ylash fotilde h jeks mrudKql fyda wKql mszligudK weiqfrka jl lu Nduacutehg
ksntildeka ksfrac34Kh llt hq= =K wkaugravelaISh =K fotilde
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
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Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
31
bull ufyalaI =K
moaOshl iuia fyda ufyalaI =K wjiadj yd wkqnoaO =K ufyalaI =K kiuml
fotilde mSvkh mszligudj WIaKajh idkaoslashKh gtkajh yumliaiduacutedj mDIaAgravel wdsh
jfrac34kdxlh jfrac34Kh wdEgraveh ufyalaI =Kjg ksoiqka fotilde
moaOshl wes ufyalaI =K jfrac34 follg fnEgraveh yels h
bull uacuteas =K
moaOshl ialkaOh fkdfyda ru u oS mjsk =K uacuteas =K kiuml fotilde
mszligudj ujq mudKh ialkaOh Ylash wNHkar Ylash wdEgraveh fuhg ksoiqka
fotilde moaOsfha iuia uacuteas =Kh moaOsh fnod fjka lsIacutefiuml sect wes jQ ta ta
fldgiaj uacuteas =Kj ftlHhg iudk fotilde ialkaOhka m1 m2 yd m3 ( aiuml) ntildeY lr moaOshla idod wea kiuml moaOsfha uqiquest ialkaOh (m1+m2+m3) gg iudk
fotilde tkiuml ialkaOh uacuteas =Khls
bull gtgkd =K
moaOsfha ialkaOfhka fyda mudKfhka iajdha jQ =K gtgkd =K kiuml fotilde
moaOshl jfrac34kdxlh mDIaAgravel wdsh gtkajh WIaKajh dmdxlh ysudxlh
wdEgraveh gtgkd =Kjg WodyrK fotilde fiuml =K moaOsfha wes oslashjHj ujq mudKh
u oS fkd mjS
lsishiuml uacuteas =Khla ujqhg (mol-1) auhg (g-1) gtk fikaaacuteoacutegrhg (cm-3) fyda jfrac34 fikaaacuteoacutegrhg (cm-2) fi olajd wes uacuteg th gtgkd =Khla njg ma
fotilde ksoiqka fi ialkaOh mszligudj dm Odszligdj uacuteas =K jk wr gtkajh
ujqsl mszligudj yd uacuteYsIag dm Odszligdj gtgkd =K fotilde
2 1 4 moaOshl wjiadj
moaOshl uacuteas =Kj iquacutefYaI w hka okakd uacuteg ta moaOsh uacutefYaIs jQ fNsl
wjiadjl mjskafka hehs lshkq efiacute ksoiqkla fi modfrac34fha jdhq wjiadj mSvkh
(P) mszligudj (V) WIaKajh (T) jeks mrdntildes u` ska uacuteiar llt yels h modfrac34h oslashj
wjiadfotilde mjakd l fiuml mrdntildesj w hka fjkia fotilde fiuml wkqj moaOshl wjiadj
moaOsfha iquacutefYaIj ueksh yels ufyalaI =K u` ska wfrac34 oelafotilde
moaOshl wdriumlNl wjiadj hkq moaOsh jgmsgdj iu` fldhs hiuml fyda wdldrfha
wkafrac34lshdjla isyuml lsIacuteug fmr moaOsh wkqnoaO uqa wjiadjhs
moaOshl wjika wjiadj hkqfjka woyia lrkafka moaOsh jgmsgdj yd isyuml lrk
wkafrac34lshdjska miq tltfUk wjiadjhs moaOshlg jgmsgdj iu` modfrac34 Ylash dmh fyda ta ishau fyda yqjudre lr ekSfuka ta iu` wkafrac34lshd llt yels h
moaOshl wjiadj uacuteiar lsIacuteug fhdod kakd P V T yd ixhqsh fyda ujq mudKh fyda
namp jeks uacutepHjg wjiad uacutepH fyja wjiad Ys hehs lshkq efiacute moaOshl wjiadj
fjkia jk uacuteg moaOsh wdYs wjiad uacutepHj w hka o fjkia fotilde fiuml ksid wjiad
Ys pound mjskafka moaOshl wdriumlNl yd wjika wjiadj u ntildei fjki isyuml jQ wdldrh
u fkdfotilde j o moaOshl wjiad Ysj w hka okafka kiuml moaOsfha ialkaOh
yumliaiduacutedj gtkajh wdEgrave wfkl=a ishuml =K okafka kiuml moaOsh iquacutefYaIs moaOshla
njg ma fotilde wjiad uacutepH wfkHdkHdha neuacuteka moaOshl wjiadj iquacutefYaIj oelaugraveu
i`oyd ishuml wjiad uacutepH oek ekSu wjYH fkdjk wr bka lsysmhla muKla oek
isagraveu mudKja h
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
32
iiumlu wjiadj
moaOshl dm uacutemfrac34hdihka ilk uacuteg ksYaNtilde WIaKajhl sect Pθ fi ixflaja
lrkq nk iiumlu mSvkhla ksfrac34EgraveIag mSvkhla fia Nduacute lsIacuteu wjYH fotilde fok
o ljr fyda Nduacute aajhla i`oyd iiumlu mSvkhg weafa ksh w hls
IUPAC ksfrac34foaYjg wkqj Pθ iiumlu mSvkfha w h 1 atm (101325 Pa) fotilde ^wfrac34
olajk o iiumlu WIaKajhla fkdues jqja weeiuml uacuteg 298 K iquacutefYaIs ksYaNtilde
WIaKajhla fia ieflaamp ixY=oaO oslashjHhl iiumlu wjiadj ldm i|yd iquacutefYaIs gtgkd uacutepH u ska uacuteiar l yels ksfrac34EgraveIag wjiadjls ksoiqkla fi 500 Kys
wes gtk hlvj iiumlu aajh jkafka 500 K yd 105 Pa hgfa wes ixY=oaO
hlv fotilde iiumlu aaj ixflaja flfrkqfha wodlt rdYsfha ixflahg ol=Kq
miska yd byltska θ hkak fhoSfuks ^Wod( ΔHθ ΔGθ ΔSθwdEgraveamp oslashdjK fhdod kakd
wjiad jsect idkaoslashKh 1 mol dm-3 oslashdjKh iiumlu wjiadj fi iefla
bull iajhxisoaO lshdjsh
iajhxisoaO lshdjshla hkq iajhxlshj isyuml jk lshdjshls fday oKavl WKqiqiuml
flltjfrys isg isisa flltjr olajd dmh d hEu oacuteg ksoiqkls fujeks
lshdjsj moaOsh wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh ugraveu tla
iquacutefYaI EgraveYdjla tafa muKla isyuml fotilde iajhxisoaO lshdjsjska fndfyduhla
iajdNduacutel lshdjs jk wr wmsjfrac34H o fotilde
bull iajhxisoaO fkdjk lshdjs
iajhxisoaO fkdjk lshdjs hkq iajhxlshj isyuml ugravefiuml mjKdjla ffkifrac34 slj
moaOsh =lt fkdues lshdjs h ldnka oykh ugraveu fuhg WodyrKhls ldnka
jdfha oykh ugrave dmh msg lrntildeka ldnka vfhdlaihsacirc idohs tfya msgska
dmh iemfhk fla jdfha nd wes ldnka sks fkd kS
bull msjfrac34H lshdjsh
msjfrac34H lshdjshla hkq wdriumlNl wjiadfjka wjika wjiadjg mszligjfrac34kh
lsIacutefiuml sect moaOshla u isyuml flfrk uacutemfrac34hdi ikash fndfyda uacuteg ta jQ wdldrfhka
u wdmiq isyuml llt yels uacutemfrac34hdihls fuh isyuml llt yels jkafka moaOsh wdriumlNl
wjiadfotilde isg wjika wjiadj olajd f k tafiuml sect isyuml flfrk fjkialiuml bd
fifuka yd mshjr fndfyda Kklska isyuml flfrk uacuteg h tfia lsIacutefiuml sect efnk
tla tla wrueEgrave wjiadj jgmsgdj yd iu=sj mjskq we tjka aaj hgfa
moaOsfha wdriumlNl yd wjika wjiad iiumlmQfrac34Kfhka msjfrac34H fotilde ksoiqkla fi
whsia oslashj ugravefiuml sect hiuml dm mudKhla wjfYdaIKh fotilde iEfok cfhka tu dm
mudKh u bja llt fyda ch hlts whsia njg mszligjfrac34kh llt yels h
bull wmsjfrac34H lshdjsh
wmsjfrac34H lshdjshla hkq jgmsgdfjys iaOgraver fjkila isyuml lsIacutefuka fdrj moaOsh
hlts wdriumlNl wjiadjg f k wd fkdyels lshdjs h fndfyda iajhxisoaO lshdjs
iajNdjfhka wmsjfrac34H fotilde ksoiqkla fi( ffcugraveh jhia ugraveu wmsjfrac34H
lshdjshls lkaolska myltg iajhxisoaOj ch d tau wmsjfrac34H lshdjshls
2 1 5 tkaeamsh (H)fndfyda fNsl yd ridhksl lshdjs isyuml jkafka fyda isyuml lrkq nkafka ksh mSvk
aaj hgfa sect h ksoiqka fi( uacuteoHd drfha oS idudkHfhka mslshd isyuml lrkq nkafka
jgmsgdjg uacutejD jQ mIacutelaId klt icirclr yd madial= =lt jk wr tajd isyuml jkafka wdikak
fi jdhqf da tll (1 atm sim 105 Pa) mSvkhla hgfa h ksh mSvk aaj hgfa
isyuml jk lshdjshl sect moaOshla =ltg fyda bka bjg dmh eSu mudKdaulj olajkq
msKsi ridhkfhda tkaeamsh kiuml jQ =Kh Nduacutehg kss tkaeamsh H hkafkka
ixflaja flffrac34 tkaeamsh uacuteas =Khls tkiuml tys uacuteYdajh wodlt oslashjHfha mudKh
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
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Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
33
u r|d mjS oslashjHhl tkaeamsh ksfrac34Kh llt fkdyels wr wm ieneuacuteka u ukskafka
tkaeams fjki ΔH h
mslshdjl tkaeams fjki ΔH hkq Mj tkaeamsh yd mslshlj tkaeamsh wr
fjkihs
2 1 6 dmh
ksh mSSvkfha sect dmh (q) tkaeamshg iudk jk ksid wm dm uacutemfrac34hdij ntildekqiuml
ek ild nuq uacuteoHd drfha sect fNsl yd ridhksl lshdjsj dm uacutemfrac34hdih ukskq
nkafka ta i`oyd u uacutefYaIsj imhk o ixjD Ndckhla jk leszligoacutegrhla fhdod
ksntildeks dm uacutemfrac34hdi ksudkh lsIacutefiuml sect mltuqj dm Odszligdj iy uacuteYsIag dm Odrsdj
msltsn`o wjfndaOhla nd hq= h
uacuteYsIag dm Odszligdj iy dm Odszligdj
hiuml oslashjHhl uacuteYsIag dm Odszligdj (c) hkq tu oslashjHfha aiuml 1l ialkaOhl WIaKajh
fiaishia wxYl 1lska bylt kexugraveug wjYH dm mudKhhs hiuml oslashjHhl dm Odszligdj
(C) hkq tu oslashjHfha fok o mudKhl WIaKajh fiaishia wxYl 1lska bylt kexugraveug
wjYH dm mudKhhs uacuteYsIag dm Odszligdj gtgkd =Khla jk wr dm Odszligdj uacuteas
=Khls hiuml oslashjHhl dm Odszligdj iy uacuteYsIag dm Odszligdj wr iiumlnkaOh fufia h(
fuys m - oslashjHfha ialkaOh ^ aiumljskaamp
igyk iuyr wjiadj sect uacuteYsIag dm Odszligdj i`oyd s Nduacute fotilde
ksoiqkla fi( cfha uacuteYsIag dmh 4 184 J g-1 degC-1 fotilde kiuml
ch 100 0 g l dm Odszligdj = (100 0) g times (4 184 J g-1 degC-1) = 418 4 J degC-1
igyk uacuteYsIag dm Odszligdfotilde tallh J g-1 degC-1 fyda J g-1 K-1) jk wr dm Odszligdj i`oyd
tallh J degC-1 ^fyda J K-1) fotilde
hiuml oslashjHhl ialkaOh uacuteYsIag dm Odszligdj yd tu idiumlmfha isyuml jk WIaKaj fjki
Δt ^WIAKajh degC jskaamp fyda ΔT ^WIAKajh K jskaamp okakd uacuteg wjfYdaIKh jk dm
mudKh fyda ksoyia jk dm mudKh (Q) my ioacutelrKh u ska Kkh llt yels h
fuys m = idiumlmfha ialkaOh
Δt = WIaKaj fjkiiexcl tkiuml Δt = twjidk - twdriumlNl
q i`oyd il=K tkaeams fjkfiys il=Kg iudk fotilde dmdjfYdaIl lshdjs i`oyd
q Ok jk wr dmodhl lshdjs i`oyd q RK fotilde
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
34
2 2 uacuteuacuteO dm - ridhksl lshdjs$ mslshd wdYs tkaeams uacutemfrac34hdi yd
iiumlu tkaeams uacutemfrac34hdi
ΔH hkafkka mslshdjl sect uacutefudapkh jQ fyda wjfYdaIKh jQ fyda dm mudKh ksrEmKh
fotilde lshdjsh wkqj mslshd tkaeamsh Ok fyda RK fyda uacuteh yels h tkaeams fjki
moAOshl wes oslashjH mudKhg wkqfdauj iudkqmdsl h
2 2 1 dmodhl yd dmdjfYdaIl lshdjs
dm sl lshdjsh ridhksl mslshdjla fyda fNsl mszligjfrac34khla jk lays iuia
lshdjsh wdYs dm uacutemfrac34hdifha iajNdjh wkqj lshdjs dmodhl yd dmdjfYdaIl
fi jfrac34 SlrKh flffrac34 fiuml lshdjs fojfrac34 h wr fjkialiuml my oelafjk wdldrhg
fjka llt yels h
2 1 j =j dmodhl yd dmdjfYdaIl lshdjs ixikaokh lsIacuteu
dmdjfYdaIl mslshd dmodhl mslshd
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh wjfYdaIKh
jk lshdjs dmdjfYdaIl lshdjs fotilde
wdriumlNl wjiadfjka wjika wjiadjg
mszligjfrac34kh ugravefiuml sect dmh uacutefudapkh
jk lshdjs dmodhl lshdjs fotilde
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd jeauml h wjYH wur Ylash
moaOsh uacuteiska dmh fi jgmsgdfjka
wjfYdaIKh lr kq efiacute
Wod( wefudakshiuml lafdarhsacirc cfha
EgravehlsIacuteu
moaOsfha wjika wjiadfotilde sect Ylash
tys wdriumlNl wjiadfotilde sect Ylashg
jvd wvq h wur Ylash dmh fi
jgmsgdjg ksoyia fotilde
Wod( ishuml oyk lshdjs dmodhl h
idudkHfhka dmdjfYdaIl fNsl
mszligjfrac34khl sect wdriumlNl wjiadj
wjika wjiadj fj f k tau i`oyd
dmh iemhsh hq=h
Wod( dmh iemhSfuka gtkhla oslashj njg
ma lsIacuteu dmdjfYdaIl lshdjshls
fNsl mszligjfrac34kh dmodhl kiuml
wdriumlNl wjiadj wjika wjiadj fj
f k tau i`oyd dmh bja llt hq= h
Wod( ysudxlfha sect oslashjhla ysudhkh lsIacuteu
dmodhl lshdjshls
mslshl + Ylash ^dmhamp rarr M mslshl rarr M + Ylash ^dmhamp
moaOsh uacuteiska jgmsgdfjka dmh
wjfYdaIKh lr kakd dmdjfYdaIl
lshdjshl ΔH Ok fotilde
^tkiuml ΔH gt O fotildeamp
moaOsh uacuteiska jgmsgdjg dmh ksoyia
lrk dmodhl lshdjshl ΔH RK
fotilde
^tkiuml ΔH lt O fotildeamp
2 21 1N (g) O (g) 90 kJ NO(g)2 2
+ + rarr 2 2 21H (g) O (g) H O(g) + 242 kJ2
+ rarr
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
35
tk
ae
amsh
M
ΔH gt 0
mslshl
tk
ae
amsh
M
ΔH lt 0
mslshl
ksh mSvkhla hgfa ukskq nk dm uacutemfrac34hdi u` ska moaOshl tkaeams fjki
oelafotilde ksh mSvkhla hgfa fhdod kakd leszligoacutegr u` ska lshdjshl tkaeams
fjki flltska u uek yels h
iiumlu tkaeams uacutemfrac34hdi
mslshdjla i`oyd ukskq nk tkaeams fjkig ksYaNtilde w hla mejfrkafka wdriumlNl
wjiadj ^mslshlamp yd wjika wjiadj ^Mamp iquacutefYaI fi uacuteiar lr wefda muKs
mslshl yd M i`oyd wm uacuteiska iiumlu aaj (105 Pa mSvkh yd wNsu WIaKajh) wfrac34
olajd wefda wmg wodlt mslshdfotilde tkaeams uacutemfrac34hdih iiumlu mslshd tkaeamsh
fi ye`Egravekauacuteh yels h fiuml iiumlu mslshd tkaeamsh θ ixflah iys ΔH u` ska
ixflaja flffrac34 iiumlu aajh ksfrac34jpkh lsIacutefiuml sect WIAKajh tys fldgila fkdjk
kuqyuml ΔH j j = lr wes w hhka mldY lsrSfiuml sect WIaKajh oelauacuteh hq= jkafka th
tkaeamsh WIaKajh wkqj fjkia jk fyhsks uacutefYaIfhka i`oyka lr kes kiuml fuys
i`oyka ishuml w hka WIaKajh 25degCg fyja 298 15 Kg wodlt fotilde
irj lsjfyda
mslshdjl iiumlu tkaeams uacutemfrac34hdih hkq iiumlu aaj hgfa sect
mslshdfotilde oelafjk mudK u ska iiumlu wjiadfotilde wes M iEsectfiuml sect isyuml
jk tkaeams uacutemfrac34hdihhsiexcl
2 2 2 dm--ridhksl ioacutelrK
Nduacute iiumluqs aaj yd msslshdjg wodlt ΔH (fyda ΔHθ ) w h we=lta jk =s ridhksl
ioacutelrKhla dm--ridhksl ioacutelrKhla fi ye`Egravekafotilde dm--ridhksl ioacutelrKhla
sugravefiuml sect my oelafjk iiumluqs wjYHfhka u Nduacutehg efka
(i) =s dm--ridhksl ioacutelrKhl ix =Kljska mslshdfjys mslshlj yd
Mj mslshdjg iyNd s jk ujq mudK ksrEmKh fotilde
(ii) mslshdjl tkaeams uacutemfrac34hdifhys tallh kJ mol-1 jk wr mslshlj yd
Mj ujq tllg jeauml Kkla mslshdjg iyNd s jqj o th tfia u mjS
tfya w fhys uacuteYdajh muKla fjkia uacuteh yels h
(iii) mslshdjla msjfrac34kh llt uacuteg ΔH ys il=K udre jk wr uacuteYdajh
fkdfjkiaj mjS
(iv) ΔH (fyda ΔHθ) ys w h mslshlj yd Mj fNsl wjiadj ^ldmamp wkqj
fjkia fotilde tneuacuteka dm-ridhksl ioacutelrKj ishuml uacutefYaIj fNsl wjiadj
oelaugraveu wHjYH fotilde
(v) iuia dm--ridhksl ioacutelrKh lsishiuml ixLHdjlska =K lrk oafoa kiuml
tkaeams fjki o tu ixLHdfjka u =K llt hq= h
(vi) ΔHθ ys il=K RK fotilde kiuml bka ye` fjkafka mslshdj dmodhl nj h ΔHθ ys
il=K Ok kiuml bka mldY jkafka mslshdj dmdjfYdaIl nj h
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
36
ksoiqkmy oelafjk mslshd ilkak
2H2(g) + O2(g) rarr 2H2O(g) ΔHθ = - 483 7 kJ mol-1
2H2(g) + O2(g) rarr 2H2O(l) ΔHθ = - 571 6 kJmol-1
by dm--ridhksl ioacutelrK lsysm wdldrhlg wfrac34lkh llt yels h
bull mslshd ujqhlg 483 7 kJla ksoyia fotildebull jeh jk H2(g) ujq 2 lg 483 7 kJla ksoyia fotilde
bull jeh jk O2(g) ujqhlg 483 7 kJla ksoyia fotilde
bull iEfok c jdIam ujq 2 lg 483 7 kJla ksoyia fotilde
iafgdhslsfhdntildesl ix =Kljg wkqj ujq mudK mslshd lrhs kiuml ΔHθ u` ska tkaeams
fjki fldmuK o hkak bEgraveszligma flffrac34
igyk fuys oS 483 7 kJ mol-1 hkafkka woyia jkafka yhsvcka jdhq ujq 2la Tlaiscka
jdhq ujq 1la iu` mslshd lr jdhquh ch ujq 2la iEsectfiuml oS 483 7 kJl dm Ylashla
ksoyia jk njhs
iuyr wjiadj by mslshdj fufi shQ uacuteg 2H2(g) + O2 (g) rarr 2H2O(g) ΔHθ = - 483 7 kJ
igyk fuyssect ydividekajd wes mslshd-mudKhla (extent) shd wes wdldrhg isyuml jk uacuteg
483 7 kJ l dmhla msg jk nj ksrEmKh fotilde mslshd-mudKfhys tallh ujq (mol) fotilde
by mslshdj i|yd ΔH = Hθ times mol = - 483 7 kJ mol-1 times mol = - 483 7 kJ
ksoiqkla fi( my mslshdj iluq
4H2(g) + 2O2 (g) rarr 4H2O(g)
fuu mslshdfjys ΔH =Hθ times 2= - 967 4 kJ fi shd olajkq efiacute
tkiuml uqa ΔH w h 2ka =K llt hq= wr fjka wdldrhg lsjfyda ΔH ys w h
mslshd lrk oslashjHhkays mudKfhka (mol) =K lrhs tneuacuteka mslshd mudKh fjkqjg
tu wjiadfotilde wes mslshd lrk oslashjHfhys uacuteoHd udk jk mudKh yelsh tkiuml
tys iru =s ridhksl ioacutelrKfhys iafgdhslsfhdntildesl ix =Klfhka fnosh hq=h
tneuacuteka by mslshdj (Tlaiscka) i|yd ΔH =- 483 7 kJ mol-1 times = - 967 4 kJ
wm i|yka lrkafka ΔHθ muKla u kiuml th ndash 967 4 kJ mol-1 fotilde
wm my wdldrhg ioacutelrK shQ uacuteg
tkaeams w hhka by w hhkaf a wfrac34Oh jk nj wmg fmfka
idudkHfhka jegfyk mszligEgrave yhsvcka jdhqj oykfhka ch ksmfok nj by
ioacutelrKfhka uacuteiar fotilde mltuq mslshdj c jdIam iEsectula fi ielsh yels wr
fojeks mslshdj oslashj ch iEoSula fi ielsh yels h mslshd folg u ksh WIaKajh
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
37
yd ksh mSvkh wodlt fotilde ΔH ys RK il=Kska oelafjkafka mslshdj dmodhl njhs
bEgraveszlig EgraveYdjg dmodhl jk mslshdjla wdmiq EgraveYdjg dmdjfYdaIl fotilde fuys uacutefdau
aajh o tfia u jx = h tfia u fiuml kSsh fNsl yd ridhksl lshdjs i`oyd o
jx = h
2H2O(l) rarr 2H2(g) + O2(g) ΔHθ = + 571 6 kJ mol-1
2H2O(g) rarr 2H2(g) + O2(g) ΔHθ = + 483 7 kJ mol-1
2 2 3 tkaeams rEmigyka
my oelafjk mslshdj ilkak
C12H22O11(s) + 12 O2(g) rarr12 CO2(g) + 11 H2O(l) ΔH = -5650 kJmol-1
by ioacutelrKfhys ΔH ys il=K RK ugravefuka uH jkafka Mj tkaeamsh
mslshlj tkaeamshg jvd wvq njhs tkaeamsfhys isyuml jk fiuml wvq ugraveu jgmsgdjg
ksoyia jk dmh iajrEmfhka mldYhg ma fotilde iqfldaia oykh dmodhl fotilde
N2(g) + O2(g) rarr 2NO(g) ΔH = 180 50 kJ mol-1
by sect wes mslshdfjys mslshlj tkaeamshg jvd jeauml tkaeamshla Mjg we
fufia tkaeamsh bylt kxjkq msKsi jgmsgdfjka dmh wjfYdaIKh flffrac34 tneuacuteka
mslshdj dmdjfYdaIl fotilde tkaeams rEmigykla hkq hiuml lshdjshl sect isyuml jk
tkaeams uacutemfrac34hdij rEmSh mldYkhls 2 1 j =fjka o fmkakqiuml lrk mszligEgrave rEmigyka
u` ska dmodhl yd dmdjfYdaIl mslshd ksrEmKh lrkafka flfia o my 2 3 rEmfhys
oelafotilde
2 3 rEmh ^aamp dmdjfYdaIl ^bamp dmodhl lshdjs i|yd tkaeams
rEmigyka
2 2 4 tkaeams uacutemfrac34hdi yd iiumlu tkaeams uacutemfrac34hdi
iiumlu Wamdok tkaeams uacutemfrac34hdih ΔHθf
oslashjHhl iiumlu Wamdok tkaeamsh ΔHθf hkq iiumlu wjiadfotilde wes tu oslashjHhl ujqhla
iiumlu wjiadfotilde iuqoafoaY iajrEmfhka wes tys ixgtaacute uQoslashjHjska Wamdokh ugravefiuml
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
38
sect isyuml jk tkaeams uacutemfrac34hdihhs iqiquest ixLHdjl yereKq uacuteg uQoslashjHj iuqoafoaY iajrEm
hkq atm tll mSvkhla (101325 Pa) yd fok o WIaKajhla hgfa tajdfha jvda u
iadhs wdldrh h θ ixflafhka wodlt tkaeams fjki iiumlu tkaeams fjkila nj
o lsquo f rsquo hgl=frka mslshdfotilde sect uQoslashjHjska wodlt oslashjHh Wamdokh jk nj o fmkakqiuml
flffrac34 uQoslashjHhl jvda u iadhs wjiadj thska u Wamdokh ugraveu uacutemfrac34hdihla fkdjk
neuacuteka iuqoafoaY iajrEmfha wes ixY=oaO uQoslashjHhl iiumlu Wamdok tkaeamsh 0 fotilde
ksoiqka fi my sect weafa idudkHfhka dm--ridhksl oa j = lsIacutefiuml sect fhdod
kakd WIaKajh jk 298 15 K sect uQoslashjH lsysmhl jvda u iadhs wdldr h
Na(s) H2(g) N2(g) O2(g) C(s graphite) Br2(l)
ksoiqkldnka i`oyd uacutefYaIhla uka oehs flkl=g issh yels h ntildeksrka ^ a hsUumlamp wdldrhg
wurj Egravehukas ^vhukaacircamp iajrEmfhka o iajdNduacutelj ldnkajg mejsh yels h ta
fol wr o ueksh yels rfiuml tkaeams fjkila mjsk neuacuteka ta foflys u ΔHf i`oyd
Y+kH w h mejszligh fkdyels h
C(s graphite) C(s diamond) ΔHθf = 1 9 kJ mol-1
iuqoafoaY wdldrh fi wm ilkafka jvd iadhs wdldrh fyja wvq tkaeams w fhka
hqa wdldrhhs tneuacuteka ΔHθf [C(s graphite)] = 0 fia ilkq efiacute
25 degC sect yd 1 atm mSvkfha sect mjakd jvda u iadhs iajrEmh fkdjk lays Wamdok
mslshdfotilde Mj fNsl aaj meyeEgraves j oelauacuteh hq= h
by ΔHθf w h fol wr fjki cfha jdIamSlrK dmh (44 kJ mol-1) nj jgyd kak
fndfyda Kkh lsIacuteiumlj sect wms ksrkarfhka iiumlu Wamdok tkaeams Nduacutehg ksuq
my sect wes ksoiqkajska uacuteoyd oelafjk mszligEgrave wm uacuteiska isyuml llt hq= mltuq lghqa
jkafka ΔHf fhfok ridhksl ioacutelrKh sugraveuhs
298 K sect fdaueaaumlyhsacircj (HCHO) iiumlu Wamdok tkaeamsh -108 kJ mol-1 fotilde fiuml
lreK my oelafjk ioacutelrKfhka mldY fotilde
ksoiqka iuyrla idlEacutePd lsIacuteug fmr weeiuml ridhksl mslshd$ ixisoaecirc wdYs iiumlu
tkaeams lsysmhla wfrac34 olajd sicircu jagrave
iiumlu oyk tkaeams uacutemfrac34hdih ΔHθC
iiumlu wjiadfotilde wes uQoslashjHhl fydA ixfhda hl fyda ujqhla iiumlu wjiadfotilde
wes wsszligla Tlaiscka mudKhl ^ke fyda jdfhaamp iiumlmQfrac34Kfhka oykh ugrave iiumlu
wjiadfotilde wes M nd sectfiuml sect isyuml jk tkaeams uacutemfrac34hdih tys iiumlu oyk tkaeamsh
fotilde
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) = - 2219 9 kJ mol-1
C(s) + O2(g) rarr CO2(g) = - 393 5 kJ mol-1
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
39
iiumlu nkaOk uacutegtgk tkaeams uacutemfrac34hdih ΔHθD
tkiuml nkaOk ujqhla uacutegtgkh lrntildeka iiumlu wjiadfotilde wes jdhquh uacutefYaIhla iiumlu
wjiadfotilde wes jdhquh uQoslashjH fyda ixrpl njg uacutegtgkh ugravefiuml sect isyuml jk tkaeams
uacutemfrac34hdihhs
H2(g) rarr 2H(g) ΔHθD = 432 kJ mol-1
CH4(g) rarr CH3(g) + H(g) ΔHθD = 428 kJ mol-1
CH3(g) rarr CH2(g) + H(g) ΔHθD = 441 kJ mol-1
CH2(g) rarr CH(g) + H(g) ΔHθD = 454 kJ mol-1
CH (g) rarr C(g) + H(g) ΔHθD = 344 kJ mol-1
tu ksid fufaka j nkaOk uacutegtgk Ylas fjki hkq by whka yfrys uOHkHh
wh fotilde
CH4(g) ys uOHkH iiumlu nkaOk uacutegtgk = (428 + 441 + 454 + 344) 4tkaeams uacutemfrac34hdih
= 416 75 kJ mol-1
iiumlu WodisklrK tkaeams uacutemfrac34hdih ΔHθneu
tkiuml iiumlu wjiadfotilde wes cSh H+ whk ujqhla yd cSh OH- whk fuhla
mslshd ugrave ch fuhla iEsectu wdYs tkaeams uacutemfrac34hdihhs
H+(aq) + OH-(aq) rarr H2O(l) ΔHθneu = -57 kJ mol-1
iiumlu ioslashdjK tkaeams uacutemfrac34hdih ΔHθsol
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla oslashdjl mudKhla yuqfotilde
1 0 mol dm-3 mszligmQfrac34K oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Mn+(g) + solventrarr Mn+(solvent)
iiumlu ick tkaeams uacutemfrac34hdih ΔHθhyd
tkiuml iiumlu wjiadfotilde wes jdhquh whk ujqhla wsszligla c mudKhl oslashjKh ugrave
1 0 mol dm-3 oslashdjK aajhg ma ugraveu wdYs tkaeams uacutemfrac34hdihhs
Na+(g) + water rarr Na+(aq) ΔHθhyd = - 406 kJ mol-1
iiumlu oslashdjK tkaeams uacutemfrac34hdih ΔHθdissolution
tkiuml iiumlu wjiadfotilde wes oslashjHhl ujqhla oslashdjl mudKhl oslashjKh ugrave 1 0 mol dm-3
oslashdjKhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) + water rarr NaCl(aq) ΔHθdissolution = 1 kJ mol-1
iiumlu Wfrac34Ojmdk tkaeams uacutemfrac34hdih ΔHθsub
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes uQoslashjHhl fyda ixfhda hl fyda
ujqhla iiumlmQfrac34Kfhkau iiumlu wjiadfotilde wes jdhquh ajhg mszligjfrac34kh ugravefiuml sect isyuml
jk tkaeams uacutemfrac34hdihhs
Ca(s) rarr Ca(g) ΔHθsub = 193 kJ mol-1
iiumlu jdIamSlrK tkaeams uacutemfrac34hdih ΔHθevap
tkiuml iiumlu wjiadfotilde wes oslashj uQoslashjHhl fyda ixfhda hl ujqhla iiumlu wjiadfotilde
wes jdhq wjiadjg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Br2(l) rarr Br2(g) ΔHθevap = 30 91 kJ mol-1
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
40
iiumlu uacutehk tkaeams uacutemfrac34hdih ΔHθfus
tkiuml iiumlu wjiadfotilde wes gtk uQoslashjHhl fyda ixfhda hl ujqhla oslashj wjiadjg
mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Al(s) rarr Al(l) ΔHθfus = 10 7 kJ mol-1
iiumlu mrudKqlrK tkaeams uacutemfrac34hdih ΔHθat
tkiuml iiumlu wjiadfotilde wes uQoslashjHhla iiumlu wjiadfotilde wes tys jdhquh mrudKq
ujqhla njg mszligjfrac34kh ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
frac12 Cl2(g) rarr Cl(g) ΔHθat = 121 kJ mol-1
iiumlu mltuq whkSlrK Ylas tkaeams uacutemfrac34hdih ΔHθIE1
tkiuml iiumlu wjiadfotilde wes uQoslashjHhl jdhquh mrudKq ujqhlska ta tltll kHIaaacutehg
jvd u sysa fi ne|S wes bflafgdakhla ne ska bja ugrave iiumlu wjiadfotilde wes jdhquh
tal Ok whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
Na(g) rarr Na+(g) + e ΔHθIE1 = 496 kJ mol-1
iiumlu bflafgdaklrK tkaeams uacutemfrac34hdih ΔHθEG
tkiuml iiumlu wjiadfotilde wes jdhquh mrudKq ujqhlaa bflafgdakhla ne ska ms yKh
lr ksntildeka iiumlu wjiadfotilde wes jdhquh tal-RK whk ujqhla iEsectfiuml sect isyuml jk tkaeams uacutemfrac34hdihhs Cl(g) + e rarr Cl- (g) ΔHθ
EG = -349 kJ mol-1
tneuacuteka Cl(g) ys bflafgdak nkaOqdjh 349 kJ mol-1 fotilde
whksl ixfhda hl iiumlu oesia uacutegtgk tkaeams uacutemfrac34hdih ΔHθL
tkiuml iiumlu wjiadfotilde wes gtk aajfha wes whksl ixfhda hl ujqhla tys jdhquh
Ok yd RK whk njg ma ugravefiuml sect isyuml jk tkaeams uacutemfrac34hdihhs
NaCl(s) rarr Na+(g) + Cl-(g) ΔHθL = +788 kJ mol-1
2 2 5 jl fi ΔH (ΔHθ) ksfrac34Kh lsIacuteu( fyia kshuh
tkaeams ixlamh furiuml mfhdackja ugraveug tla fya=jla jkafka tu ska l=vd ntildekqiuml
ixLHdjla Wmfhda s lr ksntildeka mslshd tkaeams uacutemfrac34hdi uacuteYd ixLHdjla Kkh llt
yels ugraveu h tkaeams uacutemfrac34hdij wes my oelafjk laIK lrK fldg f k fiuml
yelshdj eicirc we
ΔH uacuteas =Khla jk wr wjiad Yshla o fotilde 25degC sect ixgtaacutel uQoslashjHjska NO(g)
Wamdokh ugraveug wodlt tkaeams uacutemfrac34hdih ild nuq
N2(g) + O2(g) rarr2 NO(g) ΔHθ = 180 50 kJ mol-1
NO(g) tla ujqhla wdYs tkaeams fjki mldY lsIacuteu i`oyd wms ishuml ix =Kl yd ΔHθ
w h foflka fnouq
wjiad Yshl EgraveYdj fjkia ugravefiuml sect tkaeams fjkfiys il=K o fjkia jk neuacuteka
by lshdjsh msjfrac34kh lsIacutefiuml sect ΔH θys l=K udre fotilde
fyia dm iudlk kshuh i`oyd ksoiqkla(
N2(g) yd O2 (g) uQoslashjHjska NO2(g) Wamdokhg wodlt iiumlu Wamdok tkaeamsh
ksfrac34Kh lsIacuteu msltsn`o ild nuq
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
41
Wla mslshdj mshjr folla Tiafia isyuml fjehs wmg issh yels h mltuqj wms N2(g) yd
O2 (g)jska NO (g) idouq wk=rej NO(g) yd O2(g) jska NO2(g) idouq fiuml mshjr folg
wodlt dm ridhksl ioacutelrK tajdg iquacutefYaI ΔHθ w hka o iu` tl= llt fyda wmg
wm fidhk ΔHθ w h o iu` iuia ioacutelrKh efiacute
________________________________________________________
by ksoiqkg wodlt uQOfrac34uh fyia kshufhka fufia mldY fotilde
lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka ^lamsj jqj oamp isyuml fotilde kiuml
iuia lshdjsh i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj tkaeams
uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys wjiad Ys =Kfhys
msMhls wdriumlNl wjiadfotilde isg wjika wjiadj fj tltocircfha l=uk
udfrac34 hlska jqj o ΔH fyda ΔHθ ^lshdjsh iiumlu wjiadfotilde oS isyuml lrk
o kiumlamp i`oyd weafa tl u w hla jk wr th udfrac34 fhka iajdha h
my uacuteiar flfrk mszligEgrave fiuml ixlamh tkaeams rEmigyklska fia u dm-ridhksl
plhlska o bEgraveszligma llt yels h fuh msltsfjska 2 4 yd 2 5 rEmigyka j ksrEmkh fotilde
2 4 rEmh dmodhl mslshdjl A mslshlj isg B M olajd hd yels
udfrac34 folla ^aamp Rcq mszligjfrac34kh ^bamp wrueEgrave iysj mshjr
follska flfrk mszligjfrac34kh
2 4 rEmfhka fyia kshuh jyumlrga meyeEgraves flffrac34 A mslshl B M njg ma lsIacuteu
tla mshjrlska llta mshjr follska llta mshjr Kkdjlska llta iuia tkaeams
uacutemfrac34hdih tlla u fotilde ulaksid o ha( th SrKh jkafka tkaeams rEmigyfkys
mslshl yd Mj idfmalaI mssysagraveiuml u muKla fyhsks
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
42
Kkh lsIacuteiuml by olajd wes wdldrfha tkaeams rEmigyka u` ska muKla fkdj Bg
jvd ir wdldrhlg o llt yels h ta i`oyd mslshl M njg mszligjfrac34kh ugraveu ksrEmKh
flfrk my oelafjk wdldrfha plhla wjYH h thska o A mslshl B M njg ma
flfrk udfrac34 fol mldYs h
2 5 rEmh dm--ridhksl plh
dm--ridhksl plhla sugravefiuml sect my Wmfoia wkq ukh llt hq= fotildeiexcl
mltuqj tkaeams fjki fiugraveug wes ridhksl mslshdj shd tys Bh Waumlka ΔH
ixflah shkak bka miq dm ridhksl plhla (fyia kshu plhla) f dvkef k mszligEgrave
dm sl fdr=re iys wfkl=a mslshd we=lta lr ta tla tla mslshdfotilde Bh
Waumlka okakd tkaeams uacutemfrac34hdi shkak yeu uacuteg u Bj EgraveYdj wkq ukh lrntildeka
rEmigyk =lt udfrac34 folla fidhd kak tajdfhys tlsfklg msuacutereoaO EgraveYdjg fhduq
jk B fkduacuteh hq= h
oacuteg wurj okakd tkaeams w hka wkqrEm mslshdjg iiumlnkaO ujq ixLHdfjka
=K llt hq= h ksoiqkla fi( iiumlu oyk tkaeamsh oykhg Ndck jk oslashjHfha
(Wod ldnka) ujqhlska werfograve kiuml wodlt tkaeams w h mslshdjg iyNd s jk ldnka
mrudKq ixLHdfjka =K llt hq= h egumlj ioacutelrK Nduacute lr uacuteidivideja fuh isyuml llt
hq= nj ul nd kak (my ksoiqk nkak)
ksoiqk wmg my oelafjk mslshdfjys iiumlu tkaeams uacutemfrac34hdih fiugraveug wjYHj weehs
isuq
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ =
oeka wm yuqfotilde weafa wm flfia bEgraveszlighg hd hq= o hk mYakhhs wm uacuteiska ntildeksrka
yd yhsvcka mslshd lsIacuteug iik oafoa kiuml isyuml jkq weafa wam jQ mslshdjla jk
wr th iiumlmQfrac34Kajh lrd fkd hhs yera fuys sect Mh fmdfmakajg iSud fkdjk
wr fjka yhsfvdldnk o ta iu` iEfokq we tkiuml( wmg by mslshdfotilde ΔHθ w h flltska u ueksh fkdyels h ta fjkqjg wmg llt yelafla mIacutelaIKdaulj ksfrac34Kh
llt yels ΔHθ w hka Wmfhda s lr ksntildeka jl fi wodlt mslshdfotilde ΔHθ w h Kkh
lsIacuteuhs fyia kshufhys uqLH jaacutekdlu oS weafa fuys h th wmg Rcqj ueksh
fkdyels ΔHθ w hka Kkh lsIacuteug u uacutejr lrhs
fyia kshuh Nduacutefhka tkaeams fjkila ksfrac34Kh lsIacutefiuml sect wms wodlt ridhksl
ioacutelrK ixfhdackh llt hq= fjuq fiuml i`oyd iqqyumliq wdriumlNl laIHhla jkafka fok o
mslshlfhys ujqhla mokiuml lr ksntildeka sect wes oyk mslshd i`oyd ridhksl ioacutelrK
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
43
sugraveuhs ldnka yhsvcka Tlaiscka wkafrac34 ixfhda j oyk M CO2(g) yd H2O(l) nj
ielsag ksntildeka my oelafjk mszligEgrave wmg egumlfotilde uacutei`yumliuml udfrac34 h fidhd yels h
C3H8(g) + 5O2(g) rarr 3CO2(g) + 4H2O(l) ΔHθ = -2219 9 kJ mol-1 (a)C(s) + O2(g) rarr CO2(g) ΔHθ = - 393 5 kJ mol-1 (b)
(a) ys wdmiq mslshdj C3H8(g) ys Wamdokh fotilde tneuacuteka wmg fufia suacuteh yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime
blal mslshdfjys mslshl C(s) yd H2(g) fotilde ta tltflka wodlt ujq mudK
we=lta ugraveu i`oyd (b) ioacutelrKh =fkka o (c) ioacutelrKh yfrka o =K llt hq= fotilde
3C(s) + 3O2(g) rarr 3CO2(g) ΔHθ = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHθ = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
fuys sect C(s) ujq =kla yd H2(g) ujq yrla jeh ugrave wes wr C3H8(g) ujqhla iEsect
we fiuml wmg wjYH jQ mslshdjhs oeka wmg msixuacuteOdkh lrk o ioacutelrK =k tl=
lsIacutefuka (a)prime + (b)prime + (c)prime wjYH ixfhdackh nd yels h
3CO2(g) + 4H2O(l) rarr C3H8(g) + 5O2(g) ΔHθ = 2219 9 kJ mol-1 (a)prime3C(s) + 3O2(g) rarr 3CO2(g) ΔHdeg = 3(- 393 5 kJ mol-1) = -1180 5 kJ mol-1 (b)prime2O2(g) + 4H2(g) rarr 4H2O(l) ΔHdeg = 4(-285 8 kJ mol-1) = -1143 2 kJ mol-1 (c)prime
3C(s) + 4H2(g) rarr C3H8(g) ΔHθ = -103 8 kJ mol-1
dm--ridhksl plhla Nduacutefhka by egumlj fufia uacutei`Egraveh yels h
ΔH = 3(- 393 5 kJ mol-1) + 4(-285 8 kJ mol-1) + 2219 9 kJ = -103 8 kJ mol-1
tkaeams rEmigykla Nduacutefhka o tys uacutei`yumlu fufia nd yels h
wm uacuteiska w`Egravek o tkaeams rEmigyfkys wm tkaeams wlaIfhys lsisyuml ixLHdaul
w hla olajd ke ta H tkaeamsfhys ksrfmalaI w hka wmg ksfrac34Kh llt fkdyels
fyhsks tfya tkaeamsh wjiad Yshla neuacuteka ΔH tkaeams fjkig wkkH jQ w hka
we fiuml fjki iu` wmg lghq= llt yels h tfya fjka fndfyda =Kjg fia u
Bg o wdriumlNl laIHhla fyja Y+kH laIHhla wjYH h
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
44
2 6 rEmh 3C(s) + 4H2(g) rarr C3H8(g) mslshdfotilde tkaeams rEmigyk
(a) rEmfhka mslshdfotilde EgraveYdjg wkqj tla tla lshdjsh tajdg
wodlt tkaeams w h o iuOtilde oelafotilde (b) rEmfhka tkaeams
mrrh fmkakqiuml flfrk wr wjYH mslshdfotilde EgraveYdjg
wkqj wmg il=K SrKh llt yels h
iiumlu mslshd tkaeams
mslshdjl mslshl yd M iiumlu wjiadfotilde mjsk uacuteg tys tkaeams fjki iiumlu
tkaeams uacutemfrac34hdih jk nj wms W suq th ΔHθ fyda ΔHθrxn u` ska ixflaja flffrac34
iiumlu Wamdok tkaeamsj tla mOdk mfhdackhla kiuml iiumlu mslshd tkaeams
Kkh lsIacuteuhs
ksoiqk 21fiacutelsx fidavd Nduacute lr msaacute wdydr mssiaiSfiuml sect wam fi isyuml jk my oelafjk
mslshdj wdYs iiumlu tkaeams uacutemfrac34hdih fyia kshuh Nduacute fldg Kkh lrk
wdldrh uacuteuid nuq
2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθrxn =
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
45
mslts=rfyia kshuhg wkqj my ioacutelrK yr tlg tl= llt uacuteg by ioacutelrKh nd
yel
________________________________________________________________2NaHCO3(s) rarr Na2CO3(s) + H2O(l) + CO2(g) ΔHθ
rxn =
(a) ioacutelrKh uQoslashjHjska NaHCO3(s) ujq folla WAmdokh ugravefuys uacutefdau
ioacutelrKhhs tkiuml (a) mslshdfotilde ΔHθ ΔHθf (NaHCO3(s)) ys RK wfha fo=Khhs
(b) (c) yd (d) ioacutelrKjska Na2CO3(s) H2O(l) yd CO2(g) hk tajdfhys tla ujqhla
Wamdokh ugraveu ksfhdackh fotilde oeka wmg wfma wjYH mslshdfjys ΔHθ fufia mldY
llt yels h
tfi u tkaeams rEmigyk fyia kshu luh oDYHudk wdldrfhka fmkakqiuml lsIacuteuga
tkaeamsfhys wjiad Ys =Kh by ioacutelrKh idOkh lr ekSug wmg Wmldr jk
wdldr fmkakqiuml lsIacuteuga Nduacute llt yels h
fidaaumlhiuml nhsldnfkaUumlys uacutefhdackh mshjr follska isyuml jkafka hehs Wmlamkh lruq
mltuq mshjffrac34 sect n`yumlkl wes NaHCO3(s) ujq 2la Na(s) ujq 2lg C(s graphite) ujq
2lg H2(g) ujq 1lg yd O2(g) ujq 3lg uacutefhdackh fotilde hehs isuq fojeks mshjffrac34
sect by (b) (c) (d) ioacutelrKjska mldYs mszligEgrave M idokq msKsi Na(s) ujq 2la C(s graphite) ujq 2la H2(g) ujq 1la yd O2(g) ujq 3la msixfhdackh lruq
mshjr 1 2 times [NaHCO3(s) rarr Na(s) + 12H2(g) + C(graphite) + 32O2(g)] ΔHθ = 2times (ndashΔHθ
f [NaHCO3(s)]) = (2 mol)[ndash(ndash95081 kJ mol-1)]
mshjr 2 2Na(s) + C(graphite) + 32O2(g) rarr Na2CO3(s) ΔHθ = ΔHθ
f [Na2CO3(s)] = (1 mol Na2CO3)(ndash113068 kJ mol-1)] C(graphite) + O2(g) rarr CO2(g) ΔHθ = ΔHθ
f [CO2(g)] = (1 mol CO2)(ndash39351 kJ mol-1)] H2(g) + 12 O2(g) rarr H2O(l) ΔHθ = ΔHθ
f [H2O(l)] = (1 mol H2O)(ndash18778 kJ mol-1)]
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
46
tkaeamsh wjiad Yshla neuacuteka o acutekE u wjiad Yshl fjkiaugraveu udfrac34 fhka
iajdha neuacuteka o fyia kshuhg wkqj by ioacutelrKjska fmkakqiuml flfrk mszligEgrave
iuia mslshdfotilde tkaeams uacutemfrac34hdih Bg =vq fok fjka fjka mslshdj iiumlu
tkaeams uacutemfrac34hdij ftlHh fotilde tneuacuteka mQfrac34fjdala ioacutelrKh mslshdjl iiumlu
tkaeams uacutemfrac34hdih i`oyd jk my oelafjk jvd idOdrK ioacutelrKfhys tla iquacutefYaI
Nduacutehls
fuys vp yd vr hkq msltsfjltska Mj yd mslsshlj iafgdhslsfhdntildesl ix =Kl fotilde
Mjg wodlt moj tl=fjka mslshljg wodlt moj tl=j wvq llt uacuteg mslshdfotilde
tkaeams fjki ΔHθrxn (iuyr wjiadj fuh ΔHθ
r fi o ye`Egravekafotilde) efiacute
ir ksoiqkla fi my oelafjk lams mslshdj ilkak
a A + b B rarr c C + d D ΔHθrxn =
fuys a b c d hkq iafgdhslsfhdntildesl ix =Kl fotilde fiuml mslshdfotilde ΔHθrxn my oelafjk
ioacutelrKfhka fokq efiacute
ΔHθrxn = [c ΔHθ
f [C] + d ΔHθf [D] ] ndash [ a ΔHθ
f [A] + b ΔHθf [B] ]
Wla ioacutelrKh Nduacutefhka ΔHθrxn Kkh lsIacuteug kiuml wm mslshdjg iyNd s jk
oslashjHj ΔHθf w hka o hq= h fiuml w hka ksfrac34Kh lrkq msKsi wmg Rcq luh fyda jl
luh Nduacutehg yels h
Rcq luh fiuml luh uQoslashjHjska myiqfjka ixYafaIKh llt yels ixfhda j ΔHθ
f ksfrac34Kh lsIacuteu
i`oyd Nduacute llt yels h wmg C2H6(g) ys oykh i`oyd ΔHθrxn fidhd hq=j weehs
isuq ta i`oyd wm iiumlu wjiadfotilde wes C2H6(g) O2(g) CO2(g) yd H2O(l) hk oslashjHj
ΔHθf w hka o hq= hbrvbar ke fyda uek hq= h
ksoiqk 22Rcq luh Nduacutefhka C2H6(g)ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rwjYH mslshdj jkafka
jl luhfndfyda wjiadj wodlt ixfhda h uQoslashjHjska flltska u ixYafaIKh llt fkdyels
h weeiuml mslshd bd fifuka isyuml jk wr ja iuyr uacutefgl w=re mslshd isyuml
ugraveu ksid wjYH ixfhda hg wurj wkjYH ixfhda o ksmfoa fujeks wjiadj by
uacuteiar lrk o mszligEgrave fyia kshuh Nduacutefhka jl mfotildeYhla Nduacute lr ΔHθf ksfrac34Kh
llt yels h
^Mamp ^mslshlamp rxn p f r fH v H v Hθ θ θ∆ = sum sum
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
47
ksoiqk 23jl luh Nduacutefhka C2H6(g) ys oykh i`oyd ΔHθ
rxn Kkh lrkak
mslts=rfuh Tng yuq jk fyia plj mfhdackhls
my oelafjk plfhys wodlt mslshdj sriaj shd wes wr plh iiumlmQfrac34K lsIacuteu
i`oyd Wamdok tkaeams wh Bg tl= lr sfiacute
C2H6(g) yd O2(g) wr mslshdj i|yd fyia kshu plh
C2H6 yd O2 wr mslshdj i|yd fyia plh Kkh lsIacuteu i`oyd udfrac34 fol imqrk
ishuml tkaeams uacutemfrac34hdi shd tajd iudk flffrac34
2 3 oesi tkaeamsh fyja whksl ixfhda hl Wamdok tkaeamsh( fndaka-ydnfrac34 plh
whkSlrK Ylash yd bflafgdaklrK tkaeams mokiuml lr ksntildeka iadhs whksl
ixfhda idokafka ljr uQoslashjH oehs wmg mqfrdalkh llt yels h whkSlrK Ylash
yd bflafgdaklrK tkaeamsh wfrac34olajkqfha jdhq ldmfha isyuml jk lshdjs i`oyd
h tfya 100 kPa (1 atm) yd 25deg C aaj hgfa sect ishuml whksl ixfhda gtk fotilde
tla tla legdhkh iquacutefYaI wekdhk ixLHdjlska o tfia u tla tla wekdhkh iquacutefYaI
legdhk ixLHdjlska o jg ugrave wes neuacuteka gtk wjiadfotilde weafa fjkia u mszligirhls
tneuacuteka gtk whksl ixfhda hl iuia iadhsdj oS mjskafkA fiuml ishuml whk wr
wkafrac34lshd u ntildei tla legdhkhla yd tla wekdhkhla wr mjsk wkafrac34lsshdj u
fkd fotilde whksl gtkhl iadhsdj msltsn`o mudKdaul ntildekqula jkafka oesi (uacutegtgk) Ylashhs th wfrac34olajkq nkafka gtk whksl ixfhda hl ujqhla jdhquh whk njg
iiumlmQfrac34Kfhka fjka lsIacuteug wjYH Ylash fi h
oesi (uacutegtgk) Ylash flltska u ueksh fkdyels h tfia jqj o wm whksl ixfhda hl
jHQyh yd ixhqsh oksa kiuml l+fdaiuml kshuh Nduacutehg ksntildeka wmg ixfhda fha oesi
Ylash Kkh llt yels h whk folla wr uacuteNj Ylash (E) tajdfha wdfrdamK wr
=Kshg wkqfdauj iudkqmdsl jk wr tajd tlsfklska fjka flfrk yumlrg msfdauj
iudkqmdsl jk nj l+fdaiuml kshufhka mldY fotilde (fuys sect idlEacutePd fkdflffrac34)whksl ixfhda hl Wamdokh mshjr Kkdjla Tiafia isyuml fjehs Wmlamkh lsIacutefuka
wmg oesi tkaeamsh jlj ksfrac34Kh llt yels h fndaka-ydnfrac34 plh hkqfjka ye`Egravekafjk
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
48
fiuml lshdjsh whksl ixfhda j oesi Ylas whkSlrK Ylas bflafgdaklrK Ylas yd fjka mrudKql yd wKql =Kjg iiumlnkaO lrhs uQsl jYfhka thg mokiuml ugrave
weafa fyia kshuhhs fndaka-ydnfrac34 plh whksl gtkhla Wamdokh ugraveug fmrd=j isyuml
jk uacuteuacuteO mshjr wfrac34 olajkafka h sshiuml aumlfjdrhsacircys oesi (uacutegtgk) Ylash ksfrac34Kh
i`oyd th fhdod kakd wdldrh fuys d uacuteiar flffrac34 sshiuml yd aumlfjdIacuteka wr
mslshdj ilkak
ΔHθrxn =
fiuml mslshdfjys iiumlu tkaeams uacutemfrac34hdih -594 1 kJ mol-1 fotilde fuh LiF(s) ys iiumlu
Wamdok tkaeamsh fotilde ixgtaacute uQoslashjHjska sshiuml aumlfjdrhsacirc Wamdokh ugraveu my
uacuteiar flfrk mszligEgrave mshjr myla Tiafia isyuml jk fia ielsh yels h fyia kshuh
Nduacutefhka whksl ixfhda hl Wamdokhg wodlt Ylas (tkaeams) uacutemfrac34hdi ksfrac34Kh
lsIacuteug fuu luh fhdod yel
1 gtk sshiuml sshiuml jdIamh njg Wfrac34Ojmdkh ugraveu
2 F2(g) F(g) njg mrudKqlrKh lsIacuteu
3 jdhquh sshiuml mrudKq whkSlrKh ugraveu
4 bflafgdak ms yKh lr F- iEsectu
5 Li+(g) yd F-(g) ixfhdackh ugraveu
LiFys oesia (uacutegtgk) Ylash wfrac34 oelafjkqfha my oelafjk mszligoafoks
ΔHθ5 ys w h my oelafjk mszligEgrave Kkh llt yels h
iuia mslshdfjys iiumlu tkaeams uacutemfrac34hdih ^ΔHθrxn )ndash 594 1 kJ mol-1 neuacuteka wmg
fufia suacuteh yels h
ΔHθrxn = ΔHθ
1 + ΔHθ2 + ΔHθ
3 + ΔHθ4 + ΔHθ
5
by mshjr 5 tl= lsIacutefuka my oelafjk iuia mslshdj efiacute
tneuacuteka -594 1 kJ mol-1 = 155 2 kJ mol-1 + 75 3 kJ mol-1 + 520 kJ mol-1 + (-328 kJ mol-1) + ΔHθ
5
ΔHθ5 = -1016 6 kJ mol-1 fotilde
tfyhska LiF(s) ys oesia uacutegtgk tkaeamsh 1016 6 kJ mol-1 fotilde
-1753 kJ mol
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
49
my 2 7 rEmigyfkka sshiuml aumlfjdrhsacircys fndaka-ydnfrac34 plh idrdxY fldg oelafotilde
1 2 3 mshjr i`oyd Ylash fhougraveu wjYH fotilde wfkla wg 4 yd 5 mshjrj sect Ylash
uacutefudapkh fotilde ΔHθ5 uacuteYd RK rdYshla jk neuacuteka LiF ys oesia uacutegtgk tkaeamsh uacuteYd
Ok w hls LiF ys iadhsdj i`oyd fuh fya= fotilde oesia uacutegtgk tkaeamsh uacuteYd ja
u whksl ixfhda fha iadhsdj o jeauml h gtkhl whk jdhq ldmfha whk njg fjka
lsIacuteu dmdjfYdaIl lshdjshla neuacuteka oesi tkaeamsh yeu uacuteg u Ok w hla kakd
nj ul nd kak
2 7 rEmh by moaOsh i|yd fndaka--ydnfrac34 plh (ΔHθ5 ys w h
-1016 6 kJ mol-1 neuacuteka LiF(s) ys oesia uacutegtgk tkaeamsh
1016 6 kJ mol-1 fotilde) (a) jska ta ta lshdjs tlaj fmkakqiuml
flfrk wr (b) rEmh tajd fjka fjkaj olajhs
2 4 ridhksl mslshdj iajhxisoaOdj
iajhxisoaO lshdjs
mIacutelaIKdaul ridhk uacuteoHdfjka jeo a fldgila iajhxisoaO lshdjs tkiuml moaOsh
msgska flfrk wLKav Ylas iemhqulska fdrj isyuml jk lshdjs yd iiumlnkaO h fkdtfia
kiuml wdriumlN ugravefuka miq mslshl wjika jk =re fyda M bja fkdlrk oafoa kiuml
iu=s wjiadjlg tltfUk =re fyda iiumlmQfrac34Kajh lrd hk mslshd fi iajhxisoaO
mslshd y`yumlkajd Egraveh yels h iajhxisoaO hkAfkka wjYHfhka u bylt mslshd fotilde hla
woyia fkdjk nj o jgyd ekSu jeo a h ldh iajhxisoaO lshdjshl dm sl wfrac34
oelaugravefuys fldgila fkd fotilde iajhxisoaO lshdjshla blaukska isyuml ugraveug fyda isyuml fkdugraveug
fyda yels h j o th fldfya u isyuml fkdugraveug o yels h
ksoiqkla fi( 25 degC WIaKajhla yd 100 kPa mSvkhla hgfa sect Egravehukas ntildeksrka njg
mszligjfrac34kh ugraveu iajhxisoaO lshdjshla jk wr th fldriuml fifuka isyuml fotilde o ha th
isyuml jkq flkl=f a Ocircuacute ldh =lt jqj o oel fkdyels h
dm sl uacuteoHdfotilde tla wruqKla jkafka fok o mslshl iuQyhla talrdYs llt uacuteg
mslshdjla isyuml fotilde o fkdfotilde o hkak mqfrdalkh lsIacuteuhs dm slh mslshdjla isyuml
fotilde o fkdfotilde o hkak mldY lrk uqa mslshdj fldriuml fotilde fhka isyuml jkafka o hkak
ek lsisjla mldY fkd lrhs iajhxisoaO mslshdjska iuyrla dmodhl (ΔH RK) jk wr dmdjfYdaIl (ΔH Ok) mslshd fndfyda Kkla o iajhxisoaOj isyuml jk nj
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
50
ksIacutelaIKh lr we tneuacutekA ΔH fyda ΔHθ iajhxisoaOdj i`oyd mudKja fhduqjla fkd
fotilde
fiuml i`oyd iajhxisoaO lshdjshl sect uacutefudapkh jk ke fyda wjfYdaIKh jk dm
mudKhg wur j tkafgdmsh hkqfjka ye`Egravekafjk ja idOlhla o ielsag hq=
h tkafgdmsh (s) hkq moaOshl wluja nj fyja wyUqdj msltsn`o ntildekquls tkafgdamsh
(s) moaOshl wmsltsfjlt fyja wyUqdj jeauml ugraveua iu` w fhka jeauml jk wjiad
Yshls tys tallh J K-1 mol-1 fotilde
fNsl wjiadj WIaKajh wKqj ru wkafrac34wKql n yd ntildeY ugraveu wdEgrave idOl
Kkdjla oslashjHhl tkafgdmshg odhl fotilde tfya fiuml uUumlgfiuml sect fNsl wjiadj yd
WIaKajh ek muKla ild nefa
jdhq wxY=j pkfha wyUqdj wecircl neuacuteka jdhq bylt tkafgdmshla wa lr ekSug
keUqre fotilde wxY=j psh fnfyuacuteka iSud ugrave wes gtkjg jvd jeauml tkafgdmshla
oslashj i= fotilde ldur WIaKajfha sect ch ujqhla i= tkafgdmshg jvd jdhqul ldnka
vfhdlaihsacirc ujqhl tkafgdmsh jeauml h tfia u ch ujqhl tkafgdmsh gtk U
fdayfha tkafgdmshg jvd bylt h jeauml jk WIaKajh iu` wKqj WadrK yd NuK
ps fotilde ja jk ksid WIaKajfha bylt hEua iu` oslashjHhl tkafgdmsh jeauml fotilde 25 degC wes cfhys tkafgdmshg jvd 50deg C wes cfhys tkafgdmsh jeauml h
ridhksl mslshdjl iiumlu tkafgdms fjki
mslshdjl iiumlu tkaeams uacutemfrac34hdih ΔHθrxn Kkh llt wdldrhg u iiumlu ujqsl
tkafgdms w hka Nduacute lrntildeka mslshdfotilde iiumlu tkafgdms fjki ΔSθrxn Kkh
lr yels h fuys sect tla tla fusl tkafgdms w h =s ridhksl ioacutelrKfha
iafgdhslsfhdntildesl ix =Kljska =K flffrac34
ΔSθrxn hkq iiumlu wjiadfotilde wes wntildeYH ixY=oaO mslshl iiumlu wjiadfotilde wes wntildeYH
ixY=oaO M njg mszligjfrac34kh ugravefiuml sect isyuml jk tkafgdms fjkihs ΔSorxn ys il=K mslshdfotilde
iafgdhslsfhdntildesh yd mslshlj yd Mj fNsl wjiad ielsag ekSfuka
lafiare llt yels h mslshl M njg ma ugravefiuml sect uqiquest jdhq ujq mudKfha jeauml ugraveula
fotilde kiuml ΔSθrxn ys w h Ok jk nj wmg fm hsh yels h fuys M mslshljg jvd
bylt tkafgdmshl mjS oacuteg uacutefdau fi jdhquh Mj ujq mudKh jdhquh mslshl
ujq mudKhg jvd wvq kiuml ΔSθrxn ys il=K RK fotilde
ksoiqk 24yhsvcka yd Tlaiscka iajhxisoaO fi mslshd lrntildeka c jdIam idohs
2H2(g) + O2(g) rarr 2H2O(g)fiuml mslshdfotilde tkafgdms fjkfiys il=K mqfrdalkh lr 25 degC sect mslshdfotilde ΔSθ
rxn
Kkh lrkak
- rxnS S S∆ = sum sum^Mamp ^mslshlamp
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
51
mslts=ryhsvcka jdhqj yd Tlaiscka jdhqj mslshd lr c jdIam iEsectfiuml sect ieu mslshd
ujqhlg u jdhq ujq =kla jdhq ujq folla njg mszligjfrac34kh fotilde mslshdfotilde sect jdhq
ujq mudKh wvq jk neuacuteka ΔSθrxn RK uacuteh hq= h
iiumlu tkafgdamsh Kkh lsIacuteu i`oyd iiumlu ujqsl tkafgdams whka Nduacute llt uacuteg
ΔSθrxn = ΔSθ(M) minus ΔSθ(mslshl)
= (2 mol)(ΔSθ [H2O(g)]) minus (2 mol)(ΔSθ
[H2(g)]) + (1 mol)(ΔSθ [O2(g)])
= (2 mol)(1888 J K-1 mol-1) minus (2 mol)(1307 J K-1 mol-1) + (1 mol)(2051 J K-1 mol-1)= minus889 J K-1 mol-1
fiuml mslshdfotilde tkafgdms fjki RK fotilde fuh mslshdfotilde iafgdhslsfhdantildesh mokiuml
lr fk isyuml l fmrhSu iuOtilde efma
mslshdjl iajhxisoaOdj ek mldY lsIacuteug kiuml tys tkaeams uacutemfrac34hdih (ΔHθrxn) yd
tkafgdms uacutemfrac34hdih (ΔSθrxn) hk fol u ielsag hq= h wm okakd mszligEgrave ir fi
wmg mejish yelafla tkaeamsfhys wvq ugraveu yd tkafgdamsfhys jeauml ugraveu mslshdjlg
yslr neuacuteka mslshdj iajhxisoaO j isyuml uacuteh yels nj h Bg wsffrac34lj weeiuml WIaKaj
aaj hgfa fiuml fm hSu lsIacuteu i`oyd my oelafjk ixhqla aajhka o ielsag
ekSu wjYH h
ΔHθrxn (-) ΔSθ
rxn (+) ishuml WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (+) bylt WIaKajj sect iajhxisoaO h
ΔHθrxn (-) ΔSθ
rxn (-) mylt WIaKajj sect iajhxisoaO h
ΔHθrxn (+) ΔSθ
rxn (-) ishuml WIaKajj sect iajhxisoaO fkd fotilde
^wdmiq mslshdj iajhxisoaO hamp
siacuteia fhdacH Ylash (G) yd iajhxisoaOdj
wm uacuteiska by olajk o mszligEgrave mslshdjl iajhxisoaOdj ksfrac34Kh jkqfha tys tkaeams
fjki yd tkafgdms fjki hk fol u u` sks siacuteia fhdacH Ylash fyja irj mejfik
mszligEgrave fhdacH Ylash (G) tkaeamsh yd tkafgdmsh ixlkh lsrSfuka nd kakd wjiad
Yshls T ksrfmalaI WIaKajfha sect G my oelafjk mszligEgrave wfrac34 oelafotilde
ksh WIaKajhla hgfa sect isyuml jk mslshdjla i|yd fhdacH Ylas fjki ΔG fufia
wfrac34 oelafotilde
ksh WIaKajhla hgfa sect yd iiumlu aaj hgfa sect isyuml jk mslshdjl fhdacH Ylas
fjki my ioacutelrKfhka mldYs h
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
52
igyk iuyr wjiadj oS ΔGθrxn fjkqjg ΔGθ
r hkako Nduacuted fotilde
bull iu=sdfotilde wes mslshdjl ΔGθrxn = 0 fotilde tjekakl bEgraveszlig fyda wdmiq
EgraveYdjg Y=oaO fjkila isyuml fkd fotilde bEgraveszlig EgraveYdjg iajhxisoaOj isyuml jk mslshdjl
ΔGθrxn lt 0 fotilde bEgraveszlig EgraveYdjg iajhxisoaO fkdjk mslshdjl ΔGo
rxn gt 0 fotilde
ksoiqk 25
ldnka fudfkdlaihsacirc yd Tlaiscka mslshd ugrave ldnka vfhdlaihsacirc iEfoa CO(g) + frac12 O2(g) rarr CO2(g)
ΔHθrxn yd ΔSθ
rxn WmfhdaS lr ksntildeka 25degC sect by mslshdfotilde iiumlu fhdacH Ylas
fjki Kkh lrkak
(ΔHθf [CO2(g)]= minus3935 kJ mol-1 ΔHθ
f [CO(g)]= minus1105 kJ mol-1Sθ [CO2(g)]= 2137 J mol-1 K-1 Sθ [CO(g)] = 1977 J mol-1 K-1Sθ [O2(g)] = 2051 J mol-1 K-1)
mslts=rmltuqj iiumlu Wamdok tkaeams Nduacute lr iiumlu aaj hgfa wodlt mslshdfotilde
tkaeams fjki Kkh lrkak
ΔHθrxn = ΔHθ
f (M) minus ΔHθf (msslshl)
= ΔHθf [CO2(g)] minus ΔHθ
f [CO(g)] minus frac12 ΔHθf [O2(g)]
= minus3935 kJ mol-1 minus (minus1105 kJ mol-1) ndash 0 kJ mol-1
= minus2830 kJ mol-1
iiumlu tkafgdms whka Wmfhdas lr ksntildeka iiumlu aaj hgfa sect Wla mslshdfotilde
tkafgdms fjki Kkh lrkak
ΔSθrxn = Sθ (M) minus Sθ (msslshl)
= Sθ [CO2(g)] minus Sθ [CO(g)] minus frac12 Sθ [O2(g)] = 2137 J mol-1 K-1 minus (1977 J mol-1 K-1) minus (frac12)(2051 J mol-1 K-1) = minus866 J mol-1 K-1
igykiafgdhslsfhdntildesh wkqj mqfrdalkh llt yels mszligEgrave ΔSθrxn wh RK nj igyka
lrkak jdhq ujq 15lska jdhq ujq 1la iEfok neuacuteks
my sect wes ioacutelrKfhka ΔGθrxn Kkh lrkak
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn
= minus2830 kJ mol-1 minus (298 K)(minus866 J mol-1 K-1)(1 kJ1000 J) = minus257 kJ mol-1
ΔGθrxn RK fotilde tneuacuteka mslshdj iajhxisoaO fotilde
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
53
2 2 j =j( ioacutelrKj idrdxYh
ioacutelrK tall
mslshdjl
tkaeams fjki
ΔH = Σvp H(M) ndash Σvr H (mslshl) kJ mol-1
mslshdjl iiumlu
tkaeams fjki
(vp yd vr hkq Mj yd mslshlj iafgdhslsfhdntildesl ix =Kl fotildeiexcl)
kJ mol-1
fyia kshuh lsishiuml lshdjshla wEgravehr fyda mshjr jYfhka
^lamsj jqj oamp isyuml fotilde kiuml iuia lshdjsh
i`oyd jQ tkaeams uacutemfrac34hdih ta ta mshjrj
tkaeams uacutemfrac34hdij tl=jg iudk fotilde
wka whqszligka lsj fyda fyia kshuh tkaeamsfhys
wjiad Ys =Kfhys msMhls wdriumlNl
wjiadfotilde isg wjika wjiadj fj tltocircfha
l=uk udfrac34 hlska jqj ΔH fyda ΔHdeg ^lshdjsh
iiumlu aaj hgfa isyuml lrk o kiumlamp i`oyd
weafa tl u w hla jk wr th udfrac34 fhka
iajdha h
mslshdjl iiumlu
tkafgdms fjki
ΔSθrxn = Σ Sθ (M) ndash Σ Sθ (mslshl) JK-1mol-1
mslshdjl iiumlu
siacuteia fhdacH Ylas
fjki
ΔGθrxn = ΔHθ
rxn ndash T ΔSθrxn kJ mol-1
mslshdjl
iajhxisoaOdj
ieu WIaKajhl sect u
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
bylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (+) ΔSθ
rxn (+)
mylt WIaKajj sect
iajhxisoaO ΔHθ
rxn (ndash) ΔSθ
rxn (ndash)
ieu WIaKajhlsectu
iajhxisoaO fkdjk
(msjfrac34H mslshdj
iajhxisoaO fotildeiexcl)
ΔHθrxn (+)
ΔSθrxn (ndash)
iajhxisoaO ΔGθrxn lt 0
iajhxisoaO fkdjk ΔGθrxn gt 0
iu=s ΔGθrxn = 0
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill
54
mrsYsk kaAtkins P and Paula J (2000) Atkinsrsquo Physical Chemistry Oxford New York Oxford
University Press
Chang R (2010) Chemistry 10th Edition New York McGraw Hill