CE1102 Lab Booklet 2014-15 3.10.14

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CO.#E.#!

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17 AI+! & O):EC#I;E! 6

27 I.#,O-/C#IO.2.1 Personnel2.2 Requirements2.3 Assessment& penalties2.4 Assessment penalties and lateness

2.4 5 Laboratory reportsReporting results2.5 6 Submission o laboratory reports2.6 ! Preparation beore t"e laboratory sessions

6546565!6

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87 !AE#Y CO!44 & +!-! (in addition to t"e session on saety? int"is laboratorybased part o t"e module. our mar's %ill be ad=usted a))ordingly i you do not attend bot"sessions unless substantiated e7tenuating )ir)umstan)es "a8e o))urred and a medi)al note or ot"er similardo)umentation is pro8ided to e7plain your absen)e. All students must register beore t"e start o ea)"laboratory session. + you do not register in any session you %ill be )onsidered absent.

ou %ill be?or"ing indi@idually throughout the course7

2. I.#,O-/C#O,Y #ALou are reFuired to attendt"e introdu)tory tal' gi8en in -res"ers perimentsduring t"e laboratory sessions. + youunderta'e e%er e7periments t"en your mar's %ill be ad=usted a))ordingly. "e e7periments %ill beassigned to you and s"ould be carried out in the order specified.

4. ,E$O,#! !/)+I!!IO. & CO!44 a)" student is required to %rite a report >in)luding S(S seesection 8 on !afety? or ea)" e7periment. /ot" reports are to be sumitted together in ?ee" Bsee se)tion2.3.3.belo%.

278 A!!E!!+E.#

"e +ntrodu)tion to Laboratory S'ills pra)ti)al )ourse )ontributes 80Gto module CE1102 a 1@ $redit odule?."e 3@ o t"e module relating to t"e pra)ti)al )ourse )omprises t"e ollo%ing:

10G Electronic #ests

20G La ,eports

Electronic #ests-or ea)" e7periment t"ere is an ele)troni) test %"i)" may be a))essed 8ia /la)'/oard. ou )an ta'e t"e test asmany times as you li'e but t"e pass mar" is 100G. +t is important t"at you ta'e and pass t"e tests be)auseunless you do t"is you %ill not be able to submit your reports ele)troni)ally. 0n)e you "a8e passed bot" o t"etests t"at you need to pass t"is %ill )ause a lin' to appear in /la)'board %"i)" %ill enable you to submit yourreports ele)troni)ally.

La ,eportsa)" report %ill be %ort" 1@. Please use t"e appropriate Lab Report Proorma >a))essible 8ia /la)'/oard? to

%rite ea)" o your lab reports. a)" report must be submitted in /0B ele)troni) and "ard )opy >i.e. printed out?ormats. le)troni) 8ersions o your reports s"ould be uploaded 8ia t"e lin' in /la)'/oard >t"is %ill only appearon)e you "a8e passed t"e appropriate ele)troni) tests C see abo8e?. Bard )opies o your reports s"ould besubmitted to t"e S)"ool 0i)e please )an you append t"e rele8ant S(S s"eets to ea)" report t"at you submitand ensure t"at t"e signed S(S s"eet is uppermost. a)" report %ill be mar'ed out o 1@ and 1 mar' %ill begi8en or "anding in t"e signed S(S s"eets.

Module Leader : Dr A. J. Sutherland 5 Revised: September 2014 - Drs !remova " Sutherland

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27=< $,E$A,A#IO. )EO,E LA) !E!!IO.!

ou are required to prepare t"oroug"ly or ea)" laboratory session in order to ma7imise your learning and mostimportantly to )arry out t"e e7periment saely. ou are required to do t"e ollo%ing or ea)" e7periment inad8an)e

-or ea)" e7periment obtain t"e ne)essary +!-!orms >see belo% or an e7amplar? or ea)"

)"emi)al efore conducting the e>periment in the la as you sign in to register or t"e )lass t"ese orms%ill be)"e)'ed. "is inormation %ill be)ome part o t"e report or ea)" e7periment >1@ )ontribution o t"ereport mar'?.

$omplete t"e ele)troni) test C alt"oug" not obligatory you are strongly ad8ised to )omplete t"eele)troni) test t"at relate to t"e e7periment t"at you "a8e been allo)ated. "ese tests %ill "elp put t"ee7periment into )onte7t and it is li'ely t"at you %ill perormperormbetter in t"e laboratory as a result o)ompleting t"e test prior to underta'ing t"e e7periment.

Read t"e introdu)tion se)tion o t"is pra)ti)al "andout beore )oming to t"e lab. Read t"e rele8ant e7perimental pro)edure in se)tion 5 o t"is manual in order to understand t"e

purpose or )arrying out t"e e7periment and to be)ome amiliar %it" t"e e7perimental te)"niques required.

87 !AE#Y

"e 4ealth and !afety at 'or" Act applies to /ni@ersities. A main tenet o t"is A)t is t"at ea)" indi8idual "asat all times a duty o )are or t"e Bealt" and Saety o "im or "ersel and o all ot"er people %"o may be ae)tedby "is or "er a)tions.

"e Chemical Agents -irecti@e CA-3is a legal rame%or' or %or'ing saely %it" )"emi)al agents. +t requires%or'ers to be prote)ted rom t"e "ealt" and saety ris's arising rom )"emi)al agents present in t"e %or'pla)eand rom %or' a)ti8ities in8ol8ing )"emi)al agents.

CA-"as t%o main strands CO!44and -!EA,: Control of !ustances 4aHardous to 4ealth CO!44? %"i)" deals %it" "ealt" ris's and

-angerous !ustances and E>plosi@e Atmosphere ,egs7 -!EA,? %"i)" )o8er saety ris's o

)"emi)al agents )lassiied as e7plosi8e o7idising e7tremely lammable "ig"ly lammable or lammable.

+!-! +aterial!aety-ata!"eets3(uring your degree )ourse and as part o your proessional training you %ill learn "o% to )omplete t"e ne)essarypaper%or' and do)uments required by $A(. As a irst step t"is year you %ill be required to )onsult t"e +!-!+aterial!aety-ata!"eet3 inormation pro8ided >8ia /la)'/oard? or %"i)" you )an a))ess 8ia t"e internet >e.g.by perorming a oogle sear)" on Da)eti) a)id S(SE t"e SigmaAldri)" site "ttp:FF%%%.sigmaaldri)".)omF? is

8ery good or obtaining S(Ss. ou )an print t"ese S(Ss out in e7a)tly t"e ormat in %"i)" t"ey are pro8idedto you and bring t"em to t"e laboratory %it" you. ou do not need to )omplete a ull $0SBB assessment orredrat t"e S(S orm into an alternati8e ormat but please do:

%& 'ead ea#h sheet pay espe#ial attention to the (ey ha)ards&*& nsure that you have an MSDS !or ea#h #ompound that you are going to handle+& Print them out in good time and bring them to the lab - you will not be allowed to do the e,periment

unless you have a #omplete set o! MSDSs !or ALL o! the #ompounds that you are going to handle&

+t is important t"at you are a%are o t"e "a9ards and properties o all )"emi)als you are %or'ing %it" >in)ludingrea)tion produ)ts? or )ome into )onta)t %it". ou %ill not be allo%ed to start any e7periment until all $"emi)al

Saety (ata Summary -orms relating to it "a8e been )ompleted and signed o by t"e person in )"arge o t"elaboratory. +n t"e )ase o an in)ident or a))ident t"ese orms )ontain 8ital inormation relating to t"e treatment ospillages and irstaid.

Module Leader : Dr A. J. Sutherland 7 Revised: September 2014 - Drs !remova " Sutherland

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)EO,E CO+I.9 #O #4E LA) C4ECLI!#

ou are required to obtain a +!-!or ea)" o t"e )"emi)als to be used and produ)t produ)ed >i

'no%n? in ea)" e7periment >S(S inormation )an be a))essed 8ia t"e internet? and must )omplete a

Chemical !afety -ata !ummary orm. #4I! O,+ +/!# )E ),O/94# #O #4E LA) O,!I9.I.9 )EO,E YO/ +AY !#A,# #4E E5$E,I+E.#7

ou are required to read and be)ome amiliar %it" t"e )ontents o t"e CEAC!afety )oo" issued

at t"e start o t"e )ourse.

ou are also required to %ear a laoratory coat and a pair o safety glassesA# ALL #I+E!%"ilein t"e laboratory and must not eat or drin' in t"e lab. Please bring your o%n lab )oats and saety glasses iyou "a8e t"em >%e )an pro8ide spares s"ould you orget?. (isposable glo8es are pro8ided.

.)7 S(S >aterial Saety (ata S"eets? inormation in)luding all ,& !p"rases >deining "a9ards? or ea)")"emi)al )an be obtained rom one o a number o sites. Bo%e8er most o t"e S(S data or t"is laboratory)ourse )an be obtained rom /la)'/oard.

-urt"er %ebsite addresses in)lude:

http**ptcl7chem7o>7ac7u"*+!-!???7chemfinder7com???7fisher7co7u"http**???7uio?a7edu*chemsafe*+!-!*

???7polymer%systems7comhttp**???7ilo7org*pulic*english*protection*safe?or"*cis*products*icsc*dtasht*inde>7htm

???7sigma%aldrich7com

-or t"e SigmaAldri)" %ebsite:17 Sear)" using )"emi)al name produ)t or $AS number 27 $li)' on GS(SH in produ)t inormation )olumn.

,E+E+)E,J

!tudying oth the e>perimental procedure and the ac"ground material

I. A-;A.CE of coming to the la?ill ensure that you ha@e a much etter chance of conducting the e>periment

safely understanding and completing the e>periment successfully in theallocated time and preparing a satisfactory ?ritten report7

Module Leader : Dr A. J. Sutherland 8 Revised: September 2014 - Drs !remova " Sutherland

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MPLA' MSDS .O' A$"/$ A$/D>do%nloaded rom SigmaAldri)" [email protected]?

Module Leader : Dr A. J. Sutherland 9 Revised: September 2014 - Drs !remova " Sutherland

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MPLA' MSDS .O' A$"/$ A$/D#ontinued

Module Leader : Dr A. J. Sutherland 10 Revised: September 2014 - Drs !remova " Sutherland

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7 A--I#IO.AL .O#E!

71 Cleaning glass?are

lass%are s"ould be 'ept )lean at all times and you are RI+R( to )lean all glass%are issued to you at t"eend o ea)" e7periment beore lea8ing t"e laboratory.

0t"er students may "a8e used some o t"e glass%are t"at you are supplied %it" t"us you s"ould 8isually )"e)'all glass%are beore use >t"is is really good lab pra)ti)e? and i it is dirty you must )lean it.

A)etone may be used to aid )leaning.

72 +ar"ing glass?are

+n a large laboratory )lass it is essential t"at your glass%are be mar'ed in order t"at you may identiy it rom t"ato ot"er students. +n analyti)al )"emistry e7periments may be )arried out in dupli)ate or tripli)ate so it isessential t"at you distinguis" one sample rom anot"er. Paper labels are pro8ided in t"e lab or please eel ree tobring your o%n mar'er pen or t"is purpose.

78 -emonstration eFuipment and apparatus

ou %ill li'ely be amiliar %it" some pro)edures and te)"niques e.g. t"e use o a )"emi)al balan)e. + you areunsure o "o% to do anyt"ing or use any pie)e o equipment >no matter "o% tri8ial you t"in' it is eg using a)"emi)al balan)e C no one %ill t"in' any t"e %orse o you or not 'no%ingJ? please =ust as' one o t"edemonstrators %"o %ill be "appy to "elp.

Remember t"e golden rule in any lab is KIf you are unsure please as"J

7 Calculation of results

any o t"e e7periments in8ol8ing te)"niques su)" as titrimetri) or gra8imetri) analysis S / $ARR+(0 +, R+PL+$A 0R (PL+$A. Results must be %or'ed out separately. 0nly in )ases %"ere t"e resultsare 8ery )lose may t"e a8erage be ta'en and %or'ed out. + you add toget"er t"e indi8idual results it is t"e sameas )arrying out a single biggers)ale e7periment o un'no%n reliability. ou may i you %is" )arry out an e7tradetermination i.e. regard t"e irst titration as a Gtrial titrationH in order to assess t"e nature o t"e end point and toobtain an appro7imate titre.

76 Accuracy in Fuoted results

+t is important to 'no% t"e le8el o a))ura)y asso)iated %it" an e7perimental result. An unsuspe)ted error o 2in t"e %or' o a proessional s)ientist )ould "a8e ma=or "ealt" or inan)ial reper)ussions.

"e a))ura)y o determination is impli)it in t"e number o signii)ant igures quoted. + you )arry out a preparationand )laim a yield o 32 t"en you are implying a 8alue bet%een 31.5 and 32.5. >,/

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7= +eaning of certain Instructions

Bere a simple system is used to distinguis" bet%een t"ose 8olumes or %eig"ts to be measured a))urately andt"ose %"i)" need to be only appro7imate. "us %"en t"e instru)tion s"eet states D?eigh out accuratelyet?een 0716 and 0720 g of a sample E t"e a))urate balan)es must be used and t"e %eig"t re)orded to ourde)imals e.g. @.16#4 g.

"e instru)tion Dadd 6 g .4ClE means t"at appro7imately t"is %eig"t is required and a D less accurate balanceEmay be used.

periment again chec"ing oncemore that you ha@e in your hand ?hat you thin" you ha@e ust efore adding it to a reaction is another

e>ample of good la practice7

7( -esiccators

(esi))ators are a8ailable %it" or %it"out 8a)uum taps or )ertain preparations.

(esi))ators %ill only ser8e to remo8e a 8olatile liquid i t"ere is t"e appropriate desi))ant %it"in t"e desi))ator. A

)ommon desi))ant is )al)ium )"loride and is generally used to 'eep you sample dry or remo8e residual %ater8apor or moisture rom your sample.

7B Care of alances

a3 Al%ays )lose t"e side doors o t"e balan)e %"en not in use.

3 ,e8er %eig" out 8olatile or )orrosi8e substan)es into an open 8essel on t"e balan)e.

c3 (o not %eig" liquids i possible )on8ert t"e mass to 8olume: mass M @olume > density7

d3 ,e8er %eig" "ot substan)es.

e3 (o not o8erload t"e balan)e.

f3 (o no lea8e anyt"ing on t"e pan ater use.

g3 AL'AY! CLEA. /$ A.Y !$ILL! I++E-IA#ELY.

h3 + t"e balan)e requires ad=ustment please as' a member o sta.

Module Leader : Dr A. J. Sutherland 12 Revised: September 2014 - Drs !remova " Sutherland

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67 E5$E,I+E.#AL $,OCE-/,E!

E>periment 1

-E#E,+I.A#IO. O #4E $E,CE.#A9E O 'A#E, O C,Y!#ALLI!A#IO. I.CO$$E, II3 !/LA#E $E.#A4Y-,A#E7

CO!44 ou must pro@ideaprint out o t"e +!-!data s"eets o ALLt"e )"emi)als used in t"is e7perimenteforeyou start any laboratory %or' C t"is is a legal requirement. -ailure to pro8ide t"em at registration %ill meant"at you %ill not be allo%ed to )ommen)e t"e e7periment. Losing your signed orms )ould )ost you up to 1@ ot"e pra)ti)alHs mar's.

Oecti@e

"is introdu)tory e7er)ise is intended to s"o% you "o% to use a balan)e a))urately and to "ig"lig"t some o t"e)ommon sour)es o errors en)ountered during manual manipulations and %eig"ing. ou are as'ed to determine 8ia %eig"t loss t"e per)entage o %ater o )rystallisation in copper II3 sulfate pentahydrate Cu!O7642O3by"eating t"e solid.

$rocedure

+ t"e %eig"t )"ange o a sample is to be measured a))urately t"e %eig"t o its )ontainer must not )"ange

signii)antly during t"e e7periment. %"ose tips "a8e been %armed in t"e lame? transer t"e "ot )ru)ible and lid to a desi))ator and allo% it to

)ool in a dry atmosp"ere. o a8oid )ontamination ma'e a support or t"e )ru)ible rom anot"er triangle.

Ater )ooling say about 1@ to 15 minutes t"e )ru)ible and lid s"ould be ta'en to a balan)e in t"e desi))atortranserred to t"e balan)e using tongs and t"en re%eig"ed and t"e %eig"t re)orded.

,o% add t%o mediumsi9ed spatulas ull o )opper >++? sulate penta"ydrate >about 2g? to t"e )ru)ible and re%eig" t"e )ru)ible and lid. $al)ulate t"e %eig"t o t"e sample added and note it do%n.

Repeat t"e "eating and %eig"ing pro)ess %it" t"e sample se8eral times using t"e same balan)e i possible untilt"e sample "as been "eated to a constant ?eight >i.e. t"e dieren)e is only in t"e ourt" de)imal pla)e?. "eloss o %ater rom t"e sample is a))ompanied by a )olour )"ange rom lue to ?hite.

(o not "eat too strongly ater t"e sample "as turned %"ite or de)omposition %ill o))ur and t"e sample %ill start todar'en.

Module Leader : Dr A. J. Sutherland 13 Revised: September 2014 - Drs !remova " Sutherland

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-or )opper >++? sulate penta"ydrate t"e loss o %ater o )rystallisation o))urs at about 15@ o$.

,eporting results

Report t"e results by illing in able 1 >t"is %ill be pro8ided in a Lab Report Proorma on /la)'/oard? andans%ering t"e questionsF)ompleting t"e tas's belo%.

#ale 1

+tem +ass * gass o empty )ru)ible and lid M

ass o empty )ru)ible and lid ater "eating M

ass o )ru)ible lid plus sample M

ass o sample ta'en M

ass o )ru)ible lid plus sample:

Ater 1stBeating M

Ater 2ndBeating M

;;;;;;....

Ater nt"Beating M

;;;;;;;

;;;;;;;

;;;;;;....

;;;;;;...

ass o residue M

Loss o mass M

IuestionsFas's:1? $uS0 4.5B20? and or

t"e t"ermal de)omposition o $uS04to $u0 in air.2? sing your data in able 1 )al)ulate t"e per)entage loss in mass due to t"e remo8al o t"e %ater o

)rystallisation. 7press your result as a per)entage 8alue.3? "eoreti)ally %"at per)entage o B20 does $uS04.5B20 )ontain and t"ereore "o% ei)ient "as your

e7periment been in remo8ing t"e %ater o )rystallisation rom your sampleN4? + your e7perimental per)entage diers rom t"e t"eoreti)al one oer an e7planation.5? (id you ma'e any ot"er signii)ant obser8ationsN + you did report t"em.6? $an you t"in' o a qui)' test to s"o% t"at t"e substan)e remo8ed rom your sample is in a)t %ater.!? Bo% %ould you ma'e )opper sulate rom i? )opper and ii? )opper o7ide and %rite do%n t"e )"emi)al

equations or t"e rea)tions t"at you mention

#?

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E>periment 2 $art 1

#4E !#A.-A,-I!A#IO. O A. A$$,O5I+A#ELY 071+ !OL/#IO. O!O-I/+ 4Y-,O5I-E

CO!44 ou must pro@ideaprint out o t"e +!-!data s"eets o ALLt"e )"emi)als used in t"is e7periment)O#4 parts 1 and 23eforeyou start any laboratory %or' C t"is is a legal requirement. -ailure to pro8ide t"emat registration %ill mean t"at you %ill not be allo%ed to )ommen)e t"e e7periment. Losing your signed orms )ould)ost you up to 1@ o t"e pra)ti)alHs mar's.

Oecti@e

+n order to obtain a))urate analyti)al data it is al%ays ne)essary to "a8e standards against %"i)" your data )anbe measured. +n t"is simple e7periment t"e standardisation o a solution used or titration is )arried out.

$rocedure

ou are pro8ided %it" a solution o sodium "ydro7ide >a? %"i)" is appro7imately @.1 . Standardise it using

sulami) a)id >also 'no%n as aminosuloni) a)id? %"i)" is a primary standard.>b? "e o8erall rea)tion is:

.42!O84 N .aO4 .42!O8.a N 42O

a? se t"is sodium "ydro7ide solution or Part 2.

>b? @.242!4 g o sulami) a)id neutralises 25.@ )m3o @.1 sodium "ydro7ide solution.>)? .

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E>periment 2 $art 2

-E#E,+I.A#IO. O #4E ,ELA#I;E +OLEC/LA, +A!! O CO+$O/.- A3

CO!44 see ao@e for part 1

Oecti@e

o ma'e use o t"e simple titrimetri) te)"nique o ac"%titrationto determine t"e mole)ular %eig"t o an un'no%n)ompound and to determine its melting point.

$rocedure

.ote"e mole)ular %eig"ts"ould "a8e t"ree signii)ant igures.?Repeat t"is %"ole pro)edure at least t%i)e more until you are )onident t"at you "a8e )arried out at least t%oa))urate titrations.sing t"e data rom your a))urate titrations determine t"e a8erage mole)ular %eig"t.

-inally determine t"e melting point o )ompound A.

,eporting resultsReport t"e results o t"is part o e7periment 2 by illing in able 2 and ans%ering t"e questionsF)ompleting t"etas's belo%.

#ale 2

ass o)ompound AF

g

Kolume osulami) a)idsolution F ml

oles o,a0B

solution

oles o)ompound A

ole)ular%eig"t o A F

gF mol1

A8eragemole)ular

%eig"t o AFgF mol1

Sample 1

Sample 2

1?

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E>periment 8

$/,IICA#IO. )Y ,EC,Y!#ALLI!A#IO.

CO!44 ou must pro@ideaprint out o t"e +!-!data s"eets o ALLt"e )"emi)als used in t"is e7periment

eforeyou start any laboratory %or' C t"is is a legal requirement. -ailure to pro8ide t"em at registration %ill meant"at you %ill not be allo%ed to )ommen)e t"e e7periment. Losing your signed orms )ould )ost you up to 1@ ot"e pra)ti)alHs mar's.

Oecti@e"is is an introdu)tory e7er)ise to t"e te)"nique o re)rystallisation. A pure sample o ben9oi) a)id is to beobtained rom an impure mi7ture by re)rystallisation rom "ot %ater. "e purity o t"e sample is t"en determinedby inrared spe)tros)opy and its melting point.

$rocedureboiling? %ater "eat appro7imately 5@ )m 3 o %ater in a 1@@ ml bea'er and add t"e mi7ture %it"

stirring. + t"e mi7ture does not dissol8e )areully add appro7imately 1@ )m 3o %ater and bring ba)' to t"e boil.Repeat t"is pro)ess until t"e solid "as =ust )ompletely dissol8ed. Allo% t"e solution to )ool slo%ly and only %"en itis )ool enoug" to "old )omortably in t"e "and )ool it in an i)e bat". -ilter o t"e desired produ)t using a /u)"nerunnel and las' and %as" t"e )olle)ted produ)t %it" )old %ater. (ry t"e produ)t by dra%ing air t"roug" t"e solidmaterial on t"e ilter paper or a e% minutes. ,ecord the mass of product t"at you "a8e obtained. ,ecord aninfrared spectrumo t"e produ)t >as' a demonstrator "o% to do t"is? and or your report )ompare it %it" t"einrared spe)tra o t"e impure and pure sample o ben9oi) a)id C t"ese are pro8ided please as'.

-etermine the melting pointo t"e puriied sample.-inally pla)e t"e puriied ben9oi) a)id in a labelled sample 8ial. "e label s"ould s"o% your name date )"emi)alstru)ture and t"e %eig"t o t"e ben9oi) a)id. 4and your sample in7

Analysis"e original )ontaminant is a t"io)yanate salt its remo8al s"ould s"o% up in t"e inrared spe)tra as t"edisappearan)e o a single s"arp medium band at a requen)y some%"ere bet%een 1#@@ )m 1and 25@@ )m1re)ord its requen)y. Also try to assign ot"er bands in t"e spe)trum using eit"er t"e )orrelation )"art pro8ided ont"e ba)' o t"e s)ript or one o your o%n. "ere is an independent )olorimetri) test or t"e anioni) impurity )anyou ind out %"at it isN

,eporting resultsReport t"e results by illing in t"e able belo% and ans%ering t"e questionsF)ompleting t"e tas's belo%

ass o sample F g ass o re)rystalli9ed

ben9oi) a)id F g

ield F elting point o t"e

puriied sampleF O$

1? Analyse t"e inrared spe)trum o your puriied sample by assigning t"e 8ibration bands present in t"e spe)trum..g. or )arbo7yli) a)ids $M0 stret)"ing o))urs around 1!6@ C 16*@ )m 1 t"e band is strong so %e %rite >s? at t"eend i.e. 1!6@ C 16*@ )m1 >s?. $ompare your spe)trum %it" t"e ot"er spe)tra pro8ided. Atta)" your inraredspe)trum as an appendi7 >s)an in or ele)troni) submission?

2?

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E>periment

#4E !$EC#,O$4O#+E#,IC -E#E,+I.A#IO. O C4,O+I/+

CO!44 ou must pro@ideaprint out o t"e +!-!data s"eets o ALLt"e )"emi)als used in t"is e7perimenteforeyou start any laboratory %or' C t"is is a legal requirement. -ailure to pro8ide t"em at registration %ill mean

t"at you %ill not be allo%ed to )ommen)e t"e e7periment. Losing your signed orms )ould )ost you up to 1@ ot"e pra)ti)alHs mar's.

Oecti@e

o introdu)e t"e analyti)al te)"nique o KF8isible spe)tros)opy and to apply t"is te)"nique to determine t"e)on)entration o )"romium in aqueous solution. For COSHH purposes, please assume the solutions are of

potassium chromate i.e. K2CrO4.

)ac"ground

any solutes absorb radiation in t"e ultra8iolet or 8isible region o t"e ele)tromagneti) spe)trum %"ere in dilutesolution equation 2 is usually obeyed. "e absorban)e >A? o a solution is deined in terms o t"e intensity o t"etransmitted radiation >I? and t"e in)ident radiation >Io? a))ording to:

A M log1@>IoFI? >quation 1?

-or a solution in a )ell o pat" lengt" l)m Ais usually related to t"e )on)entration >c? by t"e /eer Lambert La%:

A M ) l >quation 2?

A8s. )on)entration c? to be )onstru)ted. ou %ill t"en measure Aor a solution o an un'no%n )on)entration and use your )alibration grap" to )on8ert t"e absorban)e reading youobtain into a )on)entration t"us determining t"e )on)entration o t"e un'no%n solution.

%o )"romium solutions are pro8ided one is a sto)' solution o 5@ parts per million >ppm? o )"romium >presentas )"romate? %"i)" "as to be diluted to generate a range o )"romium solutions o 'no%n )on)entration. "e

ot"er solution is o un'no%n )"romium )on)entration %"i)" also "as to be diluted.

$rocedure

>i? 0btain se8en 2@ )m3 or25 )m3graduated 8olumetri) las's.

>ii? sing t"e 5@ppm )on)entration )"romium sto)' solution prepare a series o )alibration standards in t"egraduated las's using appropriately si9ed pipettes.

our )alibration standards s"ould be made up in @.4 sodium "ydro7ide solution i.e. add t"e appropriate8olume o 4 sto)' solution to ea)" o t"e graduated las's >see belo%?. our )alibration standards s"ould"a8e )"romium )on)entrations o * ! 5 3 1 and @ ppm t"e remainder o t"e solution being deionised

%ater the 0ppm is a reference. se t"e equation on t"e ne7t page to )al)ulate t"e 8olumes o @.4 sodium"ydro7ide solution and 5@ppm sto)' solution t"at are required or ea)" las'.

Module Leader : Dr A. J. Sutherland 18 Revised: September 2014 - Drs !remova " Sutherland

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>ii i? -inally prepare a las' )ontaining t"e un"no?n)"romium solution by diluting the solution pro@ided ya factor of O/,. Li'e t"e )alibration standards it s"ould be made up in @.4 sodium "ydro7ide solution.

.ote o )al)ulate t"e quantity required or ea)" dilution use t"e ollo%ing.

possessedsolutionofionconcentrat

requiredsampleofionconcentrat

7 final volume of solution requiredM )m3

)m3 is t"e 8olume o t"e original solution t"at is a))urately ta'en and t"en diluted to t"e inal 8olume required.

-or e7ample to dilute a 4 sto)' solution o sodium "ydro7ide to @.4

> @.4 F 4 ? 7 2@ M 2ml ; or ; > @.4 F 4 ? 7 25 M 2.5ml

"ereore i you are using a 2@ml las' you need to ta'e 2ml o t"e 4 sodium "ydro7ide solution and iyou are using a 25ml las' you need to ta'e 2.5ml. All your las's s"ould )ontain t"e appropriate amount o

sodium "ydro7ide and )"romiumF)"romate solution made up to t"e 8olumetri) mar' %it" deionised %ater.

Estimation y Eye

/y simple 8isual inspe)tion o t"e solutions you may be able to estimate t"e )on)entration o t"e un'no%n.Re)ord your estimation in your lab report.

!pectrophotometric -etermination

a'e t"e solutions a Pasteur pipette a paper to%el and an empty bea'er >or %aste? o8er to t"eKF8is spe)trop"otometer. sing a 1)m quart9 spe)trop"otometer )ell measure t"e absorban)e o t"e solutions

at 8A? o t"ese solutions.

able 1

$"romium solution)on)entrationF

ppm

Kolume o t"e las'F ml

Kolume o 5@ ppm)"romium solution >orun'no%n ? F )m3ml

Kolume o ,a0Bsolution F ml

Absorption >A?

@

1

3

5

!

*

23 Plot an absorban)e 8ersus )on)entration >in ppm? grap" using t"e data obtained >,ote: ou )an do it

eit"er manually >S)an it in or ele)troni) submission? or ele)troni)ally e.g. by using 7)el?.

Module Leader : Dr A. J. Sutherland 19 Revised: September 2014 - Drs !remova " Sutherland

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83 -rom t"e )ur8e determine t"e )on)entration o t"e un'no%n stoc")"romium solution.3

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=7 I.,A,E- I,3 A)!O,$#IO. )A.-! O, /.C#IO.AL 9,O/$!

Infrared I,3 asorption ands for simple functional groups

unctional 9roup +olecular +otion 'a@enumer cm%13

al'anes

$B stret)" 2*5@2#@@

$B2bend 1465

$B3bend 13!5

$B2bend >4 or more? !2@

al'enes

M$B stret)" 31@@3@1@

$M$ stret)" >isolated? 16*@163@

$M$ stret)" >)on=ugated? 164@161@

$B inplane bend 143@12*@

$B bend >monosubstituted? **@ & *1@

$B bend >disubstituted ? *!@

$B bend >disubstituted 11? #*@

$B bend >disubstituted T? !@@

aromati)s

$B stret)" 3@2@3@@@

$M$ stret)" 16@@ & 14!5

$B bend >mono? !!@!3@ & !156#5

$B bend >ort"o? !!@!35

$B bend >meta? ##@ & !#@ & 6*@

$B bend >para? #5@#@@

al)o"ols0B stret)" 365@ or 34@@33@@

$0 stret)" 126@1@@@

et"ers$0$ stret)" >dial'yl? 13@@1@@@

$0$ stret)" >diaryl? 125@ & 112@

alde"ydes$B alde"yde stret)" 2#5@ & 2!5@

$M0 stret)" 1!25

'etones$M0 stret)" 1!15

$$ stret)" 13@@11@@

)arbo7yli) a)ids

0B stret)" 34@@24@@

$M0 stret)" 1!3@1!@@

$0 stret)" 132@121@

0B bend 144@14@@