Tyler Thomas November 9,2012 Period 3 lonicvs. Covalent Bonding Lablnvestigation Introduction: Mostatoms need to form chemical bonds to become stable and in doing so,theytend to create an octet.In otherwordsrthey start to forma fu!.lglell of valglle eleglgns. There are two maintypes of chemical bonding, whichrrl,ol'. ,!d corg.!:l!._ lonicbonding normally consists of both arnetaland nonmetal element. In the process.metals lose valence electrons q}-_ I \ \ I (.-\l dueto their low electronegativity enlfgy, or ability to attract electronsrand then become €l\- -r negatively charged cations; whereai nonmetals typically gainelectrons because they contain a high electronegativity and become{a positively charged anion. lonic compounds transfer electrons and laterbecome crystals, whichleads them to onlyconducting electricity when dissociating in water. In contrast, covalent bonds areformedfrom two nonmetal elements. In <-*-.**-* covalent bonds, electrons are shared between bonds. Covalent bonds tend to result in a -*''z'' f'C) molecule structure andneye!:*conduct eleciriiny due to thei|oW}nd++r€3-]nt and t electronegativity. The purpose of this experiment wasto conclude whethereach of the different compound were either ionic or covalent bonds. rr-.. ( ,.. r: l- -.\ \__\_/ * t t.". pus-h
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Tyler Thomas
November 9,2012
Period 3
lonic vs. Covalent Bonding Lab lnvestigation
Introduction:
Most atoms need to form chemical bonds to become stable and in doing so, they tend
to create an octet. In other wordsrthey start to form a fu!.lglell of valglle eleglgns. There are
two main types of chemical bonding, which rr l ,ol ' . , !d corg.!: l ! ._ lonic bonding normally
consists of both arnetal and nonmetal element. In the process.metals lose valence electronsq}-_
I
\
\I
(.-\ ldue to their low electronegativity enlfgy, or abil i ty to attract electronsrand then become
€l\ - - rnegatively charged cations; whereai nonmetals typical ly gain electrons because they contain a
high electronegat iv i ty and become{a posi t ively charged anion. lonic compounds transfer
electrons and later become crystals, which leads them to only conduct ing electr ic i ty when
dissociating in water. In contrast, covalent bonds are formed from two nonmetal elements. In<-*-.**-*
covalent bonds, electrons are shared between bonds. Covalent bonds tend to resul t in a
-* ' 'z ' ' f 'C)
molecule structure and neye!:*conduct eleciriiny due to thei|oW}nd++r€3-]nt and t
electronegativity. The purpose of this experiment was to conclude whether each of the
di f ferent compound were ei ther ionic or covalent bonds.
rr-.. (,..
r: l- -.\\__\_/
*
t t ." .pus-h
Tyler Thomas
November 9,2012
Period 3
Hypotheses:
Table 1: The expected Results of different substances
Procedures:
PART f . Melting Point ond Strength of Bonds
1. Fold aluminum foi l into a square to f i t on the r ing- stand. Place a smal l sample of each of
the four di f ferent compounds on your square of a luminum foi l at the same t ime. Be careful not
to mix them up.
2. Careful ly place the tray on the r ing stand and heat wi th the Bunsen Burner, no longer than
1-2 minutes.
3. lmmediately begin recording your detai led observat ions, keeping track of the order in
which the samples melt . Some samples may not melt , a lso decide which sample have strong
and weak bonds.
4. Al low the square of foi l to cool then wash it .
Part 2. Electr ical ConductivitY
1. Weigh an approximately 0.1- gram sample of each compound in di f ferent sect ions of a wel l
p late (make sure to zero the wel l p late on the balance)
2. Test the dry compound for conductivity with the tester. Record your observations.
3. Add enough drops of d ist i l led water to the wel l to dissolve the compound as best as you
can.
Compounds tobe Tested
ChemicalFormula
Hypothesis 1:lonic or Covalent
Hypothesis 2: Highor Low Melt ingPoint?
Hypothesis 3: Wi l l i tconduct electr icity?
Dist i l led Water Hzo Covalent Low No
SodiumChlor ide
NaCl lonic High Yes
Sucrose C12H 12O11 Covalent Low No
Dextrose CoHrzOo Covalent Low No
Sodium Sulfate NaSOa lonic High Yes
Tyler Thomas
November 9,2012
Period 3
4. Test the solution for conductivity with the tester. Record your observations, and be sure towash the conductivity tester with dist i l led water after every use.
5. Repeat for a l l samples unt i l f in ished.
Results:
Conclusion/Analysis:
After this laboratory, i t was concluded that sodium chloride and sodium sulfate wergjoni.c
compounds, whi le dist i l led water, sucrose, and dextrose were covalent compounds. Al l of the*t.-*- ,*'
in i t ia l hypotheses were correct . From the resul ts, the ionic compounds were those that
conducted electr ic i ty in water and had high melt ing points. However, the covalent compounds
had low melt ing points and did not conduct electr ic i ty. lonic bonds are formed from cat ions (+)*-g"
" ; ; ; ; " they dissolve in water,electr ic i ty is able to f low through the solut ion.
t \
\ and anions (-) fp when they dissol ' . ,
Addit ionally, ionic bonds are very strong because the electrostqtic attractio,n that holds the/--1^ ^.-n[- r:{Lo.]t- I 'n' .o \\r-, .^g, \r?ai,^f ,i(Lt tl* f..p \.'r i^*r V?o,.
:rnic corinoJnds iontain twd elements, 6oth a
r le \ )
^Act. \ \
cat ion and anion together( is s Typical ly ionic compounds contain two elements, b
Table 2: The Results of Testing Five Different Chemicals
Name/Chemical
Formula:
PART I:
Melt ing Point (1-5;
High, Med. Or Low?)
Part l l : Conduct
electricity? (Yes/No)
FINAL CONCLUSION:
lonic or Covalent
Bonds?Dry Dissolved
Disti l led Water/ H2O L N/A No Covalent
Sodium Chlor ide/
NaCl
5 No Yes lonic
Sucrose (sugar)/
CsHrzOo
2 No No Covalent
Dextrose/ CoHrzOo 3 No No Covalent
,Sodium Sulfate/
IKrtoo4 No Yes lonic
metal and nonmetal which wai$ 'e evidence that led to the conclusion that they are ionic
-'7
Tyler Thomas
November 9,2012
Period 3
compounds. When a metal reacts wi th a nonmetal an ionic crystal is produced because the
electrons were t ransferred from the metal to the nonmetal . When ionic crystals dissolve in
water, the cation and anion break apart which al lows them to (nove freely aqd conduct '{ ' )"r ' ' J - i-,
,>._^, t[r\ i'.
electr icity. lonic bonds are able to conduct electr icity because the cation and anion move free ,S.. i l -1,,^ru --.-.--'-.."^
and carry an electric current. \r q. "r-1 , t ' l", :.--*-*--. rp'l). .:-{J .]
However, sucrose, dextrose, and dist i l led water were al l covalent compounds. Covalent i . l ' ) Q..,.(, t ' '^
bonds do not conduct electr ic i ty and have low melt ing points. Covalent bonds contain two
nonmetals, which always have high electronegativity. Nonmetals strongly attract electrons, so
nei therelement loses electrons. Instead the electrons are shared between the bonds. Instead\--_ -------
of forming crystals l ike ionic bonds, covalent bonds create Tl l lgpups of molecules. The
molecule is held together because the posit ive nucleus is attracted to the negat ive electrons
being shared between them. Covalent bonds cannot conduct electr ic i ty l , 1. \]
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The Introduction coversall needed backgroundknowledge clearly andinsightfully andintroduces the purposeof the lab. Hypothesesare presented clearly.
and
uceso lab
The Introductioncovers most of theneeded backgroundknou4edge unclearlyand introduces thepurpose ofthe lab.Hvnotheces are
presented unclearlv.
The Introductioncovers some of theneeded backgroundknowledge poorlyand introduces thepurpose ofthe lab.Hypotheses arepresented poorly.
9q
xq
3&r.
Procedures Methods used in theexperiment ar6\-.
completelv.
'\explalner m srudiown wo{ds and 19what w{donejli
N4ethods used in theawnprimpnt a.-
explained in sludent'sown words andmostly reflect whatwas done in lab.
Methods used in thecvncr imcnt arp
explained in student'sown words andsomewhat reflectwhat was done in lab.
Methods used in theewnarimart a"o
explained in student'sown words andsomewhat reflectwhat was done in labwith other errors-
Results All observations madeauring-tfJiipen\are npatly entered'are npat.ly enterectable\ The table hHead\S that desywhat itp ,9Jz6.
loa
60-80" observationsmade drrr ino fhe
experiment are neatlyentered into a table.The tabie has aheading that describeswhat it contains.
40-60Yo observationsmorlo ,1". i - - t l ' -
evner imenf r .p na.r l ! ,
entered into a tab1e.The tabie has aheading that describeswhat it contains.
Z0-4Ao observationsmade during theexperiment are neatlyentered into a table.The table has aheading that describeswhat it contains.
q
U
of ResultsUse All of t fesu
rncorporexplained theconclusion
60-80"4 ofthe resultsare incorporated arrdevnlained in the
conclusion paragraoh.
40-609/' of the resultsare incorporated andexplained in theconclusion paragraph.
2A-40o4 ofthe resultsare rncorporated andelnlaincd in the
conclusion paragraph.ConceptualUnderstanding ofTypes of Bonding
Response clearlydemonstrates arrinsightful & excellentunderstalding ofbondilg includingionic vs covalent [.pes.
Resporlgg-.-..--demgffitrates h,gqodun$brstanding of ),L. . , ' , /Dopomg. rncluoFsorhe exnianad6n of. .\_:_/,lonlc vs covalent
bond rypes.
Responsedernonstrates anunclearunderstanding ofbonding and onlybasically explainsionic vs covalentfypes.
Response does notdemonstratg anunderstanding ofbonding & does notmention ionic vscovalent bonding.
Use of Vocabularystabie. octeVfullshell. ionic. covalent.share valence e-.transfer valence e-.eiectricitv, crystal.cation. anion. ion.elecirostaticatfraction, molecu-ie.etc.
Response uses ATLEASTSwocabula"r.r*"fl,
"o*Jgtfy no*
thy'list on thb 1\ft to- L- - i i ^thq hst on thF lFlt tohdlp supporrthdir
"lit^uri/" /f /
Response uses 4vocabulary wordscorrectly from the liston the left to helpcrrnnnrt fhcir
explanation
Response uses only 3vocabulary wordscorectly fiom the liston the left to helpqrrnnnrf their
expianation
Response uses 2 orfewer (or useswords incorrectly)vocabular,v wordscorrectly from the iiston the left to helpsr rnnnrt fheir
explanation
o
Format andGrammar-double spaced witilnumbered pages-third person is used-no grammatical errors-subscripts are usedr.r'hen appropriate-repofi sections utilizeheadings-Tahlec and f isrrre<
contair headings u'ithdescripfions.
The conventions to theleft are foilowed withno mistakes
The conventions tothe left are followedwith l-5 mistakes
The conventions to The conventions tothe left are foliowedwith 11-15 mistakes