AdvancedPlacementProgram

PracticeExam

ThequestionscontainedinthisAP?ChemistryPracticeExamarewrittentothecontentspecificationsofAPExamsforthissubject.TakingthispracticeexamshouldprovidestudentswithanideaoftheirgeneralareasofstrengthsandweaknessesinpreparingfortheactualAPExam.BecausethisAPChemistryPracticeExamhasneverbeenadministeredasanoperationalAPExam,statisticaldataarenotavailableforcalculatingpotentialrawscoresorconversionsintoAPgrades.

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AP?Chemistry

Contents

DirectionsforAdministration ii

SectionI:Multiple-ChoiceQuestions 1

SectionII:Free-ResponseQuestions 21

StudentAnswerSheetforMultiple-ChoiceSection 32

Multiple-ChoiceAnswerKey 33

Free-ResponseScoringGuidelines 34

TheCollegeBoard:ConnectingStudentstoCollegeSuccess

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APCentralistheofficialonlinehomefortheAPProgram:.

-i-

AP?ChemistryDirectionsforAdministration

TheAPChemistryExamis3hoursand5minutesinlengthandconsistsofamultiple-choicesectionandafree-responsesection.

The90-minutemultiple-choicesectioncontains75questionsandaccountsfor50percentofthefinalgrade.

The95-minutefree-responsesectioncontains6questionsandaccountsfor50percentofthefinalgrade.PartAistimedandis55minuteslong;PartBis40minuteslong.

A10-minutebreakshouldbeprovidedafterSectionIiscompleted.

TheactualAPExamisadministeredinonesession.Studentswillhavethemostrealisticexperienceifacompletemorningorafternoonisavailabletoadministerthispracticeexam.Ifascheduledoesnotpermitonetimeperiodfortheentirepracticeexamadministration,itwouldbeacceptabletoadministerSectionIonedayandSectionIIonasubsequentday.

Manystudentswonderwhetherornottoguesstheanswerstothemultiple-choicequestionsaboutwhichtheyarenotcertain.Itisimprobablethatmereguessingwillimproveascore.However,ifastudenthassomeknowledgeofthequestionandisabletoeliminateoneormoreanswerchoicesaswrong,itmaybetothestudent’sadvantagetoanswersuchaquestion.

Theuseofacalculator*ispermittedONLYduringSectionII,PartAoftheexam.AftertimeiscalledforPartA,studentsmustplacetheircalculatorsundertheirchairs.Theuseofanyotherelectronicdevices(includingacellphone)isnotpermittedduringanyportionoftheexam.

ItissuggestedthatSectionIofthepracticeexambecompletedusingapenciltosimulateanactualadministration.StudentscanuseeitherapencilorapenforSectionII.

Teacherswillneedtoprovidepaperforthestudentstowritetheirfree-responseanswers.Teachersshouldprovidedirectionstothestudentsindicatinghowtheywishtheresponsestobelabeledsotheteacherwillbeabletoassociatethestudent’sresponsewiththequestionthestudentintendedtoanswer.

AperiodictableoftheelementsisprovidedwithbothSectionIandSectionIIoftheexam.ForSectionII,atableofstandardreductionpotentialsandtablesofcommonlyusedequationsandconstantsarealsoprovided.

Rememberthatstudentsarenotallowedtoremoveanymaterials,includingscratchwork,fromthetestingsite.

*CalculatorscannothaveQWERTYkeyboardsorbedesignedtocommunicatewithothercalculators(suchasviainfraredports).

-ii-

SectionI

Multiple-ChoiceQuestions

-1-

MATERIALINTHEFOLLOWINGTABLEMAYBEUSEFULINANSWERINGTHEQUESTIONSINTHISSECTIONOFTHEEXAMINATION.

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-2-

CHEMISTRY

SectionI

Time—1hourand30minutes

NOCALCULATORMAYBEUSEDWITHSECTIONI.

Note:Forallquestions,assumethatthetemperatureis298K,thepressureis1.00atmosphere,andsolutionsareaqueousunlessotherwisespecified.

Throughoutthetestthefollowingsymbolshavethedefinitionsspecifiedunlessotherwisenoted.

T=

P=

V=

S=

H=

G=

R=

n=

M=

m=

temperaturepressurevolumeentropyenthalpy

Gibbsfreeenergymolargasconstantnumberofmolesmolar

molal

L,mL=liter(s),milliliter(s)

gnmatm

=gram(s)

=nanometer(s)

=atmosphere(s)

mmHg=millimetersofmercury

J,kJV

mol

=joule(s),kilojoule(s)

=volt(s)

=

mole(s)

PartA

Directions:Eachsetofletteredchoicesbelowreferstothenumberedstatementsimmediatelyfollowingit.Selecttheonethatisbestineachcaseandthenplacetheletterofyourchoiceinthecorrespondingboxonthestudentanswersheet.Achoicemaybeusedonce,morethanonce,ornotatallineachset.

Questions1-4refertothefollowingchemicalcompounds.

Questions5-7refertothefollowingmolecules.

(A)

(B)

(C)

(D)

(E)

COCH4HF

PH3

(A)

(B)

(C)

(D)

(E)

CH4CCl3F

H2SH2O2K2CrO4

F

2

5.Containstwo-bonds

1.

Commonlyusedasadisinfectantforminorskinwounds

6.Hasthehighestdipolemoment

2.

Arefrigerantimplicatedinthethinningofthestratosphericozonelayer

7.Hasamoleculargeometrythatistrigonalpyramidal

3.

Amajorcomponentofthefuelknownasnaturalgas

4.

Ayellowsolidatroomtemperatureand1atm

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-3-

Questions8-11refertoneutralatomsforwhichtheatomicorbitalsarerepresentedbelow

(A)

(B)

(C)

(D)

(E)

8.Isinanexcitedstate

9.Hasexactlyfivevalenceelectrons

10.Hasthehighestfirstionizationenergy

11.Formsanaqueouscationthatiscolored

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-4-

Questions12-15refertothechemicalreactionsrepresentedbelow.

+

(A)HC2H3O2(aq)+NH3(aq)C2H3O2(aq)+NH4(aq)

2

(B)Ba2+(aq)+SO (aq)BaSO(s)

4

4

(C)Zn(OH)2(s)+2OH(aq)[Zn(OH)4]2(aq)

(D)2K(s)+Br2(l)2KBr(s)

(E)N2O4(g)2NO2(g)

12.Anoxidation-reductionreaction

13.Aprecipitationreaction

14.Areactioninwhichacoordinationcomplexisformed

15.ALewisacid-basereactionthatisnotaBr?nsted-Lowryacid-basereaction

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Questions16-17refertovariouspointsintimeduringanexperimentconductedat1.0atm.Heatisaddedataconstantratetoasampleofapuresubstancethatissolidattimet0.Thegraphbelowshowsthetemperatureofthesampleasafunction

oftime.

(A)

(B)

(C)

(D)

(E)

t1t2t3t4t5

16.Timewhentheaveragedistancebetweentheparticlesisgreatest

17.Timewhenthetemperatureofthesubstanceisbetweenitsmeltingpointanditsboilingpoint

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-6-

PartB

Directions:Eachofthequestionsorincompletestatementsbelowisfollowedbyfivesuggestedanswersorcompletions.Selecttheonethatisbestineachcaseandplacetheletterofyourchoiceinthecorrespondingboxonthestudentanswersheet.

WhichofthefollowingisthecorrectnameforthecompoundwithformulaCa3P2?

Tricalciumdiphosphorus

Calciumphosphite

Calciumphosphate

Calciumdiphosphate

Calciumphosphide

21.Whichofthesystemsinequilibriumrepresentedbelowwillexhibitashifttotheleft(towardreactants)whenthepressureonthesystemisincreasedbyreducingthevolumeofthesystem?(Assumethattemperatureisconstant.)

(A)2Mg(s)+O2(g)2MgO(s)

(B)SF4(g)+F2(g)SF6(g)

(C)H2(g)+Br2(g)2HBr(g)

(D)N2(g)+3H2(g)2NH3(g)

(E)SO2Cl2(g)SO2(g)+Cl2(g)

19.WhatmassofKBr(molarmass119gmol1)isrequiredtomake250.mLofa0.400MKBrsolution?

(A) 0.595g

(B) 1.19g

(C) 2.50g

(D)11.9g

(E)47.6g

22.Thestandardenthalpyofformation,DH,of

f

HI(g)is+26kJmol1.WhichofthefollowingistheapproximatemassofHI(g)thatmustdecomposeintoH2(g)andI2(s)torelease

500.kJofenergy?

20.Thevalueoftheacid-dissociationconstant,

Ka,

foraweakmonoproticacidHAis2.5×106.

ThepHof0.40MHAisclosestto

(A)

(B)

(C)

(D)

250g

650g

1,300g

2,500g

(A)2.0

(B)3.0

(C)4.0

(D)6.0

(E)8.0

(E)13,000g

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-7-

CaCl2(s)Ca2+(aq)+2Cl(aq)

23.Fortheprocessofsolidcalciumchloridedissolvinginwater,representedabove,theentropychangemightbeexpectedtobepositive.However,Sfortheprocessisactuallynegative.Whichofthefollowingbesthelpstoaccountforthenetlossofentropy?

(A)Clionsaremuchlargerinsizethan

Ca2+

ions.

(B)

Theparticlesinsolidcalciumchloridearemoreorderedthanareparticlesinamorphoussolids.

WatermoleculesinthehydrationshellsofCa2+andClionsaremoreorderedthantheyareinthepurewater.TheCa2+(aq)andCl(aq)ionsaremorefreetomovearoundinsolutionthantheyareinCaCl2(s).

Inthesolution,theaveragedistancebetweenCa2+(aq)andCl(aq)isgreaterthantheaveragedistancebetweenCa2+andClinCaCl2(s).

(C)

(D)

(E)

...CH3OCH3(g)+...O2(g)...CO2(g)+...H2O(g)

24.Whentheequationaboveisbalancedusingthelowestwhole-numbercoefficients,thecoefficientforO2(g)is

(A)

(B)

(C)

(D)

(E)

6

4

3

2

1

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-8-

25.Forwhichofthefollowingprocessesdoesentropydecrease(S<0)?

28.Whichofthefollowingisaformulaforanether?

(A)

H2O(s)H2O(l)

Br2(l)Br2(g)

CrystallizationofI2(s)fromanethanolsolution

ThermalexpansionofaballoonfilledwithCO2(g)

MixingofequalvolumesofH2O(l)and

CH3OH(l)

(A)

(B)

(C)

(D)

(B)

(E)

(C)

26.Inalaboratory,astudentwantstoquantitativelycollecttheCO2gasgeneratedbyadding

Na2CO3(s)to2.5MHCl.ThestudentsetsuptheapparatustocollecttheCO2gasoverwater.The

volumeofcollectedgasismuchlessthantheexpectedvolumebecauseCO2gas

(D)

(A)

(B)

(C)

(D)

isverysolubleinwater

isproducedatalowpressureismoredensethanwatervapor

hasalargermolarmassthanthatofN2gas,themajorcomponentofair

hasasloweraveragemolecularspeedthanwatervaporatthesametemperature

(E)

(E)

27.WhatmassofCu(s)wouldbeproducedif

0.40molofCu2O(s)wasreducedcompletelywithexcessH2(g)?

13g

25g

38g

51g

100g

Threegasesintheamountsshowninthetableaboveareaddedtoapreviouslyevacuatedrigidtank.Ifthetotalpressureinthetankis3.0atmat25C,thepartialpressureofN2(g)inthetank

isclosestto

0.75atm

0.50atm

0.33atm

0.25atm

0.17atm

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-9-

Gas

Amount

Ar

0.35mol

CH4

0.90mol

N2

0.25mol

30.WhichofthefollowingbestexplainswhythenormalboilingpointofCCl4(l)(350K)ishigherthanthenormalboilingpointofCF4(l)(145K)?

33.WhichofthefollowingwouldproducetheLEASTmassofCO2ifcompletelyburned

inexcessoxygengas?

(A)

TheC–ClbondsinCCl4arelesspolarthantheC–FbondsinCF4.

TheC–ClbondsinCCl4areweakerthantheC–FbondsinCF4.

ThemassoftheCCl4moleculeisgreaterthanthatoftheCF4molecule.

TheelectroncloudoftheCCl4moleculeismorepolarizablethanthatoftheCF4molecule.

ThebondsintheCCl4moleculearecovalent,whereasthebondsintheCF4moleculeareionic.

(A)10.0gCH

4

(B)10.0gCH3OH

(C)10.0gC2H4

(D)10.0gC2H6

(E)10.0gC4H5OH

(B)

(C)

34.Whichofthefollowingsubstancesexhibitssignificanthydrogenbondingintheliquidstate?

(D)

(A)

(B)

(C)

(D)

(E)

CH2F2N2H4

CH3OCH3

C2H4C2H2

(E)

31.Atwhichofthefollowingtemperaturesandpressureswouldarealgasbemostlikelytodeviatefromidealbehavior?

35.InanaqueoussolutionwithapHof11.50at25C,themolarconcentrationofOH(aq)isapproximately

Temperature

(K)

100

200

300

500

500

Pressure(atm)

(A)

(B)

(C)

(D)

(E)

50

5

0.01

0.01

1

(A)3.2×1012M

(B)3.2×103M

(C)2.5×101M

(D)2.5M

(E)3.2×1011M

95Zr

32.After195days,a10.0gsampleofpure

36.Whichofthefollowingchangestoareactionsysteminequilibriumwouldaffectthevalueoftheequilibriumconstant,Keq,forthereaction?(Assumeineachcasethatallotherconditionsareheldconstant.)

hasdecayedtotheextentthatonly1.25gofthe

95Zr

95Zr

original

remains.Thehalf-lifeof

is

closestto

(A)

(B)

(C)

(D)

(E)

195days

97.5days

65.0days

48.8days

24.4days

(A)

(B)

AddingmoreofthereactantstothesystemAddingacatalystforthereactiontothesystem

IncreasingthetemperatureofthesystemIncreasingthepressureonthesystemRemovingsomeofthereactionproductsfromthesystem

(C)

(D)

(E)

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-10-

Questions37-38refertoagalvaniccellconstructedusingtwohalf-cellsandbasedonthetwohalf-reactionsrepresentedbelow.

Zn2+(aq)+2eZn(s)Fe3+(aq)+eFe2+(aq)

E

E

=0.76V

= 0.77V

Asthecelloperates,ionicspeciesthatarefoundinthehalf-cellcontainingthecathodeincludewhichofthefollowing?

Zn2+(aq)

Fe2+(aq)

Fe3+(aq)

Ionly

IIonly

IIIonly

IandIII

IIandIII

38.Whatisthestandardcellpotentialforthegalvaniccell?

(A)0.01V

(B) 0.01V

(C) 0.78V

(D) 1.53V

(E) 2.31V

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-11-

IonizationEnergiesforElementX

ThefirstsevenionizationenergiesofelementXareshowninthetableabove.Onthebasisofthesedata,elementXismostlikelyamemberofwhichofthefollowinggroups(families)ofelements?

Alkalineearthmetals

Borongroup

Carbongroup

Nitrogengroup

Halogengroup

40.Whichofthefollowingparticlesisemittedbyan

43.Acertainreactionisspontaneousattemperaturesbelow400.Kbutisnotspontaneousattemperaturesabove400.K.IfHforthereactionis20.kJmol1anditisassumed

thatHandSdonotchangeappreciablywithtemperature,thenthevalueofSforthereactionis

(A) 50.Jmol1K1

(B) 20.Jmol1K1

(C) 0.050Jmol1K1

(D) 20.Jmol1K1(E)8,000Jmol1K1

39Ca

atomof

whenitdecaystoproduceanatom

39K?

of

4He

(A)

(B)

(C)

2

1n

0

1H

1

+

(D)

(E)

Atapproximatelywhattemperaturewill40.gofargongasat2.0atmoccupyavolumeof22.4L?

(A)1,200K

600K

550K

270K

140K

AsampleofasolutionofRbCl(molarmass121gmol1)contains11.0percentRbClbymass.Fromthefollowinginformation,whatisneededtodeterminethemolarityofRbClinthesolution?

Massofthesample

Volumeofthesample

Temperatureofthesample

Ionly

IIonly

IandIIonly

IIandIIIonly

I,II,andIII

42.Whichofthefollowingaqueoussolutionshasthehighestboilingpointat1.0atm?

(A)

(B)

(C)

(D)

(E)

0.20MCaCl2

0.25MNa2SO4

0.30MNaCl

0.30MKBr

0.40MC6H12O6

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-12-

1st

2nd

3rd

4th

5th

6th

7th

IonizationEnergy(kJmol1)

787

1,580

3,200

4,400

16,000

20,000

24,000

...Au3+(aq)+...I(aq)...Au(s)+...I2(s)

45.Whentheequationaboveisbalancedusingthelowestwhole-numbercoefficients,thecoefficientforI2(s)is

8

6

4

3

2

AclosedrigidcontainercontainsdistilledwaterandN2(g)atequilibrium.ActionsthatwouldincreasetheconcentrationofN2(g)inthewaterincludewhichofthefollowing?

Shakingthecontainervigorously

Raisingthetemperatureofthewater

InjectingmoreN2(g)intothecontainer

(A)

(B)

(C)

(D)

(E)

IonlyIIonlyIIIonly

IandIIonlyI,II,andIII

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-13-

CS2(l)+3O2(g)CO2(g)+2SO2(g)

When0.60molofCS2(l)reactsascompletelyaspossiblewith1.5molofO2(g)accordingtotheequationabove,thetotalnumberofmolesofreactionproductsis

2.4mol

2.1mol

1.8mol

1.5mol

0.75mol

ZX+Y

47.ApuresubstanceZdecomposesintotwoproducts,XandY,asshownbytheequationabove.WhichofthefollowinggraphsoftheconcentrationofZversustimeisconsistentwiththerateofthereactionbeingfirstorderwithrespecttoZ?

(A)

Questions49-50refertoanexperimenttodeterminethevalueoftheheatoffusionofice.Astudentusedacalorimeterconsistingofapolystyrenecupandathermometer.Thecupwasweighed,thenfilledhalfwaywithwarmwater,thenweighedagain.Thetemperatureofthewaterwasmeasured,andsomeicecubesfroma0Cicebathwereaddedtothecup.Themixturewasgentlystirredastheicemelted,andthelowesttemperaturereachedbythewaterinthecupwasrecorded.Thecupanditscontentswereweighedagain.

(B)

(C)

49.Thepurposeofweighingthecupanditscontentsagainattheendoftheexperimentwasto

(A)

(B)

(C)

(D)

(E)

determinethemassoficethatwasaddeddeterminethemassofthethermometerdeterminethemassofwaterthatevaporatedverifythemassofwaterthatwascooledverifythemassofthecalorimetercup

(D)

50.Supposethatduringtheexperiment,asignificantamountofwaterfromtheicebathadheredtotheicecubes.Howdoesthisaffectthecalculatedvaluefortheheatoffusionofice?

(E)

(A)

Thecalculatedvalueistoolargebecauselesswarmwaterhadtobecooled.

Thecalculatedvalueistoolargebecausemorecoldwaterhadtobeheated.

Thecalculatedvalueistoosmallbecauselessicewasaddedthanthestudentassumed.

Thecalculatedvalueistoosmallbecausethetotalmassofthecalorimetercontentswastoolarge.

Thereisnoeffectonthecalculatedvaluebecausethewateradheredtotheicecubeswasat0C.

(B)

(C)

(D)

(E)

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-14-

F(aq)+H2O(l)HF(aq)+OH(aq)

55.Whichofthefollowingspecies,ifany,actsasaBr?nsted-Lowrybaseinthereversiblereactionrepresentedabove?

51.Whichofthefollowingmoleculescontainsbondsthathaveabondorderof1.5?

(A)

(B)

(C)

(D)

(E)

N2O3NH

3

(A)

(B)

(C)

(D)

HF(aq)

H2O(l)

F(aq)only

BothF(aq)andOH(aq)actasBr?nsted-Lowrybases.

NospeciesactsasaBr?nsted-Lowrybase.

CO2

CH2CH2

Ofthefollowingmetals,whichreactsviolentlywithwaterat298K?

Au

Ag

Cu

Mg

Rb

(E)

56.Whatistheempiricalformulaofahydrocarbonthatis10.0percenthydrogenbymass?

(A)CH

3

(B)

(C)

(D)

(E)

C2H5C3H4

C4H9C9H10

53.Heatenergyisaddedslowlytoapuresolidcovalentcompoundatitsmeltingpoint.Abouthalfofthesolidmeltstobecomealiquid.Whichofthefollowingmustbetrueaboutthisprocess?

(A)

(B)

Covalentbondsarebrokenasthesolidmelts.Thetemperatureofthesolid/liquidmixtureremainsthesamewhileheatisbeingadded.Theintermolecularforcespresentamongmoleculesbecomezeroasthesolidmelts.Thevolumeofthecompoundincreasesasthesolidmeltstobecomealiquid.

Theaveragekineticenergyofthemoleculesbecomesgreaterasthemoleculesleavethesolidstateandentertheliquidstate.

Pb(s)Pb(l)

57.Whichofthefollowingistruefortheprocessrepresentedaboveat327Cand1atm?(ThenormalmeltingpointofPb(s)is327C.)

(C)

(D)

(E)

H=0

TS=0

S<0

H=TG

H=TS

54.Asteadyelectriccurrentispassedthroughmolten

MgClforexactly1.00hour,producing243gof

2

Mgmetal.IfthesamecurrentispassedthroughmoltenAlCl3for1.00hour,themassofAlmetalproducedisclosestto

(A) 27.0g

(B) 54.0g

(C)120.g

(D)180.g

(E)270.g

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-15-

N2(g)+O2(g)+Cl2(g)2NOCl(g)

H=+104kJmol1

58.Theequilibriumsystemrepresentedaboveiscontainedinasealed,rigidvessel.Whichofthefollowingwillincreaseifthetemperatureofthemixtureisraised?

(A)[N2(g)]

(B)

(C)

(D)

(E)

TherateoftheforwardreactiononlyTherateofthereversereactiononly

TheratesofboththeforwardandreversereactionsThetotalnumberofmolesofgasinthevessel

59.IfametalXformsanionicchloridewiththeformulaXCl3,thenwhichofthefollowingformulasismostlikelytobethatofastable

sulfideofX?

(A)

(B)

(C)

(D)

(E)

XS2X2S3XS6X(SO3)3

X2(SO3)3

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-16-

Questions60-61refertothefiguresbelow.ThefiguresshowportionsofaburetusedinatitrationofanacidsolutionofknownconcentrationwithasaturatedsolutionofBa(OH)2.Figures1and2showtheleveloftheBa(OH)2solutionatthestartandattheendpointofthetitration,respectively.Phenolphthaleinwasusedastheindicatorforthetitration.

60.Whatistheevidencethattheendpointofthetitrationhasbeenreached?

(A)

Thecolorofthesolutionintheburetchangesfrompinktocolorless.

Thecolorofthesolutionintheburetchangesfrombluetored.

Thecolorofthecontentsoftheflaskbelowtheburetchangesfromcolorlesstopink.Thecolorofthecontentsoftheflaskbelowtheburetchangesfrombluetored.

Thecontentsoftheflaskbelowtheburetchangefromcleartocloudy.

(B)

(C)

(D)

(E)

61.ThevolumeofsaturatedBa(OH)2neutralizetheacidwasclosestto

usedto

(A)

(B)

(C)

6.60mL

22.80mL

23.02mL

(D)23.20mL

(E)29.80mL

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-17-

C(diamond)C(graphite)

62.Forthereactionrepresentedabove,thestandardGibbsfree

energychange,G,hasavalueof2.90kJmol1.Which

298

ofthefollowingbestaccountsfortheobservationthatthe

reactiondoesNOToccur(i.e.,diamondisstable)at298Kand1.00atm?

Sforthereactionispositive.

Theactivationenergy,Ea,forthereactionisverylarge.Thereactionisslightlyexothermic(H<0).

Diamondhasadensitygreaterthanthatofgraphite.

Diamondhasaheatcapacitylowerthanthatofgraphite.

(A)

(B)

(C)

(D)

(E)

8H2(g)+S8(s)8H2S(g)

65.Bymixingonly0.15MHCland0.25MHCl,itispossibletocreateallofthefollowingsolutionsEXCEPT

63.When25.6gofS8(s)(molarmass256gmol1)reactscompletelywithanexcessofH2(g)

accordingtotheequationabove,thevolumeof

(A)

(B)

(C)

(D)

(E)

0.23MHCl

0.21MHCl

0.18MHCl

0.16MHCl

0.14MHCl

HS(g),measuredat0Cand1.00atm,produced

2

isclosestto

(A)

(B)

(C)

(D)

(E)

30L

20L

10L

5L

2L

66.At25Casaturatedsolutionofametalhydroxide,M(OH)2,hasapHof9.0.Whatisthevalueofthesolubility-productconstant,Ksp,ofM(OH)2(s)

at25C?

(A)5.0×1028(B)1.0×1027(C)5.0×1019(D)5.0×1016(E)1.0×1015

2HClO

2HClO+3O

2

4

Asthereactionrepresentedaboveproceedstotheright,theoxidationnumberofchlorinechangesfrom

1to+3

1to+5

(C)+1to+5

(D)+1to+7

(E)+3to+7

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67.Astudentweighsout0.0154molofpure,dryNaClinordertopreparea0.154MNaClsolution.Ofthefollowingpiecesoflaboratoryequipment,whichwouldbemostessentialforpreparingthesolution?

Whenasolutionisformedbyaddingsomemethanol,CH3OH,towater,processesthatareendothermicincludewhichofthefollowing?

Methanolmoleculesmovewatermoleculesapartasthemethanolgoesintosolution.

Watermoleculesmovemethanolmoleculesapartasthemethanolgoesintosolution.

Intermolecularattractionsformbetweenmoleculesofwaterandmethanolasthemethanolgoesintosolution.

Ionly

IIIonly

IandIIonly

IIandIIIonly

I,II,andIII

Largecruciblewithlid

50mLvolumetricpipet

100mLErlenmeyerflask

100mLgraduatedbeaker

100mLvolumetricflask

68.Inwhichofthefollowingarethechemicalspeciescorrectlyorderedfromsmallestradiustolargestradius?

(A)

(B)

(C)

(D)

(E)

B<C<N

Ar<Xe<Kr

72.Ofthefollowinggases,whichhasthegreatestaveragemolecularspeedat298K?

S2

Cl<S<

<Na+<K

(A)

(B)

(C)

(D)

(E)

Cl2(g)

NO(g)

H2S(g)

HCN(g)

PH3(g)

Na

K+

Ca2+

<

<K

69.Alargepieceofwoodcanburnslowly,butwoodintheformofsawdustcancombustexplosively.Theprimaryreasonforthedifferenceisthatcomparedwithalargepieceofwood,sawdust

Typesofhybridizationexhibitedbycarbonatomsinamoleculeofpropyne,CH3CCH,includewhichofthefollowing?

sp

sp2

sp3

(A)

(B)

(C)

hasagreatersurfaceareaperkilogramhasagreatercarboncontentperkilogramabsorbsmoreatmosphericmoistureperkilogram

containsmorecompoundsthatactascatalystsforcombustion

containsmorecompoundsthathavehigherheatsofcombustion

(D)

(A)

(B)

(C)

(D)

(E)

IonlyIIIonly

IandIIIonlyIIandIIIonlyI,II,andIII

(E)

70.Ofthefollowingelements,whichwouldbeexpectedtohavechemicalpropertiesmostsimilartothoseofsulfur,S?

Br

Cl

N

P

Se

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XY2(aq)X2+(aq)+2Y(aq)

74.AsolublecompoundXY2dissociatesinwateraccordingtotheequationabove.Ina0.050msolutionofthecompound,theXY2(aq)speciesis40.0percentdissociated.Inthesolution,thenumberofmolesofparticlesofsoluteper1.0kgofwaterisclosestto

(A)0.15

(B)0.090

(C)0.070

(D)0.040

75.Inwhichofthefollowingprocessesarecovalentbondsbroken?

(A)

(B)

(C)

(D)

(E)

Solidsilvermelts.

Solidpotassiumchloridemelts.Solidcarbon(graphite)sublimes.Solidiodinesublimes.

Glucosedissolvesinwater.

(E)

0.020

ENDOFSECTIONI

IFYOUFINISHBEFORETIMEISCALLED,YOUMAYCHECKYOURWORKONTHISSECTION.

DONOTGOONTOSECTIONIIUNTILYOUARETOLDTODOSO.

-20-

SectionII

Free-ResponseQuestions

-21-

INFORMATIONINTHETABLEBELOWANDINTHETABLESONPAGES23-25MAYBEUSEFULINANSWERINGTHEQUESTIONSINTHISSECTIONOFTHEEXAMINATION.

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-22-

STANDARDREDUCTIONPOTENTIALSINAQUEOUSSOLUTIONAT25∞C

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Half-reaction E∞(V)

F2(g)+2e- ? 2F- 2.87

Co3++e- ? Co2+ 1.82

Au3++3e- ? Au(s) 1.50

Cl2(g)+2e- ? 2Cl- 1.36

O2(g)+4H++4e- ? 2H2O(l) 1.23

Br2(l)+2e- ? 2Br- 1.07

2Hg2++2e- ? Hg2+ 0.92

2

Hg2++2e- ? Hg(l) 0.85

Ag++e- ? Ag(s) 0.80

Hg22++2e- ? 2Hg(l) 0.79

Fe3++e- ? Fe2+ 0.77

I2(s)+2e- ? 2I- 0.53

Cu++e- ? Cu(s) 0.52

Cu2++2e- ? Cu(s) 0.34

Cu2++e- ? Cu+ 0.15

Sn4++2e- ? Sn2+ 0.15

S(s)+2H++2e- ? H2S(g) 0.14

2H++2e- ? H2(g) 0.00

Pb2++2e- ? Pb(s) –0.13

Sn2++2e- ? Sn(s) –0.14

Ni2++2e- ? Ni(s) –0.25

Co2++2e- ? Co(s) –0.28

Cd2