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PreparedbyJEPaa/forBSChemGraduate2006
Physical
Chemistry
INSTRUCTION:Selectthecorrectanswerforeachofthefollowing
sections. Markonlyoneanswerforeachitembyshadingthebox
correspondingtotheletterofyourchoiceontheanswersheet
provided. STRICTLYNOERASURESALLOWED. Usepencilno.1only.
1. Chemicalequilibriumreactionsarecharacterizedby
Ga. >0
b. 0G
b.
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16.Thespecificheatcapacityatconstantvolumeofaleadsilveralloy
isequalto0.0383cal/degg. Theatomicmassesofleadandsilver
are207and107,respectively. Assumingthatthealloyfollows
DulongandPetitLaw,findthemoleratioofleadtosilver.
12.At35oC,thevaporpressureofwaterisincreasedfrom30to31
mmHgagainstanexternalpressureof10atm. Ifthevapor
pressureistobemaintainedat0.0395atmfor100gofwaterat
35oCand10atm,howmuchingNaClistobeaddedtothewater?
a.
58.55
b. 61.18
c. 52.88
d. 47.36
13.Givenasolutionoftolueneinbenzeneat20oCwiththemole
fractionoftolueneequalto0.20,thepartialpressureofthe
solvent,benzene,isequalto2.19torr. TheHenryconstantfor
tolueneis10.95torr. Calculatetheactivityofthesolute.
a.
0.800
b. 1.000
c. 0.500
d. 0.200
14.
A
certain
sugar
has
a
molar
mass
of
342
g/mol.
At
0o
C,
the
osmoticpressureofanaqueoussolutionofconcentrationof1.5g
ofsugarper150cm3solventis0.649atm. Whatistheosmotic
pressureofthesolution?
a. 222atm
b. 0.32atm
c. 50atm
d. 0.65atm
15.Giventhereaction: 3 3( ) ( )KNO energy K aq NO aq+ + + ,which
ofthefollowingchangestothesystemwouldincreasethe
concentrationofK+ionsatequilibrium?
a. Thepressureofthesystemisdecreased
b. AdditionalsolidKNO3isaddedtothesolution
c.
Thetemperatureofthesolutionisincreased
d.
Thevolumeofthesolutionisaddedtothesolution
a.
b. 2
c. 1
d. 4
17.CalculatethetemperaturechangeinoCoftwomolesofa
diatomicgascontainedinapistongiventhatq=65Jandw=210J.
a.
2.5
b. 4.5
c.
5.5
d. 3.5
18.Aleadstoragebatteryinvolvesthetwohalfreactions:2
4 4( ) 2PbSO s e Pb SO + + ;E
o(volts)=0.36
22 4 4 2( ) 4 2PbO s H SO PbSO H O+ + + + ;Eo(volts)= 1.69
Foracellthatduplicatestheleadstoragebatterydischarge
reactionatunitconcentrations,whatis G inkJ?
a. 792
b.
396
c. +792
d. +396
19.Whatistheheatcapacityatconstantpressureofgraphite
assumingitobeystheDulongandPetitsLaw?
a. 6cal/Kmol
b. 6atm/molL
c. 6Latm/mol
d. 6ergs/K
PreparedbyJEPaa/forBSChemGraduate2006
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PreparedbyJEPaa/forBSChemGraduate2006
20.AsealedisothermalcontainerinitiallycontainsthreemolesofCO
gasandfourmolesofO2gas. Thefollowingreversiblereaction
tookplace:
2 2
2 ( ) ( ) 2 ( )CO g O g CO g+
Atequilibrium,thereweretwomolesofCO2inthecontainer.
Whatwasthetotalnumberofmolesofgaspresentinthe
containeratequilibrium?
a.
6
b. 4
c. 5
d. 7
21.
At1035oC,twomolesofrutheniumchangesfromthetothe
solidstate. The H forthetransitionis142J/mol. The
surroundingcoolingbathisatSTP. Find S inJ/Koftheuniverse.
a. 1.040
b. 0.642
c. 0.823
d. 0.217
22.
Determinethebarometricdecreaseinatmosphericpressurefrom
sealeveltoanaltitudeof1.8x106cm. Assumeairtobea
uniformgasofmolecularmass29,andauniformtemperatureof
0oC.
a.
0.307
b. 0.998
c. 0.105
d.
304.1
23.Twomolesofanidealgasareexpandedreversiblyand
isothermallyat0oCfrom1atm. Calculatethefinalvolume
occupiedbythegasiftheheatabsorbedduringtheprocessisq=
750cal. Theexternalpressureoverthesystemis1atm.
a. 69.6L
b. 98.2L
c.
118.7L
d. 304.1L
24.A B C D+ +
A C D E+ +
Amultistepreactiontakesplacebytheabovemechanism.
Whichofthespeciesshownaboveisanintermediateinthe
reaction?
a. A
b. D
c. B
d. C
25.Abulbisfilledwithargongasattheambientpressureandis
foundtocontain7.98gofargonatatemperatureT. Thebulbis
thenimmersedinabathwhosetemperatureis30oChotterthan
thefirstone. Thestopcockonthebulbisopenedsothatthe
argongaspressurereturnstotheinitialvalue. Thebulbisnow
foundtocontain5.33gofargon. Whatisthevalueofthefinal
temperature? Theatomicmassofargonis39.9.
a. 242oC
b.
90.9
o
C
c.
212oC
d. 182oC
26.Ammoniadissolvesinwaterat20oCtogiveasolutioncontaining
0.040molefractionofammonia. Thetotalvaporpressureofthe
solutionis6.58x102
atmandthevaporpressureforwateris
17.00torratthesametemperature. ApplyingHenrysand
Raoultslaws,calculatetheHenrysconstant.
a.
1200
b. 50.00
c. 842.5
d. 16.98
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31.Arefrigeratorismaintainedat25o
Cinaroomatambient
temperatureof35oC. Theheatintotherefrigeratorisestimated
as104J/min. Assumingthattheunitisoperatingat45%ofits
maximumthermodynamicefficiency,determineitspower
requirementinwatts.
PreparedbyJEPaa/forBSChemGraduate2006
27.Asampleofanidealgasat29oCand420torroccupiedavolume
of382cm3. Whatwasthenumberofmolesofgasinthissample?
a. 8.5x103
b. 4.9x102
c.
6.5
d. 8.9x102
28.Thehalflifeforagivendecompositionreactionwashalvedasthe
initialconcentrationofasolereactantwasdoubled. Whatisthe
orderofthereaction?
a. 2
b.
1
c. 3
d.
0
29.Givenanatomofmass10,followingemissionofa2MeVgamma
ray,calculatetherecoilenergy.
a.
450eV
b.
198
eV
c. 214eV
d. 222eV
30.Forthefollowingreactionat25oC:
2 2( ) ( ) ( ) ( )CuO s H g Cu s H O g+ +
Valuesoftheabsoluteentropiesfortheabovesubstancesareas
follows:
S
o
(J/mol
K):
CuO=43.5; H2=130.5; Cu=33.5; H2O=188.7
Calculatethe inJ/molKofthereactionassumingstandard
conditions.
oS
a. 48.2
b. 309.2
c. 135.2
d.
18.8
a. 40.4
b. 89.8
c. 5380
d. 2299
32.Atacertaintemperature,2atmofCOareintroducedintoavessel
containingexcesssolidsulfurandafinalequilibriumpressureof
1.18atmisobserved. Giventhereaction,
2( ) 2 ( ) ( ) 2 ( )S s CO g SO g C s+ + ,finditsKp.
a. 6.33
b. 2.28
c. 0.73
d. 0.87
33.
Giventhefollowingo
fG inkJ/mol:
C6H12O6(s)=912; CO2(g)=393; H2O(l)=238;
Calculatethestandardfreeenergy(Gibbsenergy)inkJ/molfor
theoxidationofglucose,
6 12 6 2 2 2( ) 6 ( ( ) 6 ( )C H O s O g O g H O l+ +) 6C
a. 14370
b. 1842
c. 4698
d. 2874
34.Themassofanelectronis9.109x1028
g. Whatisthemolarmass
oftheelectron?
a. 4.39x1025
b.
6.61x1050
c.
5.48x104
d. 1.51x1051
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39.4.000picogram(pg)of33
Pdecaysbyemissionto0.500pgin
75.9days. Findtherateconstantofthereactioninperdaybasis.
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35.Howmany particlespersecondwouldbeemittedform4x1012
gramof210
Po. Thehalflifeof210
Pois138days.
a. 728
b. 543
c.
667
d. 401
36.Thevalveonacylindercontaininginitially15Lofanidealgasat
25atm,25o
Cisopenedtotheatmospherewherethepressureis
760torr. Assumingthattheprocessisisothermal,howmuch
workisKJisdoneontheatmospherebytheactionofexpanding
gas?
a.
0.86
b. 3.64
c. 4.28
d. 5.85
37.At30oC,Henryslawconstantforthesolubilityofoxygengasin
wateris2O
K =3.30x107torr. Calculatethesolubilityofoxygenin
grams
at
this
temperature
per
100
g
of
water.
Assume
air
to
be
20%O2atroomtemperature.
a. 3.1x107
b. 2.6x105
c. 4.6x106
d. 8.3x104
38.InanidealsolutionofliquidsAandB,thevaporpressureofa
mixtureof0.60molofAand2.4molofBis0.42atmat70oC.
1.80molesofAisaddedtothesolutionat70oCandthevapor
pressureofthesolutionrisesto0.55atm. Calculatethevapor
pressureifsomeofthevaporinequilibriumwiththefirstsolution
werecompletelycondensed.
a. 0.51atm
b. 0.35atm
c.
0.20atm
d. 0.80atm
a. 9.13x103
b. 2.74x102
c.
3.65x102
d. 4.18x103
40.At1482Kand12atm,theequilibriumcompositionofsodium
vaporcontains3.10molesofNamonomerand0.624molesofNa
dimer. CalculatetheKpforthedimerizationofsodiumat1482K.
a. 2.01x102
b.
3.68x101
c.
2.47
d. 2.89x101
41.At600oC,acetonedecomposesproducingCOandvarious
hydrocarbons. Thereactionisfoundtobefirstorderinacetone
concentrationwithahalflifeof81.0s. Givenat600oC,aoneliter
containerintowhichacetoneisinjectedat0.48atm,approximate
howlongwouldittakefortheacetonepressuretodropto0.45
atm?
a. 39.8s
b. 7.5s
c. 81.0s
d. 15.0s
42.Duringwinter,thegaugepressureinanautomobiletirewhen
measuredat28oFwas30poundspersquareinch(psi). thesame
tirewasusedduringsummer. Assumingthatthevolumeofthe
tiredidnotchange,andnogasleakedoutfromthetirebetween
winterandsummer,whatisthenewpressureasmeasuredonthe
gaugeifthetemperatureroseto115oF?
a. 47.6
b. 37.9
c.
25.5
d. 35.3
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48.WhichoftheofthefollowingstatementsisTRUEaboutthe
electromotiveforceofasystemwhenallconcentrationsare
unity?
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PreparedbyJEPaa/forBSChemGraduate2006
43.EstimatethezeropointentropyofNOincal/molK.
a. 0
b. 2.76
c. 1.38
d.
4.18
44.Determinetheheattransferredwhen627Jofworkisdoneona
systemconsistingof2molesofanidealgasatconstant
temperature.
a. 0
b. 627J
c. 627J
d.
1254J
45.When[C]and[D]aredoubled,theinitialrateofthereaction
C D E+ increasesbyafactorofeight. Whichofthefollowing
ratelawsisconsistentwiththisobservation?
a. Rate=k[C][D]
b. Rate=k[C]2[D]
2
c. Rate=k[D]2
d.
Rate=k[C]2[D]
46.After66minutes,asampleof44
19Kisfoundtohavedecayedto
12.5%oftheoriginalamountpresent. Whatisthehalflifeof
?44
19 K
a. 22min
b. 66min
c.
44min
d. 88min
47.Whatisthepressureofacolumnofairataheightof10kmanda
temperatureof2oC? Assumethatthepressureatzeroheightis
760mmHgandthemolarmassofairis29.
a. 449
b. 340
c.
219
d. 759
a. EEo
49.AhypotheticalgasempiricalformulaisBCB. Predictthe
structureofthegasiftheratioofheatcapacities /P VC C is1.32.
a. Nonlinear
b.
Trigonal
c. Linear
d. Cannotbedetermined
50.AmixtureofthevaporsoftwoliquidsXandYwhichformideal
solutionsiscontainedinacylinderwithapistonatconstant
temperatureT. Themixturecontains60%X,withvaporpressures
oXP and oYP givenas1.2and0.4atm,respectively. Themixtureis
thenslowlycompressed. Calculatethetotalpressureatwhichthe
liquidfirstcondenses.
a. 0.475atm
b. 1.200atm
c. 0.800atm
d. 0.666atm
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55.FindthestandardenergyinkJofthecombustionreactionof
propeneat25oCassumingallreactantsandproductsbehaveas
idealgases.
10
PreparedbyJEPaa/forBSChemGraduate2006
SITUATIONAL
PROBLEMS:
Situation#01Theactivationenergyforthethermaldecomposition
ofgaseousacetaldehydeis190.37kJ/molandthemolecular
diameter,
,
of
a
molecule
of
acetaldehyde
is
5
x
10
8
cm.
This
decompositionisasecondorderreaction.
51.Determinethenumberofmoleculescollidingpermilliliterper
secondat800Kand760torr.
a. 2.10x1031
b. 4.75x1015
c. 9.17x1021
d.
2.88
x
10
28
52.
Calculatethesecondorderrateconstant,k,inL/molsec.
a. 6.9x102
b. 7.7x102
c. 8.3x104
d. 6.0x1023
53.
Determine
the
pre
exponential
factor
A
at
800
K.
a. 1.10x1013
b. 2.07x1011
c. 1.86x1015
d. 2.24x1017
Situation#02Thestandardenthalpyofthehydrogenationof
propeneis214kJ/mol. Thestandardenthalpyoftheoxidationof
propanetocarbondioxideandwateris2222kJ/mol. Thestandard
heatofformationofwateris286kJ/mol.
54.FindthestandardenthalpyinkJ/molofthecombustionreaction
ofpropaneat25oC.
a. 2076
b. 2068
c.
2060
d. 2084
a. 2068
b.
2075
c. 2069
d. 2094
56.FindWinkJofthecombustionreactionofpropeneat25oC.
a. 2.0
b. 1.0
c. 4.0
d.
0
Situation#03Akilogramofacetylenewascompressedfrom102
L
to103
Lataconstanttemperatureof150oC. Calculatetheminimum
workthatmustbeexpendedinthecompressionprocessassuming
thegastobe
57.IDEAL.
a. 1.09x103J
b.
3.12x105J
c. 1.11x105J
d. 3.08x103J
58.vanderWaals. ThevaluesofvanderWaalsconstantsaandbare
4.47L2atmmol
2and0.0571L/mol,respectively.
a. 4.98x109J
b. 1.55 x107J
c.
8.15x109J
d. 0.95x107J
59.IfacetylenesatisfiesthevanderWaalsequation,whatwouldbe
itscriticalpressureinatm?
a. 282
b. 197
c. 50.8
d.
1371
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64.theadiabaticexpansioninkJwherethefinaltemperaturewas
243oC.
10
PreparedbyJEPaa/forBSChemGraduate2006
Situation#04Amovingboundaryexperimentwasperformed
initiallyat25oCwith0.100MKClonthebottomand0.0700MNaCl
ontop. ThetransportnumbersofK+andNa
+ionsinthesesolutions
are0.490and0.388,respectively. Theboundarymoveddownward.
Thecrosssectionalareaofthetubewas0.100cm2. Thecharge
passedthroughwas96.5coulombs.
60.Howmanyequivalentsweretransported?
a. 1.00x103
b. 1.43x103
c. 0.25x103
d.
0.68x103
61.
Howfar(incentimeters)didtheboundarymove?
a. 65.4
b. 79.2
c. 49.0
d.
57.6
62.Whilethecurrentwasflowing,whatwastheconcentrationin
mol/LofNaCljustabovetheboundary?
a. 7.92x102
b. 2.18x101
c. 8.14x104
d. 6.24x105
Situation#05Fourmolesofanidealnitrogengaswasexpanded
from10Lto25L. Theinitialtemperaturewas35oC. AssumeCv=2.5
R. Calculatethemaximumworkobtainedby:
63.theisothermalexpansioninJ.
a. 92.7
b. 9385.4
c.
7039.6
d. 2243.0
a. 16.7
b. 9.2
c.
5.8
d. 23.1
65.FindtheenthalpychangeinJifthefinaltemperaturewas243oC.
a. 24,210
b. 59,164
c. 8,090
d.
32,358
Situation#06At1atm,120gofbenzeneisvaporizedatitsboiling
pointof80.2oC. Theheatofvaporizationis94.4cal/g.
66.CalculateWinunitsofjoule.
a.
4522
b.
293.6
c. +293.6
d. +4522
67.Calculateqinjoules.
a. 39497
b. 7480
c. 15627
d.
395
68.Calculate injoules.U
a. 34975
b. 44019
c. 0
d. 15921
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PreparedbyJEPaa/forBSChemGraduate2006
Situation#07TwoequimolarsolutionsAandBwithequalvolume
ofsolutionsaremixedtogetherandthereactionA B C+ occurs.
After60minutes,Ais75%reacted. HowmuchofAwillNOTreact
aftertwohoursif:
69.thereactioniszeroorderinbothAandB?
a. 50%
b. 0%
c. 25%
d. 75%
70.ifthereactionisfirstorderinbothAandB?
a.
62.8%
b. 25.0%
c. 35.7%
d. 14.3%
71.thereactionisfirstorderinAandzeroorderinB?
a. 21.7%
b. 6.26%
c. 32.2%
d. 52.08%
Situation#08Twogramsofliquidwaterat100oCisinitiallyat1.00
atmpressureandisconfinedtoavolumeinwhichnovaporis
present. Avalveisthenopenedandthewaterevaporatesintoan
evacuatedspaceofsuchvolumethatthefinalpressureis0.10atm.
Theentireapparatusisinaheatreservoirat100oC.The E forthe
vaporizationofwateris2259J/gat100oC. Assumingthatthevaporis
anidealgasandthatthevolumeoftheliquidisnegligibleas
comparedtothevolumeofthevapor,calculate:
72.qinjoulesforthewater.
a.
4173
b. 4863
c.
2617
d. 1914
73. S forwaterinJ/K.
a. 50.40
b. 28.16
c. 14.24
d.
45.20
74. S fortheuniverseinJ/K.
a. 34.01
b. 3.05
c. 15.68
d. 25.43
Situation#09Threemolesofanidealmonoatomicgasinitiallyat1
atmand300Kareputthroughthefollowingcycle,allstagesofwhich
arereversible:
(I) isothermalcompressionto2atm
(II) isobarictemperatureincreaseto400K
(III)returntotheinitialstatebythepath,P=a+bT,whereaandb
are
constants.
75.Calculate injoulesforthesecondstep.U
a. 3741
b. 1247
c. 8107
d. 6236
76.
Calculate inJ/Kforthefirststep.S
a. 8.6
b. 17.3
c. 5.8
d. 14.2
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PreparedbyJEPaa/forBSChemGraduate2006
79.Determinethevolumeadsorbedat3500secifVeisequalto0.451
cm3.
Situation#10GiventhedatabelowwhereVeisthevolume
adsorbedatequilibriumandVisthevolumeadsorbedattimet. The
adsorptionratefollowsfirstorderkinetics.
t(sec) 1380 3000 4260 7320
VeV(cm3
) 0.284 0.179 0.121 0.043
77.WhichofthefollowingstatementsisTRUEabout U and S for
thecycledescribed?
U
78.
DeterminetherateconstantKinpersecond.
a. Both and arezero.
S
b. ispositiveand iszero.
S
U S
c.
iszeroand ispositive.
S
U
d. ispositiveand isnegative.U
80.
DetermineVeViftis800seconds.
a. 3.20x104
b. 1.80x102
c. 1.60x103
d.
2.30x105
a. 0.281
b. 0.302
c. 0.325
d. 0.290
a. 0.354
b. 0.418
c. 0.166
d. 0.201