ACS EXAM (CHEM 161) EXAM QUESTIONS WITH CORRECT ANSWERS RATED A+.pdf

ACS EXAM (CHEM 161) EXAM QUESTIONS WITH
CORRECT ANSWERS RATED A+
ChapterZ9Z-ZSolutionsZandZAqueousZReactions,ZPartZ2Z-ZCORRECTZANSWERS-
ZSolutionZformationZincludingZintermolecularZforcesZinZsolutionsZ



-ZSolubilityZasZitZrelatesZtoZintermolecularZforcesZ

-ZConcentrationZunitsZandZconversionsZbetweenZ

-ZSolubilityZofZsolidsZandZgases,ZparticularlyZinZaqueousZsolutionZ

-
ZColligativeZpropertiesZincludingZfreezingZpointZdepression,ZboilingZpointZelevationZandZosmoticZpr


essure



AZsolutionZofZNaClZinZwaterZhasZaZconcentrationZofZ20.5%ZbyZmass.ZWhatZisZtheZmolalZconcentratio
nZofZtheZsolution?

a)Z0.205Zm

b)Z0.258Zm

c)Z3.51Zm

d)Z4.41ZmZ-
ZCORRECTZANSWERSpercentZbyZmassZ=Z(massZbyZoneZcomponent)/(totalZmass)ZxZ100%Z=Z(massZsol


ute)/((massZsolution)ZxZ100%Z=Z(massZsolute)/(massZsoluteZ+ZmassZsolvent)ZxZ100%



molalZconcentrationZ=Z(molZsolute)/(massZsolventZkg)



SOLUTION:Z100ZgZsolutionZ-Z20.5ZgZNaClZ=Z79.5ZgZwaterZ

->Z(20.5ZgZNaCl)(molZNaCl/58.44ZgZNaCl)/0.0795ZkgZwaterZ=Z4.41Zm



WhatZisZtheZmoleZfractionZofZwaterZinZ200.0ZgZofZ89%Z(byZmass)Zethanol,ZC2H5OH?ZTheZmolarZmas
sZofZC2H5OHZ=Z46Zg/mol

,a)Z0.11Z

b)Z0.24Z

c)Z0.32Z

d)Z0.76Z-ZCORRECTZANSWERSb)Z0.24Z



1)ZsetZyourZsampleZsizeZtoZ100ZgZsolution,Zmaking:Zmass(solute)Z=Z%ZbyZmassZandZmass(solvent)Z=Z1
00-%ZbyZmass

2)ZuseZmolarZmassZ(solute)ZtoZdetermineZN(solute)Z

3)ZuseZmolarZmassZ(solvent)ZtoZdetermineZN(solvent)Z

4)ZcalculateZtheZmoleZfraction



AZmixtureZofZ100ZgZofZK2Cr2)7ZandZ200ZgZofZwaterZisZstirredZatZ60CZuntilZnoZmoreZofZtheZsaltZdissolv
es.ZTheZresultingZsolutionZisZpouredZoffZintoZaZseparateZbeaker,ZleavingZtheZundissolvedZsolidZbehin
d.ZTheZsolutionZisZnowZcooledZtoZ20C.ZWhatZmassZofZK2Cr2O7ZcrystallizesZfromZtheZsolutionZduringZ
theZcooling?



a)Z9Zg

b)Z18Zg

c)Z31Zg

d)Z62ZgZ-ZCORRECTZANSWERSb)Z62Zg



CarbonatedZbeveragesZhaveZaZfizzZbecauseZofZgasZdissolvedZinZtheZsolution.ZWhatZincreasesZtheZco
ncentrationZofZgasZinZaZsolution?



a)ZcoolingZtheZsolutionZ

b)ZheatingZtheZsolutionZ

,c)ZincreasingZtheZvolumeZofZsolutionZ

d)ZdecreasingZtheZvolumeZofZsolutionZ-ZCORRECTZANSWERSa)ZcoolingZtheZsolutionZ



Henry'sZlawZc=kPZ

Henry'sZlawZconstantZisZaZconstantZforZaZgasZatZaZgivenZtemperatureZandZasZtemperatureZincreases,Z
solubilityZofZtheZgasZdecreasesZorZkZdecreases.ZTherefore,ZheatingZtheZbeverageZwillZdecreaseZtheZc
oncentrationZofZtheZgas



WhenZ100.0ZgZofZanZunknownZcompoundZwasZdissolvedZinZ1.00ZkgZofZwater,ZtheZfreezingZpointZwas
ZloweredZbyZ6.36C.ZWhatZisZtheZidentityZofZthisZunknownZcompound?Z(KfZforZwaterZ=Z1.86ZC/m)




a)ZCsClZ

b)ZKCl

c)ZLiF

d)ZNaClZ-ZCORRECTZANSWERSd)ZNaCl



molalZconcentrationZ=Z(molZsolute)/(massZsolvent)



WhichZ0.1ZmolalZaqueousZsolutionZwillZhaveZtheZlowestZfreezingZpoint?Z



a)ZAl(NO3)3Z

b)ZCaCl2

c)ZC2H5OH

d)ZNaClZ-ZCORRECTZANSWERSa)ZAl(NO3)3



WhichZpairZofZcompoundsZwillZformZhydrogenZbondZwithZoneZanother?

, a)ZCH4ZandZH2O

b)ZCH4ZandZNH3

c)ZHFZandZCH4

d)ZH2OZandZNH3Z-ZCORRECTZANSWERSd)ZH2OZandZNH3



WhatZwouldZbeZexpectedZtoZbeZtheZmostZsolubleZinZethanolZ(CH3CH2OH)?



a)ZCH3CH2CH3

b)ZCO2

c)ZNH3Z

d)ZSF6Z-ZCORRECTZANSWERSc)ZNH3



WhichZsubstanceZisZmostZsolubleZinZwater?Z



a)Zethane,ZCh3CH3Z

b)Zethanol,ZCH3CH2OHZ

c)Zn-butane,ZCH3CH2CH2CH3

d)Z1-butanol,ZCH2CH2CH2CH2OHZ-ZCORRECTZANSWERSb)Zethanol,ZCH3CH2OH



ConsiderZtheZstructureZofZVitaminZV1Z(C20H30O).ZVitaminZA1ZshouldZbeZ



a)ZinsolubleZinZwaterZandZinZoilZ

b)ZlessZsolubleZinZwaterZthanZinZoilZ

c)ZequallyZsolubleZinZwaterZandZoilZ

d)ZmoreZsolubleZinZwaterZthanZinZoilZ-ZCORRECTZANSWERSb)ZlessZsolubleZinZwaterZthanZinZoil