signature:
139
version number
Yasmeen Zubair
(ykz57)
EXAM 1
Sparks Class (50155)
Water Data
K
f
= 1
.
86
◦
C/
m
K
b
= 0
.
512
◦
C/
m
C
ice
= 2
.
09 J/g
◦
C
C
water
= 4
.
184 J/g
◦
C
C
steam
= 2
.
09 J/g
◦
C
Δ
H
fusion
= 334 J/g
Δ
H
vapor
= 2260 J/g
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Version 139 – Exam 1 – sparks – (50155)
2
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print-out
should
have
20
questions.
Multiple-choice questions may continue on
the next column or page – find all choices
before answering.
0014.0pointsThe lattice energy of NaBr is 735 kJ/mol. Theheat of hydration for NaBr is -736 kJ/mol.What is the ΔHsolnfor NaBr dissolving inwater?1.negative ; small
1.1471 kJ/mol2.none of the other answers is correct3.+1 kJ/mol4.-1471 kJ/mol5.-1 kJ/molcorrectExplanation:None0024.0pointsIdentify the FALSE statement aboutKsp.1.Kspis dependent on temperature.2.Kspis called the solubility product for asaturated solution.3.Kspis used to describe salt solutionswhere the minimum amount of salt has beendissolved into the solvent.correct4.Kspis a constant that is specific to eachcompound.5.Kspis a function of the concentrations ofions coming from a given salt.Explanation:Kspis used to describe a solution at satura-tion which is a condition with themaximumconcentration of ions is present (not mini-mum).0034.0pointsA compound is extremely soluble in water.2.negative ; largecorrect3.positive ; small4.positive ; largeExplanation:extremely soluble = spontaneous = nega-tive ΔGextremely soluble = much higher concen-trations when saturated which means a largevalue forKsp0044.0pointsWhat isKspfor Ag3PO4, if its molar solubilityis 2.7×10−6mol/L?1.5.3×10−232.1.7×10−143.5.3×10−164.2.0×10−175.4.8×10−226.7.3×10−127.1.4×10−21correctExplanation:S= 2.7×10−6mol/LThe solubility equilibrium isAg3PO4(s)⇀↽3 Ag+(aq) + PO3−4(aq)[Ag+] = 3S= 8.1×10−6mol/L[PO3−4] =S= 2.7×10−6mol/LKsp= [Ag+]3[PO
You would expect Δ
G
for this dissolution
process to be (negative/positive) and that this
compound would have a (large/small)
K
sp
value.
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- Fall '07
- Holcombe
- Solubility, Solubility equilibrium
