Name:
Student Number:
CHEM 120 – Quiz 3, 4 September 2013
For each of the following questions, circle the correct answer.
1
For solid PbI2 is in contact with pure water (Ksp for PbI2 = 7.9 x 10-9), what is the molar
concentrations of ions in solution?
A. [Pb2+] = 1.3 x 10-3 M and [I-] = 2.5 x 10 -3 M
B. [Pb2+] = 1.6 x 10-3 M and [I-] = 3.2 x 10-3 M
C. [Pb2+] = 2.0 x 10-3M and [I-] = 2.0 x 10-3M
D. [Pb2+] = 4.4 x 10-5M and [I-] = 2.2 x 10-5M
2
A mass of 100.0 g of water was placed in a calorimeter. The temperature of the water was
recorded as 295.0 K. A 20.0 g copper block was heated to 353.0 K and then dropped into the
water in the calorimeter. What was the final temperature of the water if the specific heat
capacities of water and copper are 4.18 and 0.385 J K–1 g–1, respectively?
A. 307.2 K
B. 296.0 K
C. 293.9 K
D. 283.3 K
3
For a spontaneous reaction,
A. H < 0, S > 0, G < 0
B. H >0, S >0, G > 0
C. H > 0, S <0, G > 0
D. H = 0, S = 0, G = 0
4
Carbon occurs in two forms, graphite and diamond. Given that the enthalpy for combustion of
graphite is  393.5 k J mol-1 and that of diamond is  395.4 k J mol-1, the enthalpy for the
conversion of graphite to diamond is
A. 788.9 k J
B. + 1.9 k J
C. + 788.9 k J
D. 3.8 k J
Name:
Student Number:
CHEM 120 – Quiz 3, 6 September 2013
For each of the following questions, circle the correct answer.
1
The molar solubility of PbBr2 is 2.17 x 10-3 M at a certain temperature. The Ksp for PbBr2, is:
A. 6.2 x 10-6
B. 6.4 x 10-7
C. 4.1 x 10-8
D. 3.4 x 10-6
2
The specific heat capacity of water is 4.18 J K–1 g–1. What is the enthalpy change when 10.00 g
of water is heated from 285.0 to 300.0 K?
A. 627 kJ
B. 627 J
C. 6.27 kJ
D. 2.79 J
3
Which statement is incorrect about entropy?
A. For a phase change, ΔS = 0.
B. The value of So for a compound or element depends on temperature.
C. The entropy of a system + surroundings increases during a spontaneous, irreversible process.
D. A pure, perfect crystal has zero entropy at 0 K.
4
For the reaction: Fe2O3(s) + 2Al(s) → 2Fe(s) + Al2O3(s), what is the value of ΔrGo( at 298 K)
given that: ΔfGo(Fe2O3,s) = 742 k J mol–1 and ΔfGo(Al2O3,s) = 1582 k J mol–1?
A.
+840 k J per mole of Al2O3
B.
840 k J per mole of Al
C.
840 k J per mole of Fe2O3
D.
+ 2324 k J per mole of Fe2O3 and Al