1.
[7 points] The solubilty of lead (II) chloride is 1.6  10-2 M. What is the Ksp of
PbCl2?
a.
b.
c.
d.
e.
2.
[7 points] The Ksp for Zn(OH)2 is 5.0  10-17. Determine the molar solubility of
Zn(OH)2 in buffered solution with a pH of 11.50?
a.
b.
c.
d.
e.
3.
5.0  106
1.2  10-12
1.6  10-14
5.0  10-12
5.0  10-17
[7 points] For which salt should the aqueous solubility be most sensitive to pH?
a.
b.
c.
d.
e.
4.
5.0  10-4
4.1  10-6
3.1  10-7
1.6  10-5
1.6  10-2
Ca(NO3)2
CaF2
CaCl2
CaBr2
CaI2
[7 points] Which of the following reagents would increase the solubility of
Ni(OH)2(s)?
Ni(NO3)2
a.
b.
c.
d.
e.
5.
NaOH
HCl
NH3
Ni(NO3)2 & NaOH
HCl
HCl & NH3
HCl, NaOH & NH3
None of these reagents will increase the solubility of Ni(OH)2
[7 points] The solubility of CaCO3 (limestone) is 9.5 mg in 1800 mL. What is
the Ksp of CaCO3 (Formula Weight = 100.1 g/mol)?
a.
b.
c.
d.
e.
2.8  10-5
2.8  10-9
5.2  10-5
5.2  10-9
3.8  10-7
6.
[7 points] What is the pH of a saturated solution of Cu(OH)2 (Ksp = 2.6  10-19)?
a.
b.
c.
d.
e.
7.
[7 points] The solubility of iodide ions in a saturated solution of lead (II) iodide
(Ksp = 1.4  10-8) is _________?
a.
b.
c.
d.
e.
8.
3.8  10-4
3.0  10-3
1.5  10-3
3.5  10-9
1.4  10-8
[7 points] In which one of the following solutions is silver chloride the most
soluble?
a.
b.
c.
d.
e.
9.
7.9
7.6
6.1
9.2
8.8
0.181 M HCl solution
0.0176 M NH3 solution
Pure water
0.744 M LiNO3 solution
0.181 M NaCl solution
[7 points] A solution contains three anions with the following concentrations,
0.20 M CrO42-, 0.10 M CO32- and 0.01 M Cl-. If a dilute AgNO3 solution is slowly
added to the solution what is the first precipitate to form: Ag2CrO4 (Ksp = 1.2 
10-12), Ag2CO3 (Ksp = 8.1  10-12), AgCl (Ksp = 1.8  10-10)?
a.
b.
c.
d.
Ag2CrO4
Ag2CO3
AgCl
No precipitates will form
10. [7 points] The Ksp for BaF2 is 1.0  10-6. When 10 mL of 0.010 M NaF is mixed
with 10 mL of 0.01 M BaNO3 will a precipitate form?
a. No, because Q = 1.0  10-4 and since it is larger than Ksp no precipitate will form
b. Yes, because Q = 1.0  10-4 and since it is larger than Ksp a precipitate will form
c. No, because Q = 1.3  10-7 and since it is less than Ksp no precipitate will
form
d. Yes, because Q = 1.3  10-7 and since it is less than Ksp a precipitate will form
e. Not enough information is given to answer this question
The qualitative analysis procedure for Group III cations (Al3+, Fe3+, Cr3+, Ni2+, Co2+,
Zn2+) begins with the following three steps. Use this information to answer
questions 11-12.
i. Treatment with HCl and H2O2
ii. Evaporation to a paste, followed by addition of dilute HCl
iii. Treatment with a solution containing NH4Cl and NH3
11. [7 points] What is the main purpose of the hydrogen peroxide in the first
step?
a.
b.
c.
d.
e.
To prevent formation of complex ions with chloride
To oxidize Cr3+ to Cr6+
To oxidize Co2+ to Co3+
To insure all of the iron is present as Fe3+
None of the above
12. [7 points] How will the separation be affected if the ammonium chloride is
omitted and excess ammonia is added in the third step?
a. Ni(OH)2 precipitate will form and the Ni2+ ions will end up in the aluminum
subgroup
b. Fe(NH3)63+ complex ions will form and the Fe3+ ions will end up in the nickel
subgroup
c. Al(NH3)63+ complex ions will form and the Al3+ ions will end up in the nickel
subgroup
d. Al(OH)4- complex ions will form and the Al3+ ions will end up in the
nickel subgroup
e. The Cr3+ ions will be oxidized to form CrO42- ions
13. [7 points] What color is Ni(NH3)62+(aq)?
a.
b.
c.
d.
e.
blue
red
orange
yellow
pink
14. [7 points] A solution contains three of the following cations: Sn4+, Sb5+, Co2+,
Fe3+, Cr3+, Bi3+ and Ag+. When HCl was added and the test tube was chilled, a
white precipitate (ppt A) formed. The supernatant liquid (sol’n B) was
decanted from the precipitate. HNO3 and thioacetamide (CH3CSNH2) were
added to sol’n B and the solution was heated. This led to the formation of a
yellow precipitate (ppt C). The supernatant liquid (sol’n D) was decanted from
the precipitate, and the solution was evaporated to a paste. The residue was
dissolved in dilute HCl. Finally NH4Cl and NH3 were added and a pink solution
was formed in the but no precipitate. Which three cations must be present?
a.
b.
c.
d.
e.
Ag+, Co2+ & Sb4+
Cr3+, Co2+ & Sn4+
Bi3+, Co2+ & Fe3+
Ag+, Cr3+ & Sn4+
Ag+, Co2+ & Sn4+
15. [7 points] A solution may contain any or all of the following ions: Cu2+, Ni2+,
Pb2+, Al3+ and Sn4+. The acidity of the solution was adjusted to a pH = 0.4 with
HNO3 and thioacetamide (CH3CSNH2) was added. Heating produced a black
precipitate (ppt A), and a green solution (sol’n B). Ppt A didn’t dissolve in 3 M
NaOH but it did dissolve in 6 M HNO3 producing a colorless solution. Sol’n B
was evaporated to a paste and dissolved in dilute HCl. Finally NH4Cl and NH3
were added and a blue solution was formed but no precipitate. Which cations
must be present?
a.
b.
c.
d.
e.
Pb2+ and Al3+
Cu2+, Ni2+ and Sn4+
Pb2+, Ni2+ and Al3+
Pb2+ and Ni2+
Pb2+, Ni2+ and Sn4+
16. [7 points] What reagent could be used to separate Pb2+ and Bi3+?
a.
b.
c.
d.
e.
H2SO4
HNO3
Thioacetamide, CH3CSNH2 and heat
NH3
NaOH
17. [7 points] What happens when Bi(OH)3 is brought in contact with Sn(OH)3ions?
a.
b.
c.
d.
e.
A Sn(OH)2 precipitate forms
Tin is reduced to metallic tin, Sn, and bismuth is oxidized to Bi5+
Tin is oxidized to Sn4+, and bismuth is reduced to metallic bismuth, Bi
The Bi(OH)3 dissolves due to the common ion effect
There is no reaction between these two substances
18. [7 points] The formation constant, Kf, for Ni(NH3)62+ is 5.5  108. What is the
concentration of free nickel ions in a solution that contains 0.045 M Ni2+ and
3.0 M NH3 (concentrations refer to the moment before the formation of the
complex ion)?
a.
b.
c.
d.
e.
0.045 M
3.0  10-11 M
1.1  10-7 M
2.95
None of the above
19. [7 points] The entropy of the universe is _____________?
a. constant
b. continually decreasing
c. continually increasing
d. zero
e. the same as the energy, E
20. [7 points] For which of the following reactions would you expect Srxn to be
positive?
a. 2H2(g) + O2(g)  2H2O(g)
b. 2NO2(g)  N2O4(g)
c. CO2(g)  CO2(s)
d. 2Hg(l) + O2(g)  2HgO (s)
e. None of the above reactions will have a positive S
21. [7 points] The combustion of butane can be expressed with the following
reaction:
2 C4H10(g) + 13 O2(g)  8 CO2(g) + 10 H2O(g)
What sign would you expect for the enthalpy, entropy and Gibbs free energy?
a.
b.
c.
d.
e.
S < 0 (negative), H < 0 (negative), G < 0 (negative)
S > 0 (positive), H < 0 (negative), G < 0 (negative)
S > 0 (positive), H > 0 (positive), G > 0 (positive)
S < 0 (negative), H > 0 (positive), G > 0 (positive)
S > 0 (positive), H < 0 (negative), but the sign of G is hard to know for
sure and may change with temperature
Consider the combustion of ethene:
C2H4 (g) + 3O2 (g)  2CO2(g) + 2H2O(l)
And use the following standard thermodynamic quantities as appropriate in problems
22-24.
Hfº
(kJ/mol)
Gfº
(kJ/mol)
Sº
(J/mol-K)
52.3
68.1
219.4
O2 (g)
0
0
205.0
CO2 (g)
-393.5
-394.4
213.6
H2O (l)
-285.8
-237.1
69.9
Compound
C2H4 (g)
22. [7 points] What is the value of S for the combustion of ethene?
a.
b.
c.
d.
e.
-267.4 J/K
-140.9 J/K
-347.6 J/K
+347.6 J/K
+140.9 J/K
23. [7 points] What is the value of G0 for the combustion of ethene under
standard conditions (pressure = 1 atm, T = 298 ºC)?
a.
b.
c.
d.
e.
-699.6 kJ
-1263 kJ
-1124 kJ
-1331 kJ
None of the above
24. [7 points] What is the value of G0 for the combustion of ethene at 800 ºC?
a.
b.
c.
d.
e.
25.
-699.6 kJ
-1197 kJ
-1124 kJ
-1331 kJ
None of the above
[7 points] With thermodynamics one cannot determine ___________ ?
a.
b.
c.
d.
e.
the value of the equilibrium constant
the speed of a reaction
the direction of a spontaneous reactions
the extent of a reaction
the temperature at which a reaction will be spontaneous