Chem 1120 Pretest 3 Summer I 2016
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____
1.
a.
b.
c.
d.
e.
Which of the following solubility product expressions is incorrect?
Cu2S, Ksp = [Cu+][S2]
Co2S3, Ksp = [Co3+]2[S2]3
Ni(CN)2, Ksp = [Ni2+][CN]2
AuI, Ksp = [Au+][I]
Cr(OH)3, Ksp = [Cr3+][OH]3
____
2.
At 25C, 1.4  105 mole of Cd(OH)2 dissolves to give 1.0 liter of saturated aqueous solution. What is
the solubility product for Cd(OH)2?
a. 1.7  105
b. 2.9  1010
c. 1.1  1014
d. 5.8  1015
e. 4.1  1012
____
3.
If X = the molar solubility (mol/L) of Ni(OH)2, which of the following represents the correct
relationship between the Ksp and X, the molar solubility of Ni(OH)2?
a. Ksp = 4 X2
b. Ksp = 4 X3
c. Ksp = 2 X2
d. Ksp = X3
e. Ksp = X2
____
4.
The Ksp for magnesium arsenate is 2.1  1020 at 25C. What is the molar solubility of Mg3(AsO4)2 at
25C?
a. 6.7  103 M
b. 3.6  104 M
c. 4.5  105 M
d. 7.0  105 M
e. 1.4  106 M
____
5.
a.
b.
c.
d.
e.
____
6.
Calculate the concentration of carbonate ion in a saturated solution of calcium carbonate to which
calcium chloride has been added until [Ca2+] = 0.015 M at 25C. Ksp for CaCO3 = 2.8  109.
a. 4.2  1011 M
b. 1.9  107 M
c. 1.2  105 M
Which of the following has the lowest molar solubility in water at 25C?
Ni(CN)2, Ksp = 3.0  1023
ZnS, Ksp = 1.1  1021
PbS, Ksp = 8.4  1028
Co3(AsO4)2, Ksp = 7.6  1029
CaF2, Ksp = 3.9  1016
d. 6.3  1013 M
e. 1.5  102 M
____
7.
The molar solubility of BaCO3 is 9.0  105 M at 25C. What is the solubility product constant for
BaCO3?
a. 1.2  108
b. 8.1  109
c. 5.3  1012
d. 4.0  1015
e. 6.7  1011
____
8.
A solution contains 0.05 M Au+, 0.05 M Cu+, and 0.05 M Ag+ ions. When solid NaCl is added to the
solution, what is the order in which the chloride salts will begin to precipitate? Ksp(AgCl) = 1.8  1010, Ksp(AuCl) =
2.0  1013, Ksp(CuCl) = 1.9  107
a. AuCl > AgCl > CuCl
b. AuCl > AgCl > NaCl
c. AgCl > CuCl > AuCl
d. CuCl > AgCl > AuCl
e. NaCl > CuCl > AgCl
____
9.
A solution is 0.0010 M in both Ag+ and Au+. Some solid NaCl is added slowly until the second solid
compound just begins to precipitate. What is the concentration of Au + ions at this point? Ksp for AgCl = 1.8 
1010 and for AuCl is 2.0  1013.
a. 2.0  1010 M
b. 4.5  107 M
c. 1.8  107 M
d. 3.0  104 M
e. 1.1  106 M
____
10.
Solid silver nitrate is added slowly to a solution that is 0.0010 M in sodium chloride and 0.0010 M in
sodium bromide. What % of the bromide ions remain in solution, i.e., unprecipitated, just before silver
chloride begins to precipitate? Ksp for AgCl = 1.8  1010, Ksp for AgBr = 3.3  1013
a. 0.18%
b. 0.018%
c. 0.0010%
d. 0.00010%
e. 0.0018%
____
11.
a.
b.
c.
d.
e.
____
12.
AgCl would be least soluble at 25C in ____.
a. pure water
b. 0.1 M CaCl2
c. 0.1 M HCl
Calculate the concentration of F ions in saturated CaF2 solution at 25C. Ksp = 3.9  1011.
2.1  104 M
4.3  104 M
0.016 M
0.032 M
0.10 M
d. 0.1 M HNO3
e. It is equally soluble in all of these substances.
____
13.
Given the following values of Ksp for four slightly soluble sulfides at 25C.
Sulfide
CdS
CuS
Ksp
3.6  1029
8.7  1036
Sulfide
PbS
MnS
Ksp
8.4  1028
5.1  1015
Which one of the following ions exists in the lowest concentration in a solution in which the sulfide ion
concentration had been fixed at some (fairly large) constant value at 25C?
a. Cd2+
b. Cu2+
c. Pb2+
d. Mn2+
e. Cannot be answered without knowing the sulfide ion concentration.
Ksp for lead fluoride is 3.7  108. What is the molar solubility of PbF2 in 0.10 M NaF?
4.6  105 M
1.9  104 M
3.7  107 M
3.7  106 M
8.5  108 M
____
14.
a.
b.
c.
d.
e.
____
15.
If a solution is to be made 0.010 M in Mg(NO3)2 and 0.20 M in aqueous NH3, how many mol/L of
NH4Cl are required to prevent the precipitation of Mg(OH) 2 at 25C? The Kb for aqueous NH3 is 1.8  105
and the Ksp for Mg(OH)2 is 1.5  1011.
a. 0.054
b. 0.56
c. 0.092
d. 1.8
e. 0.86
Chapter 19 Values
The following equilibrium constants will be useful for the problems in this chapter.
Substance
HCO2H
HNO2
HOCl
HF
HCN
H2SO4
HOBr
____
Constant
Ka = 1.8  104
Ka = 4.5  104
Ka = 3.5  108
Ka = 7.2  104
Ka = 4.0  1010
K1 = very large
K2 = 1.2  102
Ka = 2.5  109
Substance
H2CO3
(COOH)2
CH3COOH
HOCN
C6H5NH2
NH3
Constant
K1 = 4.2  107
K2 = 4.8  1011
K1 = 5.9  102
K2 = 6.4  105
Ka = 1.8  105
Ka = 3.5  104
Kb = 4.2  1010
Kb = 1.8  105
16.
A(n) ____ solution contains a conjugate acid-base pair with both the acid and the base in reasonable
concentrations.
a. saturated
b.
c.
d.
e.
electrolytic
buffer
titrated
equivalence
____
17.
a.
b.
c.
d.
e.
Calculate the [H3O+] of a solution that is 0.20 M in HF and 0.10 M in NaF.
3.2  104 M
4.0  106 M
1.4  103 M
6.3  105 M
5.0  103 M
____
18.
a.
b.
c.
d.
e.
A solution that is 0.20 M in NH3 is also 0.30 M in NH4Cl. What is the [OH] in this solution?
4.5  106 M
1.2  105 M
7.4  105 M
6.4  104 M
2.4  107 M
____
19.
a.
b.
c.
d.
e.
What is the [H3O+] of a solution that is 0.010 M in aqueous NH3 and 0.030 M in NH4NO3?
7.2  106 M
6.0  106 M
1.7  109 M
1.4  109 M
1.2  109 M
____
20.
Choose the response that includes all the following combinations that are buffer solutions and none
that are not buffer solutions. All components are present in 0.10 M concentrations.
I.
HCN and NaCN
II.
NH3 and NH4Cl
III.
HNO3 and NH4NO3
IV.
H2SO4 and Na2SO4
a.
b.
c.
d.
e.
I, III, and IV
I and II
II, III, and IV
III and IV
I and III
____
21.
A solution is initially 0.100 M in HOCl and 0.300 M in NaOCl. What is the pH if 0.030 mol of solid
NaOH is added to 1.00 L of this solution? Assume no volume change.
a. 5.24
b. 5.38
c. 8.02
d. 8.13
e. 9.06
____
22.
What is the pH of a solution that is 0.15 M in HOCl and 0.25 M NaOCl after 0.050 mol HCl/L has
been bubbled into the solution?
a. 7.46
b.
c.
d.
e.
6.15
6.98
7.23
7.93
____
23.
It is desired to buffer a solution at pH = 4.30. What molar ratio of CH 3COOH to NaCH3COO should
be used?
a. 1.2/1
b. 0.8/1
c. 0.12/1
d. 2.8/1
e. 6.2/1
____
24.
Calculate the mass of solid NaCH3COO that must be added to 1.0 liter of 0.20 M CH3COOH solution
so that the pH of the resulting solution will be 5.00. Assume no volume change due to addition of solid
NaCH3COO.
a. 15 g
b. 20 g
c. 25 g
d. 30 g
e. 35 g
____
25.
Calculate the pH for a buffer solution prepared by mixing 100. mL of 0.60 M NH3 and 200. mL of
0.45 M NH4Cl.
a. 8.65
b. 9.08
c. 9.87
d. 4.90
e. 6.62
____
26.
Which titration curve could describe the titration of a solution of CH 3COOH by addition of a solution
of KOH?
a.
b.
c.
d.
e.
____
27.
a.
b.
c.
d.
e.
What is G0 at 25C for the reaction below? (F = 96,500 J/Vmol e)
Cu2+ + Cd  Cu + Cd2+
71.1 kJ
143 kJ
597 kJ
193 kJ
+71.1 kJ
Chapter 21 Values
A table of standard electrode potentials is necessary for many of the following question(s).
____
28.
Which of the following shorthand galvanic cell notations for the zinc  copper standard cell is
correct?
Cu2+ + Zn  Zn2+ + Cu
a.
b.
c.
d.
e.
Cu2+ | Cu || Zn | Zn2+
Cu2+ | Cu || Cu | Cu2+
Cu2+ | 2e || 2e | Zn
Zn | Zn2+ || Cu2+ | Cu
Zn | Cu2+ || Zn2+ | Cu
____
29.
A voltaic cell is constructed by immersing a strip of copper metal in 1.0 M CuSO4 solution and a strip
of aluminum in 0.50 M Al2(SO4)3 solution. A wire and a salt bridge complete the circuit. The aluminum strip
loses mass, and the concentration of aluminum ions in the solution increases. The copper electrode gains
mass, and the concentration of copper ions decreases. What is the cell potential?
a. +1.28 V
b. +2.00 V
c. +2.34 V
d. +2.50 V
e. +3.66 V
____
30.
Calculate the cell potential for the following voltaic cell.
Cr|Cr3+(1.0  102 M)||Co2+(1.0  105 M)|Co
a. +0.35 V
b.
c.
d.
e.
+0.91 V
+0.57 V
+0.28 V
1.13 V
____
31.
Which of the following statements about the operation of a standard galvanic cell made of a Cu/Cu 2+
half-cell and a Ag/Ag+ half-cell is false?
a. The mass of the copper electrode decreases.
b. The electrons flow from the copper electrode to the silver electrode.
c. The [Cu2+] increases.
d. Positive ions enter into the Ag/Ag+ half-cell from the salt bridge.
e. The copper electrode is positive.
____
32.
Which one of the following reactions is spontaneous (in the direction given) under standard
electrochemical conditions?
a. Pb2+ + 2I  Pb + I2
b. Cu2+ + Fe  Cu + Fe2+
c. 2Au + Pt2+  2Au+ + Pt
d. Mg2+ + 2Br  Mg + Br2
e. 2Hg + 2Cl + 2H+  Hg2Cl2 + H2
____
33.
The electrolysis of an aqueous sodium chloride solution using inert electrodes produces gaseous
chlorine at one electrode. At the other electrode gaseous hydrogen is produced, and the solution becomes
basic around the electrode. Which of the following is the equation for the cathode half-reaction in this
electrolytic cell?
a. 2Cl  Cl2 + 2e
b. 2H2O + 2e  H2 + 2OH
c. Cl2 + 2e  2Cl
d. H2 + 2OH  2H2O + 2e
e. none of these
____
34.
An aqueous copper(II) sulfate solution is electrolyzed for 45 minutes. A 3.2 ampere current is used.
What mass of copper is produced?
a. 0.95 g
b. 1.9 g
c. 2.8 g
d. 4.6 g
e. 5.5 g
____
35.
a.
b.
c.
d.
e.
____
The equilibrium constant, at 25C, for the reaction below is 1.99  1020. What is E0 for this reaction?
NO3 + 3H+ + Cu  Cu2+ + HNO2 + H2O
0.090 V
0.60 V
0.88 V
1.05 V
0.21 V
36.
The Ksp for Zn3(AsO4)2 is 1.1  1027. When 100 mL of 5.5  104 M Zn2+ is mixed with 50 mL of
1.2  104 M AsO43, which of the following statements is true?
a.
b.
c.
d.
e.
A precipitate forms, because Qsp > Ksp.
A precipitate forms, because Qsp < Ksp.
No precipitate forms, because Qsp > Ksp.
No precipitate forms, because Qsp < Ksp.
None of these statements is true.
____
37.
The solubility of magnesium carbonate, MgCO3, can be increased by acidifying the solution in which
MgCO3 is suspended. This is an example of dissolution via ____.
a. formation of a weak electrolyte
b. reduction of the anion
c. oxidation of the anion
d. formation of a complex ion
e. changing an ion to another species which is not a weak electrolyte
____
38.
Calculate the number of moles of ammonia needed to dissolve 0.0010 mole of silver chloride in 4000.
mL of solution at 25C. Ksp for AgCl is 1.8  1010 and the dissociation constant for [Ag(NH3)2]+ is 6.3  108.
a. 0.16 mole
b. 0.021 mole
c. 14 moles
d. 0.28 mole
e. 1.5 moles
____
39.
In an electrolytic cell, the electrode that acts as a source of electrons to the solution is called the
____; the chemical change that occurs at this electrode is called ____.
a. anode; oxidation
b. anode; reduction
c. cathode; oxidation
d. cathode; reduction
e. Cannot answer unless we know the species being oxidized and reduced.
____
40.
What product is formed at the anode when molten sodium chloride, NaCl, is electrolyzed using a
Downs Cell?
a. O2
b. Cl2
c. NaOH
d. H2
e. Na metal
____
41.
How long would a constant current of 4.5 amperes be required to flow in order to plate out 15 g of
chromium from a chromium(III) sulfate solution?
a. 268 hr
b. 309 hr
c. 5.15 hr
d. 23.2 hr
e. 1.72 hr
____
42.
a.
b.
c.
d.
____
43.
Which of the following is not a feature of the lead storage battery?
The electrolyte is hydrochloric acid.
Lead is oxidized at the anode.
PbO2 is reduced at the cathode.
Lead (II) sulfate forms during discharge and sticks to the electrodes.
Which one of the following formulas could represent a cycloalkane?
a.
b.
c.
d.
e.
C2H6
C3H8
C4H10
C6H12
C7H16
____
44.
a.
b.
c.
d.
e.
When carbon bonds in organic compounds, which of the following are true:
Carbon makes 4 bonds.
Carbon can form single, double or triple bonds.
Carbon atoms can form branched chains.
Carbon forms covalent bonds.
All of these are true.
____
45.
a.
b.
c.
d.
e.
What is the molecular formula for heptane?
C7H14
C7H12
C9H18
C7H16
C9H20
____
46.
a.
b.
c.
d.
e.
____
47.
a.
b.
c.
d.
e.
____
48.
The correct IUPAC name for the compound shown below is ____.
2,2,4-trimethyl-7-propylnonane
7-ethyl-2,2,4-trimethyldecane
3-propyl-6,8,8-trimethylnonane
4-ethyl-7,9,9-trimethylnonane
4-ethyl-7,9,9-trimethyldecane
Give the correct IUPAC name for the compound with the following structural formula.
2-ethyl-1,4-dimethylcyclopentane
3-ethyl-1,4-dimethylcyclohexane
1-ethyl-2,5-dimethylcyclohexane
2-ethyl-1,4-dimethylcyclohexane
cyclic-2-ethyl-1,4-dimethylhexane
Which of the following is the correct formula for 2-methyl-1-butene?
a.
b.
c.
d.
e. none of these
____
____
____
____
49.
a.
b.
c.
d.
e.
50.
is an example of a(n) ____.
acid
aldehyde
phenol
ketone
ether
What is the name for the following compound?
a.
b.
c.
d.
e.
4-ethyl-1,3,5-trimethylbenzene
2-ethyl-1,3,5-trimethylbenzene
1,3,5-trimethyl-4-ethylbenzene
6-ethyl-1,3,5-trimethylbenzene
1-ethyl-2,4,6-trimethylbenzene
51.
a.
b.
c.
d.
e.
acid
aldehyde
phenol
ketone
ether
is an example of a(n) ____.
52.
Which one of the following compounds is not an amine?
a. (CH3)2NH
b. CH3CH2NH2
c. C6H5NH2
d.
e. (CH3)3N
Chem 1120 Pretest 3 Summer I 2016
Answer Section
MULTIPLE CHOICE
1.
ANS:
A
PTS:
1
TOP:
Solubility Product Constants
2.
ANS:
C
PTS:
1
TOP:
Determination of Solubility Product
Constants
3.
ANS:
B
PTS:
1
TOP:
Determination of Solubility Product
Constants
4.
ANS:
C
PTS:
1
TOP:
Uses of Solubility Product Constants
5.
ANS:
C
PTS:
1
TOP:
Uses of Solubility Product Constants
6.
ANS:
B
PTS:
1
TOP:
Uses of Solubility Product Constants
7.
ANS:
B
PTS:
1
TOP:
Determination of Solubility Product
Constants
8.
ANS:
A
PTS:
1
TOP:
Fractional Precipitation
9.
ANS:
E
PTS:
1
TOP:
Fractional Precipitation
10.
ANS:
A
PTS:
1
TOP:
Fractional Precipitation
11.
ANS:
B
PTS:
1
TOP:
Uses of Solubility Product Constants
12.
ANS:
B
PTS:
1
TOP:
Uses of Solubility Product Constants
13.
ANS:
B
PTS:
1
TOP:
Uses of Solubility Product Constants
14.
ANS:
D
PTS:
1
TOP:
Uses of Solubility Product Constants
15.
ANS:
C
PTS:
1
TOP: Simultaneous Equilibria Involving Slightly Soluble Compounds
16.
ANS:
C
PTS:
1
TOP:
The Common Ion Effect and Buffer
Solutions
17.
ANS:
C
PTS:
1
TOP:
The Common Ion Effect and Buffer
Solutions
18.
ANS:
B
PTS:
1
TOP:
The Common Ion Effect and Buffer
Solutions
19.
ANS:
C
PTS:
1
TOP:
The Common Ion Effect and Buffer
Solutions
20.
ANS:
B
PTS:
1
TOP:
Buffering Action
21.
ANS:
D
PTS:
1
TOP:
Buffering Action
22.
ANS:
A
PTS:
1
TOP:
Buffering Action
23.
ANS:
D
PTS:
1
DIF:
Harder Question
TOP: Preparation of Buffer Solutions
24.
ANS:
D
PTS:
1
TOP:
Preparation of Buffer Solutions
25.
ANS:
B
PTS:
1
TOP:
Preparation of Buffer Solutions
26.
ANS:
E
PTS:
1
TOP: Weak Acid/Strong Base and Weak Base/Strong Acid Titration Curves
27.
ANS:
B
PTS:
1
TOP:
The Relationship of E°cell to Delta G° and
K
28.
ANS:
D
PTS:
1
TOP:
The Zinc – Copper Cell
29.
ANS:
B
PTS:
1
TOP:
Uses of Standard Electrode Potentials
30.
ANS:
A
PTS:
1
TOP:
The Nernst Equation
31.
ANS:
E
PTS:
1
TOP:
The Copper – Silver Cell
32.
33.
34.
TOP:
35.
K
36.
37.
38.
TOP:
39.
40.
TOP:
41.
Cells
42.
43.
44.
45.
46.
47.
48.
49.
50.
51.
52.
ANS:
B
PTS:
1
TOP:
Uses of Standard Electrode Potentials
ANS:
B
PTS:
1
TOP:
The Electrolysis of Aqueous Salt Solutions
ANS:
C
PTS:
1
Counting Electrons: Coulometry and Faraday's Law of Electrolysis
ANS:
B
PTS:
1
TOP:
The Relationship of E°cell to Delta G° and
ANS:
A
PTS:
1
TOP:
Uses of Solubility Product Constants
ANS:
A
PTS:
1
TOP:
Dissolving Precipitates
ANS:
B
PTS:
1
DIF:
Harder Question
Dissolving Precipitates
ANS:
D
PTS:
1
TOP:
Electrodes
ANS:
B
PTS:
1
The Electrolysis of Molten Sodium Chloride (the Downs Cell)
ANS:
C
PTS:
1
TOP:
Commercial Applications of Electrolytic
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
A
D
E
D
B
D
A
B
B
D
D
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
1
1
1
1
1
1
1
1
1
1
1
TOP:
TOP:
TOP:
TOP:
TOP:
TOP:
TOP:
TOP:
TOP:
TOP:
TOP:
The Lead Storage Battery
Alkanes and Cycloalkanes
Alkanes and Cycloalkanes
Alkanes and Cycloalkanes
Naming Saturated Hydrocarbons
Naming Saturated Hydrocarbons
Alkenes
Aldehydes and Ketones
Other Aromatic Hydrocarbons
Aldehydes and Ketones
Amines