Electrochemistry
Practice Test
1.
Which of the following states that an equilibrium system that is disturbed will respond in a manner to restore equilibrium?
SC.A.1.4.4
a.
Dalton’s law
b.
Le Châtelier’s principle
c.
Charles’s law
d.
Boyle’s law
2.
What is the oxidation number of O in Na
2
SO
4
?
a.
-2
b.
6
c.
2
d.
1
3.
A cell is constructed by immersing a strip of lead in a 1.0
M
Pb
NO
3
2
solution and a strip of silver in a 1.0
M
AgNO
3
solution. The circuit is completed by a wire and a salt bridge. As the cell operates, the strip of silver gains mass
only silver
, the strip of lead loses mass, and the concentration of lead ions increases in the solution around the lead strip. Which of the following represents the reaction that occurs at the cathode in this cell?
a.
Pb → Pb
2+
+ 2e
-
b.
Ag
+
+ e
-
→ Ag
c.
Ag → Ag
+
+ e
-
d.
Pb
2+
+ 2e
-
→ Pb
4.
Why are alkaline dry cell batteries smaller in size than zinc-carbon dry cells?
a.
Alkaline batteries do not require steel cases.
b.
No zinc is reduced in the alkaline batteries.
c.
Zinc paste takes up less space than zinc powder.
d.
Alkaline batteries do not need the carbon rod cathode.
5.
Balance the following equation. How many electrons must be transferred between the reducing agent and the oxidizing agent in this reaction?
H
2
S+HNO
3
→S+NO+H
2
0
SC.B.1.4.2
a.
6
b.
4
c.
3
d.
2
6.
How many grams of MgF
2
will dissolve in 150 mL of 0.100
M
NaF solution? Ksp for MgF
2
is 6.4 x 10
-9
.
SC.A.1.4.4
a.
6.0 x 10
-6
g
b.
1.0 x 10
-5
g
c.
6.4 x 10
-7
g
d.
4.1 x 10
-6
g
7.
For the system, H2
g
+ CO2
g
→ H2O
g
+ CO
g
at equilibrium, the addition of H2
g
would cause ____________.
SC.A.1.4.4
a.
more H
2
O and CO to form
b.
only more CO
2
to form
c.
only more H
2
O to form
d.
only more CO to form
8.
Compared to strong acids, weak acids produce __________ ions and conduct electricity __________ efficiently.
SC.C.2.4.5
a.
more, less
b.
fewer, less
c.
fewer, more
d.
more, more
9.
The value of the
K
sp
for SrSO
4
is 2.8 x 10
-7
. What is the molar solubility of SrSO
4
?
SC.A.1.4.5
a.
5.3 x 10
-4
M
b.
5.8 x 10
-13
M
c.
7.6 x 10
-7
M
d.
5.7 x 10
-3
M
10.
A 0.001
M
solution of HCl is ____________.
SC.A.1.4.4
a.
a concentrated acid solution
b.
a dilute acid solution
c.
neutral
d.
a weak acid solution
11.
When the following equation is balanced what is the coefficient of Sn?
Sn +HNO
3
→SnO
2
+NO
2
+H
2
O
SC.B.1.4.2
a.
3
b.
1
c.
4
d.
2
12.
How does paint protect steel surfaces from corrosion?
SC.C.2.4.2
a.
Paint galvanizes steel.
b.
Paint acts as a sacrificial anode.
c.
Paint prevents the oxidation-reduction reaction of corrosion from occurring.
d.
Paint corrodes leaving steel intact.
13.
A voltaic cell consists of a standard hydrogen electrode connected by a salt bridge and a wire to an electrode consisting of a strip of Cd metal dipping into a 1
M
solution of Cd
NO
3
2
. When the cell produces a current, the electrons flow through the wire from the _________ electrode to the ________ electrode. In this cell, the _______ electrode acts as the cathode.
SC.C.2.4.2
a.
H
2
, Cd, H
2
b.
Cd, H
2
, Cd
c.
H
2
, Cd, Cd
d.
Cd, H
2
, H
2
14.
Name the spectator ion in the following equation, including the correct coefficient:
Cu
s
+ 4HNO
3
aq
→ Cu
NO
3
2
aq
+ 2NO
2
+ 2H
2
O
l
a.
3NO
2
b.
3NO
3
c.
2NO
2
d.
2NO
3
15.
Which of the following salts will produce a basic solution?
SC.A.1.4.1
a.
KBr
b.
Ca
NO
3
2
c.
NaCl
d.
KCN
16.
A balanced reaction that shows only the oxidation process is a ___________.
a.
balanced chemical equation
b.
single-replacement reaction
c.
synthesis reaction
d.
half-reaction
17.
During the electrolysis of molten sodium iodide, sodium ions move ________.
SC.A.1.4.1
a.
to the cathode, which is negatively charged
b.
to the anode, which is negatively charged
c.
to the cathode, which is positively charged
d.
to the anode, which is positively charged
18.
Electroplating is an example of __________.
a.
a primary battery
b.
a fuel cell
c.
electrolysis
d.
a galvanic cell
19.
Calculate the H
+
ion and OH
-
ion concentrations in a 0.50
M
solution of HBr.
SC.A.1.4.4
a.
H
+
= 0.50
M
and
OH
-
= 2.0 ´ 10
-14
M
b.
H
+
= 0.50
M
and
OH
-
= 0.50
M
c.
H
+
= 1.0 ´ 10
-7
M
and
OH
-
= 1.0 ´ 10
-7
M
d.
H
+
= 0.50
M
and
OH
-
= 2.0
M
20.
Which of the following reactions is a redox reaction?
a.
2KBr
aq
+ Pb
NO
3
2
aq
→ 2KNO
3
aq
+ PbBr
2
s
b.
2Al
s
+ 3H
2
SO
4
aq
→ Al
2
SO
4
3
aq
+ 3H
2
g
c.
CaBr
2
aq
+ H
2
SO
4
aq
→ CaSO
4
s
+ 2HBr
aq
d.
H
+
aq
+ OH
-
aq
→ H
2
O
l
