Chemistry: Matter and Change

Chapter 20: Electrochemistry

Chapter Test Practice

1
Under standard conditions, which of the following is the net reaction that occurs in the cell?

Cd|Cd2+ || Cu2+|Cu
A)Cu + Cd2+ → Cd + Cu2+
B)Cu + Cd → Cu2+ + Cd2+
C)Cu2+ + Cd2+ → Cu + Cd
D)Cu2+ + Cd → Cu + Cd2+
2
Explain why current will not flow in the cell shown.

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A)Copper is not a good conductor.
B)There is no salt bridge to move ions.
C)There is no potential between zinc and copper.
D)There is no load on the wire.
3
When compared to the standard hydrogen electrode, zinc has a reduction potential of -0.762 volts and copper a reduction potential of + 0.342 volts. What is the reduction potential when zinc and copper are connected to one another?

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A)+0.420 volts
B)-0.420 volts
C)+1.104 volts
D)-1.104 volts
4
How does paint protect steel surfaces from corrosion?
A)Paint acts as a sacrificial anode.
B)Paint corrodes leaving steel intact.
C)Paint galvanizes steel.
D)Paint prevents the oxidation-reduction reaction of corrosion from occurring.
5
A redox reaction that is easily reversed, can produce electric energy, and can be recharged is a(n) __________.
A)primary battery
B)secondary battery
C)fuel cell
D)electrolytic cell
6
In a zinc-carbon dry cell, the cell "dies" when ________ is produced.

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A)water vapor
B)manganese (IV) oxide
C)ammonia gas
D)manganese (III) oxide
7
In the diagram, magnesium is the sacrificial anode. Why can magnesium perform this function?

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A)Magnesium is less dense than iron.
B)Magnesium is non-magnetic.
C)Magnesium oxidizes more easily than iron.
D)Magnesium is a better electrical conductor than iron.
8
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 around the electrode becomes basic. Which of the following equations is the correct 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-
9
In the process shown in the diagram, what products are oxidized and what products are reduced?

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A)Chlorine is oxidized, hydrogen is reduced.
B)Water is oxidized, sodium is reduced.
C)Water is reduced, chlorine and water are oxidized.
D)Water is oxidized, chlorine and water are reduced.
10
The Hall-Heroult process uses huge amounts of ________.

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A)electricity
B)carbon
C)electrolyte
D)carbon dioxide
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