Name ________________
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Electrochemical Cells Practice Exam
Date:_________________
1. Which energy change occurs in an operating voltaic cell?
1) chemical to electrical
2) electrical to chemical
3) chemical to nuclear
4) nuclear to chemical
2. What is the voltage for a chemical cell that has reached equilibrium?
1) 1.00 V
2) greater than 1.00 V
3) greater than 0.00 V and less than 1.00 V
4) 0.00 V
3. Which half-reaction can occur at the anode in a voltaic cell?
1) Ni 2+ + 2e - ® Ni
2) Sn + 2e - ®Sn2+
3) Zn ® Zn2+ + 2e 4) Fe 3+ ® Fe 2+ + e -
4. Which statement is true for any electrochemical cell?
1)
2)
3)
4)
Oxidation occurs at the anode, only.
Reduction occurs at the anode, only.
Oxidation occurs at both the anode and the cathode.
Reduction occurs at both the anode and the cathode.
5. Base your answer to the following question on the diagram of the chemical cell at 298 K and on the equation
below.
In the given reaction, the Ag + ions
1) gain electrons
2) lose electrons
3) gain protons
4) lose protons
6. The electricity produced by a battery results from
1)
2)
3)
4)
an oxidation reaction, only
a reduction reaction, only
both an oxidation reaction and a reduction reaction
neither an oxidation reaction nor a reduction reaction
7. When a voltaic cell operates, ions move through the
1) anode
2) cathode
3) salt bridge
4) external circuit
Chemistry!
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Electrochemical Cells Practice Exam
8. Which component of an electrochemical cell is correctly paired with its function?
1)
2)
3)
4)
external conductor – allows the solutions to mix
external conductor – permits the migration of ions
salt bridge – allows the solutions to mix
salt bridge – permits the migration of ions
9. The diagram below represents an electrochemical cell.
What occurs when the switch is closed?
1) Zn is reduced.
2) Cu is oxidized.
3) Electrons flow from Cu to Zn.
4) Electrons flow from Zn to Cu.
10. The diagram below represents a chemical cell at 298 K.
When the switch is closed, electrons flow from
1) Al(s) to Ni(s)
2) Ni(s) to Al(s)
3) Al 3+(aq) to Ni 2+(aq)
4) Ni 2+(aq) to Al 3+(aq)
Chemistry!
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Electrochemical Cells Practice Exam
11. Base your answer to the following question on the diagram of the chemical cell shown below. The reaction
occurs at 1 atmosphere and 298 K.
When the switch is closed, what occurs?
1)
2)
3)
4)
Pb is oxidized and electrons flow to the Zn electrode.
Pb is reduced and electrons flow to the Zn electrode.
Zn is oxidized and electrons flow to the Pb electrode.
Zn is reduced and electrons flow to the Pb electrode.
12. Which energy conversion occurs in an operating electrolytic cell?
1) chemical energy to electrical energy
2) electrical energy to chemical energy
3) nuclear energy to thermal energy
4) thermal energy to nuclear energy
13. Which reaction occurs at the cathode in an electrochemical cell?
1) combustion
2) neutralization
3) oxidation
4) reduction
14. The diagram below shows a key being plated with copper in an electrolytic cell
Given the reduction reaction for this cell:
Cu2+(aq) + 2e-
Cu(s)
This reduction occurs at
1) A, which is the anode
2) A, which is the cathode
3) B, which is the anode
4) B, which is the cathode
Chemistry!
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Electrochemical Cells Practice Exam
15. Which process requires an external power source?
1) neutralization
2) synthesis
3) fermentation
4) electrolysis
16. Which statement best describes the key?
1) It acts as the cathode and is negative.
2) It acts as the cathode and is positive.
3) It acts as the anode and is negative.
4) It acts as the anode and is positive.
17. Given the redox reaction:
2 Cr(s) + 3 Cu2+(aq) ® 2 Cr3+(aq) + 3 Cu(s)
Which reaction occurs at the cathode in an electrochemical cell?
1) reduction of Cu 2+(aq)
2) reduction of Cu(s)
3) oxidation of Cr3+(aq)
4) oxidation of Cr(s)
18. Base your answer to the following question on the diagram below which represents the electroplating of a
metal fork with Ag(s).
Which equation represents the half-reaction that takes place at the fork?
1) Ag+ + NO 3– ® AgNO3
2) AgNO3 ® Ag+ + NO 3–
3) Ag+ + e – ® Ag(s)
4) Ag(s) ® Ag+ + e –
19. The reaction 2 H2O ( ) ® 2 H2(g) + O 2(g) is forced to occur by use of an externally applied electric
current. This procedure is called
1) neutralization
2) esterification
3) electrolysis
Chemistry!
4) hydrolysis
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Electrochemical Cells Practice Exam
20. Which equation represents the half-cell reaction that occurs at the negative electrode during the electrolysis
of fused calcium chloride?
1) Ca2+ ® Ca(s) + 2e–
2) Ca2+ + 2e – ® Ca(s)
3) 2 Cl – + 2e – ® Cl 2(g)
4) 2 Cl – ® Cl 2(g) + 2e–
Base your answers to questions 21 and 22 on
the information below.
A student constructs an electrochemical cell during a laboratory investigation. When the switch is
closed, electrons flow through the external circuit. The diagram and equation below represent this cell
and the reaction that occurs.
21. State, in terms of energy, why this cell is a voltaic cell.
22. State the direction of electron flow through the wire when the switch is closed.
Chemistry!
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Electrochemical Cells Practice Exam
Base your answers to questions 23 through 25 on the information below.
The diagram below represents an operating electrolytic cell used to plate silver onto a
nickel key. As the cell operates, oxidation occurs at the silver electrode and the mass of the
silver electrode decreases.
23. Explain, in terms of Ag atoms and Ag + (aq) ions, why the mass of the silver electrode decreases as the cell
operates.
24. State the purpose of the power source in the cell.
25. Identify the cathode in the cell.
Chemistry!
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Answer Key
Electrochemical Cells Practice Exam
1.
1
2.
4
3.
3
4.
1
5.
1
6.
3
7.
3
8.
4
9.
4
10.
1
11.
3
12.
2
13.
4
14.
2
15.
4
16.
1
17.
1
18.
3
19.
3
20.
2
21.
&#151;A spontaneous
reaction converts
chemical energy to
electrical energy.
&#151;A battery is
not required to
provide energy for the
cell to operate.
22.
—Electrons flow from
the Al electrode to the
Ni electrode.
—Electrons move left
to right through the
wire.
23.
&#151;Silver atoms
lose electrons and
become silver ions in
the solution. &#151;
Some of the Ag atoms
become Ag + ions.
&#151;Silver atoms
are oxidized to silver
ions.
24.
&#151;The cell
requires electrical
energy for the
non-spontaneous
reaction to occur.
&#151;The power
source causes some
Ag(s) atoms to
oxidize.
25.
Ni(s) key / nickel
Chemistry!
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