Nomen
Dies
Recitation
Magistra
1. In a redox reaction, how does the total number of
electrons lost by the oxidized substance compare to the
total number of electrons gained by the reduced
substance?
7. Base your answer to the following question on the
diagram below which represents a chemical cell at 298 K
and 1 atmosphere.
A) The number lost is always greater than the number
gained.
B) The number lost is always equal to the number
gained.
C) The number lost is sometimes equal to the number
gained.
D) The number lost is sometimes less than the number
gained.
2. In an electrolytic cell, to which electrode will a positive
ion migrate and undergo reduction?
A)
B)
C)
D)
the anode, which is negatively charged
the anode, which is positively charged
the cathode, which is negatively charged
the cathode, which is positively charged
3. Given the redox reaction:
2 Cr(s) + 3 Sn2+(aq)
B) Sn2+
2 Cr 3+(aq) + 3 Sn(s)
C) Cr 3+
D) Sn
4. What is the oxidation number of sulfur in Na2S2O3?
A) –2
B) +2
C) +6
D) 0
5. An oxidation-reduction reaction involves the
A)
B)
C)
D)
A) Zn
B) Zn2+
C) Cu
D) Cu2+
8. What occurs during the reaction below?
4 HCl + MnO2 ® MnCl2 + 2 H2O + Cl2
Which species serves as the reducing agent?
A) Cr
Which species represents the cathode?
A) The manganese is reduced and its oxidation
number changes from +4 to +2.
B) The manganese is oxidized and its oxidation
number changes from +4 to +2.
C) The manganese is reduced and its oxidation number
changes from +2 to +4.
D) The manganese is oxidized and its oxidation
number changes from +2 to +4.
sharing of electrons
sharing of protons
transfer of electrons
transfer of protons
6. Which half-reaction can occur at the anode in a voltaic
cell?
A) Ni 2+ + 2e - ® Ni
C) Zn ® Zn2+ + 2e -
B) Sn + 2e - ®Sn2+
D) Fe 3+ ® Fe 2+ + e -
Version 1
9. Base your answer to the following question on the
equation and diagram below represent an electrochemical
cell at 298 K and 1 atmosphere.
13. In a chemical cell composed of two half-cells, ions are
allowed to flow from one half-cell to another by means
of
A)
B)
C)
D)
electrodes
a voltmeter
an external conductor
a salt bridge
14. Which energy conversion must occur in an operating
electrolytic cell?
A)
B)
C)
D)
electrical energy to chemical energy
electrical energy to nuclear energy
chemical energy to electrical energy
chemical energy to nuclear energy
15. The overall reaction in a electrochemical cell is
Zn(s) + Cu2+(aq) ® Zn2+(aq) + Cu(s).
As the reaction in this cell takes place, the
Which species is oxidized when the switch is closed?
B) Mg 2+ (aq)
D) Ag+ (aq)
A) Mg(s)
C) Ag(s)
10. What is the oxidation state of nitrogen in the compound
NH 4Br?
A) –1
B) +2
C) –3
electrical energy spontaneously
chemical energy spontaneously
electrical energy nonspontaneously
chemical energy nonspontaneously
12. Given the reaction:
Cu(s) + 4 HNO 3(aq)
H2O( )
mass of the Zn(s) electrode decreases
mass of the Cu(s) electrode decreases
Cu2+(aq) concentration remains the same
Zn2+(aq) concentration remains the same
16. Given the balanced equation representing a redox
reaction:
D) +4
11. During the operation of a voltaic cell, the cell produces
A)
B)
C)
D)
A)
B)
C)
D)
2Al + 3Cu2+ ® 2Al3+ + 3Cu
Which statement is true about this reaction?
A)
B)
C)
D)
Each Al loses 2e – and each Cu 2+ gains 3e–.
Each Al loses 3e– and each Cu 2+ gains 2e–.
Each Al3+ gains 2e– and each Cu loses 3e –.
Each Al3+ gains 3e– and each Cu loses 2e –.
17. Which energy conversion occurs in a voltaic cell?
Cu(NO 3) 2(aq) + 2 NO2(g) + 2
As the reaction occurs, what happens to copper?
A) It undergoes reduction and its oxidation number
decreases.
B) It undergoes reduction and its oxidation number
increases.
C) It undergoes oxidation and its oxidation number
decreases.
D) It undergoes oxidation and its oxidation,
number increases.
A)
B)
C)
D)
chemical energy to electrical energy
chemical energy to nuclear energy
electrical energy to chemical energy
nuclear energy to electrical energy
18. Given the balanced equation representing a reaction:
2KClO 3(s)
2KCl(s) + 3O 2(g)
The oxidation state of chlorine in this reaction changes
from
A) –1 to +1
C) + l to –1
B) –1 to +5
D) +5 to –1
Version 1
19. Which balanced equation represents a redox reaction?
A)
B)
C)
D)
AgNO3 + NaCl ® AgCl + NaNO 3
BaCl2 +K2CO 3 ® BaCO 3 +2KCl
CuO + CO ® Cu + CO2
HCl + KOH ® KCl + H 2O
20. Given the balanced ionic equation:
24. Given the balanced equation representing a reaction:
2Fe + 3Cu2+ ® 2Fe 3+ + 3Cu
When the iron atoms lose six moles of electrons, how
many moles of electrons are gained by the copper ions?
A) 12 moles
C) 3 moles
B) 2 moles
D) 6 moles
25. Which is the oxidizing agent in the reaction
Which equation represents the oxidation half-reaction?
A)
B)
C)
D)
2e–
Zn2+(aq)
Zn(s) +
Zn(s)
Zn2+(aq) + 2e–
Cu2+(aq)
Cu(s) + 2e–
Cu2+(aq) + 2e– Cu(s)
21. The diagram below shows a key being plated with
copper in an electrolytic cell
2 Fe2+ + Cl2 ® 2 Fe3+ + 2 Cl– ?
A) Fe 2+
B) Cl 2
C) Fe 3+
D) Cl –
26. According to Reference Table J, which metal will react
with Zn 2+ but will not react with Mg2+?
A) Al(s) B) Cu(s) C) Ni(s) D) Ba(s)
27. Base your answer to the following question on the
information below.
During a laboratory activity, a student reacted a piece of
zinc with 0.1 M HCl(aq).
Based on Reference Table J, identify one metal that
does not react spontaneously with HCl(aq).
Given the reduction reaction for this cell:
Cu2+(aq) + 2e-
Cu(s)
This reduction occurs at
A)
B)
C)
D)
A, which is the anode
A, which is the cathode
B, which is the anode
B, which is the cathode
22. Which reaction occurs spontaneously?
A)
B)
C)
D)
Cl 2(g) + 2NaBr(aq)
Br2( ) + 2NaCl(aq)
Cl 2(g) + 2NaF(aq) F2(g) + 2NaCl(aq)
I 2(s) + 2NaBr(aq) Br 2( ) + 2NaI(aq)
I 2(s) + 2NaF(aq) F2(g) + 2NaI(aq)
23. During which process does an atom gain one or more
electrons?
A) transmutation
C) oxidation
B) reduction
D) neutralization
Version 1
28. Base your answer to the following question on the following redox reaction, which occurs spontaneously.
Which species loses electrons and which species gains electrons?
Base your answers to questions 29 and 30 on
the information below.
Metallic elements are obtained from their ores by reduction. Some metals, such as zinc, lead, iron, and
copper, can be obtained by heating their oxides with carbon.
More active metals, such as aluminum, magnesium, and sodium, can not be reduced by carbon. These
metals can be obtained by the electrolysis of their molten (melted) ores. The diagram below represents an
incomplete cell for the electrolysis of molten NaCl. The equation below represents the reaction that occurs
when the completed cell operates.
29. Identify one metal from the passage that is more active than carbon and one metal from the passage that is
less active than carbon.
30. Identify the component required for the electrolysis of molten NaCl that is missing from the cell diagram.
Version 1
Base your answers to questions 31 through 33 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.
31. Determine the number of moles of Al(s) needed to completely react with 9.0 moles of Ni 2+(aq) ions.
32. State, in terms of energy, why this cell is a voltaic cell.
33. Write a balanced half-reaction equation for the oxidation that occurs when the switch is closed.
34. Zinc metal reacts with hydrochloric acid to produce zinc chloride and hydrogen gas according to the
reaction below:
Zn(s) + HCl(aq)
ZnCl2 + H2(g)
a Explain why this reaction is classified as an oxidation-reduction reaction.
b Which reactant is oxidized? Explain your answer.
c What is the oxidation number of zinc in zinc chloride?
Version 1
Base your answers to questions 35 and 36 on the information below.
Underground iron pipes in contact with moist soil are likely to corrode. This corrosion can be prevented
by applying the principles of electrochemistry. Connecting an iron pipe to a magnesium block with a wire
creates an electrochemical cell. The magnesium block acts as the anode and the iron pipe acts as the
cathode. A diagram of this system is shown below.
35. Explain, in terms of reactivity, why magnesium is preferred over zinc to protect underground iron pipes.
Your response must include both magnesium and zinc.
36. State the direction of the flow of electrons between the electrodes in this cell.
Version 1
Version 1
Chemistry[2015-2016 Redox Practice Test[4/27/2016]]- New York
Total Questions: 36
3. Matter is made up of particles whose properties determine the observable characteristics
of matter and its reactivity. (22)
3.2. Use atomic and molecular models to explain common chemical reactions. (22)
3.2.d. An oxidation-reduction (redox) reaction involves the transfer of electrons (e-). (4)
3.2.l. An electrolytic cell requires electrical energy to produce a chemical change. This process is
known as electrolysis. (2)
3.2.i. Oxidation numbers (states) can be assigned to atoms and ions. Changes in oxidation
numbers indicate that oxidation and reduction have occurred. (5)
3.2.j. An electrochemical cell can be either voltaic or electrolytic. In an electrochemical cell,
oxidation occurs at the anode and reduction at the cathode. (3)
3.2.k. A voltaic cell spontaneously converts chemical energy to electrical energy. (5)
3.2.h. A half-reaction can be written to represent oxidation. (2)
3.2.e. Reduction is the gain of electrons. (1)
Exam Question Summary
2015-2016 Redox Practice Test
#
QID# Ans Thinking Skills
1
5419
2
4/27/2016
Difficulty
Standards
B
Intermediate
3.2.d.
1009
C
Basic
3.2.l.
3
4290
A
Unassigned
4
2456
B
Intermediate
3.2.i.
5
7051
C
Unassigned
3.2.d.
6
5527
C
Intermediate
3.2.j.
7
894
C
Intermediate
3.2.k.
8
4339
A
Intermediate
3.2.i.
9
2382
A
Basic
3.2.j.
10
6725
C
Advanced
3.2.i.
11
7475
A
Unassigned
12
4836
D
Unassigned
3.2.i.
13
43
D
Basic
3.2.k.
14
7563
A
Unassigned
15
1921
A
Intermediate
3.2.j.
16
5930
B
Intermediate
3.2.d.
17
6290
A
Basic
3.2.k.
18
6476
D
Unassigned
3.2.i.
19
5842
C
Intermediate
3.2.h.
20
5615
B
Unassigned
3.2.h.
21
5273
B
Unassigned
3.2.l.
22
6639
A
Intermediate
3.2.k.
23
6537
B
Intermediate
3.2.e.
24
6535
D
Advanced
3.2.d.
25
276
B
Basic
26
4453
A
Basic
27
6044
n/a
Unassigned
28
4931
n/a
Intermediate
29
7437
n/a
Unassigned
Applying
3.2.k.
Version 1
Exam Question Summary
2015-2016 Redox Practice Test
#
QID# Ans Thinking Skills
Difficulty
30
7436
n/a
Unassigned
31
7354
n/a
Unassigned
32
7355
n/a
Unassigned
33
7353
n/a
Unassigned
34
4723
n/a
Unassigned
35
6581
n/a
Advanced
36
6580
n/a
Advanced
4/27/2016
Standards
Version 1
Answer Key
2015-2016 Redox Practice Test
1.
B
30.
–source of electrical
energy –battery
2.
C
3.
A
31.
6.0 mol.
4.
B
32.
5.
C
6.
C
7.
C
8.
A
9.
A
—A spontaneous
reaction converts
chemical energy to
electrical energy.
—A battery is
not required to
provide energy for the
cell to operate.
10.
C
33.
11.
A
12.
D
—Al ® 3e – +
Al 3+ — 2Al ®
2Al 3+ + 6e –
13.
D
34.
14.
A
15.
A
16.
B
17.
A
18.
D
a) There is a transfer
of electrons. or The
oxidation states
changed. b) The zinc
is oxidized because it
lost electrons. or The
zinc because it went
from a zero oxidation
state to a +2. c) +2
19.
C
35.
20.
B
21.
B
22.
A
23.
B
24.
D
25.
B
Examples: –
Magnesium atoms
lose electrons more
easily than zinc
atoms. – Mg oxidizes
more readily than Zn.
– Mg is more active
than Zn.
26.
A
36.
Examples: – Electrons
flow from the
magnesium block to
the iron pipe. –
Electrons flow from
the Mg to the Fe
through the wire. –
Electrons flow from
the anode to the
cathode in a voltaic
cell. – from the block
to the pipe
27.
Examples: –Cu –Ag
–gold
28.
Zn (not Zn2+ ) loses
electrons and Cr3+
(not Cr) gains
electrons.
29.
–More active than
carbon: aluminum,
Mg, or Na
–Less active than
carbon: zinc, Pb, Fe,
copper
Version 1
Question ID's in Test
Order
1. 5419
2. 1009
3. 4290
4. 2456
5. 7051
6. 5527
7. 894
8. 4339
9. 2382
10. 6725
11. 7475
12. 4836
13. 43
14. 7563
15. 1921
16. 5930
17. 6290
18. 6476
19. 5842
20. 5615
21. 5273
22. 6639
23. 6537
24. 6535
25. 276
26. 4453
27. 6044
28. 4931
29. 7437
30. 7436
31. 7354
32. 7355
33. 7353
34. 4723
35. 6581
36. 6580
Version 1