_
Name
:
Date
Class
OXIDATION-REDUCTION REACTIONS
Chapter Test B
A. Matching
March each term in Column B with the correct descrip
tion in Column A. Write the
letter ofthe correct term on the line.
Column A
Column B
1. the substance in a redoxreact1on that accepts
electrons
a. oxidation-numberchange method
2. the complete or partial gain of electrons or the loss
of
oxygen
b. reducing agent
3. those ions that do not change oxidation number
or
composition during a reaction
c. oxidation-reduction
reactions
4. a positive or negative number assigned to an atom
according to a set of arbitrary rules
d. spectator ions
5. the complete or partial loss of electrons or the gain
of
oxygen
e. oxidizing agent
6. the balancing of a redox reaction by comparing
the
increases and decreases in oxidation numbers
f. reduction
7. the chemical changes that occur when electrons are
transferred between reactants
g. oxidation number
8. a method of balancing redox reactions by balanc
ing
the oxidation and reduction half-reactions
h. half-reaction method
9. the substance in a redox reaction that donates
electrons
I. oxidation
10. another name for an oxidation-reduction reactio
n.
I. redox reaction
B. Multiple Choice
Choose the best answer and write its letter on the line.
11. Which of the following is true about oxidation reactio
ns?
a. Oxidation reactions are the principal source of energy
on Earth.
b All oxidation reactions are accompanied by reducti
on reactions.
c. The burning of wood ins fireplace and the metabo
lizatlon of
food by your body are oxidation reactions.
d. alloftheahove
12. What Is the oxidized substance In the following reaction?
Fe + 2HCI 2 + H
2
a.Fe
2
c.FeQ
b.HCI
13. The reducing agent in the reaction described in question 12 Is
a.Fe,
.
2
cFeG
h.HCI.
.
2
d.H
14. What is occurring in the following reaction?
2 + Cl
H
2 214(3
a. 2 is being reduced.
b. CL
2 Is being oxidized.
c. H
2 Is gaining two electrons.
d. ci
2 is acting as an oxidizing agent
15. What is the oxidation number of sulfur In 3
S0
2
H
?
a.+1
c.+3
b.+2
d.+4
16. What is the usual oxidation number of oxygen in a compound?
a.—1
c.+1
b.—2
d.+2
17. In the unbalanced equation below; what element is being reduced?
2 + HID! -. H
Mn0
0 + MnCI
2
2 + Cl
2
a.Mn
c.H
b..O
d.Cl
18. Which of the following Is an oxidation reaction?
a. Co—’Co
b. c1
2 —* clO
c. Q-.AuQ
d. Mn
7
—
a reaction?
an oxidationig. Among the oil lg.wh1Ch1S
a. Na+CaC0s2 + ZilsO
)z
3
3 + Mg(OH)- Mg(N0
K ZIiNO
.
0
2
(PO
3
8a
)
z + 6H
P0
3
2H
.4
3Ba(OH) + 4
d. 2
ngonigthe reaction below?
0
2
—’ S + NO + H
3
+
H HNO
S
2
c. Nisreduced.
a. S Is reu
4. Ols
b. Hisoxidized.
coefficient
question 20 Is balanced. what Is the
21. When the equation in
for I4O?
c,3
2
4.6
b.4
20. Which
—
f the foil
0
2 + 4HCI
22. In the equation Pb0
electrons are transferred?
a.1
b.2
-,
O
2
2H
2
PbC1
+
+
, how many
2
Cl
c.3
d.4
23. The element oxidized In the reaction described in question 22 Is
c.H.
a.Pb.
d.CL
b.O.
24. In the unbalanced equation given below, what is the element that Is
gaining electrons?
0 +Q
2
2+H
2 MaO
HO ÷ Mn0
c.Mn
d.O
b.Cl
-,
25. When the equation In question 24 Is balanced, what Is the coefficient
for HCI?
c.3
5.1
4.4
b.2
28. Which of the following Is true concerning redox reactions?
a. Double-replacement reactions are always redox reactions.
b. Single-replacement reactions may be redox reactions.
c. Acid-base reactions are always redox reactions.
d. ailoftheabove
27. Identify afalee statement about how to protect iron from corrosion.
a. Coat the surface withoil, paint, or plastic.
b. Attach a metal that Is more easily reduced.
c. Exclude air and watez
d. Attach a metal that Is a better reducing agent.
28. From the unbalanced equations below, identify the one that does not
represent a redox reaction.
OU
2
C
2
H
(
aq)
0 -. CO(gi + H
a. 3
O(gl—.CO(g+H
C(s)+H
g
K 2
O(aq) + l(aq)
4
O(aq) + l2() S
2
c. S
(aq)
3
(aq) + Br
2
(fl FeBr
2
d. FeBr
-
C. Questions
Answer the following questions In the space provideS
29. For each of the following reactions, identify the element oxidized, the element
reduced, the oxidizing agent, and the reducing agent
OTfdfrlng
Oxidfrd
Reduced
.. K+I-2Kl
K 2Na
+ 2H
0
2
-,
2NaOH
+
2
H
+CuO—+Cu+H
H
O
c. 2
l
+Mg-+MNO+Cu
2
)
3
Cu(NO
30. Determine the oxidation number of each element In the following.
a. 4
S0
2
K
K Cu(N0
2
)
3
3
c. HAsO
4. MnO
Reducing
Apes
31. Use the oxidatIon-number-Cha5 method to balance the equations given
below Show all your work.
HN
+
*
NO+H
Ag*.A
O
zO
gNO
a. 3
B
+
S
2
+
SOi+HzO_+
HBt
0
r
H
b. 4
32. Use the half-reaction method to balance the equations given be1ow Show all
your work.
+NO+H
HNO
+
0
H1-.1
a. 2
C
K
+
7
O
+
2
+
+
3
Hcl—’
KQ+
Fec
b. 0
H
CrC1
FeC
r
l
I
D. Essay
33. Explain why oxidation cannot occur without reduction, and vice versa.
Chapter 20 Test B
A. Matching
1. e
2.1
3.d
l.g
5. i
8. a
7. c
Lii
-,
9. ii
lO. j
-
-,
-,
B. Multiple Choic.
l1.d
I2.a
l3.a
14.d
15.d
lLb
l?.a
l&b
lS.c
0.c
2
21.b
22.b
C. Questions
29. a. 2
K1;J
;
K
b. Ns,H;H
Q.N
2
C. H; Cu; CuO;
2
H
d. Mg; Cu; Cu(NO
; Mg
2
)
3
30. a. 4
S0 = + 1, +6, —2
2
K
b. Cu(NO
2 = +2, +5, —2
)
3
C. 52
=+j
3
HAsO
d. Mn0
4 = +7, —2
31. a.
b.
32. a. C
2
HNO+FII_*1
)
+NO+H
W(aq) + NO(aq) + H(aq) + l(aq)
(aq) + NOinJ + H
2
1
0(l)
2
Oxidation: 21(aq)
12 + 2e
Reduction: 2[2H(aq) + N0
(aq) + 1e
2
NO + H
01
2
4H + 2NO
2 + 2e
2NO + 2l1O
4lI + 2t + 2NO -.I+ 2N0 + H
O
2
Final: 2HN0
2 + 2H1 12+ 2N0 + 2H
0
2
b. K+FeQ
+HQ,
2
3 + ci + FeG
CtG
3 + H
O
2
2K(aq) + 2
7 (aq) + Fe
O
(aq) + 2Q
2
+ H(aq) + Q(aq)
aq) + 3cr(aq) + r(aq) + 0(aq)
+ Fe
(aq) + 3C1(aq) + H
3
0
2
Oxidation: 6(Fe
+ 1eJ
Reduction: 2Cr + 6e
3
2Cr
6Fe 3
-.6Fe +2Cr
8
+2Cr
Final: 2
Cr + 6FeQ
IC
7
O
2 + 14HCI
3 + 2KCI + 6FeCI
2CrCI
3 + 7I4O
23.
24.
25.
28.
27.
28.
d
d
ii
b
a
—
—,
D. Essay
33. Since oxidation is the loss of electrons, it can
only occur in the presence of another
substance that will accept the lost electrons.
The accepting substance gains electrons, and
thus, undergoes reduction. In other words, a
loss of electrons can only occur if a gain takes
piece concurrentI
__
__
___
_____J8.
___
___
_
___
___
___
___
__
___
__
__
___
___
___
___
___
__
__
__
__
__
__
__
___
____
____
___
___
____
____
____
____
____
____
____
____
____
____
____
____
Class
Date
Name
TRY
ELECTROCHEMIS
Chapter Test B
A. Matching
to the correct description in
March each term in Column B
Column A.
Column A
to
1. the ability of a voltaic cell
produce an electric current
chemical energy Into electrical
2. any device that converts
energy
Column B
a. fuel cells
b. salt bridge
chemical
energy or electrical energy into
rical
3. the process In which elect
about a chemical change
energy in used to bring
ation occurs
4. the electrode at which oxid
are connected together
5. a group of voltaic cells that
are used to convert chemical
6. electrochemical cells that
gy
ener
rical
elect
into
gy
ener
rolyte is a paste
7. a vokaic cell In which the elect
ction
8. the electrode at which redu
occurs
g solution that lets ions
9. a tube containing a conductin
a voltaic cell to another
pass from one compartment of
undergoes oxidation and from
10. voltaic cells in which a fuel
ined continuously
obta
is
gy
ener
rical
elect
which
c. battery
d. electrochemical cell
e. cathode
f. electrolysis
g. voltaic cells
11. electrical potential
I. anode
Jdry cell
B. Multiple Choice
Reference Section
its letter on the line. Refer to the
Choose the best answer and write
ed.
need
ntials as
on p.561 for the reduction pote
n below?
true concerning the reaction give
Ii. Which of the following is
g)
(
2
H
+
)
n
aq
Z
(
2
Zn(s) + 2H(aq)
a. Zn(s) is being reduced,
b. H(aq) is being oxidized.
d from Zn(s) to W(aq).
c. Electrons are being transferre
ove
d. alloftheab
wing
ity series of metals, which of the follo
12. If Al Is above Co in the activ
Co(NOJ
?
ed into a solution of 2
dipp
Is
Al
of
strip
a
if
r
occu
Co.
will
c. The Al strip becomes coated with
.
a. A redox reaction takes place
e
abov
the
of
all
d.
b. The Al strip dissolvns.
-
13. In an electrocheniical cell, the anode is
a. the electrode at which reduction occurs.
.
b. the electrode at which electrons are produced
c. the positive electrode.t
d. alloftheabove
s of metals, which of the following
14. If Mg is above Ni in the activity serie
Ni(NO)
?
a solution of 2
into
ed
dipp
is
Mg
of
strip
a
r
if
occu
will
is oxidized.
Mg
The
c.
rs.
occu
ion
No
react
a.
d. none of the above
2 loses electrons.
b. The Ni
rochemical cell
g
15. Which of the following is true concernin the elect
?
wing
follo
d
the
by
sente
repre
) I Pb(s)
SO
aq
Pb
(
0 II 4
(N)
aq
Mn
(
2
)
Mn(s) I 3
a. Pb is oxidized.
b. Mn is reduced.
Mn(N0
.
2
)
c. A strip of Pb is dipped into a solution of 3
d. Electrons are lost at the Mn electrode.
acjryce
Whichofthefollowingistrueabout
e a paste.
a. It is a voltaic cell in which the electrolyt Is
b, Zn serves as the cathode.
e.
C. Graphite serves as the anod
d. alloftheabove
17. In a lead storage battery
cathode is packed
a. the anode is packed with spongy lead, and the
with leadllV) oxide.
b. the electrodes are immersed In sulfuric acid.
ric current
of
c. the system can be recharged by the passage elect
through the cell.
d. alloftheabove
18. lIthe metais Ca, Zn, Fe, and Cu are listed
In that order in the activity
series of metals, the one that would be most
readily oxidized is
a. Ca.
c. Fe.
b. Zn.
ci. Cu.
19. Among the metals listed In question
18, the one that would be most
readily reduced Is
a.a.
c.Fe.
b.Zn.
cLCu.
20. In
a.
b.
c.
ci.
a hydrogen-oxygen fuel cell
oxygen is fed into the anode compartment.
hydrogen is fed into the cathode compartment
.
the net reaction is the oxidation of hydrogen
to form water.
alloftheabove
21. The standard reference electrode that
is used with other electrodes to
measure their reduction potentials consists
of
a. Zn.
C. Cu.
b. H
.
2
d.Ag.
22. Which of the following is true concerning standard reduction
potentials?
a. A positive value indicates that the tendency for a specified
substance to be reduced is less tpan that of H.
b. A negative value indicates that the tendency for a specified
substance to be reduced is more than that of W.
c. The half-reactions at the top of the standard reduction potential
table have the greatest tendency to occur as oxidations.
ci. alloftheabove
E. Essay
Write a short essay for the following.
36. Give at least three similarities and three differences between voltaic and
electrolytic cells.
23. The standard cell potential of a cell composed of the half-cells
Zn Zn
2 II Pb Pb is
a. +O,89V.
c. -O.89V.
b. +O.63V.
ci. -O.63V.
24. In the voltaic cell described in question 23, the anode is
a. Zn.
.
2
c. Pb
.
2
b. Zn
ci. Pb.
25. Among the following reactions, which would be expected to occur
spontaneously?
a. Cu(s) + Mg(aq) —. Cu
(aq) + Mg(s)
2
b. 2Na(s) + Pb
2 (aq) -. 2Na (aq) + Pb(s)
C. 2Ag(s) + Zn
(aq) -+ 2Ag(aq) + Zn(s)
2
ci. alloftheabove
26. Which of the following is true about an electrolytic cell?
a. Electrons flow from the cathode to the anode in the external
circuit.
I,. Oxidation occurs at the cathode.
c. The redox reaction involved in such a cell is nonspontaneous.
ci. alloftheabove
27. The net products that result from the electrolysis of water are
a. H
2 and 0H.
c. H and 0H.
b. 02 and H.
ci. H
2 and 02.
C.True-False
Classify each of these statements as always true, AJ sometimes true, S7 or never true, NT
28. Given any two elements in the activity series of metals, the one that
appears above the other undergoes reduction.
29. The salt bridge in a voltaic cell provides a pathway for the electrons to
flow from one electrode to the other.
30. A flashlight battery is an example of a thy cell.
31. The specific gravity of the sulfuric acid contained in a lead storage
battery is an indication of the condition of that battery
32. Half-cell potentials cannot be measured.
33. The standard cell potential for a voltaic cell consisting of some
combination of Zn. ZII
, F- and F would be a positive value.
2
D. Questions
Answer the following questions in the space provided.
34. Given the following voltaic cell, draw tJe cell and label the cathode, anode, salt
bridge, and direction of flow of the electrons.
(aq) IAgNO
2
)
3
Cu(s) Cu(N0
(aq) jAg(s)
3
35. Based on the information given in question 34, write the two half-reaction
s, as
well as the final net reaction for the Cu-Ag voltaic cell, Use the information
provided in the Reference Section to calculate the standard cell potential
for
this voltaic cell.
Reference Section
Reduction Potentials at 25°C
Electrode
E°(V)
N/Na
—2.71V
Mg/Mg
—2.37V
Al
f
3
AI
-L66V
Zn
/
2
Zn
—O76V
Pb
/
2
Pb
—O.13V
Cu
/
2
Cu
+O34V
Ag/Ag
+O,80V
F
/
2
F
+287V
_
______
______
Class
Date
Name
A. Matching
in the space prouide€L
Answer the following questions
following voltalc cell.
ions and the net reaction for the
37. Write the half-cell react
for the cell.
ntial
pote
cell
ard
stand
the
Calculate
b I Pb(s)
aq>
P
(
) j2
1
aq
A
(
Al(s) 3
9.b
1O.a
S.c
6.g
7.)
8.e
l.h
ad
3.f
4.1
F. Additional Questions
B. Multiple Choice
23.
24.
25.
28.
27.
17.4
l8.a
19.4
20,c
21.b
22.c
1l.c
lad
13.b
14.c
lS.d
16.a
C. True-False
taneously and
r spon
following redox reactions will occu
38. Determine which of the
ntial in each case.
pote
cell
ard
stand
the
late
calcu
) -. 2Na(aq) + Cu(s)
u
aq
C
(
a. 2Na(s) + 2
32. AT
33. ST
30.AT
31. AT
28.NT
29. NT
b
a
b
c
4
0. Question
34.
)
g
aq
2
M
b. 2Ag(s) + (
—.
2Ag(aq)
+
fl
Mg(s)
e..
/
c. 2A1(s)
+
)
aqn
2
3Z
(
2AP(aq)
+
3Zn(s)
Salt
bridge
--
-
:.
CaL
O (sql
2
Cu(N
corresponding
ents W, X, Y, and Z, along with their
39. Given the hypothetical elem
w to detennlne
belo
ided
prov
on
mati
Infor
, use the
2
and Z
,
2
ions W
ity series of
ents should be listed in the activ
the order in which these elem
metals.
(reacts spontaneously)
2
2 + Z-..X+ Z
Reaction l:X
(does not react)
+
2
X
W
Reaction 2:
(reacts spontaneously)
+
Z
+Z
3:Y
Y
ion
.
React
2
3 (aq)
A5NO
) + 2e
u
aq
C
(
35. Cu(s) —r 2
2Ag(s)
2Ag(aq) + 2e
) + ZAg(s)
u
Net: Cu(s) + 2Ag(aq) —* 2
aq
C
(
—
=
+0.80 V
+Q.46V
-
(+0.34V)
E. Essay
36. In both voltaic and electrolytic cells,
electrons flow from the anode to the cathode
through the external circuit, reduction occurs
at the cathode, and oxidation occurs at the
anode. Howevet while the flow of electrons
in a vokaic cell is caused by a spontaneous
chemical reaction, in an electrolytic cell the
flow of electrons is being pushed by an
outside source such as a battery Additionall
while the anode is the negative electrode and
the cathode is the positive electrode in a
voltaic cell, the reverse is true in an
electroLytic cell—the anode in an electrolytic
cell is the positive electrode and the cathode
is negative.
F. Additional Questions
37. SinceAl is above Pb in the reduction potential
table, Al is oxidized and Pb is reduced. Thus,
the two half-cell reactions are as follows:
l + 3eJ
aq)
A
(
2(A1(s) — 3
) + 2e —+ Pb(s))
(aqb
3[P
*
2
l + 3PbGs)
aq)
) —‘ 3
2A
(
aqb
3P
(
Net: 2A1(s) + 2
b. The half-reactions are
Oxidation: Ag(s).- Ag(aq) + e
= +0.80V
) + 2e — Mg(s)
g
aq
M
(
Reduction: 2
=
—2.37V— (+0.80V)
—3.l7V
is
Since the standard cell potential
negative, the redox reaction will be
nonspontaneous.
c. The half-reactions are:
Oxidation: Al(s) —‘ Al(aq) + 3e
=
=
£0 = -l.66V
)
n
aq
Z
(
Reduction: 2
= -0.76V
—O.13V-- (-1.66V)
+1.53V
38. a. The half-reactions are:
Oxidation: Na(s) — Na(aq)
= -2.71 V
=
)
u
aq
C
(
Reduction: 2
= +034V
+
2e
+
—
e
Cu(s)
Eeu
+0.34v— (—2.7(V)
+3.05V
Since the standard cell potential is
positive, the redox reaction will be
spontaneous.
=
=
+
2e
-.
Zn(s)
—0.76V (—1.66V)
+O.90V
Since the standard cell potential is
positive, the redox reaction will be
spontaneous.
2 is
X
39. Reaction 1: since z is oxidized and
ity
reduced, Z appears above X in the activ
series.
Reaction 2: since W is not oxidized in the
, W should appear below X.
2
presence of X
2 is
Reaction 3: sinceY is oxidized and Z
reduced, Y appears above Z.
ws:
The elements should be Listed as follo
Y, Z, X, andW.
=
=
=
—2.37V
Udd
—