VOLTAIC CELL QUIZ Part I

1.If the two half-cells below were combined, what would be the correct chemical equation to represent the spontaneous REDOX process?
Cu2+ + 2e- <====> Cu (+0.34V)
H+ + e- <====> 1/2 H2 (0.00V)
(A) Cu2+ + H+ ==> 1/2 H2 + Cu
(B) Cu2+ + 2H+ ==> H2 + Cu
(C) Cu2+ + 1/2 H2 ==> H+ + Cu
(D) Cu2+ + H2 ==> 2H+ + Cu
(E) Cu + 2H+ ==> H2 + Cu2+
2.If the two half-cells below were combined, what would be the voltage generated by the spontaneous REDOX process?
Cu2+ + 2e- <====> Cu (+0.34V)
H+ + e- <====> 1/2 H2 (0.00V)
(A) +0.34V
(B) -0.34V
(C) 0.00V
(D) +0.68V
(E) -0.68V
3.If the two half-cells below were combined, which cell would undergo reduction?
Cu2+ + 2e- <====> Cu (+0.34V)
H+ + e- <====> 1/2 H2 (0.00V)
(A) Hydrogen half-cell
(B) Neither
(C) Both
(D) Copper half-cell
(E) Not enough information to tell
4.If the two half-cells below were combined, what would be the expected products of the spontaneous chemical reaction?
Zn2+ + 2e- <====> Zn (-0.76V)
H+ + e- <====> 1/2 H2 (0.00V)
(A) H+ and Zn2+
(B) H+ and Zn
(C) Zn and H2
(D) H2 and Zn2+
(E) None of the above
5.Which of the following statements is FALSE?
(A) Oxidation involves a loss of electrons
(B) Reduction involves a gain of electrons
(C) In the cell, electric current flows from a positive pole
(D) A spontaneous REDOX reaction has a positive Ecell voltage
(E) Metal can be used for salt bridge
6.The following REDOX reactions all have positive Ecell voltages.
Cl2 + 2Br- ==> Br2 + 2Cl-
Br2 + 2I- ==> I2 + 2Br-
Cl2 + 2I- ==> I2 + 2Cl-
Which is the correct order of strength of oxidizing agent, from weakest to strongest?
(A) Chlorine < Iodine < Bromine
(B) Bromine < Chlorine < Iodine
(C) Iodine < Bromine < Chlorine
(D) Chlorine < Bromine < Iodine
(E) Iodine < Chlorine < Bromine
7.The standard reduction potential for Zn2+ + 2e- ==> Zn, is -0.76 V, and the standard reduction potential for Fe3+ + e- ==> Fe2+, is +0.77V. What is the Ecell for the reaction below?
2Fe3+ + Zn ==> Zn2+ + 2Fe2+
(A) +2.30V
(B) +1.53V
(C) -2.30V
(D) -1.53V
(E) -0.75V
8.Iron rusts when it comes into contact with water and oxygen. The change that the iron undergoes can be summarized thus; Fe ==> Fe2+ + 2e-. When iron metal is coated with solid zinc in a process called galvanizing, the oxidation of iron is prevented even if the zinc coating does not completely cover the iron metal. Which of the following statements serves best to explain these observations?
(A) Solid zinc metal is more easily reduced than iron
(B) Solid zinc metal is more easily oxidized than iron
(C) Zinc ions are more easily reduced than iron
(D) Zinc ions are more easily oxidized than iron
(E) Solid zinc metal is more easily reduced than iron (II) ions
9.In the spontaneous reduction of Copper (II) ions with Nickel metal to form Copper metal and Nickel (II) ions, what will happen to the Ecell value when the concentration of Copper (II) ions is increased?
Cu2+ + 2e- <====> Cu (+0.34V)
Ni2+ + 2e- <====> Ni (-0.25V)
(A) Ecell will increase
(B) Ecell will decrease
(C) Ecell will be unchanged
(D) Not enough information to tell
(E) None of the above
10.If the two half-cells below were combined, into which cell do anions from the salt bridge flow?
Cu2+ + 2e- <====> Cu (+0.34V)
H+ + e- <====> 1/2 H2 (0.00V)
(A) Hydrogen
(B) Copper
(C) Neither
(D) Cannot tell from the information given
(E) None of the above
11.What value of Ecell do you expect for
Pb(s) → Pb2+ + 2e-
in 0.015 M Pb2+ solution? E0 = +0.13 V
a.E = +0.27V
b.E = +0.83V
c.E = +0.13V
d.E = 0.00V
e.E = +0.18V
12.Reduction potential is:
a. measured in amperes
b. an intensive property
c. an extensive property
d. always positive
13.The standard hydrogen electrode is assigned a potential of ….
a.0.76 volts
b.-1.00 volts
c.1.00 volts
d.zero volts
e.mines volts
14.Calculate the value of E0cell for a galvanic cell that contains the following half cells:
Cl2 + 2e- → 2Cl- (E0 = 1.36v)
Cu+ + e- → Cu (E0 = 0.52v)
a.E0cell = 0.84 volts
b.E0cell = 1.88 volts
c.E0cell = 0.32 volts
d.E0cell = -0.32 volts
e.E0cell = -0.84 volts
15.In all electrochemical cells, the process that takes place at the anode is … and the process that takes place at the cathode is ….
a.reduction, oxidation
b.oxidation, oxidation
c.reduction, reduction
d.oxidation, reduction