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© 2014 Pearson Education, Inc.
Chapter 18
Electrochemistry
Clicker Questions
Allison SoultUniversity of Kentucky
© 2014 Pearson Education, Inc.
What is the coefficient of Fe2+ when the following redox equation is balanced?
a) 1
b) 2
c) 3
d) 4
e) 5
Fe2+ (aq) + MnO4– (aq) → Fe3+ (aq) + Mn2+ (aq)
© 2014 Pearson Education, Inc.
What is the coefficient of Fe2+ when the following redox equation is balanced?
a) 1
b) 2
c) 3
d) 4
e) 5
Fe2+ (aq) + MnO4– (aq) → Fe3+ (aq) + Mn2+ (aq)
© 2014 Pearson Education, Inc.
The following reaction occurs in a lead storage battery. How many moles of electrons are transferred in the following balanced redox equation per reaction cycle?
a) 2.34
b) 1.35
c) 1.30
d) 2.41
Pb (s) + PbO2 (aq) + 2 HSO4– (aq) + 2 H+ (aq) → 2 PbSO4 (s) + 2 H2O (l)
© 2014 Pearson Education, Inc.
The following reaction occurs in a lead storage battery. How many moles of electrons are transferred in the following balanced redox equation per reaction cycle?
a) 2.34
b) 1.35
c) 1.30
d) 2.41
Pb (s) + PbO2 (aq) + 2 HSO4– (aq) + 2 H+ (aq) → 2 PbSO4 (s) + 2 H2O (l)
© 2014 Pearson Education, Inc.
How many water molecules will there be when
MnO4– + CN– MnO2 + CNO–
is balanced in base?
a) 4 on the reactant side
b) 4 on the product side
c) 2 on the reactant side
d) 2 on the product side
© 2014 Pearson Education, Inc.
How many water molecules will there be when
MnO4– + CN– MnO2 + CNO–
is balanced in base?
a) 4 on the reactant side
b) 4 on the product side
c) 2 on the reactant side
d) 2 on the product side
© 2014 Pearson Education, Inc.
Which transformation could take place at the anode of an electrochemical cell?
a) NO → NO3–
b) VO2+ → VO2+
c) O2 → H2O2
d) All of the above would function as cathodes.
e) All of the above would function as anodes.
© 2014 Pearson Education, Inc.
Which transformation could take place at the anode of an electrochemical cell?
a) NO → NO3–
b) VO2+ → VO2+
c) O2 → H2O2
d) All of the above would function as cathodes.
e) All of the above would function as anodes.
© 2014 Pearson Education, Inc.
The purpose of the salt bridge in an electrochemical cell is
a) to maintain electrical neutrality in the half-cells via migration of ions.
b) to provide a source of ions to react at the anode and cathode.
c) to provide oxygen to facilitate oxidation at the anode.
d) to provide a means for electrons to travel from the anode to the cathode.
e) to provide a means for electrons to travel from the cathode to the anode.
© 2014 Pearson Education, Inc.
The purpose of the salt bridge in an electrochemical cell is
a) to maintain electrical neutrality in the half-cells via migration of ions.
b) to provide a source of ions to react at the anode and cathode.
c) to provide oxygen to facilitate oxidation at the anode.
d) to provide a means for electrons to travel fromthe anode to the cathode.
e) to provide a means for electrons to travel from the cathode to the anode.
© 2014 Pearson Education, Inc.
What is the reducing agent in the following electrochemical cell?
a) Ni
b) Ni2+
c) Ag
d) Ag+
e) There is no reducing agent in an electrochemical cell.
Ni (s) | Ni2+ (aq) || Ag+ (aq) | Ag (s)
© 2014 Pearson Education, Inc.
What is the reducing agent in the following electrochemical cell?
a) Ni
b) Ni2+
c) Ag
d) Ag+
e) There is no reducing agent in an electrochemical cell.
Ni (s) | Ni2+ (aq) || Ag+ (aq) | Ag (s)
© 2014 Pearson Education, Inc.
Which of the following is the best reducing agent?
a) Ni2+
b) Ni
c) Zn
d) Ag
Ni2+ (aq) + 2 e– → Ni (s) –0.23 V
Zn2+ (aq) + 2 e– → Zn (s) –0.76 V
Ag+ (aq) + e– → Ag (s) 0.80 V
© 2014 Pearson Education, Inc.
Which of the following is the best reducing agent?
a) Ni2+
b) Ni
c) Zn
d) Ag
Ni2+ (aq) + 2 e– → Ni (s) –0.23 V
Zn2+ (aq) + 2 e– → Zn (s) –0.76 V
Ag+ (aq) + e– → Ag (s) 0.80 V
© 2014 Pearson Education, Inc.
Calculate the cell potential for the following reaction under standard conditions:
a) +2.04
b) –2.04
c) +2.71
d) –1.36
e) +1.36
Mg (s) + Cu2+ (aq) → Cu (s) + Mg2+ (aq)
Cu2+ (aq) + 2 e– → Cu (s) 0.34 V
Mg2+ (aq) + 2 e– → Mg (s) –2.37 V
© 2014 Pearson Education, Inc.
Calculate the cell potential for the following reaction under standard conditions:
a) +2.04
b) –2.04
c) +2.71
d) –1.36
e) +1.36
Mg (s) + Cu2+ (aq) → Cu (s) + Mg2+ (aq)
Cu2+ (aq) + 2 e– → Cu (s) 0.34 V
Mg2+ (aq) + 2 e– → Mg (s) –2.37 V
© 2014 Pearson Education, Inc.
Which of the following metals will dissolve in nitric acid but not in hydrochloric acid?
a) Au
b) Ag
c) Fe
d) Pb
e) Ni
© 2014 Pearson Education, Inc.
Which of the following metals will dissolve in nitric acid but not in hydrochloric acid?
a) Au
b) Ag
c) Fe
d) Pb
e) Ni
© 2014 Pearson Education, Inc.
Consider a cell that employs the following overall reaction:
What is ΔG° for the cell?
a) 636 kJ/mol
b) –648 kJ/mol
c) –216 kJ/mol
d) –636 kJ/mol
e) –1270 kJ/mol
2 Al (s) + 3 I2 (s) → 2 Al3+ (aq) + 6 I– (aq)
I2 (s) + 2 e– → 2 I– (aq) 0.54
Al3+ (aq) + 3 e– → Al (s) –1.66
© 2014 Pearson Education, Inc.
Consider a cell that employs the following overall reaction:
What is ΔG° for the cell?
a) 636 kJ/mol
b) –648 kJ/mol
c) –216 kJ/mol
d) –636 kJ/mol
e) –1270 kJ/mol
2 Al (s) + 3 I2 (s) → 2 Al3+ (aq) + 6 I– (aq)
I2 (s) + 2 e– → 2 I– (aq) 0.54
Al3+ (aq) + 3 e– → Al (s) –1.66
© 2014 Pearson Education, Inc.
What is the value of the equilibrium constant when the cell potential is found to be −0.29 V for a transfer of 2 moles of electrons?
a) 1.6 × 10–10
b) 0.56
c) 0.72
d) 0.87
e) 6.4 × 10–2
© 2014 Pearson Education, Inc.
What is the value of the equilibrium constant when the cell potential is found to be −0.29 V for a transfer of 2 moles of electrons?
a) 1.6 × 10–10
b) 0.56
c) 0.72
d) 0.87
e) 6.4 × 10–2
© 2014 Pearson Education, Inc.
Calculate the cell potential (Ecell) of an electrochemical cell at 298 K with Mg/Mg2+ and Fe/Fe2+ electrodes. [Mg2+] = 0.200 M and [Fe2+] = 0.050 M.
a) 1.90
b) 1.92
c) 1.94
d) 2.82
e) 2.80
Fe2+ (aq) + 2 e– → Fe (s) –0.45
Mg2+ (aq) + 2 e– → Mg (s) –2.37
© 2014 Pearson Education, Inc.
Calculate the cell potential (Ecell) of an electrochemical cell at 298 K with Mg/Mg2+ and Fe/Fe2+ electrodes. [Mg2+] = 0.200 M and [Fe2+] = 0.050 M.
a) 1.90
b) 1.92
c) 1.94
d) 2.82
e) 2.80
Fe2+ (aq) + 2 e– → Fe (s) –0.45
Mg2+ (aq) + 2 e– → Mg (s) –2.37
© 2014 Pearson Education, Inc.
A concentration cell is assembled with a copper anode and cathode. One cell has [Cu2+] = 0.25 M and the other has [Cu2+] = 2.5 M. What is the cell potential?
a) 0 V
b) −0.030 V
c) 0.030 V
d) − 0.0592 V
e) 0.0592 V
© 2014 Pearson Education, Inc.
A concentration cell is assembled with a copper anode and cathode. One cell has [Cu2+] = 0.25 M and the other has [Cu2+] = 2.5 M. What is the cell potential?
a) 0 V
b) −0.030 V
c) 0.030 V
d) − 0.0592 V
e) 0.0592 V
© 2014 Pearson Education, Inc.
What mass of nickel can be plated from a solution containing Ni2+ with a current of 3.6 A for 14 minutes?
a) 0.92 g
b) 1.8 g
c) 3.7 g
d) 1.0 g
e) 0.071 g
© 2014 Pearson Education, Inc.
What mass of nickel can be plated from a solution containing Ni2+ with a current of 3.6 A for 14 minutes?
a) 0.92 g
b) 1.8 g
c) 3.7 g
d) 1.0 g
e) 0.071 g
© 2014 Pearson Education, Inc.
Which of the following is the best sacrificial electrode for iron?
a) Au
b) Cu
c) Ni
d) Pb
e) Mg
Au3+ (aq) + 3 e– → Au (s) 1.50 V
Cu2+ (aq) + 2 e– → Cu (s) 0.34 V
Pb2+ (aq) + 2 e– → Pb (s) –0.13 V
Ni2+ (aq) + 2 e– → Ni (s) –0.23 V
Mg2+ (aq) + 2 e– → Mg (s) –2.37 V
Fe3+ (aq) + 3 e– → Fe (s) –0.036 V
© 2014 Pearson Education, Inc.
Which of the following is the best sacrificial electrode for iron?
a) Au
b) Cu
c) Ni
d) Pb
e) Mg
Au3+ (aq) + 3 e– → Au (s) 1.50 V
Cu2+ (aq) + 2 e– → Cu (s) 0.34 V
Pb2+ (aq) + 2 e– → Pb (s) –0.13 V
Ni2+ (aq) + 2 e– → Ni (s) –0.23 V
Mg2+ (aq) + 2 e– → Mg (s) –2.37 V
Fe3+ (aq) + 3 e– → Fe (s) –0.036 V