© 2014 Pearson Education, Inc. Chapter 18 Electrochemistry Clicker Questions Allison Soult...

Chapter 18

Electrochemistry

Clicker Questions

Allison SoultUniversity of Kentucky

What is the coefficient of Fe2+ when the following redox equation is balanced?

Fe2+ (aq) + MnO4– (aq) → Fe3+ (aq) + Mn2+ (aq)

What is the coefficient of Fe2+ when the following redox equation is balanced?

Fe2+ (aq) + MnO4– (aq) → Fe3+ (aq) + Mn2+ (aq)

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)

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)

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

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

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.

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.

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.

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.

What is the reducing agent in the following electrochemical cell?

b) Ni2+

d) Ag+

e) There is no reducing agent in an electrochemical cell.

Ni (s) | Ni2+ (aq) || Ag+ (aq) | Ag (s)

What is the reducing agent in the following electrochemical cell?

b) Ni2+

d) Ag+

e) There is no reducing agent in an electrochemical cell.

Ni (s) | Ni2+ (aq) || Ag+ (aq) | Ag (s)

Which of the following is the best reducing agent?

a) Ni2+

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

Which of the following is the best reducing agent?

a) Ni2+

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

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

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

Which of the following metals will dissolve in nitric acid but not in hydrochloric acid?

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

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

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

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

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

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

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

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

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

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

Which of the following is the best sacrificial electrode for iron?

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

Which of the following is the best sacrificial electrode for iron?

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. Chapter 18 Electrochemistry Clicker Questions Allison Soult...

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