Question 1

Which substance is the reducing agent in the reaction below? Pb + PbO2 + 2H2SO4 → 2PbSO4 + 2H2O

Accepted Answer

A) Pb 
B) H2SO4 
C) PbO2 
D) PbSO4 
E) H2O 
A) Pb 
B) H2SO4 
C) PbO2 
D) PbSO4 
E) H2O A

Question 2

What is the coefficient of the permanganate ion when the following equation is balanced? MnO4- + Br- → Mn2+ + Br2 (acidic solution)

Accepted Answer

A) 1 
B) 2 
C) 3 
D) 5 
E) 4 
A) 1 
B) 2 
C) 3 
D) 5 
E) 4 B

Question 3

The standard cell potential (E° cell)for the reaction below is +1.10 V. The cell potential for this reaction is ________ V when the concentration of [Cu2+] = 1.0 × 10-5 M and [Zn2+] = 3.0 M. Zn (s) + Cu2+ (aq) → Cu (s) + Zn2+ (aq)

Accepted Answer

A) 1.42 
B) 1.26 
C) 0.94 
D) 0.78 
E) 1.10 
A) 1.42 
B) 1.26 
C) 0.94 
D) 0.78 
E) 1.10 C

Question 4

How many seconds are required to produce 1.0 g of silver metal by the electrolysis of a AgNO3 solution using a current of 60 amps?

Accepted Answer

A) 5.4 × 104 
B) 3.2 × 103 
C) 15 
D) 3.7 × 10-5 
E) 30 
A) 5.4 × 104 
B) 3.2 × 103 
C) 15 
D) 3.7 × 10-5 
E) 30

Question 5

How many minutes will it take to plate out 4.56 g of Ni metal from a solution of Ni2+ using a current of 50.5 amps in an electrolytic cell?

Accepted Answer

A) 2.47 
B) 4.95 
C) 4.55 
D) 148 
E) 297 
A) 2.47 
B) 4.95 
C) 4.55 
D) 148 
E) 297

Question 6

Consider an electrochemical cell based on the reaction: 2H+ (aq) + Sn (s) → Sn2+ (aq) + H2 (g)
Which of the following actions would not change the measured cell potential?

Accepted Answer

A) lowering the pH in the cathode compartment 
B) addition of more tin metal to the anode compartment 
C) increasing the tin (II)ion concentration in the anode compartment 
D) increasing the pressure of hydrogen gas in the cathode compartment 
E) Any of the above will change the measured cell potential. 
A) lowering the pH in the cathode compartment 
B) addition of more tin metal to the anode compartment 
C) increasing the tin (II)ion concentration in the anode compartment 
D) increasing the pressure of hydrogen gas in the cathode compartment 
E) Any of the above will change the measured cell potential.

Question 7

Table 20.2  
-The standard cell potential (E°cell)for the voltaic cell based on the reaction below is ________ V. 2Cr (s) + 3Fe2+ (aq) → 3Fe (s) + 2Cr3+ (aq)

Accepted Answer

A) +0.30 
B) +2.80 
C) +3.10 
D) +0.83 
E) -0.16 
A) +0.30 
B) +2.80 
C) +3.10 
D) +0.83 
E) -0.16

Question 8

The purpose of the salt bridge in an electrochemical cell is to ________.

Accepted Answer

A) maintain electrical neutrality in the half-cells via migration of ions 
B) provide a source of ions to react at the anode and cathode 
C) provide oxygen to facilitate oxidation at the anode 
D) provide a means for electrons to travel from the anode to the cathode 
E) provide a means for electrons to travel from the cathode to the anode 
A) maintain electrical neutrality in the half-cells via migration of ions 
B) provide a source of ions to react at the anode and cathode 
C) provide oxygen to facilitate oxidation at the anode 
D) provide a means for electrons to travel from the anode to the cathode 
E) provide a means for electrons to travel from the cathode to the anode

Question 9

Which transformation could take place at the cathode of an electrochemical cell?

Accepted Answer

A) MnO2 → MnO4- 
B) Br2 → BrO3- 
C) NO → HNO2 
D) HSO4- → H2SO3 
E) Mn2+ → MnO4- 
A) MnO2 → MnO4- 
B) Br2 → BrO3- 
C) NO → HNO2 
D) HSO4- → H2SO3 
E) Mn2+ → MnO4-

Question 10

Table 20.2  
-Which of the following reactions will occur spontaneously as written?

Accepted Answer

A) Sn4+ (aq) + Fe3+ (aq) → Sn2+ (aq) + Fe2+ (aq) 
B) 3Fe (s) + 2Cr3+ (aq) → 2Cr (s) + 3Fe2+ (aq) 
C) Sn4+ (aq) + Fe2+ (aq) → Sn2+ (aq) + Fe (s) 
D) 3Sn4+ (aq) + 2Cr (s) → 2Cr3+ (aq) + 3Sn2+ (aq) 
E) 3Fe2+ (aq) → Fe (s) + 2Fe3+ (aq) 
A) Sn4+ (aq) + Fe3+ (aq) → Sn2+ (aq) + Fe2+ (aq) 
B) 3Fe (s) + 2Cr3+ (aq) → 2Cr (s) + 3Fe2+ (aq) 
C) Sn4+ (aq) + Fe2+ (aq) → Sn2+ (aq) + Fe (s) 
D) 3Sn4+ (aq) + 2Cr (s) → 2Cr3+ (aq) + 3Sn2+ (aq) 
E) 3Fe2+ (aq) → Fe (s) + 2Fe3+ (aq)

Question 11

1V = ________.

Accepted Answer

A) 1 amp ∙ s 
B) 1 J/s 
C) 96485 C 
D) 1 J/C 
E) 1 C/J 
A) 1 amp ∙ s 
B) 1 J/s 
C) 96485 C 
D) 1 J/C 
E) 1 C/J

Question 12

The standard emf for the cell using the overall cell reaction below is +2.20 V: 2Al (s) + 3I2 (s) → 2Al3+ (aq)+ 6I- (aq)
The emf generated by the cell when [Al3+] = 3.5 × 10-3 M and [I-] = 0.30 M is ________ V.

Accepted Answer

A) 2.20 
B) 2.28 
C) 2.12 
D) 2.36 
E) 2.23 
A) 2.20 
B) 2.28 
C) 2.12 
D) 2.36 
E) 2.23

Question 13

In a voltaic cell, electrons flow from the ________ to the ________.

Accepted Answer

A) salt bride, anode 
B) anode, salt bridge 
C) cathode, anode 
D) salt bridge, cathode 
E) anode, cathode 
A) salt bride, anode 
B) anode, salt bridge 
C) cathode, anode 
D) salt bridge, cathode 
E) anode, cathode

Question 14

What is the oxidation number of manganese in MnO2?

Accepted Answer

A) +3 
B) +2 
C) +1 
D) +4 
E) +7 
A) +3 
B) +2 
C) +1 
D) +4 
E) +7

Question 15

At constant temperature and pressure the Gibbs free energy value is a measure of the ________ of a process.

Accepted Answer

The answer of At constant temperature and pressure the Gibbs...

Question 16

Which transformation could take place at the anode of an electrochemical cell?

Accepted Answer

A) Cr2O72- → Cr2+ 
B) F2 to F- 
C) O2 to H2O 
D) HAsO2 to As 
E) None of the above could take place at the anode. 
A) Cr2O72- → Cr2+ 
B) F2 to F- 
C) O2 to H2O 
D) HAsO2 to As 
E) None of the above could take place at the anode.

Question 17

Which element is reduced in the reaction below? I-  + MnO4- + H+ → I2 + MnO2 + H2O

Accepted Answer

A) I 
B) Mn 
C) O 
D) H 
A) I 
B) Mn 
C) O 
D) H

Question 18

Which substance is the oxidizing agent in the reaction below? Pb + PbO2 + 2H2SO4 → 2PbSO4 + 2H2O

Accepted Answer

A) Pb 
B) H2SO4 
C) PbO2 
D) PbSO4 
E) H2O 
A) Pb 
B) H2SO4 
C) PbO2 
D) PbSO4 
E) H2O

Question 19

Which substance is the oxidizing agent in the following reaction? Fe2S3 + 12HNO3 → 2Fe(NO3)3 + 3S + 6NO2 + 6H2O

Accepted Answer

A) HNO3 
B) S 
C) NO2 
D) Fe2S3 
E) H2O 
A) HNO3 
B) S 
C) NO2 
D) Fe2S3 
E) H2O

Question 20

The standard cell potential (E°cell)of the reaction below is +1.34 V. The value of ΔG° for the reaction is ________ kJ/mol. 3 Cu (s) + 2 MnO4- (aq)+ 8H+ (aq) → 3 Cu2+ (aq)+ 2 MnO2 (s) + 4 H2O (l)

Accepted Answer

A) -24.3 
B) +259 
C) -259 
D) +776 
E) -776 
A) -24.3 
B) +259 
C) -259 
D) +776 
E) -776

Exam 20: Electrochemistry

Which substance is the reducing agent in the reaction below? Pb + PbO2 + 2H2SO4 → 2PbSO4 + 2H2O

What is the coefficient of the permanganate ion when the following equation is balanced? MnO4- + Br- → Mn2+ + Br2 (acidic solution)

The standard cell potential (E° cell)for the reaction below is +1.10 V. The cell potential for this reaction is ________ V when the concentration of [Cu2+] = 1.0 × 10-5 M and [Zn2+] = 3.0 M. Zn (s) + Cu2+ (aq) → Cu (s) + Zn2+ (aq)

How many seconds are required to produce 1.0 g of silver metal by the electrolysis of a AgNO3 solution using a current of 60 amps?

How many minutes will it take to plate out 4.56 g of Ni metal from a solution of Ni2+ using a current of 50.5 amps in an electrolytic cell?

Consider an electrochemical cell based on the reaction: 2H+ (aq) + Sn (s) → Sn2+ (aq) + H2 (g) Which of the following actions would not change the measured cell potential?

Table 20.2 -The standard cell potential (E°cell)for the voltaic cell based on the reaction below is ________ V. 2Cr (s) + 3Fe2+ (aq) → 3Fe (s) + 2Cr3+ (aq)

The purpose of the salt bridge in an electrochemical cell is to ________.

Which transformation could take place at the cathode of an electrochemical cell?

Table 20.2 -Which of the following reactions will occur spontaneously as written?

1V = ________.

The standard emf for the cell using the overall cell reaction below is +2.20 V: 2Al (s) + 3I2 (s) → 2Al3+ (aq)+ 6I- (aq) The emf generated by the cell when [Al3+] = 3.5 × 10-3 M and [I-] = 0.30 M is ________ V.

In a voltaic cell, electrons flow from the ________ to the ________.

What is the oxidation number of manganese in MnO2?

At constant temperature and pressure the Gibbs free energy value is a measure of the ________ of a process.

Which transformation could take place at the anode of an electrochemical cell?

Which element is reduced in the reaction below? I- + MnO4- + H+ → I2 + MnO2 + H2O

Which substance is the oxidizing agent in the reaction below? Pb + PbO2 + 2H2SO4 → 2PbSO4 + 2H2O

Which substance is the oxidizing agent in the following reaction? Fe2S3 + 12HNO3 → 2Fe(NO3)3 + 3S + 6NO2 + 6H2O

The standard cell potential (E°cell)of the reaction below is +1.34 V. The value of ΔG° for the reaction is ________ kJ/mol. 3 Cu (s) + 2 MnO4- (aq)+ 8H+ (aq) → 3 Cu2+ (aq)+ 2 MnO2 (s) + 4 H2O (l)

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Which substance is the reducing agent in the reaction below? Pb + PbO₂ + 2H₂SO₄ → 2PbSO₄ + 2H₂O

What is the coefficient of the permanganate ion when the following equation is balanced? MnO₄^- + Br^- → Mn²⁺ + Br₂ (acidic solution)

The standard cell potential (E° cell)for the reaction below is +1.10 V. The cell potential for this reaction is ________ V when the concentration of [Cu²⁺] = 1.0 × 10^-⁵ M and [Zn²⁺] = 3.0 M. Zn (s) + Cu²⁺ (aq) → Cu (s) + Zn²⁺ (aq)

How many seconds are required to produce 1.0 g of silver metal by the electrolysis of a AgNO₃ solution using a current of 60 amps?

How many minutes will it take to plate out 4.56 g of Ni metal from a solution of Ni²⁺ using a current of 50.5 amps in an electrolytic cell?

Consider an electrochemical cell based on the reaction: 2H⁺ (aq) + Sn (s) → Sn²⁺ (aq) + H₂ (g) Which of the following actions would not change the measured cell potential?

Table 20.2 -The standard cell potential (E°_cell)for the voltaic cell based on the reaction below is ________ V. 2Cr (s) + 3Fe²⁺ (aq) → 3Fe (s) + 2Cr³⁺ (aq)

The standard emf for the cell using the overall cell reaction below is +2.20 V: 2Al (s) + 3I₂ (s) → 2Al³⁺ (aq)+ 6I^- (aq) The emf generated by the cell when [Al³⁺] = 3.5 × 10^-³ M and [I^-] = 0.30 M is ________ V.

In a voltaic cell, electrons flow from the to the .

What is the oxidation number of manganese in MnO₂?

Which element is reduced in the reaction below? I^- + MnO₄^- + H⁺ → I₂ + MnO₂ + H₂O

Which substance is the oxidizing agent in the reaction below? Pb + PbO₂ + 2H₂SO₄ → 2PbSO₄ + 2H₂O

Which substance is the oxidizing agent in the following reaction? Fe₂S₃ + 12HNO₃ → 2Fe(NO₃)₃ + 3S + 6NO₂ + 6H₂O

The standard cell potential (E°_cell)of the reaction below is +1.34 V. The value of ΔG° for the reaction is ________ kJ/mol. 3 Cu (s) + 2 MnO₄^- (aq)+ 8H⁺ (aq) → 3 Cu²⁺ (aq)+ 2 MnO₂ (s) + 4 H₂O (l)