Question 1

The relationship between the change in Gibbs free energy and the emf of an electrochemical cell is given by __________.

Accepted Answer

A) ΔG =   
B) ΔG =   
C) ΔG = -nFE 
D) ΔG = -nRTF 
E) ΔG =   
A) ΔG =   
B) ΔG =   
C) ΔG = -nFE 
D) ΔG = -nRTF 
E) ΔG =

Question 2

How many minutes will it take to plate out 16.22 g of Al metal from a solution of Al+3 using a current of 13.8 amps in an electrolytic cell?

Accepted Answer

A) 56.0 
B) 70.0 
C) 162 
D) 210. 
E) 12600 
A) 56.0 
B) 70.0 
C) 162 
D) 210. 
E) 12600

Question 3

What is the cathode in an alkaline battery?

Accepted Answer

A) MnO2 
B) KOH 
C) Zn powder 
D) Mn2O3 
E) Pt 
A) MnO2 
B) KOH 
C) Zn powder 
D) Mn2O3 
E) Pt

Question 4

The balanced half-reaction in which chlorine gas is reduced to the aqueous chloride ion is a __________ process.

Accepted Answer

A) one-electron 
B) two-electron 
C) four-electron 
D) three-electron 
E) six-electron 
A) one-electron 
B) two-electron 
C) four-electron 
D) three-electron 
E) six-electron

Question 5

How many grams of copper will be plated out by a current of 2.3 A applied for 30 minutes to a 0.50 M solution of copper(II)sulfate?

Accepted Answer

A) 1.4 
B) 2.7 
C) 1.8 × 10-2 
D) 3.6 × 10-2 
E) 0.019 
A) 1.4 
B) 2.7 
C) 1.8 × 10-2 
D) 3.6 × 10-2 
E) 0.019

Question 6

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 7

The standard cell potential (E°cell)of the reaction below is -0.34 V. The value of ΔG° for the reaction is __________ kJ/mol. Cu (s)+ 2H+ (aq)→ Cu2+ (aq)+ H2 (g)

Accepted Answer

A) -0.34 
B) +66 
C) -130 
D) +130 
E) none of the above 
A) -0.34 
B) +66 
C) -130 
D) +130 
E) none of the above

Question 8

The dependence of cell emf on concentration is expressed in the __________ equation.

Accepted Answer

The answer of The dependence of cell emf on concentration...

Question 9

The standard cell potential (E°cell)for the voltaic cell based on the reaction below is __________ V. Sn2+ (aq)+ 2Fe3+ (aq)→ 2Fe2+ (aq)+ Sn4+ (aq)

Accepted Answer

A) +0.46 
B) +0.617 
C) +1.39 
D) -0.46 
E) +1.21 
A) +0.46 
B) +0.617 
C) +1.39 
D) -0.46 
E) +1.21

Question 10

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 11

Which substance is serving as the oxidizing agent in the following reaction? 14H+ + Cr2O72- + 3Ni → 3Ni2+ + 2Cr3+ + 7H2O

Accepted Answer

A) Ni 
B) H+ 
C) Cr2O72- 
D) H2O 
E) Ni2+ 
A) Ni 
B) H+ 
C) Cr2O72- 
D) H2O 
E) Ni2+

Question 12

In a half reaction the amount of a substance that is reduced or oxidized is directly proportional to the number of electrons generated in the cell.

Accepted Answer

A) True 
 B)False

Question 13

__________ is oxidized in the following reaction: Cr2O72- + 6S2O32- + 14H+ → 2Cr3+ + 3S4O62- + 7H2O

Accepted Answer

A) Cr6+ 
B) S2+ 
C) H+ 
D) O2- 
E) S4O62- 
A) Cr6+ 
B) S2+ 
C) H+ 
D) O2- 
E) S4O62-

Question 14

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 15

How many grams of Ca metal are produced by the electrolysis of molten CaBr2 using a current of 30.0 amp for 9.0 hours?

Accepted Answer

A) 20.2 
B) 404 
C) 0.0622 
D) 202 
E) 101 
A) 20.2 
B) 404 
C) 0.0622 
D) 202 
E) 101

Question 16

Disadvantages of the methanol fuel cell compared to the hydrogen fuel cell are consumption of catalyst and the production of a less environmentally safe product.

Accepted Answer

A) True 
 B)False

Question 17

What is the oxidation number of chromium in Cr2O   ion?

Accepted Answer

A) +3 
B) +12 
C) +7 
D) +6 
E) +14 
A) +3 
B) +12 
C) +7 
D) +6 
E) +14

Question 18

The lithium ion battery has more energy per unit mass than nickel-cadmium batteries.

Accepted Answer

A) True 
 B)False

Question 19

Consider an electrochemical cell based on the reaction: 2H+ (aq)+ Sn (s)→ Sn2+ (aq)+ H2 (g)
Which of the following actions would change the measured cell potential?

Accepted Answer

A) increasing the pH in the cathode compartment 
B) lowering the pH in the cathode compartment 
C) increasing the [Sn2+] in the anode compartment 
D) increasing the pressure of hydrogen gas in the cathode compartment 
E) Any of the above will change the measure cell potential. 
A) increasing the pH in the cathode compartment 
B) lowering the pH in the cathode compartment 
C) increasing the [Sn2+] in the anode compartment 
D) increasing the pressure of hydrogen gas in the cathode compartment 
E) Any of the above will change the measure cell potential.

Question 20

How many kilowatt-hours of electricity are used to produce 3.00 kg of magnesium in the electrolysis of molten MgCl2 with an applied emf of 4.50 V?

Accepted Answer

A) 0.0336 
B) 0.0298 
C) 7.4 
D) 29.8 
E) 14.9 
A) 0.0336 
B) 0.0298 
C) 7.4 
D) 29.8 
E) 14.9

Exam 20: Electrochemistry

The relationship between the change in Gibbs free energy and the emf of an electrochemical cell is given by __________.

How many minutes will it take to plate out 16.22 g of Al metal from a solution of Al+3 using a current of 13.8 amps in an electrolytic cell?

What is the cathode in an alkaline battery?

The balanced half-reaction in which chlorine gas is reduced to the aqueous chloride ion is a __________ process.

How many grams of copper will be plated out by a current of 2.3 A applied for 30 minutes to a 0.50 M solution of copper(II)sulfate?

Which of the following reactions will occur spontaneously as written?

The standard cell potential (E°cell)of the reaction below is -0.34 V. The value of ΔG° for the reaction is __________ kJ/mol. Cu (s)+ 2H+ (aq)→ Cu2+ (aq)+ H2 (g)

The dependence of cell emf on concentration is expressed in the __________ equation.

The standard cell potential (E°cell)for the voltaic cell based on the reaction below is __________ V. Sn2+ (aq)+ 2Fe3+ (aq)→ 2Fe2+ (aq)+ Sn4+ (aq)

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

Which substance is serving as the oxidizing agent in the following reaction? 14H+ + Cr2O72- + 3Ni → 3Ni2+ + 2Cr3+ + 7H2O

In a half reaction the amount of a substance that is reduced or oxidized is directly proportional to the number of electrons generated in the cell.

__________ is oxidized in the following reaction: Cr2O72- + 6S2O32- + 14H+ → 2Cr3+ + 3S4O62- + 7H2O

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

How many grams of Ca metal are produced by the electrolysis of molten CaBr2 using a current of 30.0 amp for 9.0 hours?

Disadvantages of the methanol fuel cell compared to the hydrogen fuel cell are consumption of catalyst and the production of a less environmentally safe product.

What is the oxidation number of chromium in Cr2O ion?

The lithium ion battery has more energy per unit mass than nickel-cadmium batteries.

Consider an electrochemical cell based on the reaction: 2H+ (aq)+ Sn (s)→ Sn2+ (aq)+ H2 (g) Which of the following actions would change the measured cell potential?

How many kilowatt-hours of electricity are used to produce 3.00 kg of magnesium in the electrolysis of molten MgCl2 with an applied emf of 4.50 V?

Introduction: Matter and Measurement

Atoms, Molecules, and Ions

Stoichiometry: Calculations With Chemical Formulas and Equations

Aqueous Reactions and Solution Stoichiometry

Thermochemistry

Electronic Structure of Atoms

Periodic Properties of the Elements

Basic Concepts of Chemical Bonding

Molecular Geometry and Bonding Theories

Gases

Liquids and Intermolecular Forces

Solids and Modern Materials

Properties of Solutions

Chemical Kinetics

Chemical Equilibrium

Acid-Base Equilibria

Additional Aspects of Aqueous Equilibria

Chemistry of the Environment

Chemical Thermodynamics

Nuclear Chemistry

Chemistry of the Nonmetals

Transition Metals and Coordination Chemistry

The Chemistry of Life: Organic and Biological Chemistry

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How many minutes will it take to plate out 16.22 g of Al metal from a solution of Al⁺³ using a current of 13.8 amps in an electrolytic cell?

The standard cell potential (E°_cell)of the reaction below is -0.34 V. The value of ΔG° for the reaction is __________ kJ/mol. Cu (s)+ 2H⁺ (aq)→ Cu²⁺ (aq)+ H₂ (g)

The standard cell potential (E°_cell)for the voltaic cell based on the reaction below is __________ V. Sn²⁺ (aq)+ 2Fe³⁺ (aq)→ 2Fe²⁺ (aq)+ Sn⁴⁺ (aq)

Which substance is serving as the oxidizing agent in the following reaction? 14H⁺ + Cr₂O₇^2- + 3Ni → 3Ni²⁺ + 2Cr³⁺ + 7H₂O

__________ is oxidized in the following reaction: Cr₂O₇^2- + 6S₂O₃^2- + 14H⁺ → 2Cr³⁺ + 3S₄O₆^2- + 7H₂O

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

How many grams of Ca metal are produced by the electrolysis of molten CaBr₂ using a current of 30.0 amp for 9.0 hours?

What is the oxidation number of chromium in Cr₂O ion?

Consider an electrochemical cell based on the reaction: 2H⁺ (aq)+ Sn (s)→ Sn²⁺ (aq)+ H₂ (g) Which of the following actions would change the measured cell potential?

How many kilowatt-hours of electricity are used to produce 3.00 kg of magnesium in the electrolysis of molten MgCl₂ with an applied emf of 4.50 V?