Question 1

For the reaction occurring in a voltaic (galvanic) cell, ΔG > 0.

Accepted Answer

A) True 
 B)False

Question 2

In the shorthand notation for cells, a single vertical line represents a salt bridge.

Accepted Answer

A) True 
 B)False

Question 3

A primary battery is one that can be recharged.

Accepted Answer

A) True 
 B)False

Question 4

A concentration cell consists of two Zn/Zn2+ electrodes. The electrolyte in compartment A is 0.10 M Zn(NO3)2 and in compartment B is 0.60 M Zn(NO3)2. What is the voltage of the cell at 25°C?

Accepted Answer

A) 0.010 V 
B) 0.020 V 
C) 0.023 V 
D) 0.046 V 
E) None of these choices are correct. 
A) 0.010 V 
B) 0.020 V 
C) 0.023 V 
D) 0.046 V 
E) None of these choices are correct.

Question 5

A solution is prepared by dissolving 32.0 g of NiSO4 in water. What current would be needed to deposit all of the nickel in 5.0 hours?

Accepted Answer

A) 1.1 A 
B) 2.2 A 
C) 3.3 A 
D) 4.4 A 
E) 5.5 A 
A) 1.1 A 
B) 2.2 A 
C) 3.3 A 
D) 4.4 A 
E) 5.5 A

Question 6

The line notation, Pt | H2(g) | H+(aq) || Cu2+(aq) | Cu(s), indicates that

Accepted Answer

A) copper metal is a product of the cell reaction. 
B) hydrogen gas (H 2)is a product of the cell reaction. 
C) Cu is the anode. 
D) Pt is the cathode. 
E) Cu 2+ is the reducing agent. 
A) copper metal is a product of the cell reaction. 
B) hydrogen gas (H 2)is a product of the cell reaction. 
C) Cu is the anode. 
D) Pt is the cathode. 
E) Cu 2+ is the reducing agent.

Question 7

In the electrolyte of an electrochemical cell, current is carried by anions moving toward the anode and cations moving in the opposite direction.

Accepted Answer

A) True 
 B)False

Question 8

Oxidation occurs at the cathode of a galvanic cell, but at the anode of an electrolytic cell.

Accepted Answer

A) True 
 B)False

Question 9

Select the incorrect statement relating to the corrosion of iron in air.

Accepted Answer

A) Fe 2+ is formed in the anodic region. 
B) O 2 is oxidized in the cathodic region. 
C) Electrons travel through the iron metal between the anodic and cathodic regions. 
D) Moisture provides a pathway for ions to migrate. 
E) Rust is a hydrated form of iron(III)oxide. 
A) Fe 2+ is formed in the anodic region. 
B) O 2 is oxidized in the cathodic region. 
C) Electrons travel through the iron metal between the anodic and cathodic regions. 
D) Moisture provides a pathway for ions to migrate. 
E) Rust is a hydrated form of iron(III)oxide.

Question 10

Examine the following half-reactions and select the weakest oxidizing agent among the species listed. AuBr4(aq) + 3e− ⇄ Au(s) + 4Br−(aq) E° = 0.854 V
Mn2+(aq) + 2e−⇄ Mn(s) E° = −1.185 V
K+(aq) + e−⇄ K(s) E° = −2.931 V
F2O(aq) + 2H+(aq) + 4e−⇄ 2F−(aq) + H2O(l) E° = 2.153 V

Accepted Answer

A) AuBr 4−( aq) 
B) Mn 2+( aq) 
C) K +( aq) 
D) F 2O( aq) 
E) H +( aq) 
A) AuBr 4−( aq) 
B) Mn 2+( aq) 
C) K +( aq) 
D) F 2O( aq) 
E) H +( aq)

Question 11

A voltaic cell has a standard cell potential equal to 0.74 V. If the standard electrode (reduction) potential for the anode is −0.22 V, what is the standard electrode potential for the cathode?

Accepted Answer

A) 0.96 V 
B) 0.52 V 
C) -0.52 V 
D) -0.96 V 
E) Need to know the cell reaction in order to calculate the answer. 
A) 0.96 V 
B) 0.52 V 
C) -0.52 V 
D) -0.96 V 
E) Need to know the cell reaction in order to calculate the answer.

Question 12

Calculate E°cell and indicate whether the overall reaction shown is spontaneous or nonspontaneous. H2O2(aq) + 2H+(aq) + 2e− ⇄ 2H2O(l) E° = 1.77 V
Fe3+ (aq) + e− ⇄ Fe2+(aq) E° = 0.77 V
Overall reaction:
2Fe3+(aq) + 2H2O(l) → H2O2(aq) + 2H+(aq) + 2Fe2+(aq)

Accepted Answer

A) E° cell = −1.00 V, nonspontaneous 
B) E° cell = −1.00 V, spontaneous 
C) E° cell = 1.00 V, nonspontaneous 
D) E° cell = 1.00 V, spontaneous 
E) E° cell = −0.23 V, nonspontaneous 
A) E° cell = −1.00 V, nonspontaneous 
B) E° cell = −1.00 V, spontaneous 
C) E° cell = 1.00 V, nonspontaneous 
D) E° cell = 1.00 V, spontaneous 
E) E° cell = −0.23 V, nonspontaneous

Question 13

Predict the products of the cell reaction when a molten salt mixture of sodium bromide and calcium fluoride is electrolyzed (spectator ions are not considered to be products).

Accepted Answer

A) Calcium and Bromine 
B) Sodium and Fluorine 
C) Calcium bromide 
D) Calcium and Fluorine 
E) Sodium and Bromine 
A) Calcium and Bromine 
B) Sodium and Fluorine 
C) Calcium bromide 
D) Calcium and Fluorine 
E) Sodium and Bromine

Question 14

In the electrolyte of an electrochemical cell, current is carried by electrons moving from the anode to the cathode.

Accepted Answer

A) True 
 B)False

Question 15

In the absence of oxygen, iron will rust as long as moisture is present.

Accepted Answer

A) True 
 B)False

Question 16

Which, if any, of the following metals would not be capable of acting as a sacrificial anode when used with iron E°Fe = −0.44 V; all E° values refer to the M2+/M half-cell reactions.

Accepted Answer

A) Manganese, Mn, E° = −1.18 V 
B) Cadmium, Cd, E° = −0.40 V 
C) Magnesium, Mg, E° = −2.37 V 
D) Zinc, Zn, E° = −0.76 V 
E) All of these metals are capable of acting as sacrificial anodes with iron. 
A) Manganese, Mn, E° = −1.18 V 
B) Cadmium, Cd, E° = −0.40 V 
C) Magnesium, Mg, E° = −2.37 V 
D) Zinc, Zn, E° = −0.76 V 
E) All of these metals are capable of acting as sacrificial anodes with iron.

Question 17

What product forms at the anode during the electrolysis of molten NaBr?

Accepted Answer

A) Na +( l) 
B) Na( l) 
C) Br −( l) 
D) Br 3 −( l) 
E) Br 2( g) 
A) Na +( l) 
B) Na( l) 
C) Br −( l) 
D) Br 3 −( l) 
E) Br 2( g)

Question 18

What product forms at the cathode during the electrolysis of molten lithium iodide?

Accepted Answer

A) Li +( l) 
B) Li( l) 
C) I −( l) 
D) I 2( g) 
E) I 3 −( l) 
A) Li +( l) 
B) Li( l) 
C) I −( l) 
D) I 2( g) 
E) I 3 −( l)

Question 19

What is the E°cell for the cell represented by the combination of the following half-reactions? ClO4(aq) + 8H(aq) + 8e ⇄ Cl-(aq) + 4H2O(l) E° = 1.389 V
VO2(aq) + 2H(aq) + e- ⇄ VO(aq) + H2O(l) E° = 0.991 V

Accepted Answer

A) -0.398 V 
B) -2.380 V 
C) 0.398 V 
D) 2.380 V 
E) None of these choices are correct. 
A) -0.398 V 
B) -2.380 V 
C) 0.398 V 
D) 2.380 V 
E) None of these choices are correct.

Question 20

A voltaic cell consists of a Cd/Cd2+ electrode (E° = −0.40 V) and a Fe/Fe2+ electrode (E° = −0.44 V). If Ecell = 0 and the temperature is 25°C, what is the ratio [Fe2+]/[Cd2+]?

Accepted Answer

A) 2 × 10 1 
B) 1 × 10 1 
C) 1 
D) 1 × 10 −1 
E) 5 × 10 −2 
A) 2 × 10 1 
B) 1 × 10 1 
C) 1 
D) 1 × 10 −1 
E) 5 × 10 −2

Exam 21: Electrochemistry: Chemical Change and Electrical Work

For the reaction occurring in a voltaic (galvanic) cell, ΔG > 0.

In the shorthand notation for cells, a single vertical line represents a salt bridge.

A primary battery is one that can be recharged.

A concentration cell consists of two Zn/Zn2+ electrodes. The electrolyte in compartment A is 0.10 M Zn(NO3)2 and in compartment B is 0.60 M Zn(NO3)2. What is the voltage of the cell at 25°C?

A solution is prepared by dissolving 32.0 g of NiSO4 in water. What current would be needed to deposit all of the nickel in 5.0 hours?

The line notation, Pt | H2(g) | H+(aq) || Cu2+(aq) | Cu(s), indicates that

In the electrolyte of an electrochemical cell, current is carried by anions moving toward the anode and cations moving in the opposite direction.

Oxidation occurs at the cathode of a galvanic cell, but at the anode of an electrolytic cell.

Select the incorrect statement relating to the corrosion of iron in air.

A voltaic cell has a standard cell potential equal to 0.74 V. If the standard electrode (reduction) potential for the anode is −0.22 V, what is the standard electrode potential for the cathode?

Calculate E°cell and indicate whether the overall reaction shown is spontaneous or nonspontaneous. H2O2(aq) + 2H+(aq) + 2e− ⇄ 2H2O(l) E° = 1.77 V Fe3+ (aq) + e− ⇄ Fe2+(aq) E° = 0.77 V Overall reaction: 2Fe3+(aq) + 2H2O(l) → H2O2(aq) + 2H+(aq) + 2Fe2+(aq)

Predict the products of the cell reaction when a molten salt mixture of sodium bromide and calcium fluoride is electrolyzed (spectator ions are not considered to be products).

In the electrolyte of an electrochemical cell, current is carried by electrons moving from the anode to the cathode.

In the absence of oxygen, iron will rust as long as moisture is present.

Which, if any, of the following metals would not be capable of acting as a sacrificial anode when used with iron E°Fe = −0.44 V; all E° values refer to the M2+/M half-cell reactions.

What product forms at the anode during the electrolysis of molten NaBr?

What product forms at the cathode during the electrolysis of molten lithium iodide?

What is the E°cell for the cell represented by the combination of the following half-reactions? ClO4(aq) + 8H(aq) + 8e ⇄ Cl-(aq) + 4H2O(l) E° = 1.389 V VO2(aq) + 2H(aq) + e- ⇄ VO(aq) + H2O(l) E° = 0.991 V

A voltaic cell consists of a Cd/Cd2+ electrode (E° = −0.40 V) and a Fe/Fe2+ electrode (E° = −0.44 V). If Ecell = 0 and the temperature is 25°C, what is the ratio [Fe2+]/[Cd2+]?

Keys to the Study of Chemistry: Definitions, Units, and Problem Solving

The Components of Matter

Stoichiometry of Formulas and Equations

Three Major Classes of Chemical Reactions

Gases and the Kinetic-Molecular Theory

Thermochemistry: Energy Flow and Chemical Change

Quantum Theory and Atomic Structure

Electron Configuration and Chemical Periodicity

Models of Chemical Bonding

The Shapes of Molecules

Theories of Covalent Bonding

Intermolecular Forces: Liquids, Solids, and Phase Changes

The Properties of Mixtures: Solutions and Colloids

Periodic Patterns in the Main-Group Elements

Organic Compounds and the Atomic Properties of Carbon

Kinetics: Rates and Mechanisms of Chemical Reactions

Equilibrium: the Extent of Chemical Reactions

Acid-Base Equilibria

Ionic Equilibria in Aqueous Systems

Thermodynamics: Entropy, Free Energy, and Reaction Direction

The Elements in Nature and Industry

Transition Elements and Their Coordination Compounds

Nuclear Reactions and Their Applications

Filters

A concentration cell consists of two Zn/Zn²⁺ electrodes. The electrolyte in compartment A is 0.10 M Zn(NO₃)₂and in compartment B is 0.60 M Zn(NO₃)₂. What is the voltage of the cell at 25°C?

A solution is prepared by dissolving 32.0 g of NiSO₄ in water. What current would be needed to deposit all of the nickel in 5.0 hours?

The line notation, Pt | H₂(g) | H⁺(aq) || Cu²⁺(aq) | Cu(s), indicates that

Calculate E°_cell and indicate whether the overall reaction shown is spontaneous or nonspontaneous. H₂O₂(aq) + 2H⁺(aq) + 2e⁻ ⇄ 2H₂O(l) E° = 1.77 V Fe³⁺ (aq) + e⁻ ⇄ Fe²⁺(aq) E° = 0.77 V Overall reaction: 2Fe³⁺(aq) + 2H₂O(l) → H₂O₂(aq) + 2H⁺(aq) + 2Fe²⁺(aq)

Which, if any, of the following metals would not be capable of acting as a sacrificial anode when used with iron E°_Fe = −0.44 V; all E° values refer to the M²⁺/M half-cell reactions.

What is the E°_cell for the cell represented by the combination of the following half-reactions? ClO₄(aq) + 8H(aq) + 8e ⇄ Cl^-(aq) + 4H₂O(l) E° = 1.389 V VO₂(aq) + 2H(aq) + e^- ⇄ VO(aq) + H₂O(l) E° = 0.991 V

A voltaic cell consists of a Cd/Cd²⁺ electrode (E° = −0.40 V) and a Fe/Fe²⁺ electrode (E° = −0.44 V). If E_cell = 0 and the temperature is 25°C, what is the ratio [Fe²⁺]/[Cd²⁺]?