Question 1

The standard Gibbs energy change for the following voltaic cell is ΔG° = -89.3 kJ at 25°C. What is E°cell? Cu(s) | Cu2+(aq) || Ag+(aq) | Ag(s)

Accepted Answer

A)  +0.463 V 
B)  -0.926 V 
C)  -0.463 V 
D)  +0.926 V 
E)  +0.231 V 
A)  +0.463 V 
B)  -0.926 V 
C)  -0.463 V 
D)  +0.926 V 
E)  +0.231 V

Question 2

Choose the INCORRECT statement.

Accepted Answer

A)  Electrons are transferred in oxidation-reduction reactions. 
B)  A strip of metal in a solution of ions of that metal is an electrode potential. 
C)  Reduction is the gain of electrons. 
D)  Oxidation is the loss if electrons. 
E)  A salt bridge maintains electrical contact between two half cells. 
A)  Electrons are transferred in oxidation-reduction reactions. 
B)  A strip of metal in a solution of ions of that metal is an electrode potential. 
C)  Reduction is the gain of electrons. 
D)  Oxidation is the loss if electrons. 
E)  A salt bridge maintains electrical contact between two half cells.

Question 3

What is the standard cell potential if the Gibbs energy is -2108 kJ in the reaction: C3H8 + O2(g) → CO2(g) + H2O(l) (not balanced)?

Accepted Answer

A)  -10.92 V 
B)  10.92 V 
C)  21.85 V 
D)  -1.092 V 
E)  1.092 V 
A)  -10.92 V 
B)  10.92 V 
C)  21.85 V 
D)  -1.092 V 
E)  1.092 V

Question 4

What is the concentration of Cu2+ in the following cell at 25°C if the cell voltage is 1.253 V? Zn ∣ Zn2+ (0.125 M) || Cu2+(?) ∣ Cu
Cu2+ + 2 e- → Cu(s) E° = 0.340 V
Zn2+ + 2 e- → Zn(s) E° = -0.763 V

Accepted Answer

A)  0.6 M 
B)  1 × 10-2 M 
C)  1 × 10-6 M 
D)  9 × 10-4 M 
E)  4 × 10-4 M 
A)  0.6 M 
B)  1 × 10-2 M 
C)  1 × 10-6 M 
D)  9 × 10-4 M 
E)  4 × 10-4 M

Question 5

What is ΔG° at 25°C for the reaction (not balanced): C3H8 + O2(g) → CO2(g) + H2O(l) if the standard cell potential is 1.092 V?

Accepted Answer

A)  -105 kJ 
B)  -211 kJ 
C)  105 kJ 
D)  -2107 kJ 
E)  211 kJ 
A)  -105 kJ 
B)  -211 kJ 
C)  105 kJ 
D)  -2107 kJ 
E)  211 kJ

Question 6

Find Ecell for the following voltaic cell at 25°C: Ti(s) ∣ Ti2+(aq) (0.550M) || Sn2+(aq) (0.005 M) ∣ Sn(s) The half-reactions are:
Ti2+(aq) + 2 e- ⇔ Ti(s)   &emsp; E° = -1.630 V
Sn2+(aq) + 2 e- ⇔ Sn(s)   &emsp; E° = -0.137 V

Accepted Answer

A)  1.372 V 
B)  1.707 V 
C)  1.646 V 
D)  1.433 V 
E)  -1.646 V 
A)  1.372 V 
B)  1.707 V 
C)  1.646 V 
D)  1.433 V 
E)  -1.646 V

Question 7

Choose the INCORRECT statement.

Accepted Answer

A)  An electrode is often a strip of metal. 
B)  An electrode in a solution of its ions is a half cell. 
C)  An electrochemical cell is a half cell. 
D)  The electromotive force (emf) is the cell potential. 
E)  The cell potential is the potential difference between the half cells. 
A)  An electrode is often a strip of metal. 
B)  An electrode in a solution of its ions is a half cell. 
C)  An electrochemical cell is a half cell. 
D)  The electromotive force (emf) is the cell potential. 
E)  The cell potential is the potential difference between the half cells.

Question 8

The following half-reactions are used in the zinc-air battery. Zn(OH)42- (aq) + 2 e- → Zn(s) + 4 OH-(aq)   &emsp; E° = -1.199 V
O2(g) + 2 H2O(l) + 4 e- → 4 OH-  &emsp; (aq) E° = +0.401 V
How much charge is transferred per gram Zn(s) in this voltaic cell?

Accepted Answer

A)  5.90 × 103 C 
B)  2.95 × 103 C 
C)  1.47 × 103 C 
D)  3.39 × 10-4 C 
E)  1.69 × 10-4 C 
A)  5.90 × 103 C 
B)  2.95 × 103 C 
C)  1.47 × 103 C 
D)  3.39 × 10-4 C 
E)  1.69 × 10-4 C

Question 9

Calculate Ecell at 25°C for the following voltaic cell. Ksp for NiCO3 is 1.42 × 10-7. Ni(s) ∣ Ni2+(aq) [sat'd NiCO3(s)] || Ni2+(aq) (0.010M) ∣ Ni(s)
The half-reaction is: Ni2+(aq) + 2 e- → Ni(s) E° = -0.257 V

Accepted Answer

A)  +0.257 V 
B)  -0.257 V 
C)  0.000 V 
D)  +0.0844 V 
E)  +0.0422 V 
A)  +0.257 V 
B)  -0.257 V 
C)  0.000 V 
D)  +0.0844 V 
E)  +0.0422 V

Question 10

What mass of aluminum can be deposited by the passage of a constant current of 5.00 A through a Al(NO3)3 solution for 2.00 hours?

Accepted Answer

A)  3.36 g 
B)  1.12 g 
C)  0.0559 g 
D)  0.672 g 
E)  0.125 g 
A)  3.36 g 
B)  1.12 g 
C)  0.0559 g 
D)  0.672 g 
E)  0.125 g

Question 11

Determine E°cell for the reaction: 2 Ag + Mg2+ → 2 Ag+ + Mg. The half reactions are: Mg2+(aq) + 2 e- → Mg(s) E° = -2.356 V
Ag+(aq) + e- → Ag(s) E° = 0.800 V

Accepted Answer

A)  0.756 V 
B)  -0.756 V 
C)  3.156 V 
D)  -3.156 V 
E)  1.556 V 
A)  0.756 V 
B)  -0.756 V 
C)  3.156 V 
D)  -3.156 V 
E)  1.556 V

Question 12

One mole of electrons has a charge of:

Accepted Answer

A)  96,485 A 
B)  1.60 × 10-19 
C)  6.02 × 1023 A 
D)  96,485 C 
E)  96,485 F 
A)  96,485 A 
B)  1.60 × 10-19 
C)  6.02 × 1023 A 
D)  96,485 C 
E)  96,485 F

Question 13

Choose the INCORRECT statement.

Accepted Answer

A)  A concentration cell consists of half cells with identical electrodes but different ion concentrations. 
B)  Primary batteries' cell reactions cannot be reversed. 
C)  Secondary batteries' cell reaction can be reversed. 
D)  A primary battery is recharged by passing electricity through the battery. 
E)  Cells can be joined in series to increase the total voltage. 
A)  A concentration cell consists of half cells with identical electrodes but different ion concentrations. 
B)  Primary batteries' cell reactions cannot be reversed. 
C)  Secondary batteries' cell reaction can be reversed. 
D)  A primary battery is recharged by passing electricity through the battery. 
E)  Cells can be joined in series to increase the total voltage.

Question 14

The lithium-ion battery is based on:

Accepted Answer

A)  Li+/Li couple 
B)  Co3+/Co2+ couple 
C)  Co(III)/Co(IV) couple 
D)  both Li+/Li and Co3+/Co2+ 
E)  both Li+/Li and Co(III)/Co(IV) 
A)  Li+/Li couple 
B)  Co3+/Co2+ couple 
C)  Co(III)/Co(IV) couple 
D)  both Li+/Li and Co3+/Co2+ 
E)  both Li+/Li and Co(III)/Co(IV)

Question 15

Calculate the mass of I2 produced at the anode if a current of 2.85 A is passed through a solution of KI for 56 minutes.

Accepted Answer

A)  0.42 g 
B)  0.13 g 
C)  13 g 
D)  25 g 
E)  4.3 g 
A)  0.42 g 
B)  0.13 g 
C)  13 g 
D)  25 g 
E)  4.3 g

Question 16

Determine Keq at 25°C for the following reaction: Pb2+(aq) + Cu(s) ⇔ Cu2+(aq) + Pb(s)
The half-reactions are:
Pb2+(aq) + 2 e- ⇔ Pb(s) E° = -0.125 V
Cu2+(aq) + 2 e- ⇔ Cu(s) E° = +0.337 V

Accepted Answer

A)  2 × 1069 
B)  2 × 10-16 
C)  2 × 1016 
D)  2 × 10-8 
E)  6 × 107 
A)  2 × 1069 
B)  2 × 10-16 
C)  2 × 1016 
D)  2 × 10-8 
E)  6 × 107

Question 17

A solution of AgNO3 is electrolyzed by passing 144 A of current for 102 min. What mass of silver plates out?

Accepted Answer

A)  16.4 g 
B)  5.91 × 104 g 
C)  985 g 
D)  9.13 g 
E)  6.84 g 
A)  16.4 g 
B)  5.91 × 104 g 
C)  985 g 
D)  9.13 g 
E)  6.84 g

Question 18

Determine E°cell for the reaction: Pb + Cu2+ → Pb2+ + Cu. The half reactions are: Pb2+(aq) + 2 e- → Pb(s) E° = -0.125 V
Cu2+ + 2 e- → Cu E° = 0.340 V

Accepted Answer

A)  0.215 V 
B)  0.465 V 
C)  0.930 V 
D)  -0.215 V 
E)  -0.465 V 
A)  0.215 V 
B)  0.465 V 
C)  0.930 V 
D)  -0.215 V 
E)  -0.465 V

Question 19

What is the Ecell for the following cell at 25°C? 
Pt ∣ Sn2+ (0.233 M), Sn4+ (1.05 M) || Ag+ (2.22 × 10-2 M) ∣ Ag
Ag+ + e- → Ag(s)   &emsp; E° = 0.800 V
Sn4+ + 2 e- → Sn2+   &emsp; E° = 0.154 V

Accepted Answer

A)  0.763 V 
B)  0.529 V 
C)  0.412 V 
D)  0.680 V 
E)  0.578 V 
A)  0.763 V 
B)  0.529 V 
C)  0.412 V 
D)  0.680 V 
E)  0.578 V

Question 20

Choose the INCORRECT statement.

Accepted Answer

A)  SHE stands for Standard Helium Electrodes. 
B)  E° is the standard electrode potential. 
C)  The standard electrode potential is the reduction potential of a half cell. 
D)  The standard cell potential is the potential difference between two half cells. 
E)  E°cell is the standard cell potential. 
A)  SHE stands for Standard Helium Electrodes. 
B)  E° is the standard electrode potential. 
C)  The standard electrode potential is the reduction potential of a half cell. 
D)  The standard cell potential is the potential difference between two half cells. 
E)  E°cell is the standard cell potential.

Exam 20: Electrochemistry

The standard Gibbs energy change for the following voltaic cell is ΔG° = -89.3 kJ at 25°C. What is E°cell? Cu(s) | Cu2+(aq) || Ag+(aq) | Ag(s)

Choose the INCORRECT statement.

What is the standard cell potential if the Gibbs energy is -2108 kJ in the reaction: C3H8 + O2(g) → CO2(g) + H2O(l) (not balanced)?

What is the concentration of Cu2+ in the following cell at 25°C if the cell voltage is 1.253 V? Zn ∣ Zn2+ (0.125 M) || Cu2+(?) ∣ Cu Cu2+ + 2 e- → Cu(s) E° = 0.340 V Zn2+ + 2 e- → Zn(s) E° = -0.763 V

What is ΔG° at 25°C for the reaction (not balanced): C3H8 + O2(g) → CO2(g) + H2O(l) if the standard cell potential is 1.092 V?

Find Ecell for the following voltaic cell at 25°C: Ti(s) ∣ Ti2+(aq) (0.550M) || Sn2+(aq) (0.005 M) ∣ Sn(s) The half-reactions are: Ti2+(aq) + 2 e- ⇔ Ti(s) E° = -1.630 V Sn2+(aq) + 2 e- ⇔ Sn(s) E° = -0.137 V

Choose the INCORRECT statement.

The following half-reactions are used in the zinc-air battery. Zn(OH)42- (aq) + 2 e- → Zn(s) + 4 OH-(aq) E° = -1.199 V O2(g) + 2 H2O(l) + 4 e- → 4 OH- (aq) E° = +0.401 V How much charge is transferred per gram Zn(s) in this voltaic cell?

Calculate Ecell at 25°C for the following voltaic cell. Ksp for NiCO3 is 1.42 × 10-7. Ni(s) ∣ Ni2+(aq) [sat'd NiCO3(s)] || Ni2+(aq) (0.010M) ∣ Ni(s) The half-reaction is: Ni2+(aq) + 2 e- → Ni(s) E° = -0.257 V

What mass of aluminum can be deposited by the passage of a constant current of 5.00 A through a Al(NO3)3 solution for 2.00 hours?

Determine E°cell for the reaction: 2 Ag + Mg2+ → 2 Ag+ + Mg. The half reactions are: Mg2+(aq) + 2 e- → Mg(s) E° = -2.356 V Ag+(aq) + e- → Ag(s) E° = 0.800 V

One mole of electrons has a charge of:

Choose the INCORRECT statement.

The lithium-ion battery is based on:

Calculate the mass of I2 produced at the anode if a current of 2.85 A is passed through a solution of KI for 56 minutes.

Determine Keq at 25°C for the following reaction: Pb2+(aq) + Cu(s) ⇔ Cu2+(aq) + Pb(s) The half-reactions are: Pb2+(aq) + 2 e- ⇔ Pb(s) E° = -0.125 V Cu2+(aq) + 2 e- ⇔ Cu(s) E° = +0.337 V

A solution of AgNO3 is electrolyzed by passing 144 A of current for 102 min. What mass of silver plates out?

Determine E°cell for the reaction: Pb + Cu2+ → Pb2+ + Cu. The half reactions are: Pb2+(aq) + 2 e- → Pb(s) E° = -0.125 V Cu2+ + 2 e- → Cu E° = 0.340 V

What is the Ecell for the following cell at 25°C? Pt ∣ Sn2+ (0.233 M), Sn4+ (1.05 M) || Ag+ (2.22 × 10-2 M) ∣ Ag Ag+ + e- → Ag(s) E° = 0.800 V Sn4+ + 2 e- → Sn2+ E° = 0.154 V

Choose the INCORRECT statement.

Matter - Its Properties and Measurement

Atoms and the Atomic Theory

Chemical Compounds

Chemical Reactions

Introduction to Reactions in Aqueous Solutions

Gases

Thermochemistry

Electrons in Atoms

The Periodic Table and Some Atomic Properties

Chemical Bonding I: Basic Concepts

Chemical Bonding II: Additional Aspects

Intermolecular Forces: Liquids and Solids

Solutions and Their Physical Properties

Chemical Kinetics

Principles of Chemical Equilibrium

Acids and Bases

Additional Aspects of Acid-Base Equilibria

Solubility and Complex-Ion Equilibria

Spontaneous Change: Entropy and Free Energy

Main Group Elements I: Groups 1, 2, 13, and 14

Main Group Elements II: Groups 18, 17, 16, 15, and Hydrogen

The Transition Elements

Complex Ions and Coordination Compounds

Nuclear Chemistry 1-41

Structures of Organic Compounds

Reactions of Organic Compounds

Chemistry of the Living State

Filters

What is the standard cell potential if the Gibbs energy is -2108 kJ in the reaction: C₃H₈ + O₂(g) → CO₂(g) + H₂O(l) (not balanced)?

What is the concentration of Cu²⁺ in the following cell at 25°C if the cell voltage is 1.253 V? Zn ∣ Zn²⁺ (0.125 M) || Cu²⁺(?) ∣ Cu Cu²⁺ + 2 e- → Cu(s) E° = 0.340 V Zn²⁺ + 2 e- → Zn(s) E° = -0.763 V

What is ΔG° at 25°C for the reaction (not balanced): C₃H₈+ O₂(g) → CO₂(g) + H₂O(l) if the standard cell potential is 1.092 V?

Find Ecell for the following voltaic cell at 25°C: Ti(s) ∣ Ti²⁺(aq) (0.550M) || Sn²⁺(aq) (0.005 M) ∣ Sn(s) The half-reactions are: Ti²⁺(aq) + 2 e- ⇔ Ti(s) E° = -1.630 V Sn²⁺(aq) + 2 e- ⇔ Sn(s) E° = -0.137 V

The following half-reactions are used in the zinc-air battery. Zn(OH)₄^2- (aq) + 2 e- → Zn(s) + 4 OH-(aq) E° = -1.199 V O₂(g) + 2 H₂O(l) + 4 e- → 4 OH- (aq) E° = +0.401 V How much charge is transferred per gram Zn(s) in this voltaic cell?

Calculate Ecell at 25°C for the following voltaic cell. Ksp for NiCO₃ is 1.42 × 10^-7. Ni(s) ∣ Ni²⁺(aq) [sat'd NiCO₃(s)] || Ni²⁺(aq) (0.010M) ∣ Ni(s) The half-reaction is: Ni²⁺(aq) + 2 e- → Ni(s) E° = -0.257 V

What mass of aluminum can be deposited by the passage of a constant current of 5.00 A through a Al(NO₃)₃ solution for 2.00 hours?

Calculate the mass of I₂ produced at the anode if a current of 2.85 A is passed through a solution of KI for 56 minutes.

Determine Keq at 25°C for the following reaction: Pb²⁺(aq) + Cu(s) ⇔ Cu²⁺(aq) + Pb(s) The half-reactions are: Pb²⁺(aq) + 2 e- ⇔ Pb(s) E° = -0.125 V Cu²⁺(aq) + 2 e- ⇔ Cu(s) E° = +0.337 V

A solution of AgNO₃ is electrolyzed by passing 144 A of current for 102 min. What mass of silver plates out?

What is the Ecell for the following cell at 25°C? Pt ∣ Sn²⁺ (0.233 M), Sn⁴⁺ (1.05 M) || Ag+ (2.22 × 10^-2 M) ∣ Ag Ag⁺ + e- → Ag(s) E° = 0.800 V Sn⁴⁺ + 2 e- → Sn²⁺ E° = 0.154 V