Question 1

In a fuel cell, an external source of electrical power is used to drive a non-spontaneous reaction in which a fuel is produced.

Accepted Answer

A) True 
 B)False  False

Question 2

A primary battery is one which can be recharged.

Accepted Answer

A) True 
 B)False  False

Question 3

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 the above 
A)  0.010 V 
B)  0.020 V 
C)  0.023 V 
D)  0.046 V 
E)  none of the above C

Question 4

A concentration cell is based on the aqueous reaction
Cu2+(1.00 M) F1F1F1S1F1F1F10 Cu2+(0.0100 M)
The cell consists of copper electrodes dipping into solutions of Cu2+ ions. The anions present are sulfate ions. Draw a neat diagram to represent this cell, showing and labeling all necessary components including: anode, cathode, electron flow, cation flow, and anion flow.

Accepted Answer

Question 5

When the following redox equation is balanced with smallest whole number coefficients, the coefficient for zinc will be _____. Zn(s) + ReO4-(aq) F1F1F1S1F1F1F10 Re(s) + Zn2+(aq) (acidic solution)

Accepted Answer

A)  2 
B)  7 
C)  8 
D)  16 
E)  none of the above 
A)  2 
B)  7 
C)  8 
D)  16 
E)  none of the above

Question 6

Examine the following half-reactions and select the strongest reducing agent among the species listed.

Accepted Answer

A)  Hg(l) 
B)  Zn(s) 
C)  Ag(s) 
D)  BH4-(aq) 
E)  Zn(OH)2(s) 
A)  Hg(l) 
B)  Zn(s) 
C)  Ag(s) 
D)  BH4-(aq) 
E)  Zn(OH)2(s)

Question 7

A concentration cell is based on the aqueous reaction
Cu2+(1.00 M) F1F1F1S1F1F1F10 Cu2+(0.0100 M)
The cell consists of copper electrodes dipping into solutions of Cu2+ ions. The anions present are sulfate ions. Write the shorthand cell notation for this cell.

Accepted Answer

Cu(s) F1F1F1S1F1F1F

Question 8

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 9

When the following redox equation is balanced with smallest whole number coefficients, the coefficient for the iodide ion will be _____. I-(aq) + NO3-(aq) F1F1F1S1F1F1F10 NO(g) + I2(s) (acidic solution)

Accepted Answer

A)  2 
B)  3 
C)  6 
D)  8 
E)  none of the above 
A)  2 
B)  3 
C)  6 
D)  8 
E)  none of the above

Question 10

a. Write a balanced equation to represent the overall reaction you would expect to occur in the electrolysis of molten KCl.
b. Write a balanced equation to represent the overall reaction you would expect to occur in the electrolysis of aqueous KCl.
c. Clearly explain why the products of the two processes are not the same.

Accepted Answer

a. 2KCl(l) F1F1F1S1F1F1F10 2K(l) + Cl₂(g

Question 11

Which one of the following pairs of substances could be used to construct a single redox electrode (i.e., they have an element in common, but in different oxidation states)?

Accepted Answer

A)  HCl and Cl- 
B)  H+ and OH- 
C)  H2O and H+ 
D)  Fe3+ and Fe2O3 
E)  MnO2 and Mn2+ 
A)  HCl and Cl- 
B)  H+ and OH- 
C)  H2O and H+ 
D)  Fe3+ and Fe2O3 
E)  MnO2 and Mn2+

Question 12

Two cells are connected in series, so that the same current flows through two electrodes where the following half-reactions occur Cu2+(aq) + 2e- F1F1F1S1F1F1F10 Cu(s) and Ag+(aq) + e- F1F1F1S1F1F1F10 Ag(s)
For every 1.00 g of copper produced in the first process, how many grams of silver will be produced in the second one?

Accepted Answer

A)  0.294 g 
B)  0.588 g 
C)  0.850 g 
D)  1.70 g 
E)  3.40 g 
A)  0.294 g 
B)  0.588 g 
C)  0.850 g 
D)  1.70 g 
E)  3.40 g

Question 13

The lead-acid battery is an example of a secondary battery.

Accepted Answer

A) True 
 B)False

Question 14

When the following redox equation is balanced with smallest whole number coefficients, the coefficient for nitrogen dioxide will be _____.
 I2(s) + HNO3(aq) F1F1F1S1F1F1F10 HIO3(aq) + NO2(g) + H2O(l)

Accepted Answer

A)  1 
B)  2 
C)  4 
D)  10 
E)  none of the above 
A)  1 
B)  2 
C)  4 
D)  10 
E)  none of the above

Question 15

Electrolytic cells utilize electrical energy to drive non-spontaneous redox reactions.

Accepted Answer

A) True 
 B)False

Question 16

Calculate E°cell and indicate whether the overall reaction shown is spontaneous or nonspontaneous. 
 
 reaction: 2Cr(s) + 3I2(s) F1F1F1S1F1F1F10 2Cr3+(aq) + (aq) + 6I-(aq)

Accepted Answer

A)  E°cell = -1.27 V, spontaneous 
B)  E°cell = -1.27 V, nonspontaneous 
C)  E°cell = 1.27 V, spontaneous 
D)  E°cell = 1.27 V, nonspontaneous 
E)  E°cell = 1.54 V, spontaneous 
A)  E°cell = -1.27 V, spontaneous 
B)  E°cell = -1.27 V, nonspontaneous 
C)  E°cell = 1.27 V, spontaneous 
D)  E°cell = 1.27 V, nonspontaneous 
E)  E°cell = 1.54 V, spontaneous

Question 17

What is the value of the equilibrium constant for the cell reaction below at 25°C? E°cell = 0.61 V 2Cr(s) + 3Pb2+(aq)   3Pb(s) + 2Cr3+(aq)

Accepted Answer

A)  4.1 × 1020 
B)  8.2 × 1030 
C)  3.3 × 1051 
D)  7.4 × 1061 
E)  > 9.9 × 1099 
A)  4.1 × 1020 
B)  8.2 × 1030 
C)  3.3 × 1051 
D)  7.4 × 1061 
E)  > 9.9 × 1099

Question 18

Which of the following statements about voltaic and electrolytic cells is correct?

Accepted Answer

A)  The anode will definitely gain weight in a voltaic cell. 
B)  Oxidation occurs at the cathode of both cells. 
C)  The free energy change, F1F1F1S1F1F1F10G, is negative for the voltaic cell. 
D)  The electrons in the external wire flow from cathode to anode in an electrolytic cell. 
E)  None of the above statements is correct. 
A)  The anode will definitely gain weight in a voltaic cell. 
B)  Oxidation occurs at the cathode of both cells. 
C)  The free energy change, F1F1F1S1F1F1F10G, is negative for the voltaic cell. 
D)  The electrons in the external wire flow from cathode to anode in an electrolytic cell. 
E)  None of the above statements is correct.

Question 19

Which of the following elements could be prepared by electrolysis of the aqueous solution shown?

Accepted Answer

A)  sodium from Na3PO4(aq) 
B)  sulfur from K2SO4(aq) 
C)  oxygen from H2SO4(aq) 
D)  potassium from KCl(aq) 
E)  nitrogen from AgNO3(aq) 
A)  sodium from Na3PO4(aq) 
B)  sulfur from K2SO4(aq) 
C)  oxygen from H2SO4(aq) 
D)  potassium from KCl(aq) 
E)  nitrogen from AgNO3(aq)

Question 20

A battery that cannot be recharged is a

Accepted Answer

A)  fuel cell. 
B)  primary battery. 
C)  secondary battery. 
D)  simple battery. 
E)  flow battery. 
A)  fuel cell. 
B)  primary battery. 
C)  secondary battery. 
D)  simple battery. 
E)  flow battery.

Exam 21: Electrochemistry: Chemical Change and Electrical Work

In a fuel cell, an external source of electrical power is used to drive a non-spontaneous reaction in which a fuel is produced.

A primary battery is one which 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?

When the following redox equation is balanced with smallest whole number coefficients, the coefficient for zinc will be _____. Zn(s) + ReO4-(aq)  Re(s) + Zn2+(aq) (acidic solution)

Examine the following half-reactions and select the strongest reducing agent among the species listed.

A concentration cell is based on the aqueous reaction Cu2+(1.00 M)  Cu2+(0.0100 M) The cell consists of copper electrodes dipping into solutions of Cu2+ ions. The anions present are sulfate ions. Write the shorthand cell notation for this cell.

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).

When the following redox equation is balanced with smallest whole number coefficients, the coefficient for the iodide ion will be _____. I-(aq) + NO3-(aq)  NO(g) + I2(s) (acidic solution)

Which one of the following pairs of substances could be used to construct a single redox electrode (i.e., they have an element in common, but in different oxidation states)?

The lead-acid battery is an example of a secondary battery.

When the following redox equation is balanced with smallest whole number coefficients, the coefficient for nitrogen dioxide will be _____. I2(s) + HNO3(aq)  HIO3(aq) + NO2(g) + H2O(l)

Electrolytic cells utilize electrical energy to drive non-spontaneous redox reactions.

Calculate E°cell and indicate whether the overall reaction shown is spontaneous or nonspontaneous. reaction: 2Cr(s) + 3I2(s)  2Cr3+(aq) + (aq) + 6I-(aq)

What is the value of the equilibrium constant for the cell reaction below at 25°C? E°cell = 0.61 V 2Cr(s) + 3Pb2+(aq) 3Pb(s) + 2Cr3+(aq)

Which of the following statements about voltaic and electrolytic cells is correct?

Which of the following elements could be prepared by electrolysis of the aqueous solution shown?

A battery that cannot be recharged is a

Keys to the Study of Chemistry

The Components of Matter

Stoichiometry of Formulas and Equations

The 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: Bonding, Structure, and Reactivity

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 the Direction of Chemical Reactions

The Elements in Nature and Industry

The 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?

When the following redox equation is balanced with smallest whole number coefficients, the coefficient for zinc will be _____. Zn(s) + ReO₄^-(aq)  Re(s) + Zn²⁺(aq) (acidic solution)

A concentration cell is based on the aqueous reaction Cu²⁺(1.00 M)  Cu²⁺(0.0100 M) The cell consists of copper electrodes dipping into solutions of Cu²⁺ ions. The anions present are sulfate ions. Write the shorthand cell notation for this cell.

When the following redox equation is balanced with smallest whole number coefficients, the coefficient for the iodide ion will be _____. I^-(aq) + NO₃^-(aq)  NO(g) + I₂(s) (acidic solution)

When the following redox equation is balanced with smallest whole number coefficients, the coefficient for nitrogen dioxide will be _____. I₂(s) + HNO₃(aq)  HIO₃(aq) + NO₂(g) + H₂O(l)

Calculate E^°_cell and indicate whether the overall reaction shown is spontaneous or nonspontaneous. reaction: 2Cr(s) + 3I₂(s)  2Cr³⁺(aq) + (aq) + 6I^-(aq)

What is the value of the equilibrium constant for the cell reaction below at 25°C? E°_cell = 0.61 V 2Cr(s) + 3Pb²⁺(aq) 3Pb(s) + 2Cr³⁺(aq)