Question 1

What is the oxidation number of potassium in KMnO4?

Accepted Answer

A) 0 
B) +1 
C) +2 
D) -1 
E) +3 
A) 0 
B) +1 
C) +2 
D) -1 
E) +3

Question 2

The standard cell potential (E°cell)of the reaction below is +0.126 V. The value of ΔG° for the reaction is __________ kJ/mol. Pb (s)+ 2H+ (aq)→ Pb2+ (aq)+ H2 (g)

Accepted Answer

A) -24.3 
B) +24.3 
C) -12.6 
D) +12.6 
E) -50.8 
A) -24.3 
B) +24.3 
C) -12.6 
D) +12.6 
E) -50.8

Question 3

The standard reduction potential, E°red, is proportional to the stoichiometric coefficient.

Accepted Answer

A) True 
 B)False

Question 4

The half-reaction occurring at the cathode in the balanced reaction shown below is __________. 3MnO4- (aq)+ 24H+ (aq)+ 5Fe (s)→ 3Mn2+ (aq)+ 5Fe3+ (aq)+ 12H2O (l)

Accepted Answer

A) MnO4- (aq)+ 8H+ (aq)+ 5e- → Mn2+ (aq)+ 4H2O (l) 
B) 2MnO4- (aq)+ 12H+ (aq)+ 6e- → 2Mn2+ (aq)+ 3H2O (l) 
C) Fe (s)→ Fe3+ (aq)+ 3e- 
D) Fe (s)→ Fe2+ (aq)+ 2e- 
E) Fe2+ (aq)→ Fe3+ (aq)+ e- 
A) MnO4- (aq)+ 8H+ (aq)+ 5e- → Mn2+ (aq)+ 4H2O (l) 
B) 2MnO4- (aq)+ 12H+ (aq)+ 6e- → 2Mn2+ (aq)+ 3H2O (l) 
C) Fe (s)→ Fe3+ (aq)+ 3e- 
D) Fe (s)→ Fe2+ (aq)+ 2e- 
E) Fe2+ (aq)→ Fe3+ (aq)+ e-

Question 5

__________ is the oxidizing agent in the reaction below. Cr2O72- + 6S2O32- + 14H+ → 2Cr3+ + 3S4O62- + 7H2O

Accepted Answer

A) Cr2O72- 
B) S2O32- 
C) H+ 
D) Cr3+ 
E) S4O62- 
A) Cr2O72- 
B) S2O32- 
C) H+ 
D) Cr3+ 
E) S4O62-

Question 6

Galvanized iron is iron coated with __________.

Accepted Answer

A) magnesium. 
B) zinc. 
C) chromium. 
D) phosphate. 
E) iron oxide. 
A) magnesium. 
B) zinc. 
C) chromium. 
D) phosphate. 
E) iron oxide.

Question 7

What is the oxidation number of manganese in the MnO   ion?

Accepted Answer

A) +1 
B) +2 
C) +5 
D) +4 
E) +7 
A) +1 
B) +2 
C) +5 
D) +4 
E) +7

Question 8

Which one of the following reactions is a redox reaction?

Accepted Answer

A) NaOH + HCl → NaCl + H2O 
B) Pb2+ + 2Cl- → PbCl2 
C) AgNO3 + HCl → HNO3 + AgCl 
D) None of the above is a redox reaction. 
A) NaOH + HCl → NaCl + H2O 
B) Pb2+ + 2Cl- → PbCl2 
C) AgNO3 + HCl → HNO3 + AgCl 
D) None of the above is a redox reaction.

Question 9

__________ is reduced 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 10

The gain of electrons by an element is called __________.

Accepted Answer

A) reduction 
B) oxidation 
C) disproportionation 
D) fractionation 
E) sublimation 
A) reduction 
B) oxidation 
C) disproportionation 
D) fractionation 
E) sublimation

Question 11

One of the differences between a voltaic cell and an electrolytic cell is that in an electrolytic cell __________.

Accepted Answer

A) an electric current is produced by a chemical reaction 
B) electrons flow toward the anode 
C) a nonspontaneous reaction is forced to occur 
D) O2 gas is produced at the cathode 
E) oxidation occurs at the cathode 
A) an electric current is produced by a chemical reaction 
B) electrons flow toward the anode 
C) a nonspontaneous reaction is forced to occur 
D) O2 gas is produced at the cathode 
E) oxidation occurs at the cathode

Question 12

The half-reaction occurring at the anode in the balanced reaction shown below is __________. 3MnO4- (aq)+ 24H+ (aq)+ 5Fe (s)→ 3Mn2+ (aq)+ 5Fe3+ (aq)+ 12H2O (l)

Accepted Answer

A) MnO4- (aq)+ 8H+ (aq)+ 5e- → Mn2+ (aq)+ 4H2O (l) 
B) 2MnO4- (aq)+ 12H+ (aq)+ 6e- → 2Mn2+ (aq)+ 3H2O (l) 
C) Fe (s)→ Fe3+ (aq)+ 3e- 
D) Fe (s)→ Fe2+ (aq)+ 2e- 
E) Fe2+ (aq)→ Fe3+ (aq)+ e- 
A) MnO4- (aq)+ 8H+ (aq)+ 5e- → Mn2+ (aq)+ 4H2O (l) 
B) 2MnO4- (aq)+ 12H+ (aq)+ 6e- → 2Mn2+ (aq)+ 3H2O (l) 
C) Fe (s)→ Fe3+ (aq)+ 3e- 
D) Fe (s)→ Fe2+ (aq)+ 2e- 
E) Fe2+ (aq)→ Fe3+ (aq)+ e-

Question 13

The electrode where reduction occurs is called the anode.

Accepted Answer

A) True 
 B)False

Question 14

The electrode at which oxidation occurs is called the __________.

Accepted Answer

A) oxidizing agent 
B) cathode 
C) reducing agent 
D) anode 
E) voltaic cell 
A) oxidizing agent 
B) cathode 
C) reducing agent 
D) anode 
E) voltaic cell

Question 15

The major product of a hydrogen fuel cell is __________.

Accepted Answer

The answer of The major product of a hydrogen fuel...

Question 16

The standard cell potential (E°cell)for the voltaic cell based on the reaction below is __________ V. 3Sn4+ (aq)+ 2Cr (s)→ 2Cr3+ (aq)+ 3Sn2+ (aq)

Accepted Answer

A) +1.94 
B) +0.89 
C) +2.53 
D) -0.59 
E) -1.02 
A) +1.94 
B) +0.89 
C) +2.53 
D) -0.59 
E) -1.02

Question 17

The town of Natrium, West Virginia, derives its name from the sodium produced in the electrolysis of molten sodium chloride (NaCl)mined from ancient salt deposits. The number of kilowatt-hours of electricity required to produce 4.60 kg of metallic sodium from the electrolysis of molten NaCl(s)is __________ when the applied emf is 4.50 V.

Accepted Answer

A) 24.1 
B) 0.0414 
C) 0.0241 
D) 48.3 
E) 12.1 
A) 24.1 
B) 0.0414 
C) 0.0241 
D) 48.3 
E) 12.1

Question 18

The standard cell potential (E°cell)for the reaction below is +0.63 V. The cell potential for this reaction is __________ V when [Zn2+] = 3.5 M and [Pb2+] = 2.0 × 10-4 M. Pb2+ (aq)+ Zn (s)→ Zn2+ (aq)+ Pb (s)

Accepted Answer

A) 0.50 
B) 0.84 
C) 0.39 
D) 0.76 
E) 0.63 
A) 0.50 
B) 0.84 
C) 0.39 
D) 0.76 
E) 0.63

Question 19

What is the oxidation number of nitrogen in the HNO3?

Accepted Answer

A) -1 
B) +1 
C) +3 
D) +5 
E) +7 
A) -1 
B) +1 
C) +3 
D) +5 
E) +7

Question 20

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-

Exam 20: Electrochemistry

What is the oxidation number of potassium in KMnO4?

The standard cell potential (E°cell)of the reaction below is +0.126 V. The value of ΔG° for the reaction is __________ kJ/mol. Pb (s)+ 2H+ (aq)→ Pb2+ (aq)+ H2 (g)

The standard reduction potential, E°red, is proportional to the stoichiometric coefficient.

The half-reaction occurring at the cathode in the balanced reaction shown below is __________. 3MnO4- (aq)+ 24H+ (aq)+ 5Fe (s)→ 3Mn2+ (aq)+ 5Fe3+ (aq)+ 12H2O (l)

__________ is the oxidizing agent in the reaction below. Cr2O72- + 6S2O32- + 14H+ → 2Cr3+ + 3S4O62- + 7H2O

Galvanized iron is iron coated with __________.

What is the oxidation number of manganese in the MnO ion?

Which one of the following reactions is a redox reaction?

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

The gain of electrons by an element is called __________.

One of the differences between a voltaic cell and an electrolytic cell is that in an electrolytic cell __________.

The half-reaction occurring at the anode in the balanced reaction shown below is __________. 3MnO4- (aq)+ 24H+ (aq)+ 5Fe (s)→ 3Mn2+ (aq)+ 5Fe3+ (aq)+ 12H2O (l)

The electrode where reduction occurs is called the anode.

The electrode at which oxidation occurs is called the __________.

The major product of a hydrogen fuel cell is __________.

The standard cell potential (E°cell)for the voltaic cell based on the reaction below is __________ V. 3Sn4+ (aq)+ 2Cr (s)→ 2Cr3+ (aq)+ 3Sn2+ (aq)

The standard cell potential (E°cell)for the reaction below is +0.63 V. The cell potential for this reaction is __________ V when [Zn2+] = 3.5 M and [Pb2+] = 2.0 × 10-4 M. Pb2+ (aq)+ Zn (s)→ Zn2+ (aq)+ Pb (s)

What is the oxidation number of nitrogen in the HNO3?

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

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What is the oxidation number of potassium in KMnO₄?

The standard cell potential (E°_cell)of the reaction below is +0.126 V. The value of ΔG° for the reaction is __________ kJ/mol. Pb (s)+ 2H⁺ (aq)→ Pb²⁺ (aq)+ H₂ (g)

The standard reduction potential, E°_red, is proportional to the stoichiometric coefficient.

The half-reaction occurring at the cathode in the balanced reaction shown below is __________. 3MnO₄^- (aq)+ 24H⁺ (aq)+ 5Fe (s)→ 3Mn²⁺ (aq)+ 5Fe³⁺ (aq)+ 12H₂O (l)

__________ is the oxidizing agent in the reaction below. Cr₂O₇^2- + 6S₂O₃^2- + 14H⁺ → 2Cr³⁺ + 3S₄O₆^2- + 7H₂O

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

The half-reaction occurring at the anode in the balanced reaction shown below is __________. 3MnO₄^- (aq)+ 24H⁺ (aq)+ 5Fe (s)→ 3Mn²⁺ (aq)+ 5Fe³⁺ (aq)+ 12H₂O (l)

The standard cell potential (E°_cell)for the voltaic cell based on the reaction below is __________ V. 3Sn⁴⁺ (aq)+ 2Cr (s)→ 2Cr³⁺ (aq)+ 3Sn²⁺ (aq)

The standard cell potential (E°_cell)for the reaction below is +0.63 V. The cell potential for this reaction is __________ V when [Zn²⁺] = 3.5 M and [Pb²⁺] = 2.0 × 10^-4 M. Pb²⁺ (aq)+ Zn (s)→ Zn²⁺ (aq)+ Pb (s)

What is the oxidation number of nitrogen in the HNO₃?