19.2.1 Electrochemical Cells

Question 1

Electrochemical Cells

Answer 1

• In a galvanic cell (or voltaic cell), electrical energy is produced by separating spontaneously occurring redox reactions into half-cells.
• In an electrolytic cell, electrical energy is used to drive nonspontaneous redox reactions.

Question 2

note

Answer 2

• Spontaneously occurring redox reactions can be separated into half-cells and harnessed to do work. This type of electrochemical cell is called a galvanic cell or voltaic cell.
• The anode is the half-cell in which oxidation occurs, while the cathode is the half-cell in which reduction occurs.
• A salt bridge is used to allow non-reacting ions to flow to allow the solutions to remain neutral.
• Electrical energy can be used to drive nonspontaneous redox reactions. This type of electrochemical cell is called an electrolytic cell.
• The anode is still the half-cell in which oxidation occurs, and the cathode is still the half-cell in which reduction occurs.
• Electrolytic cells can be used to cause reactions to occur which would not occur otherwise. For example, gold and silver metal can be plated out of solution onto other metals.

Question 3

In the following reaction, which half reaction would take place at the anode?

Zn(s) + CuSO4(aq) → ZnSO4(aq) + Cu(s)

Answer 3

Zn(s) → Zn2+ (aq) + 2e−

Question 4

In the following galvanic cell, where would metal be consumed?

Answer 4

A

Question 5

What is the purpose of the salt bridge in a galvanic cell?

Answer 5

• Completing the electrical circuit
• Maintaining a balance of ions in the separate compartments
• Maintaining a balance of electrical charge in the separate compartments

Question 6

Which of the following is a nonspontaneous reaction?

Answer 6

Electrolytic cell

Question 7

Where is the site of oxidation in a galvanic cell?

Answer 7

Anode

Question 8

Where does the deposition of metal occur in an electrolytic cell?

Answer 8

Cathode

Question 9

In the following reaction, which half reaction would take place at the cathode?

Cu(s) + 2Ag+ (aq) → Cu2+ (aq) + 2Ag(s)

Answer 9

2Ag+ (aq) + 2e− → 2Ag(s)

Question 10

In the diagram of an electrolytic cell, where is oxidation taking place?

Answer 10

A

Question 11

Where does oxidation occur in an electrolytic cell?

Answer 11

Anode

Question 12

In the diagram of an galvanic cell, which is the anode?

Answer 12

A

Question 13

In the following electrolytic cell, where would metal be plated?

Answer 13

D