Chapter 19: Electrochemistry

What is a redox reaction?

A chemical reaction in which electrons are transferred from one substance to another. One substance is oxidized (loses electrons) while another is reduced (gains electrons).

What is oxidation?

The loss of electrons. (Remember: OIL = Oxidation Is Loss)

What is reduction?

The gain of electrons. (Remember: RIG = Reduction Is Gain)

What is an oxidation number?

A number assigned to an atom that shows how many electrons it has gained, lost, or shared. If the oxidation number increases, oxidation has occurred. If it decreases, reduction has occurred.

What is an electrode?

A solid conductor, usually a metal, where oxidation or reduction takes place in an electrochemical cell.

What is a half-cell?

One side of an electrochemical cell containing one electrode and one electrolyte solution where either oxidation or reduction occurs.

What is an electrochemical cell?

A device that converts chemical energy into electrical energy or electrical energy into chemical energy using redox reactions.

What is a galvanic (voltaic) cell?

An electrochemical cell that uses a spontaneous redox reaction to generate electricity.

What is an electrolytic cell?

An electrochemical cell that uses electrical energy to force a non-spontaneous redox reaction.

What is an anode?

The electrode where oxidation occurs. (Remember: AnOx = Anode Oxidation)

What is a cathode?

The electrode where reduction occurs. (Remember: Red Cat = Reduction at Cathode)

What is a salt bridge?

A device that allows ions to move between half-cells to maintain electrical neutrality and complete the circuit.

Where does oxidation occur?

At the anode.

Where does reduction occur?

At the cathode.

Which type of cell produces electricity?

A galvanic (voltaic) cell.

Which type of cell requires electricity?

An electrolytic cell.

Why is a salt bridge important?

It allows ions to flow between half-cells, preventing charge buildup and allowing the cell to continue operating.

What is the difference between a galvanic cell and an electrolytic cell?

Galvanic cells generate electricity from spontaneous reactions, while electrolytic cells use electricity to drive non-spontaneous reactions.