Unit 3: Oxidation/Reduction Reactions and Electrochemistry

These flashcards cover key concepts from Unit 3 on oxidation/reduction reactions and electrochemistry, including definitions, methods for balancing reactions, and principles of galvanic cells.

What are redox reactions?

Redox reactions are oxidation-reduction reactions where oxidation and reduction occur simultaneously, involving the transfer of electrons.

Define oxidation.

Oxidation is the loss of electrons by an atom, resulting in an increase in charge.

What is reduction?

Reduction is the gain of electrons by an atom, resulting in a decrease in charge.

What is an oxidizing agent?

An oxidizing agent is the compound that causes another atom to become oxidized (while it is reduced).

What is a reducing agent?

A reducing agent is the compound that causes another atom to become reduced (while it is oxidized).

What is the oxidation state of pure elements?

The oxidation states of pure elements is zero.

List the steps for balancing reactions by the half-reaction method.

1. Assign oxidation numbers. 2. Write half reactions. 3. Balance other atoms. 4. Balance oxygen with water. 5. Balance hydrogen with H+. 6. Balance charge with electrons. 7. Balance electrons between half reactions. 8. Cancel electrons and any identical compounds.

What is a galvanic cell?

A galvanic cell is an electrochemical cell that converts chemical energy into electrical energy through spontaneous redox reactions.

What occurs at the anode of a galvanic cell?

Oxidation occurs at the anode.

What occurs at the cathode of a galvanic cell?

Reduction occurs at the cathode.

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

A salt bridge maintains electrical neutrality by allowing ion flow.

What does a voltmeter measure?

A voltmeter measures the cell potential (emf) in volts.

What does a positive cell potential imply about a reaction?

A positive cell potential implies that the reaction is thermodynamically favorable and can act as a battery.

What does G represent in the Gibbs free energy equation?

G represents Gibbs free energy.

What is the Faraday constant?

The Faraday constant is the charge on one mole of electrons, approximately 96,485 coulombs.

How can you use standard reduction potentials to predict cell voltage?

Use the reduction and oxidation potentials of the two half-reactions to predict the cell voltage by flipping one reaction as necessary.

How does reaction quotient Q affect cell voltage?

More products decrease cell voltage, while more reactants increase cell voltage.