Chapter 19: Redox Reactions

Electrochemistry

The field of chemistry that studies how electricity and redox reactions are related.

Electrochemical Cell

A device that uses a redox reaction to produce or utilize electricity.

Electrolyte

Any substance that, when dissolved in water, allows the solution to conduct electricity.

Voltaic Cell

An electrochemical cell that uses a spontaneous chemical reaction to produce electrical energy.

Electrolytic Cell

An electrochemical cell that uses electrical energy to drive a nonspontaneous chemical reaction.

Key Concepts

• Reduction occurs at the cathode, and oxidation occurs at the anode.
• Electrolytes allow the flow of ions, enabling electrical conductivity.
• Voltaic cells generate electricity spontaneously, while electrolytic cells require electricity input.

Applications of Electrochemical Reactions

• Batteries: Devices like lithium-ion batteries utilize voltaic cells.
• Electroplating: The process of coating a material with a thin layer of metal.
• Metal Refining: Electrolysis is used to purify metals like aluminum and copper.

Example Problems

Example 19-5

Write the half-reactions for the oxidation of calcium and the reduction of iron(III) ions to iron atoms.

Mini Lab

Create a simple voltaic cell using copper and zinc strips connected by a salt bridge.

Questions for Students

1. Define electrochemistry and its importance in redox reactions.
2. Differentiate between voltaic and electrolytic cells.
3. Explain why a salt bridge is necessary in a voltaic cell.
4. Provide examples of applications of electrochemical cells in daily life.
5. Write the half-reactions for the following redox reaction: ${\mathrm{Zn}}_{\mathrm{2+}}+{\mathrm{Cu}}_{\mathrm{2+}}\to \mathrm{Zn}+\mathrm{Cu}$.