Concept preview

What you will be able to do

1. 01Explain how a galvanic cell works and label its parts
2. 02Write cell notation and identify anode and cathode
3. 03Calculate the cell voltage and relate it to free energy

In a spontaneous redox reaction electrons transfer from the reducing agent to the oxidizing agent. If the two reactants are simply mixed, that energy is released as heat. But if we physically separate the two half-reactions and force the electrons to travel from one to the other through an external wire, the moving electrons form an electric current. A device that does this — harnessing a spontaneous redox reaction to produce electricity — is a galvanic (or voltaic) cell, the basis of every battery.