Chemistry
Explainer
How a Battery Turns Chemistry into Current
A battery is just two half-reactions kept apart by a wire.
Quick check · tap an answer to continue
Lesson notes
Key points
- In a galvanic cell, a spontaneous redox reaction is split so electrons must travel through an external wire.
- Oxidation happens at the anode, reduction at the cathode, and a salt bridge keeps both solutions electrically neutral.
- For zinc and copper, zinc is oxidised to Zn²⁺ while Cu²⁺ ions gain electrons and plate out as copper.
Definitions
- Galvanic cell
- A device that converts the free energy of a spontaneous redox reaction into electrical work.
Takeaway: Separate oxidation and reduction, and electrons flow as current.
Quick check: In a galvanic cell, where does oxidation occur?
- At the cathode
- At the anode
- In the salt bridge
Galvanic cellAnode and cathodeCell reaction
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