A reaction you can plug into.
A galvanic cell separates a spontaneous redox reaction into two half-cells. Oxidation occurs at the negative anode; reduction occurs at the positive cathode. Electrons travel through the wire from anode to cathode.
In a Zn/Cu cell, Zn atoms become Zn²⁺ and leave the anode, reducing its mass. Cu²⁺ receives electrons at the cathode and deposits as copper, increasing cathode mass.
The salt bridge carries ions, not electrons. For this cell, anions move towards the zinc compartment and cations towards the copper compartment to maintain electrical neutrality. Opening the circuit or removing the salt bridge stops sustained current.
Follow the electrons
Metal/Cu galvanic cell under standard conditions. Ion and electron movement is schematic. The salt bridge carries ions; the external wire carries electrons.
Assumed knowledge
Metal ions carry positive charge; the overall reaction conserves charge.
Learning checkpoints & source
YOUR SYLLABUS CHECKPOINT- Identify half-cells, electrodes and the salt bridge.
- Explain electron and ion movement.
- Connect electrode mass to half-reactions.