01E°cell
E°cell = E°cathode − E°anode using reduction potentials. Never multiply E° by coefficients — it's intensive.
ΔG° = −nFE°: positive E° → negative ΔG° → favorable. F = 96,485 C/mol e⁻.
02Notebook box
Higher reduction potential is reduced (cathode).
Worked example: Cu²⁺/Cu +0.34, Zn²⁺/Zn −0.76 → E° = 0.34 − (−0.76) = +1.10 V.