Electrochemical Cell Voltage Calculator
Calculate standard cell voltage E°cell from half-reaction reduction potentials.
Find ΔG° and the equilibrium constant K for the cell reaction.
Cell Voltage
An electrochemical cell converts chemical energy to electrical energy (galvanic/voltaic cell) or uses electrical energy to drive chemical reactions (electrolytic cell).
Standard cell voltage:
E°cell = E°cathode − E°anode
The cathode is where reduction occurs (gains electrons). The anode is where oxidation occurs (loses electrons).
Standard reduction potentials (E°, vs SHE) at 25°C:
| Half-reaction | E° (V) |
|---|---|
| F₂ + 2e⁻ → 2F⁻ | +2.87 |
| MnO₄⁻ + 8H⁺ + 5e⁻ → Mn²⁺ | +1.51 |
| Cl₂ + 2e⁻ → 2Cl⁻ | +1.36 |
| O₂ + 4H⁺ + 4e⁻ → 2H₂O | +1.23 |
| Ag⁺ + e⁻ → Ag | +0.80 |
| Fe³⁺ + e⁻ → Fe²⁺ | +0.77 |
| Cu²⁺ + 2e⁻ → Cu | +0.34 |
| 2H⁺ + 2e⁻ → H₂ | 0.00 (SHE) |
| Pb²⁺ + 2e⁻ → Pb | −0.13 |
| Fe²⁺ + 2e⁻ → Fe | −0.44 |
| Zn²⁺ + 2e⁻ → Zn | −0.76 |
| Al³⁺ + 3e⁻ → Al | −1.66 |
| Na⁺ + e⁻ → Na | −2.71 |
| Li⁺ + e⁻ → Li | −3.04 |
Spontaneity: E°cell > 0 → spontaneous (galvanic cell)
Relationship to ΔG° and K:
ΔG° = −nFE°cell
K = e^(nFE°/RT) = 10^(nE°/0.0592) at 25°C
where F = 96,485 C/mol and n = electrons transferred.