Gibbs From Cell Potential
Enter cell potential (E) and electron moles (n) to compute ΔG in joules and kilojoules using ΔG = −nFE.
Inputs
Enter the measured or standard cell voltage (V). Positive = spontaneous cell.
Number of moles of electrons in the balanced redox equation.
Faraday constant (F)
96,485 C/mol
Result
Enter values and click Calculate to see ΔG
Formula applied
ΔG (Joules)
ΔG (Kilojoules)
Common Examples
| Reaction | E (V) | n | ΔG° (kJ/mol) |
|---|---|---|---|
| Zn + Cu²⁺ → Zn²⁺ + Cu (Daniell cell) | 1.10 | 2 | −212.3 |
| H₂ + O₂ → H₂O (hydrogen fuel cell) | 1.229 | 4 | −474.3 |
| Zn → Zn²⁺ + 2e⁻ (oxidation half-cell) | −0.76 | 2 | +146.7 |
Click any row to load the values into the calculator.
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Summary
Enter cell potential (E) and electron moles (n) to compute ΔG in joules and kilojoules using ΔG = −nFE.
How it works
- Enter the cell potential E in volts (positive for spontaneous cells).
- Enter n, the number of moles of electrons transferred in the balanced redox equation.
- Click Calculate — the tool computes ΔG = −n × 96485 × E.
- Results are shown in both joules (J) and kilojoules (kJ).
- The spontaneity verdict (spontaneous / non-spontaneous / at equilibrium) is displayed automatically.
Use cases
- Electrochemistry homework and exam problems involving cell potentials.
- Verifying whether a redox reaction proceeds spontaneously under standard conditions.
- Converting standard reduction potentials to standard Gibbs energy changes.
- Cross-checking Nernst equation calculations at non-standard concentrations.
- Lab work: estimating energy output of galvanic cells.
- Teaching thermodynamics — linking ΔG, ΔH, and cell voltage in one step.
Frequently Asked Questions
Last updated: 2026-06-18 ·
Reviewed by Nham Vu