Gibbs Free Energy Calculator to Predict Reaction...
Calculate Gibbs free energy (ΔG) from cell potential or thermodynamic data. Determine if a reaction is spontaneous, non-spontaneous, or at equilibrium.
What is Gibbs Free Energy?
Gibbs Free Energy (ΔG) predicts whether a chemical reaction will occur spontaneously at constant temperature and pressure. A negative ΔG means the reaction is spontaneous (thermodynamically favorable). It connects thermodynamics to electrochemistry through the relationship ΔG = −nFE.
⚡ Gibbs Free Energy Calculator
Use our free calculator for instant, accurate results.
📐 Formula
ΔG = −nFE
n = moles of electrons transferred, F = Faraday constant (96,485 C/mol), E = cell potential (V). Also: ΔG = ΔH − TΔS.
📝 Worked Example
Daniell cell: E = 1.10V, n = 2:
ΔG = −2 × 96485 × 1.10 = −212,267 J = −212.3 kJ/mol
Negative → spontaneous ✓
📝 How to Use the Calculator
❓ FAQ
What does ΔG = 0 mean?
The system is at thermodynamic equilibrium — no net work can be extracted and no net reaction occurs.
Can an endothermic reaction be spontaneous?
Yes — if ΔS (entropy increase) is large enough, −TΔS overcomes positive ΔH. Example: dissolving ammonium nitrate in water.
Veer Kumavat
Founder & AuthorVeer is a 14-year-old student from Nashik, Maharashtra, who built SciFi Calculators to help students worldwide master STEM subjects. He is passionate about making complex science and math problems accessible through intuitive digital tools.