# Nernst Equation Calculator

Free Nernst equation calculator. Calculate cell potential under non-standard conditions using E = E° - (RT/nF)ln(Q). Includes ΔG calculation.

## What this calculates

Calculate the cell potential under non-standard conditions using the Nernst equation: E = E° - (RT/nF)ln(Q). This relates the cell voltage to the standard potential, temperature, and reaction quotient.

## Inputs

- **Standard Cell Potential (E°)** (V) — Standard reduction potential of the cell in volts.
- **Electrons Transferred (n)** — min 1, max 20 — Number of electrons transferred in the balanced half-reaction.
- **Reaction Quotient (Q)** — min 0 — Reaction quotient ([products]/[reactants]).
- **Temperature** (K) — min 0 — Temperature in Kelvin (25°C = 298.15 K).

## Outputs

- **Cell Potential (E)** (V) — The cell potential under the given conditions.
- **Spontaneity** — formatted as text — Whether the reaction is spontaneous (E > 0).
- **ΔG** (kJ/mol) — Gibbs free energy change: ΔG = -nFE.
- **Calculation** — formatted as text — Step-by-step Nernst equation calculation.

## Frequently Asked Questions

**Q: What is the Nernst equation?**

A: The Nernst equation relates the cell potential to the standard cell potential and the reaction quotient: E = E° - (RT/nF)ln(Q). At 25°C, this simplifies to E = E° - (0.0592/n)log(Q) using log base 10.

**Q: What are R and F in the equation?**

A: R is the universal gas constant (8.314 J/(mol·K)) and F is Faraday's constant (96,485 C/mol), which represents the charge of one mole of electrons.

**Q: What happens when Q = 1?**

A: When Q = 1, ln(Q) = 0, so E = E°. This means the cell potential equals the standard potential when all species are at standard conditions (1 M, 1 atm).

**Q: How is the Nernst equation related to equilibrium?**

A: At equilibrium, E = 0 and Q = K (equilibrium constant). This gives: E° = (RT/nF)ln(K), allowing you to calculate K from E° or vice versa.

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Source: https://vastcalc.com/calculators/chemistry/nernst-equation
Category: Chemistry
Last updated: 2026-04-21