Equation and purpose
Cell potential under nonstandard conditions.
\[E = E^\circ - \frac{RT}{nF}\ln Q\]
Cell potential under nonstandard conditions.
REARRANGEMENTS
$E°=E+RT/nF lnQ$
Dimensional check: V ✓
Variables and units
| Symbol | Quantity | Unit | Notes |
|---|---|---|---|
| E | E | — | — |
| E° | E° | — | — |
| n | n | — | — |
| F | F | — | — |
| Q | Q | — | — |
Conditions and limitations
T in K; at 298 K often: E=E°−(0.05916V/n)log Q.
Worked example
Zn/Cu cell with Q=0.1 → E higher than E°.
Nernst Equation
Cell potential under nonstandard conditions.
Equation
Inline: $E = E^\circ - \frac{RT}{nF}\ln Q$$
Variables
| Symbol | Quantity | Unit | Notes |
|---|---|---|---|
| cell potential | V | — | |
| standard potential | V | — | |
| electrons transferred | — | — | |
| Faraday constant | C·mol⁻¹ | — | |
| reaction quotient | — | — |
Conditions and limitations
T in K; at 298 K often: E=E°−(0.05916V/n)log Q.
Rearrangements
Dimensional check: V ✓
Worked example
Zn/Cu cell with Q=0.1 → E higher than E°.
Steps: write equation → substitute with units → check dimensional consistency → report with correct significant figures.
Common errors
- Sign error for ln Q
- Forgetting n
Related resources
- redox-electrochemistry topic
- Calculators — linked only when a real calculator implements this formula.
- Constants — sourced constants with version when values are required.
Sources
- NIST Physical Constants 2022 — CODATA.
Reviewed 2026-08-21 by Editorial Team; due 2027-08-21.
Common errors
- Sign error for ln Q
- Forgetting n
RELATED FORMULAS
C
Chemistry Fundamentals Editorial TeamAuthor
E
Editorial Review BoardReviewer
Editorial Team — transparent review placeholder
Reviewed August 21, 2026
SOURCES
- [nist-2022]NIST Physical Constants 2022 (2022). NISThttps://physics.nist.gov/constants