This free Nernst Equation Calculator makes complex cell potential calculations simple and accurate. The Nernst equation calculates the reduction potential of an electrochemical cell under non-standard conditions. It was named after Walther Nernst, a German physical chemist who formulated the equation. This fundamental equation connects cell potential with concentration, temperature, and chemical activity.
Nernst Equation Calculator
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Understanding the Nernst Equation Formula
The Nernst equation at room temperature (25°C) is:
E = E° – (0.05916/n) × log₁₀(a_Red/a_Ox)
Where:
- E = Cell potential under actual conditions (volts)
- E° = Standard half-cell reduction potential (volts)
- n = Number of electrons transferred in the reaction
- a_Red = Chemical activity of the reductant species
- a_Ox = Chemical activity of the oxidant species
- 0.05916 = Constant at room temperature (25°C)
How to Use Nernst Equation Calculator
Our user-friendly calculator requires four simple inputs:
Step 1: Enter Standard Half-Cell Reduction Potential (E°)
- Input the standard reduction potential in volts
- Find values in electrochemistry handbooks
- Use positive values for reduction potentials
- Common values: Cu²⁺/Cu = +0.34 V, Zn²⁺/Zn = -0.76 V
Step 2: Input Number of Electrons (n)
- Count electrons in the balanced half-reaction
- This must be a whole number (1, 2, 3, etc.)
- Double-check your balanced equation
Step 3: Enter Chemical Activity of Reductant (a_Red)
- Input the activity of the reduced species
- For dilute solutions, use molar concentration
- Default value is often 1.0 for pure substances
Step 4: Add Chemical Activity of Oxidant (a_Ox)
- Enter the activity of the oxidized species
- Again, concentration works for dilute solutions
- Cannot be zero (would cause mathematical error)
Step 5: Calculate Results
Click “Calculate” to get instant, accurate cell potential values. The calculator automatically handles logarithms and unit conversions.
Advantages of Using Our Calculator
- Instant calculations
- No manual logarithm work
- Automatic error checking
- Professional-grade accuracy
- Step-by-step guidance
- Clear input labels
- Immediate feedback
- Learning-friendly interface
Frequently Asked Questions
What’s the difference between E and E°?
E° is the standard potential under ideal conditions (1 M, 25°C, 1 atm). E is the actual potential under your specific experimental conditions.
Can the Nernst equation give negative values?
Yes, negative E values indicate that the reaction is not spontaneous under those conditions. The reverse reaction would be favored.
Why does concentration affect cell potential?
The Nernst equation is useful for predicting concentration near electrodes surface at an applied potential. Higher reactant concentrations drive the reaction forward, increasing cell potential.