Nernst Equation Calculator
Calculate electrochemical cell potentials and equilibrium constants
Nernst Equation Calculations
How to Use the Nernst Equation Calculator
Getting Started
- Step 1: Select the calculation type (cell potential, equilibrium constant, or standard potential)
- Step 2: Enter the known values (standard potential, temperature, electrons transferred)
- Step 3: For cell potential calculations, enter the reaction quotient
- Step 4: Click Calculate to get the electrochemical result
Electrochemistry Concepts
- Cell Potential (E): Voltage produced by an electrochemical cell under given conditions
- Standard Potential (E°): Cell potential under standard conditions (1 M, 1 atm, 25°C)
- Reaction Quotient (Q): Ratio of product to reactant concentrations raised to their powers
- Equilibrium Constant (K): Value of Q when the system is at equilibrium
Nernst Equation Forms
- General Form: E = E° - (RT/nF) × ln(Q)
- At 25°C: E = E° - (0.0257/n) × ln(Q)
- Base 10 Form: E = E° - (0.0592/n) × log(Q)
- Equilibrium: ln(K) = nFE°/RT
Common Applications
- Battery Design: Predicting voltage output under different conditions
- Corrosion Analysis: Understanding metal oxidation in various environments
- Electroplating: Optimizing conditions for metal deposition
- Analytical Chemistry: Ion-selective electrodes and potentiometric titrations
Frequently Asked Questions
How do I calculate the reaction quotient (Q)?
Q = [products]^coefficients / [reactants]^coefficients. Use the concentrations (for solutions) or partial pressures (for gases) of species in the balanced electrode reaction.
What happens when Q = K (at equilibrium)?
When Q = K, the cell potential E = 0. The system is at equilibrium and no net current flows. This is how we derive the relationship between E° and K.
Why does temperature affect cell potential?
Temperature appears in the RT/nF term of the Nernst equation. Higher temperatures generally decrease cell potential for spontaneous reactions (positive E°).
How do I determine the number of electrons transferred?
Count the electrons in the balanced half-reactions. For example, Zn → Zn²⁺ + 2e⁻ involves 2 electrons. Make sure your overall cell reaction is balanced.
What's the difference between galvanic and electrolytic cells?
Galvanic cells have positive E values and produce electricity spontaneously. Electrolytic cells have negative E values and require external energy input.
Can I use this for multi-electron processes?
Yes, just ensure you use the correct number of electrons (n) from your balanced equation. The Nernst equation works for any electrochemical process.
Related Chemistry Calculators
- Redox Reaction Balancer - Balance redox equations for Nernst equation use
- pH Calculator - Calculate pH for electrochemical systems
- Molarity Calculator - Calculate concentrations for reaction quotients
- Gas Law Calculator - Calculate gas pressures for electrochemical cells