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Electrochemical Cell Builder

About This Model

Pick any two half-reactions and the model builds the cell for you: it works out which one acts as the anode, which acts as the cathode, and how big a voltage the cell produces. You can:

  • See where each half-reaction sits on the electrochemical series, and read the cell voltage as the gap between them
  • Follow the electrons from the anode to the cathode, and see the balanced overall reaction
  • Swap the two electrodes round to see why a cell run the wrong way needs a power supply
  • Change ion concentrations and use the Nernst equation to see how the voltage shifts away from E°

Key equations:

Cell Potential: E°cell = E°cathode − E°anode

Nernst Equation: Ecell = E°cell − (RT/nF) ln Q

where R = 8.314 J/(mol·K), T = 298 K, n = electrons transferred in the balanced cell reaction, F = 96485 C/mol, and Q = reaction quotient

Key concepts: Standard reduction potentials, electrochemical series, cell potential calculations, and the relationship between voltage and spontaneity. Useful for understanding batteries, fuel cells, and the fundamentals of electrochemistry.

Note: Q is computed assuming unit activity for solids/gases and a simplified ratio of the selected dissolved species. For multi-species reactions (e.g. lead-acid, water electrolysis) the calculated Q is therefore an approximation; the standard potential E° and qualitative trends remain correct.

Half-cell A

Pick any two half-reactions — the model works out the anode and cathode.

Half-cell B

Standard conditions are 1 M, 298 K.

Choose a half-reaction in each box above to build a cell.

Overall reaction: ---

Electrochemical Series

All reactions are written as reductions by convention. The gap between your two half-cells is the cell voltage.

e⁻ flow: low E° → high E°

Cell Potential

E°cell = E°cathode − E°anode

E°cell: --- V
Ecell: --- V
n (electrons): ---