Nernst Equation Calculator

Your details

Choose the unknown you want to find; the other fields supply the known values.
Use "half-cell mode" to enter oxidized and reduced concentrations separately.
The standard cell or electrode potential in volts, e.g. +1.10 V for the Daniell cell.
V
Number of moles of electrons exchanged in the balanced half-reaction.
Q = [products]/[reactants], each raised to its stoichiometric coefficient. Must be > 0.
Choose the unit your temperature is measured in.
Defaults to 25 °C (298.15 K), where RT/F = 0.02569 V.
°C
Also display the cell potential in millivolts alongside the volt reading.
Cell potential ESpontaneous (forward)
1.1296V
Concentration shift from E00.0296V
Nernst factor (RT/nF)0.01285V
Gibbs free energy change (deltaG)-217.976kJ/mol
Equilibrium constant K15,406,269,586,154,516,000,000,000,000,000,000,000
1.1296 V
Strongly non-spontaneous<-0.5Weakly non-spontaneous-0.5--0.001Equilibrium-0.001-0.001Weakly spontaneous0.001-0.5Strongly spontaneous0.5+

Cell potential E = 1.1296 V; deltaG = -217.98 kJ/mol.

  • E is positive, so the reaction is thermodynamically spontaneous as written. The concentration term moved the potential by 0.0296 V from the standard value.
  • Gibbs free energy: deltaG = -nFE = -217.98 kJ/mol. Negative deltaG confirms spontaneity.
  • The equilibrium constant K = 1.541e+37, meaning products are strongly favored at equilibrium.
  • Each tenfold change in Q shifts E by about 0.0592/n volts at 25 °C (the Nernst slope).

Next stepSet E to 0 and solve for Q to find the equilibrium constant K of the cell reaction.

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