Nernst Equation for Reduction Half-reactions

The Nernst Equation for reduction half reactions, E = E₀ – 0.0592/n * log([red]/[ox]), calculates cell potential under non-standard conditions. Cell potential is a method of measuring the amount of voltage that exists between two half cells of a battery, and will be measured in Volts. This equation relates cell potential to the reaction quotient (Q = [red]/[ox]) and provides an accurate method of measuring equilibrium constants.

The inputs are:

·      E₀ = initial cell potential (must be entered in Volts)

·      n = number of electrons (example: a Zn²⁺ ion has a charge of +2, making n=2)

·      [red] = molarity of the substance being reduced (must be in mols/L)

·      [ox] = molarity of the substance being oxidized (must be in mols/L)

·      x = number of moles of the substance being reduced

·      y = number of moles of the substance being oxidized

Supplemental Material

Khan Academy: Cell Potentials Under Non-standard Conditions

ChemWiki: Nernst Equation

References

Whitten, et al. "Chemistry" 10th Edition. Pp. 828

ChemWiki