Nernst Reaction Quotient and Energy
Link electrochemical voltage, activity ratios and reversible Gibbs energy.
Free theory articleLink electrochemical voltage, activity ratios and reversible Gibbs energy.
Concept & interpretation
The Nernst equation relates the cell potential of an electrochemical reaction to the standard potential, temperature, and activities of the chemical species undergoing reduction and oxidation.
Reproduce the calculation in the module
Open the Nernst Reaction Quotient and Energy experiment. Its controls let you adjust standard potential, temperature, electrons, and reaction quotient.
- Set Standard potential V to 0.05, Temperature K to 298.15, Electrons to 1, and Reaction quotient to 10. Check that the Cell potential V becomes approximately -0.009.
- Change Reaction quotient to 1. Since ln(1) = 0, the Nernst term vanishes and E becomes equal to E0 = 0.05 V.
- Change Electrons to 2 with Q=10. This halves the coefficient of the Nernst term, reducing the voltage penalty and giving a higher E = 0.02042032515760884 V compared to n=1.