Tutorials

The following pages are intended to give you a START in several directions. The pages are not to be used as a definitive guide but can be used to learn something interesting.

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1 ElectroChemistry

1.1 Nernst Equation

In the context of batteries, the Nernst Equation provides a method to relate the EQUILIBRIUM reduction potentials of the two half cells to each other and also to a standard reference. It provides a cell voltage.

E_{C e l l} = E_{C e l l}^{o} - \frac{R T}{n F} l n Q

where

E^ois the Energy of the cell or half cell under standard conditions. (P=10⁵Pa, T=298.15K, conc = 1 mol/kg)
E_Cellis the energy of the cell at the time of measurement
R is the universal Gas Constant. (R = 8.314 JK^-1mol^-1)
F is the Faraday Constant. (F = 96490 Cmol^-1)
T is the temperature in KELVINs
n is the number of mols exchanged in the reaction
Q is the reaction quotient. $Q = \frac{α_{R e d u c t i o n}}{α_{O x i d a t i o n}}$

Rewriting in Log form, we obtain

E_{C e l l} = E_{C e l l}^{o} - \frac{.059}{n} L o g Q

which tells us there will be a .059V change in the potential, per mol ‘n’, per every 10x change in the ratio of half cell concentrations.

Example:

Tutorials

1 ElectroChemistry

1.1 Nernst Equation

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