Nernst equation

In electrochemistry, the Nernst equation is an equation that relates the reduction potential of an electrochemical reaction (half-cell or full cell reaction) to the standard electrode potential, temperature, and activities (often approximated by concentrations) of the chemical species undergoing reduction and oxidation. It was named after Walther Nernst, a German physical chemist who formulated the equation. In electrochemistry, the Nernst equation is an equation that relates the reduction potential of an electrochemical reaction (half-cell or full cell reaction) to the standard electrode potential, temperature, and activities (often approximated by concentrations) of the chemical species undergoing reduction and oxidation. It was named after Walther Nernst, a German physical chemist who formulated the equation. The Nernst equation is derived from the standard changes in the Gibbs free energy associated with an electrochemical transformation. For any electrochemical reduction reaction of the form standard thermodynamics says that the actual free energy change ΔG is related to the free energy change under standard state ΔGo by the relationship where Q is the reaction quotient. The electrochemical potential E associated with the electrochemical reaction is defined as the decrease in Gibbs free energy per coulomb of charge transferred, which leads to the relationship The constant F (the Faraday constant) is a unit conversion factor F = NAq, where NA is Avogadro's number and q is the fundamental electron charge. This immediately leads to the Nernst equation.