In a fuel cell (the device used for producing electricity directly from a chemical reaction) methanol is used as a fuel and oxygen gas is used as an oxidizer. The standard enthalpy of combustion of methanol is −726kJmol−1. The standard free energies of formation of CH3OH(l).CO2(g) and H2O(l) are −166.3,−394.4 and −237.1kJmol−1 respectively.
The standard free energy change of the reaction will be: