Measurement depends on half cell and net reaction, the concentration of reactants and products, and the pressure and temperature of gaseous reactants. Determination of standard potential, Ecell, is performed under standard conditions. The standard hydrogen electrode (SHE) is the favored reaction. The reduction of hydrogen at the electrode and the oxidation of zinc at the anode are listed as half reactions. The potential energy of this reaction produces a reading of 0.76 volts as standard.