So let's use this formula to approximate how much energy this battery or this electrochemical cell can produce with the charge that it has. So, the change in gates free energy is equal to negative of the number of moles of electrons. Well, in this case, I specifically left these guys in to show you how many moles of electrons we have. Well, zinc loses two moles of electrons, and this guy gains two moles of electrons. That means we're dealing with two moles of electrons times our Faradays constant 96,500 approximately Coulombs per mole of electron times our cell voltage or electromotive force 1.1 volt. We see that these guys cancel out and our units are left Coulombs times voltage, which is simply joules.