Notice the reactants is the inside. This is where we begin, and this guy is the outside. This is where we end because electrons travel this way, but the ions want to travel this way because we have more ions on the outside on the inside than the outside. So, once again, in the electrochemical cell setup, electrons travel this way, but C plus atoms travel this way because this concentration increases while this guy decreases. Now, if we look up the cell voltage of this oxidation reaction and this reduction reaction, we find that they're the same magnitude but different signs. So if we add them up, that means they will be zero.