So we combine this equation with this equation. And so what that gives us is the following equation. And this equation is the equation that we can basically use to quantify and measure how much energy exists between the two sides of the membrane for molecules that have unequal distribution along the two membranes, as well as an unequal charge distribution. So if the charge distribution is the same, then that means this will be zero. But if the concentration distribution is the same, what that means is this quality is zero. But if neither the concentration distribution is the same, nor is the charge distribution the same, that means these two quantities are not zero.