And that means an equilibrium. Our rate forward will be the same as the rate backwards. Now let's look at the catalyzed reaction. Suppose we add a catalyst, catalyst C, to our reactants. Now, before we look at the mechanism by which it increases the rate, let's make sure we understand the fact that catalysts are not used up in reaction. In other words, if you add some catalyst to our reactants, you will get that same catalyst back at the end of your reaction.