They affect the kinetics of our reaction, but they do not affect equilibrium. Now, we're going to examine the two types of catalysts. So we have heterogeneous catalysts are molecules that are in a different state compared to the reactants. In other words, if our reactants are in a gas state or liquid state then our catalysts are in a solid state. Now, when we're dealing with heterogeneous catalysts, namely Salad catalysts, this is what happens. Our reactants absorb momentarily or bind to the catalyst which weaken the bonds, decreasing activation energy which in turn increases the reaction rate.