these maxima are intermediates. The activation energy of each step is the difference in energy
between the transition state and the “valley” immediately before it (corresponding to either
reactants or intermediates). The step with the highest activation energy is the rate-determining or
rate-limiting step. The two plots below show the potential energy diagrams for a two-step reaction.
In one, the first step is the rate-determining step while in the other, the second step is rate
determining.
A CLOSER LOOK
The factors discussed here change the rate of reaction mathematically by affecting the value
of k, the rate constant, in the rate law.