I don't understand how to get a rate determining step. I have an energy diagram for a two-step conversion where the first step Ea is about 18 units. The energy then goes down about 4 units and rises again about 10 units to the peak of the second step. Why is the rate-determining step the first one?

Question

Thanks from Sheryl

The step then goes down about 15 units. This is an endothermic reaction. Is that the reason the first step is rate determining?

Ea determines the rate - determining step. Don't bother looking this up. I managed to find it.

Sheryl

Then which peak is the rate determining step in your graph and why that peak and not the other one?