Question

A chemist finds that when platinum is added to a reaction, the reaction speeds up. He thinks the platinum may be acting as a catalyst. What measurement should the chemist make to determine whether it is a catalyst?

Answer 1

He should measure the activation energy required with and without the catalyst.
If the activation energy decreases with the predicted catalyst, then platinum is certainly a catalyst. If the activation is the same or increases, it is certainly not a catalyst.

Answer 2

He might want to construct a Gibb's Free energy graph to observe the various changes.