What type of chemist would study the energies and heats involved in chemical reactions?

The study of physical properties of molecules is physical chemistry..It deals with the principles and methodologies of both physics and chemistry. A physical chemist studies the rate of chemical reactions , the interaction between molecules and calculation of structures and properties. So it is he who studies the energies and heats involved in chemical reactions.

D. h2o + h2o > h3o + oh- confirmed.