Thermochemistry is the study of the energy and heat associated with chemical reactions. It depends on two main laws: Laplace and Hess laws. It also studies the exchange or transfer of heat energy between a system and its surroundings. Please be more specific in your question for a more specific answer. Solution Thermochemistry is the study of the energy and heat associated with chemical reactions. It depends on two main laws: Laplace and Hess laws. It also studies the exchange or transfer of heat energy between a system and its surroundings. Please be more specific in your question for a more specific answer..