What do we call the change in energy between reactants and products?

The change in energy between reactants and products in a chemical reaction is known as enthalpy. This concept is crucial in thermodynamics, relating to the total heat content of a system. Enthalpy allows us to understand whether a reaction releases energy (exothermic) or absorbs energy (endothermic). When a reaction occurs, enthalpy changes can indicate the energy difference, which is critical for predicting the behavior of reactions in various conditions.

Entropy, on the other hand, is a measure of disorder or randomness in a system, which is not directly related to the energy difference between reactants and products. Kinetics focuses on the rate of reactions and the steps involved, rather than the energy changes themselves. Activation energy refers specifically to the minimum energy needed for a reaction to take place; it is not a measure of the energy difference between the starting materials and the products. Understanding enthalpy's role in chemical reactions is vital for grasping how and why reactions occur as they do.