What is the term for reactions that release energy in the form of heat?

The term for reactions that release energy in the form of heat is exothermic reaction. In these types of reactions, the products have lower energy than the reactants, leading to the continuous release of energy, primarily as heat.

This phenomenon is commonly observed in various chemical processes, including combustion, respiration, and many oxidation reactions. The heat released can increase the temperature of the surroundings, which is a key characteristic of exothermic reactions.

In contrast, an endothermic reaction is one where energy is absorbed, resulting in a temperature drop in the surroundings. Photochemical reactions involve light energy driving the reaction, while thermochemical reactions refer more broadly to chemical reactions that involve heat, but not specifically to those that release it. Therefore, exothermic reaction is the precise term used to describe reactions that release energy in the form of heat.