Reactions that release energy into the surroundings are known as exothermic reactions. During such reactions, the total energy of the products is less than that of the reactants, resulting in the release of energy, often in the form of heat or light. Examples of exothermic reactions include combustion and respiration. Conversely, reactions that absorb energy are termed endothermic reactions. Understanding these concepts is integral in fields like thermochemistry and energy management, as they influence everything from industrial processes to biological functions.