What type of chemical reaction is an exothermic reaction?

An exothermic reaction is one that releases heat into the surroundings. This release of energy often occurs as a result of the breaking and forming of chemical bonds during the reaction. As reactants are converted into products, the energy stored in the chemical bonds is released, which typically raises the temperature of the surroundings. This can be observed in various real-life examples, such as combustion reactions, where burning a fuel not only produces products but also emits heat.

Heat transfer is a significant characteristic of these reactions, and it is one of the key differentiators from endothermic reactions, which absorb heat instead. Understanding the nature of exothermic reactions is important in fields such as thermodynamics and chemistry, especially in applications involving energy release, like in engines or heating systems. The other answer choices either describe the opposite behavior, are irrelevant to chemical reactions, or do not apply to the chemical reaction context, thereby reinforcing why the correct identification as a heat-releasing process is essential.