Which type of reaction absorbs energy in the form of heat?

An endothermic reaction is a process that absorbs energy in the form of heat from its surroundings. This occurs because the energy required to break the bonds of the reactants is greater than the energy released when new bonds are formed in the products. As a result, these reactions often cause a decrease in temperature of the surroundings, since they are pulling heat in to facilitate the reaction.

In contrast, exothermic reactions release energy, usually in the form of heat, resulting in an increase in temperature of the surroundings. Catalytic reactions involve the use of a catalyst to speed up the reaction without being consumed, while explosive reactions typically release a large amount of energy spontaneously and rapidly but do not primarily reflect the absorption of heat. Thus, the defining characteristic of endothermic reactions is their requirement for heat input, making them distinct from the other types of reactions listed.