In thermodynamics, the word Endothermic "within-heating" describes a process or reaction that absorbs energy in the form of heat. Its etymology stems from the Greek prefix endo-, meaning “inside” and the Greek suffix –thermic, meaning “to heat”. The opposite of an endothermic process is an exothermic process, one that releases energy in the form of heat. The term “endothermic” was coined by Marcellin Berthelot.
Endothermic, also incorrectly known as endergonic, refers to a chemical reaction in which a system receives heat from the surroundings.
When this occurs at constant pressure:
and constant volume:
Some examples of endothermic processes are:
Chemical endothermic reactions need heat to be performed. In a thermochemical reaction that is endothermic, the heat is placed on the reactants side (heat is necessary for and absorbed during the reaction).