What is Bond Enthalpy?
Bond enthalpy is a term used in the study of thermodynamics that refers to the amount of energy required to break the chemical bond forged between any two atoms within a molecule. Since bond strength varies among chemical reactions, the bond enthalpy values contained in the Table of Bond Enthalpies are given as averages. Usually, these values are expressed as kJ/mol, although they sometimes appear as kJ mol-1. Since this value can be used to determine the heat exchange expected to occur in chemical reactions, it is sometimes used interchangeably with the terms bond dissociation enthalpy and bond dissociation energy. Chemical bond breaking occurs in different ways. Fission or cleavage of a neutral molecule that results in an anion (negatively charged ion) and a cation (positively charged ion) has taken place via heterolysis. In contrast, if breaking the bond of a molecule results in two unpaired electrons, or free radicals, then the process has been initiated through homolytic fission.
