The bond energy of a chemical bond is the energy required to 1 mole of the bond in the phase. Because bonds is endothermic and bonds is exothermic, we can calculate the overall enthalpy change as a of the enthalpy changes associated with the required bonds in the reactants and the required bonds in the products.

The bond energy of a chemical bond is the energy required to 1 mole of the bond in the phase, the amount of energy released equals the difference between the energies of the bonded atoms and the energies of the independent atoms.

Because bonds is endothermic and bonds is exothermic, we can calculate the overall enthalpy change as a of the enthalpy changes associated with the required bonds in the reactants and the required bonds in the products, each molecule has its own characteristic bond energy, but some generalizations are possible

Explanation:

Compounds make atoms attain lower energies compared with what they attain as individual atoms. The amount of energy released in the bonded atoms is heat so the compound has a lower overall energy, it is called enthalpy change and it is positive, these are exothermic reactions, where the energy released, is a product

Within a chemical reaction, breakage, caused by energy, on molecular bonds cause other bonds to be formed into different molecules, so the enthalpy change is negative because the system is releasing energy as the bond is formed these are endothermic reactions, where the energy required is a reactant.