Bond energy means average amount of energy per molecule necessary to rupture a particular bond in a molecule and this effects a complete separation of the resulting atoms or radical from one another…
For example,diatomic molecules like H2,O2 and Cl2 it's energy is called bond dissociation energy.In poly atomic molecule,the energy required to break a given bond will depend to some extent on the nature of the remainder of the molecule and will vary from Compound to compound for instance energy needed to break O-H bond in alcohol is not same amount of energy needed to break it in organic acids therefore the bond energy in poly atomic compound is the average bamount of energy brequiree to break a particular bond in one mole of the compound.Examole in water we have
H2O. -------------> H(g) + OH(g). ∆H=119.95kcalrnol-1 to break O-H bond in hydroxyl radical requires a different heat quantity.
OH(g). = O(g) + H(g) ∆H=101.19kcal
Bond energy=. Average of two values/2
Bond energy= 119.95 + 101.17/2 = 110.57kcalmole.
In diatomic molecules the bond energy and bond dissociation energy are identical for both.
Bond energies of H-O,H-N ,H-S bond can be determined from the heats of reaction in which the molecule H2O,NH3 and HS are formed from their atoms.
When a bond break,bond enthalpy is positive but when a bond is formed bond enthalpy is negative.
Here are some bond and their energy
Bond. Bond Energy
Uses of bond energy.
1.Comparing strength of bonds.
2.Understanding structure and bonding.
3.Estimating the enthalpy changes in a reaction.