Question

What is the bond dissociation energy of the chlorine molecule (Cl2) in kilojoules per mole (kJ/mol)? Given that the bond length of Cl-Cl is 198 pm, and the enthalpy change for the reaction Cl2(g) -> 2Cl(g) is 242 kJ/mol.

Answer 1

The bond dissociation energy of a molecule is the energy required to break one mole of a specific bond in the molecule. In this case, we are looking for the energy required to break the Cl-Cl bond in the chlorine molecule  Cl2 .The enthalpy change for the reaction Cl2 g  -> 2Cl g  is given as 242 kJ/mol. This value represents the energy required to break the Cl-Cl bond in one mole of Cl2 molecules and form two moles of Cl g  atoms.Therefore, the bond dissociation energy of the chlorine molecule  Cl2  is 242 kJ/mol.