The bond dissociation energy is the energy required to break a specific chemical bond. In this case, we are looking for the energy required to break one carbon-hydrogen bond in methane CH4 . The given enthalpy change for the reaction CH4 g C g + 4H g is +1665 kJ/mol, which represents the energy required to break all four carbon-hydrogen bonds in one mole of methane.To find the bond dissociation energy for one carbon-hydrogen bond, we need to divide the total enthalpy change by the number of bonds broken:Bond dissociation energy C-H = +1665 kJ/mol / 4Bond dissociation energy C-H = 416.25 kJ/molSo, the bond dissociation energy of the carbon-hydrogen bond in methane is approximately 416.25 kJ/mol.