Question

The enthalpy of atomisation for the reaction \[\ce{CH4(g) -> C(g) + 4H(g)}\] is 1665 kJ mol^–1. What is the bond energy of \[\ce{C – H}\] bond?

Answer 1

The reaction presented in the question is \[\ce{CH4(g) -> C(g) + 4H(g)}\]

Now, Δ_aH = 1665 kJ mol^–1

The mean bond enthalpy of the \[\ce{C – H}\] bond should be used here. For the atomisation of 4 moles of \[\ce{C – H}\] bonds, the value is 1665 mol^–1. So, per mole energy = 1665/4 = 416.2 kJ / mol^–1.