The enthalpy change for CH₄(g) → C(g) + 4H(g) is +1664 kJ mol⁻¹. What is the average C–H bond energy?
Correct answer C. 416 kJ mol⁻¹
Explanation
Atomising methane breaks four C–H bonds, so the average bond energy = 1664 / 4 = 416 kJ mol⁻¹. It is an average because the four successive bond-breaking steps differ slightly in energy.
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