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Calculate the mean bond enthalpy of C-H bond in methane. |
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Answer» CH4 (g) → C (g) + 4H(g), ΔH = ? Mean bond enthalpy of C-H bond = \(\frac{1}{4}\) x Heat energy required to break four C-H bonds in CH4 (g) = \(\frac{1}{4}\) x ΔH The ΔH for the reaction, CH4 (g) → C (g) + 4H (g) is the enthalpy of atomisation of methane ΔH = ΔH1 + ΔH2 + ΔH3 + ΔH4 = (425 + 470 + 416 + 336) kJ mol-1 = 1647 kJ mol-1 Mean bond enthalpy of C-H bond in CH4 (g) = \(\frac{1}{4}\) x ΔH = \(\frac{1}{4}\) x 1647 kJ/mol = 411.7 kJ mol-1 |
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