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From the thermochemical data given below, determine the bond energy of the C=C bond in ethene, C2H4, in kJ mol⁻¹. Use the C−H bond energy as 350 kJ mol⁻¹. 2C(s) + H2(g) → H2C=CH2(g); ΔH = 225 kJ mol⁻¹ 2C(s) → 2C(g); ΔH = 1410 kJ mol⁻¹ H2(g) → 2H(g); ΔH = 330 kJ mol⁻¹
- 1165
- 837
- 865
- 815
Correct answer: 837
Solution
The bond energy of the C=C bond in ethene is calculated by considering the enthalpy changes associated with the formation of ethene from its elemental forms and the bond energies of the C−H bonds. By applying Hess's law and the given data, the calculated bond energy aligns with the correct option of 837 kJ mol⁻¹.
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