Question

The standard enthalpy of formation `(Delta_(f)H^(@))` at `298K ` for methane `(CH_(4(g)))` is `-74.8kJ mol^(-1)`. The additional information required to determine the average energy for `C-H` bond formation would be `:`
A. The dissociation energy of hydrogen molecule, `H_(2)`
B. The dissociation energy of `H_(2)` and enthlpy of sublimation of carbon
C. Latent heat vaporisation of methane
D. The first four ionisation energies of carbon and electron gain enthalpy of hydrogen

Answer 1

Correct Answer - B
`C+2H_(2)rarrCH_(4)`
`Delta_(f)H^(@)=[e_(C(Srarrg))+2xxe_(H-H)-4xxe_(C-H)]`