Calculate heat of combusion of ethene:

Explanation

`DeltaH^(Theta) =` Sum of bond energies of reactants -Sum of bond energies of products
`= [DeltaH_((C=C))+4DeltaH_((C-H)) +3xxDeltaH_((O=O))]`
`-[4 xx DeltaH_((C=O)) +4 xx DeltaH_((O-H))]`
`=[619 +4 xx 414 +3 xx 499] -[4 xx 724 +4 xx 460]`
`=- 964 kJ mol^(-1)`