Propane has the structutre `H_(3)C-CH_(2)-CH_(3)`. Use the average the bond enthalpies to estimate the change in the enthalpy, `Delta H`, for the following reaction:
`C_(3)H_(8)(g)+5O_(2)(g) rarr 3Co_(2)(g) + 4H_(2)O(g)`

Explanation

Given `B.E.` of `C-C=347 kJ mol^(-1)`
`BE` of `C-H=414 kJ mol^(-1)`
`BE` of `O=OrArr498 kJ mol^(-1)`
`BE` of `C=OrArr741 kJ mol^(-1)`
`BE` of `O-HrArr464 kJ mol^(-1)`
Structure of propane: `CH_(3)-CH_(2)-CH_(3)`
`C_(3)H_(8)(g)+5O_(2)rarr 3CO_(2)(g)+4H_(2)O(g)`
`DeltaH=Sigma BE` of Reactants `-Sigma BE` of Products
`=[(2 BE` of `C-C+8 BE of C-H)+5 BE` of `O=O]-[6 BE` of `C=O+8 BE` of `O-H]`
`=(2xx347+8xx414+5xx498]-(6xx741+8xx464]`
`=(694+3312+2490)-(4446+3712)`
`=6496-8158`
`=-1662 kJ mol^(-1)`
`=- 1.662xx10^(3) kJ mol^(-1)`