The polymerisation of ethylene to linear polyethylene is represented by the reaction
`nCH_(2)=CH_(2)rarr(-CH_(2)-CH_(2)-)_(n)`
When `n` has a large integral value. Given theat the average enthalpies of bond dissociation for `C=C` and `C-C` at `298K`are `+590` and `+331kJ mol^(-1)` respectively, calculate the enthalpy of polymerisation per mole of ethylene at `298K`.

Explanation

`Delta H = 1 xx 590 - 2 xx 331`
-72kJ