Calculate the heat of hydrogenation of `C_(2)H_(2)` to `C_(2)H_(4)`.
`H_(2)(g)+(1)/(2)O_(2)(g)toH_(2)O(l)," "DeltaH=-68.32kcal`
`C_(2)H_(2)(g)+(5)/(2)O_(2)(g)to2CO_(2)(g)+H_(2)O(l),DeltaH=-310.61kcal`
`C_(2)H_(4)(g)+3O_(2)(g)to2CO_(2)(g)+2H_(2)O(l),DeltaH=-337.32kcal`