The enthalpy of combustion of benzoic acid `(C_(6)H_(5)COOH)` at `298K` and `1atm` pressure is `-2500.0 kJ mol^(-1)`. What is `DeltaU` for the reaction?

Explanation

`C_(6)H_(5)COOH(s) +(15)/(2)O_(2)(g) rarr 7CO_(2)(g) +3H_(2)O(l)`
`Deltan_(g) =- (1)/(2) ( :' Deltan_(g) =n_(P) -n_(R))`
`DeltaU = DeltaH = Deltan_(g)RT`
`=- 2500.0 -(-(1)/(2)) xx 8.314 xx10^(-3) xx298`
`=- 2548.8 kJ`