In a constant volume calorimeter, 3.5 g of a gas with molecular weight 28 was burnt in ress oxygen at 298 K. The temperature of the calorimeter was found to Increase from 298 K to 298.45 K due to the combustion process. Given that the calorimeter constant is `2.5 KJ K^(-1)` .Calculate the enthalpy of combustion of the gas in `"kJ mol"^(-1)`.

Explanation

Given
`T_i`=298 K
`T_f` =298.45 K
`k=2.5 kJ K^(-1)`
m=3.5 g
`M_m`=28
heat evolved=`kDeltaT`
`=k(T_f-T_i)`
`=2.5 kJ K^(-1) (298.45-298)K`
=1.125 kJ
`DeltaH_C=1.125/3.5xx28 "kJ mol"^(-1)`
`DeltaH_C=9 "kJ mol"^(-1)`