Thermodynamics And Thermochemistry Result Question 15

15. In a constant volume calorimeter, $3.5 \mathrm{~g}$ of a gas with molecular weight $28$ was burnt in excess oxygen at $298.0 \mathrm{~K}$. The temperature of the calorimeter was found to increases from $298.0 \mathrm{~K}$ to $298.45 \mathrm{~K}$ due to the combustion process. Given that the heat capacity of the calorimeter is $2.5 \mathrm{~kJ} \mathrm{~K}{ }^{-1}$, the numerical value for the enthalpy of combustion of the gas in $\mathrm{kJ} $ $ \mathrm{mol}^{-1}$ is

(2009)