A gas (Molar mass = 280 $\mathrm{~g} \mathrm{~mol}^{-1}$) was burnt in excess $\mathrm{O}_{2}$ in a constant volume calorimeter and during combustion the temperature of calorimeter increased from $298.0 \mathrm{~K}$ to $298.45\mathrm{K}$. If the heat capacity of calorimeter is $2.5 \mathrm{~kJ} \mathrm{~K}^{-1}$ and enthalpy of combustion of gas is $9 \mathrm{~kJ} \mathrm{~mol}^{-1}$ then amount of gas burnt is $\underline{\hspace{2cm}}$ g. (Nearest Integer)