$2\mathrm{.}5$ mole$/$s of n$-$Pentane $($C$5$H$12)$ is burned with $20\%$ excess air. No carbon monoxide is present in the combustion products. Fractional conversion of n$-$Pentane is $90\%.$ The feed enters the combustion chamber at $25$C and the stack gas leaves at $300$C$.$ Calculate the amount of heat which must be transferred to$/$from the chamber.