Liquid octane $($C$8$H$18)$ is burned completely at $77\backslash$deg F during a steady$-$flow combustion process with $180$ percent theoretical air entering the combustion chamber at $77\backslash$deg F$.$ If the products leave at $2500$ R$,$ determine $($a$)$ the air$-$fuel ratio and $($b$)$ the heat transfer from the combustion chamber during this process.