$(1)$ Let us consider CH$4$ combustion in air with an equivalence ratio of $0\mathrm{.}9,$ where we have air flow rate of $400k\frac{g}{s}.$ Solve B

$($b$)$ If reactants enter the combustion chamber at $790$ K and $25$ bar $,$ and the products are found to leave the chamber at $1900$ K $,$ calculate the net rate of heat loss from the combustion chamber. Use constant properties for the product $($with the correct molar composition as calculated under $($a$))$ at a temperature of $2100$ K $.$