Time: $2$ h $30$min

Q$3$

In a steady state flow process, $1mols{s}^{-1}$ of air at $600K$ and $1$atm is continuously and adiabatically mixed with $2mol{s}^{-1}$ of air at $450K$ and $1$atm. The product stream is at $0\mathrm{.}75$atm.

$($a$)$ Calculate the temperature of the leaving stream. $($b$)$ Calculate the total entropy change.

$)=(\frac{7}{2}$