Problem $2(30$ points$)$

The system in the figure contains the

following ideal gases: $1$ kg of $CO,0\mathrm{.}2$

kg of $H_2$ and $0\mathrm{.}5$ kg of $H_{2}O$ and is

initially at equilibrium at $P=20$MPa and

$T=623K.$ If the black internal walls are

removed to let the three gases mix,

calculate the entropy of mixing in $k\frac{J}{K}.$

You can consider the external walls of

the tank to be adiabatic.