$(20$ points$)$ An insulated rigid tank is divided into two compartments by a partition $($see below$).$ One compartment contains $5$ kg of oxygen gas at $20C$ and $100$ kPa $,$ and the other compartment contains $1$ kg of argon at $0C$ and $500$ kPa $.$ The partition is removed and the two gases are allowed to mix. Determine the equilibrium temperature and pressure of the mixture $(10$ points each$).$

$\backslash$table$[[O_2,$Ar$],[5$ kg$,1$ kg$],[20C,0C$