A vessel, divided into two parts by a partition, contains 4 mol of nitrogen gas at 75C

Question:

A vessel, divided into two parts by a partition, contains 4 mol of nitrogen gas at 75°C and 30 bar on one side und 2.5 mol of argon gas at 130°C and 20 bar on the other. If the partition is removed and the gases mix adiabatically and completely, what is the change in entropy? Assume nitrogen to be an ideal gas with Cv = (5/2)R and argon to be an ideal gas with Cy = (3/2)R.