A 4-ft3 insulated tank contains nitrogen gas at 30 lbf/in 2 and ambient temperatures 77 F. The tank is connected by a valve to a supply line flowing carbon dioxide at 180 lbf/in 2, 190 F. A mixture of 50mole percent nitrogen and 50 mole percent carbon dioxide is to be obtained by opening the valve and allowing flow into the tank until an appropriate pressure is reached and the valve is closed. What is the pressure? The tank eventually cools to ambient temperature. Calculate the net entropy change for the overall process.