Two rigid tanks are connected by a valve. Tank A contains 0.2 m^3 of water at 400 kPa and 80 percent quality. Tank B contains 0.5 m^3 of water at 200 kPa and 250°C. The valve is now opened, and the two tanks eventually come to the same state. Determine the pressure and the amount of heat transfer when the system reaches thermal equilibrium with the surroundings at 25°C.   I am studying for a thermo exam and need help.

Two different piston – cylinder devices each contain 1 kg of air. Initially, the temperature T = 300 K and %3D pressure P= 100 kPa of the gases are both the same in both cylinders. However, one of the cylinders is insulated and the other is not. Now, both of these gases inside the cylinders are let to expand in quasi- equilibrium processes until their pressures reach to 50 kPa. The expansion process takes place isentropically in the cylinder 1 and in the cylinder 2 the expansion process takes place reversible and isothermally. a) Plot in Excel the P-V diagrams of both processes. (Take k = cp / cv = 1.4) %3D b) Calculate the work done by the gases.

A and B containers (fixed volume) are connected together by a valve. Tank A contains 400 kPa and 0.3 m3 refrigerant 134a at 60% dryness. Tank B contains 0.5 m3 of refrigerant 134a at 240 kPa pressure and 100 oC temperature. Then the valve is opened and the system reaches 280 kPa equilibrium pressure. Calculate the final temperature.

4-69E A piston-cylinder device contains 25 ft of nitro- gen at 40 psia and 700°F. Nitrogen is now allowed to cool at constant pressure until the temperature drops to 200°F. Using specific heats at the average temperature, determine the amount of heat loss.