A rigid 35 ft3 tank contains water initially at 250 F, with 50 % liquid and 50% vapor, by volume. A pressure-relief valve on the top of the tank is set to 150 lbf/in 2 (the tank pressure cannot exceed 150 lbf/in 2 - water will be discharged instead). Heat is now transferred to the tank from a 400 F heat source until the tank contains saturated vapor at 150 lbf/in 2. Calculate the heat transfer to the tank and show that this process does not violate the second law.