1) Given: Water vapor at 200 bar and 470oC.
Find: The compressibility factor using a) the generalized compressibility chart and b) data from the steam tables. Comment on the difference.
2) Given & Find: For the four cases given below, calculate the compressibility factor and comment on whether the ideal gas model is valid for these states.
a) water at 700oF and pressures of 1600 lbf/in2 and 160 lbf/in2.
b) carbon dioxide at 865 K and pressures of 75 bar and 3 bar.
3) Given: A closed, rigid tank fitted with a paddle wheel contains 0.1 kg of air, initially at 300 K, 0.1 MPa. The paddle wheel stirs the air for 20 minutes, with the power input varying with time according to = 10t, where is in Watts and t is in minutes. The final temperature of the air is 1060 K.
Find: a) the final pressure (MPa), b) work (kJ), and c) heat transfer (kJ).
Assume: 1) Air behaves as an ideal gas.
4) Given: 1.6 kg of air in a piston-cylinder device undergoes two processes in series from an initial state where P1 = 0.5 MPa, T1 = 227oC.
Process 1-2: Constant-temperature expansion until the volume is twice the initial volume.
Process 2-3: Constant volume heating until the pressure is again 0.5 MPa.
Find: a) Sketch the two process on a P-v diagram, b) calculate the pressure at state 2, c) calculate the temperature at state 3, and d) find the work and heat transfer for each process (kJ).
5) Given: A 0.2 ft3 aluminum block is initially at 200oF. It is placed in a tank with 4 ft3 of liquid water at 70oF.
Find: The equilibrium temperature of the block and water.
Assume: The heat loss to the surroundings is negligible.
6) Given: A 5 ft3 tank is initially evacuated. A leak develops and air enters at a constant rate of 0.004 lbm/s. The air is at 70oF.
Find: The pressure (lbf/in2) in the tank 30 s after the tank starts leaking.