The water vapor is manually compressed in an unknown process until the volume of water vapor (Vw2) is halved and the pressure is 200 kPa (Pw2), at which point the air and water vapor are in temperature equilibrium.
Located near the bottom of an insulated cylinder is a rigid plate. Between the rigid plate and the bottom of the cylinder is 0.4 kg (ma) of air at 250 kPa (Pa1) and 300 K (Ta1). Between the rigid plate and a moveable piston 0.5 kg (mw) of superheated water vapor at 300 Celsius (Tw1) and 100 kPa (Pw1) is added. Consider these to be the initial conditions (state 1) of this multi-component system.
The rigid plate is conductive allowing heat to pass between the air and water vapor, but the piston is well insulated. The water vapor is manually compressed in an unknown process until the volume of water vapor (Vw2) is halved and the pressure is 200 kPa (Pw2), at which point the air and water vapor are in temperature equilibrium.
Determine the following:
A. The change in entropy of air and water in kJ/K
B. The change in entropy of the combined system, S2-S1, in kJ/K, neglecting the mass of the rigid plate
C. The entropy produced, σ, of the combined system during the process
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