Question

1- A certain amount of O2, as an ideal gas, is contained in a cylinder-piston system and develops a process from T1 = 300 K, P1 = 200 kPa to T2 = 1500 K and P2 = 150 kPa. Determine the specific entropy change in kJ / (kg K).

2- A certain amount of H2O in a closed rigid cylinder is cooled from T1 = 800 ° F and P1 = 100 lbf / in2 to P2 = 20 lbf / in2. Determine the specific entropy change in Btu / (lb ° R).

3-One kilogram of air, as the ideal gas, is contained in a cylinder-piston system at a pressure of 400 kPa and 600 K. The air expands adiabatically and irreversibly up to 150 kPa. Calculate the work done by air in kJ.

4-A certain amount of CO2 enters a compressor at 1 bar and 300 K that works in a steady state and can be considered adiabatic. At the outlet, the gas is at 10 bar and 520 K. It determines the entropy generation rate, in kJ / (kg K), for the gas considered ideal.

5- Saturated steam at 300 ° F enters an adiabatic compressor with a mass flow of 5 lb / s. The outlet pressure is 800 lbf / in2. If the input power of this device is 2150 hp, determine the entropy generation rate in hp / ° R.

Answer 1