Q: A piston–cylinder device contains air that undergoes a reversible thermodynamic
A piston–cylinder device contains air that undergoes a reversible thermodynamic cycle. Initially, air is at 400 kPa and 300 K with a volume of 0.3 m3. Air is first expanded isothermally to 150 kPa, th...
See AnswerQ: A piston–cylinder device initially contains 15 ft3 of helium gas
A piston–cylinder device initially contains 15 ft3 of helium gas at 25 psia and 70°F. Helium is now compressed in a polytropic process (PVn = constant) to 70 psia and 300°F. Determine (a) the entropy...
See AnswerQ: A piston–cylinder device contains steam that undergoes a reversible thermodynamic
A piston–cylinder device contains steam that undergoes a reversible thermodynamic cycle. Initially the steam is at 400 kPa and 350°C with a volume of 0.5 m3. The steam is first expanded isothermally t...
See AnswerQ: Heat is transferred at a rate of 2 kW from a hot
Heat is transferred at a rate of 2 kW from a hot reservoir at 800 K to a cold reservoir at 300 K. Calculate the rate at which the entropy of the two reservoirs changes and determine if the second law...
See AnswerQ: One hundred kg of saturated steam at 100 kPa is to be
One hundred kg of saturated steam at 100 kPa is to be adiabatically compressed in a closed system to 1000 kPa. How much work is required if the isentropic compression efficiency is 90 percent?
See AnswerQ: Ten lbm of R-134a is expanded without any heat transfer
Ten lbm of R-134a is expanded without any heat transfer in a closed system from 120 psia and 100°F to 20 psia. If the isentropic expansion efficiency is 95 percent, what is the final volume of this re...
See AnswerQ: Refrigerant-134a at 700 kPa and 40°C is expanded
Refrigerant-134a at 700 kPa and 40°C is expanded adiabatically in a closed system to 60 kPa. Determine the work produced, in kJ/kg, and final enthalpy for an isentropic expansion efficiency of 80 perc...
See AnswerQ: A 0.8-m3 rigid tank contains carbon dioxide (
A 0.8-m3 rigid tank contains carbon dioxide (CO2) gas at 250 K and 100 kPa. A 500-W electric resistance heater placed in the tank is now turned on and kept on for 40 min, after which the pressure of C...
See AnswerQ: Air enters the evaporator section of a window air conditioner at 100
Air enters the evaporator section of a window air conditioner at 100 kPa and 27°C with a volume flow rate of 6 m3/min. The refrigerant-134a at 120 kPa with a quality of 0.3 enters the evapo...
See AnswerQ: A gasoline line is connected to a pressure gage through a double
A gasoline line is connected to a pressure gage through a double-U manometer, as shown in Fig. P2–81. If the reading of the pressure gage is 370 kPa, determine the gage pressure of t...
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