Concept explainers
(a)
The mass of argon in the tank.
(a)
Answer to Problem 99RP
The mass of argon in the tank is
Explanation of Solution
Write formula for specific volume
Here, the gas constant of argon is
Write formula for mass of the argon present in the tank.
Here, the volume of argon in the tank is
Refer Table A-1, “Molar mass, gas constant, and critical-point properties”.
The critical temperature and pressure of propane gas is as follows.
Refer Table A-2(a), “Ideal-gas specific heats of various common gases”.
The gas constant
The reduced pressure
At initial:
Refer Figure A-29, “Generalized enthalpy departure chart”.
The enthalpy departure factor
Refer Figure A-15, “Nelson–Obert generalized compressibility chart”.
The compressibility factor
Conclusion:
Substitute
Substitute
Thus, the mass of argon in the tank is
(b)
The final pressure.
(b)
Answer to Problem 99RP
The final pressure is
Explanation of Solution
The reduced pressure
Write the formula for reduced specific volume.
Here, the subscript 2 indicates the final state.
Conclusion:
Here, the specific volume at initial and final state is constant.
Substitute
Refer Figure A-15, “Nelson–Obert generalized compressibility chart”.
The compressibility factor
The reduced pressure
Refer Figure A-29, “Generalized enthalpy departure chart”.
The enthalpy departure factor
Substitute
Thus, the final pressure is
(c)
The heat transfer.
(c)
Answer to Problem 99RP
The heat transfer is
Explanation of Solution
Write formula for enthalpy departure factor
Here, the enthalpy at ideal gas state is
Rearrange the Equation (I) to obtain
Refer Equation (II) express as two states of enthalpy difference (final – initial).
The enthalpy difference at ideal gas state is expressed as follows.
Here, the specific heat at constant pressure is
Write the energy balance equation for the system (piston-cylinder).
Here, the net energy in is
The internal energy is expressed as follows.
Here, the enthalpy is
The change in internal energy is expressed as follows.
Substitute
Refer Table A-2 (a), “Ideal-gas specific heats of various common gases”.
The specific heat at constant pressure
Conclusion:
Substitute
Substitute
Substitute
Substitute
Thus, the heat transfer is
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Chapter 12 Solutions
Thermodynamics: An Engineering Approach
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