Concept explainers
Determine the enthalpy change and the entropy change of oxygen per unit mole as it undergoes a change of state from 220 K and 5 MPa to 300 K and 10 MPa (a) by assuming ideal-gas behavior and (b) by accounting for the deviation from ideal-gas behavior.
(a)
The change in specific enthalpy and entropy of oxygen per unit mole by assuming ideal-gas behavior.
Answer to Problem 73P
The change in specific enthalpy and entropy of oxygen per unit mole by assuming ideal-gas behavior is
Explanation of Solution
At ideal gas state, the enthalpy is the function of temperature only.
Write the formula for difference in molar specific enthalpy of oxygen at ideal gas state.
Here, the molar enthalpy at ideal gas state corresponding to the temperature is
Write the formula for change in molar specific entropy.
Here, the molar specific entropy at reference sate is
Refer Table A-19, “Ideal-gas properties of oxygen,
Obtain the initial properties corresponding to the temperature of
Obtain the final properties corresponding to the temperature of
The universal gas constant
Conclusion:
Substitute
Substitute
Thus, the change in specific enthalpy and entropy of oxygen per unit mole by assuming ideal-gas behavior is
(b)
The change in specific enthalpy and entropy of oxygen per unit mole by accounting for the deviation from ideal-gas behavior.
Answer to Problem 73P
The change in specific enthalpy and entropy of oxygen per unit mole by accounting for the deviation from ideal-gas behavior is
Explanation of Solution
Write formula for enthalpy departure factor
Here, the molar enthalpy at ideal gas state is
Rearrange the Equation (III) to obtain
Refer Equation (IV) express as two states of enthalpy difference (final – initial).
Write formula for entropy departure factor
Here, the molar entropy at ideal gas state is
Rearrange the Equation (VI) to obtain
Refer Equation (VII) express as two states of entropy difference (final – initial).
Refer Table A-1, “Molar mass, gas constant, and critical-point properties”.
The critical temperature and pressure of oxygen gas is as follows.
The reduced pressure
The reduced pressure
At initial:
Refer Figure A-29, “Generalized enthalpy departure chart”.
The enthalpy departure factor
Refer Figure A-30, “Generalized entropy departure chart”.
The entropy departure factor
At final:
Refer Figure A-29, “Generalized enthalpy departure chart”.
The enthalpy departure factor
Refer Figure A-30, “Generalized entropy departure chart”.
The entropy departure factor
Conclusion:
Substitute
Substitute
Thus, the change in specific enthalpy and entropy of oxygen per unit mole by accounting for the deviation from ideal-gas behavior is
Want to see more full solutions like this?
Chapter 12 Solutions
Thermodynamics: An Engineering Approach
- A 2.00 - mol sample of an ideal diatomic gas at a pressure of 1.00 atm and temperature of 440 K undergoes a process in which its pressure increases linearly with temperature, use P = Po + aT . The final temperature and pressure are 720 K and 1.60 atm. Determine (e) the change in internal energy, (b) the work done by the gas, and (c) the heat added to the gas. (Assume five active degrees of freedom . )arrow_forward7-Nitrogen is present in a closed system at a pressure of 830 kPa and a temperature of 380°C.If nitrogen is expanded isentropically to a pressure of 115 kPa, which of the following will have the lowest temperature? (take cazo = 1.4) A) 308,7 K B) 371,2 K C) 220,6 K D) 216,0 K E) 310,4 Karrow_forward(a) In reaching equilibrium, how much heat transfer occurs from 1.00 kg of water at 40.0º C when it is placed in contact with 1.00 kg of 20.0º C water in reaching equilibrium? (b) What is the change in entropy due to this heat transfer? (c) How much work is made unavailable, taking the lowest temperature to be 20.0º C ? Explicitly show how you follow the steps in the Problem-Solving Strategies for Entropy.arrow_forward
- Using the steam tables, determine the specific enthalpy, specific volume and specific enthalpy for steam at 2800 KPa and at a temperature of 390 C.c. The steam in the question above is compressed at a constant enthalpy to a pressure of 4700 KPa. What is the final temperature, specific enthalpy, specific volume and specific entropy of the steam in this new state?d. What is the change in specific enthalpy, specific volume, temperature and specificentropy?arrow_forwardDescribe the equilibrium condition in terms of the entropy changes of a system and its surroundings. What does this de-scription mean about the entropy change of the universe?arrow_forwardIf 10 kg of H2O at 90°C has an internal energy of 7.5 MJ. What is the following properties of " Specific Entropy,s"arrow_forward
- How much entropy in KJ?K is transferred to 20kg of helium at 20°C if the temperature is increased by 28°C. The pressure is remained constant.arrow_forwardPropane and methane are commonly used for heating in winter, and the leakage of these fuels, even for short periods, poses a fire danger for homes.arrow_forwardWrite down the equation for macroscopic entropy change ∆S in a process taking a system between equilibrium states a and b in terms of infinitesimal heat flow and the temperature at which it occurs.arrow_forward
- A substance whose Joule-Thomson coefficient is positive is throttled to lower pressure. During this process, (select the correct statement) (2) the temperature of the substance will increase. (b) the temperature of the substance will decrease, (€)the entropy of the substance wil remain constant. (d) the entropy of the substance will decrease. (e) the enthalpy of the substance will decrease.arrow_forwardDetermine the reversible work in kJ when 6 moles of a gas expanded reversibly from 5 ft³ to 8 ft³ at 400K.arrow_forwarda. 9.23 kg of water vapor is contained at 150 kPa and 90 percent quality in a suitable enclosure. Calculate the heat in kJ which must be added to produce a saturated vapor.b. 9.96 kg of water vapor are contained at 150 kPa and 90 percent quality in a suitable enclosure. What will the pressure be in MPa at the end of the heating process?Please include the h-s and T-s diagram in the solution, and do not round off intermediate answers only the final answer in three decimal places.arrow_forward
- Elements Of ElectromagneticsMechanical EngineeringISBN:9780190698614Author:Sadiku, Matthew N. O.Publisher:Oxford University PressMechanics of Materials (10th Edition)Mechanical EngineeringISBN:9780134319650Author:Russell C. HibbelerPublisher:PEARSONThermodynamics: An Engineering ApproachMechanical EngineeringISBN:9781259822674Author:Yunus A. Cengel Dr., Michael A. BolesPublisher:McGraw-Hill Education
- Control Systems EngineeringMechanical EngineeringISBN:9781118170519Author:Norman S. NisePublisher:WILEYMechanics of Materials (MindTap Course List)Mechanical EngineeringISBN:9781337093347Author:Barry J. Goodno, James M. GerePublisher:Cengage LearningEngineering Mechanics: StaticsMechanical EngineeringISBN:9781118807330Author:James L. Meriam, L. G. Kraige, J. N. BoltonPublisher:WILEY