# Thermodynamic Properties 2

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1. What is the equation for the speed of sound?
2. How can a new speed of sound be calculated when the temperature changes?
3. Thermal efficiency is the ratio of useful work output to energy input. What equation results from combining this definition with the First Law of thermodynamics?

First Law:

So:
4. What equation describes the First Law of thermodynamics for closed systems, and what does the equation mean?
Qin = ΔU+W

Any heat entering a closed system can either increase the energy of the system (U) or be used to perform work on the surroundings.
5. What is the equation for thermal efficiency?
6. What is the Second Law of thermodynamics?
Entropy must always increase in a real process or cycle.
7. Identify lines of constant pressure.
8. Identify lines of constant superheat.
9. Identify lines of constant moisture.
10. What equation calculates the quality of a vapor-liquid mixture?
11. What equation gives the enthalpy of a liquid-vapor mixture?

Similar equations apply for internal energy (u) and entropy (s).
12. What can be said of the kinetic and potential energies of a closed system?
The kinetic and potential energies of a closed system are negligible.
13. In the steady flow energy equation, break apart the enthalpy component and make note of the units.

and

units are BTU/lbm, and J=778.17 ft-lbf/BTU
14. In the steady flow energy equation, break apart the potential energy component and make note of the units.

units are BTU/lbm, and J=778.17 ft-lbf/BTU
15. In the steady flow energy equation, break apart the kinetic energy component and make note of the units.

units are BTU/lbm, and J=778.17 ft-lbf/BTU
16. In the steady flow energy equation, break apart the shaft work component and make note of the units.

units are BTU/lbm, and J=778.17 ft-lbf/BTU
17. Identify the lines of constant temperature ratio on this graph of compressibility factors, and define the ratios for temperature and pressure.

P/Pc and T/Tc are calculated using critical temperature and pressure listed in a chapter table.
18. What is the relationship between power, mass flow and change in internal energy?
19. What is the relationship between power, force and speed?
P=Fv
20. How do you calculate a thermodynamic property (such as cp) of a non-reacting mixture?
• Calculate the gravimatric fraction of each constituent
• and use this relationship
21. What is the relationship between power, torque and rotational speed?
P=Tω
 Author: RJVan ID: 307733 Card Set: Thermodynamic Properties 2 Updated: 2016-01-16 18:26:13 Tags: thermo Thermodynamics Mollier Folders: Mechanical Engineering Description: Mechanical Professional Engineering Exam Review Show Answers: