EML3100 - Exam #1 from Fall 1997

This is a text version of the Fall 1997 Thermo Exam #1. Solutions to this exam will be put in the CoE Library on Wednesday, September 15, 1999. Solution

1. A system where mass, heat, and work cross the system boundary is called

(a) an isolated system
(b) a closed system
(c) an open system

2. A system where mass, heat, and work do not cross the system boundary is called

(a) an isolated system
(b) a closed system
(c) an open system

Questions 3 - 6 are to test your ability to use the tables -- only answers are necessary

3. What is the specific volume of superheated R-134a vapor at 0oC, 1.4 bars?

Specific Volume________________Table #________________

4. What is the saturation pressure for Ammonia with a saturation temperature of 20oC?

Pressure________________Table #________________

5. What is the specific volume of saturated liquid R-22 at 0.90 bars?

Specific Volume________________Table #________________

6. What is the saturation temperature for R-12 with a saturation pressure of 7.0 bars?

Temperature________________Table #________________

7. Fill in:
SymbolSI UnitsEnglish Units
Force __________ __________ __________
Molecular Mass __________ __________ __________
Specific Volume __________ __________ __________

8. Label the axes, regions, lines and points on the plot below.

A p-T plot was given.

9. Using Table A-10 or Table A-11 (pg. 738 or 739, respectively ) and the plot below, determine the phase of R-134a at

(a) T = -26oC, v = 0.20 m3/kg .....phase________________

(b) T = -26oC, P = 2.00 bars .....phase________________

Label axes & regions; show table data on plot.

10. There is a new element Floridium (Fl).

(a) If Floridium has R=0.1997 kJ/(kgK), What is its molecular mass?

(b) If the critical pressure and critical temperature for Floridium are 7 kPa and 125 K, respectively, can we expect ideal gas behavior at room temperature (25oC) and atmospheric pressure (1 bar)? Why?

(c) Assuming ideal gas behavior, what is the specific volume of Floridium at 500oC, 0.30 bar?

(d) Assuming ideal gas behavior, what is the mass of 400 L (liters) of Floridium at 500oC, 0.30 bar?

(e) A 1500 L tank contains 3 kg of Floridium at 1000oC. What is the pressure in the tank (assuming ideal gas behavior)?

11. A closed, piston-cylinder assembly contains 15 kg of R-22 initially at 0oC and 0.85 quality.

The R-22 is expanded in a process such that pVn remains constant, with exponent n = 0.92, to a final pressure of 1.0 bar. (Do not assume ideal gas behavior!)

(a) Draw a picture of the initial and final states, and write the given information under each.

Find the initial
(b) phase.
(c) pressure.
(d) specific volume.
(e) volume.
Find the final
(f) volume.
(g) specific volume.
(h) phase.
(i) temperature.
(j) quality
Show all work, and specify tables used!

BONUS: A new element has been discovered,

Petersonium Pe, Atomic Mass = 6

If a molecule of Petersonium is Pe4, determine the weight of 3 lbmol of molecular Petersonium on a far-away planet where the gravitational acceleration is 10 ft/s2.