The document contains 12 problems related to thermodynamics and equations of state for analysis in class. The problems cover a range of topics including: determining pressure to achieve a given temperature for a gas in a vessel; calculating volume and pressure deviations from ideal gas behavior for real gases; defining an uncompressible substance using a phase diagram; using a manometer to measure gas pressure; relating pressure, temperature and mass for gases; determining conditions needed for boiling water in a pressure cooker; calculating gas tank volumes for different fuels; determining the mass and lifting capacity of a helium balloon; estimating gas masses from compressibility charts; relating pressure and temperature changes for air in a car tire; determining heat transfer and pressure changes in a piston-cylinder

1. UN IV ER SID AD D E AN T IOQU IA
FAC U L TAD D E IN G EN I ER ÍA
DEPARTAMENTO DE INGENIERÍA QUÍMICA
SITUATIONS TO ANALYZE - TERMODINÁMICA I – IQU 700
PROFESSOR: MAURICIO ESTEBAN SÁNCHEZ; SEMESTER 2011-1
Problems analysis and Equations Of State (EOS)
Discuss and write any question you have about those situations in order to analyze it in the class
1. What pressure, a 0.16 m3 vessel should be filled with 42 kg of ethylene, in order to get a
temperature of 40°C?
2. A tank is filled with3 moles of n-pentane at 60 bar and 285°C. Determine the deviation
percentaje for volume calulation compare with an ideal gas for each of the equations: virial,
compressibility factor (2 and 3 parameters), Peng_Robinson, Soave Redlich Kwong and Patel-
Teja. Compare against Peng Robinson equation. What is the tank volume in liters?
3. What is an uncompressible substance.? Explain it in a phase diagram.
4. An open end mercurial manometer
shown below in the figure is connected
to a gas tank. The mercury meniscus in
the left leg of the manometer is
opposite 33.8 cm on the meter stick; in
the right leg it is opposite 16.2 cm.
Atmospheric pressure is 747 mm Hg.
Find the pressure of the gas.
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5. A piston weighs 4.3 kg and has a cross sectional area of 450 mm . Determine the pressure that
is exerted by this piston on the gas in the chamber. If the gas is water, what is it saturation
temperature?
6.
A pressure cooker has the lid screwed on tight.
A small opening with A = 0.0075 in2 is covered
with a petcock that can be lifted to let steam
escape. How much mass should the petcock
have to allow boiling at 250°F with an outside
atmosphere at 15 psia? If the cooker volume is
6L and is charged with 1.0 kg of water, ¿how
much water has to be evaporated?
7. En nuestro país se viene adelantando un programa de masificación de gas natural dentro del
cual se fomenta la conversión de los vehículos de gasolina a gas natural (GNV); para tal
propósito debe implementarse un nuevo tanque para almacenar el metano a alta presión. Si
se sabe que 140 ft3 de metano a 60°F y 1.0 atm de presión equivale a 1.0 galón de gasolina,
¿cual será el volumen del tanque requerido para almacenar un equivalente a 10 galones de
gasolina como gas natural a 3000 psia en Medellín?
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2. UN IV ER SID AD D E AN T IOQU IA
FAC U L TAD D E IN G EN I ER ÍA
DEPARTAMENTO DE INGENIERÍA QUÍMICA
SITUATIONS TO ANALYZE - TERMODINÁMICA I – IQU 700
PROFESSOR: MAURICIO ESTEBAN SÁNCHEZ; SEMESTER 2011-1
8. A spherical helium balloon of 30 ft in diameter is at ambient T and P, 60 F and 14.69 psia.
How much helium does it contain? It can lift a total mass that equals the mass of
displaced atmospheric air. How much mass of the balloon fabric and cage can then be
lifted?
9. A substance is at 70°F and 300 lbf/in2 in a 10 ft3 tank. Estimate the mass from the
compressibility chart if the substance is a) air, b) butane or c) propane. Discuss.
10.
Air in a car tires a -10°Cand 2 bar. After
the car is driven for some miles the
temperature rises to 12°C. What is the
new pressure?. Make your own
assumptions.
11.
A two-phase liquid–vapor mixture of H2O with an
initial quality of 25% is contained in a piston–cylinder
assembly as shown. The mass of the piston is 40 kg,
and its diameter is 10 cm. The atmospheric pressure
of the surroundings is 1 bar. The initial and final
positions of the piston are shown on the diagram. As
the water is heated, the pressure inside the cylinder
remains constant until the piston hits the stops. Heat
transfer to the water continues until its pressure is 3
bar. Friction between the piston and the cylinder wall
is negligible. Determine the total amount of heat
transfer, in J.
12.
One kilogram of air, initially at 5 bar, 350 K, and 3
kg of carbon dioxide (CO2), initially at 2 bar, 450 K,
are confined to opposite sides of a rigid, well-
insulated container. The partition is free to move
and allows conduction from one gas to the other
without energy storage in the partition itself. The
air and carbon dioxide each behave as ideal gases.
Determine the final equilibrium temperature, in K,
and the final pressure, in bar, assuming constant
specific heats.
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