Saturated steam coming off the turbine of a steam power

Problem 2P What is the difference between saturated vapor and superheated vapor?

Problem 142P The pressure of an automobile tire is measured to be 190 kPa (gage) before a trip and 215 kPa (gage) after the trip at a location where the atmospheric pressure is 95 kPa. If the temperature of air in the tire before the trip is 25°C, the air : temperature after the trip is (a)51.1°C ________________ (b)64.2°C ________________ (c)27.2°C ________________ (d)28.3°C ________________ (e)25.0°C

Problem 1P Is iced water a pure substance? Why?

Problem 6P What is the difference between the critical point and the triple point?

Problem 4P Why are the temperature and pressure dependent properties in the saturated mixture region?

Problem 3P Is there any difference between the intensive properties of saturated vapor at a given temperature and the vapor of a saturated mixture at the same temperature?

Problem 5P Is it true that water boils at higher temperature at higher pressure? Explain

Problem 7P Is it possible to have water vapor at – 10°C?

Problem 8P A househusband is cooking beef stew for his family in a pan that is (a) uncovered, (b) covered with a light lid, and (c) covered with a heavy lid. For which case will the cooking time be the shortest? Why?

Problem 10P It is well known that warm air in a cooler environment rises. Now consider a warm mixture of air and gasoline on top of an open gasoline can. Do you think this gas mixture will rise in a cooler environment?

Problem 11P Does the amount of heat absorbed as 1 kg of saturated liquid water boils at 100°C have to be equal to the amount of heat released as 1 kg of saturated water vapor condenses at 100°C?

Problem 130P Nitrogen is maintained at 400 psia and ?100°F. Compare the specific volume of this nitrogen as predicted by (a) the ideal gas equation of state, (b) the Benedict-Webb-Rubin equation of state, and (c) with the compressibility factor.

Problem 9P In what kind of pot will a given volume of water boil at a higher temperature: a tall and narrow one or a short and wide one? Explain.

Problem 12P Does the reference point selected for the properties of a substance have any effect on thermodynamic analysis? Why?

Problem 14P Does hfgchange with pressure? How?

Problem 15P Is it true that it takes more energy to vaporize 1 kg of saturated liquid water at 100°C than it would at 120°C?

Problem 16P What is quality? Does it have any meaning in the superheated vapor region?

Problem 17P Which process requires more energy: completely vaporizing 1 kg of saturated liquid water at 1 atm pressure or completely vaporizing 1 kg of saturated liquid water at 8 atm pressure?

Problem 18P In the absence of compressed liquid tables, how is the specific volume of a compressed liquid at a given P and T determined?

Problem 19P In 1775, Dr. William Cullen made ice in Scodand by evacuating the air in a water tank. Explain how that device works, and discuss how the process can be made more efficient.

Complete this table for \(\mathrm{H}_{2} \mathrm{O}\): Phase description 400 1450 220 Saturated vapor 190 2500 4000 3040 Equation Transcription: Text Transcription: H_2 O

Reconsider Prob. 3-21. Using EES (or other) software, determine the missing properties of water. Repeat the solution for refrigerant \(-134 \mathrm{a}\), refrigerant \(-22\), and ammonia. rEquation Transcription: Text Transcription: 134a -22

Complete this table for \(\mathrm{H}_{2} \mathrm{O}\): Phase description 140 550 Saturated liquid 125 750 500 Equation Transcription: Text Transcription: H_2 O

Complete this table for \(\mathrm{H}_{2} \mathrm{O}\): psia , Btu/lbm Phase description 300 782 40 Saturated liquid 500 120 400 400 Equation Transcription: Text Transcription: H_2 O

Complete this table for refrigerant- \(-134 \mathrm{a}\): Phase description 320 10 850 Saturated vapor 90 600 Equation Transcription: Text Transcription: 134a

Problem 27P Complete this table for refrigerant-134a: T,°F P,psia h, Btu/lbm x Phase description 80 78 15 0.6 10 70 180 129.46 110 1.0

A piston-cylinder device contains \(0.85 \mathrm{~kg}\) of refrigerant \(134 \mathrm{a}\) at \(-10^{\circ} \mathrm{C}\). The piston that is free to move has a mass of \(12 \mathrm{~kg}\) and a diameter of \(25 \mathrm{~cm}\). The local atmospheric pressure is \(88 \mathrm{kPa}\). Now, heat is transferred to refrigerant-\(134 \mathrm{a}\) until the temperature is \(15^{\circ} \mathrm{C}\). Determine \((a)\) the final pressure, \((b)\) the change in the volume of the cylinder, and \((c)\) the change in the enthalpy of the refrigerant-\(134 \mathrm{a}\). FIGURE P3–29 Equation Transcription: -10? 15? Text Transcription: 0.85 kg 134a -10 degree celsius 12 kg 25 cm 15 degree celsius

Problem 30P R-134a, whose specific volume is 0.6243 ft3/lbm flows through a tube at 80 psia. What is the temperature in the tube?

Complete this table for \(\mathrm{H}_{2} \mathrm{O}\): Phase description 50 400 Saturated vapor 250 500 110 350 Equation Transcription: Text Transcription: H_2 O

A \(1.8-m^{3}\) rigid tank contains steam at \(220^{\circ} \mathrm{C}\). One-third of the volume is in the liquid phase and the rest is in the vapor form. Determine (a) the pressure of the steam, (b) the quality of the saturated mixture, and (c) the density of the mixture. FIGURE P3–28 Equation Transcription: ? Text Transcription: 1.8-m^3 220 degree celsius

Problem 31P 10-kg of R-134a fill a 1.348-m3 rigid container at an . initial temperature of ? 40°C. The container is then heated until the pressure is 200 kPa. Determine the final temperature and the initial pressure.

Problem 32P A 9-m3 container is filled with 300 kg of R-134a at 10°C. What is the specific enthalpy of the R-134a in the container?

Problem 33P Refrigerant-134a at 200 kPa and 25°C flows through a refrigeration line. Determine its specific volume.

Problem 34P The average atmospheric pressure in Denver (elevation = 1610 m) is 83.4 kPa. Determine the temperature at which water in an uncovered pan boils in Denver.

The temperature in a pressure cooker during cooking at sea level is measured to be \(250^{\circ} \mathrm{F}\). Determine the absolute pressure inside the cooker in psia and in atm. Would you modify your answer if the place were at a higher elevation? FIGURE P3–35E Equation Transcription: 250? Text Transcription: 250 degree fahrenheit

Problem 38P Three kilograms of water in a container have a pressure of 100 kPa and temperature of 1508C. What is the volume of this container?

A spring-loaded piston-cylinder device is initially filled with \(0.13\ lbm\) of an \(R-134 \mathrm{a}\) liquid-vapor mixture whose temperature is \(-30^{\circ} \mathrm{F}\) and whose quality is 80 percent. The spring constant in the spring force relation \(F=kx\) is \(37\ lbf/in\), and the piston diameter is \(12\ in\). The \(R-134 \mathrm{a}\) undergoes a process that increases its volume by 50 percent. Calculate the final temperature and enthalpy of the \(R-134 \mathrm{a}\). FIGURE P3–36E Equation Transcription: -30? Text Transcription: 0.13 lbm R-134a -30degree Fahrenheit F=kx 37 lbf/in 12 in

Problem 37P One pound-mass of water fills a 2.4264-ft3 weighted piston-cylinder device at a temperature of 600°F. The piston cylinder device is now cooled until its temperature is 200°F. Determine the final pressure of water, in psia, and the volume, in ft3.

Water is to be boiled at sea level in a \(30-cm\)-diameter stainless steel pan placed on top of a \(3-kW\) electric burner. If 60 percent of the heat generated by the burner is transferred to the water during boiling, determine the rate of evaporation of water. FIGURE P3–39 Equation Transcription: Text Transcription: 30-cm 3-kW

\(10-kg\) of R-134a at \(300 \mathrm{kPa}\) fills a rigid container whose volume is \(14 \mathrm{~L}\). Determine the temperature and total enthalpy in the container. The container is now heated until the pressure is \(600 \mathrm{kPa}\). Determine the temperature and total enthalpy when the heating is completed. FIGURE P3–41 Equation Transcription: Text Transcription: 10-kg R-134a 300 kPa 14 L 600 kPa

Problem 42P 100-kg of R-134a at 200 kPa- are contained in a piston-cylinder device whose volume is 12.322 m3. The piston is now moved until the volume is one-half its original size. This is done such that the pressure of the R-134a does not change. Determine the final temperature and the change in the total internal energy of the R-134a.

Repeat Prob, 3–39 for a location at an elevation of \(1500\ m\) where the atmospheric pressure is \(84.5\ kPa\) and thus the boiling temperature of water is \(95^{\circ} \mathrm{C}\). Equation Transcription: 95? Text Transcription: 1500 m 84.5 kPa 95 degree celsius

Problem 44P Saturated steam coming off the turbine of a steam power plant at 40°C condenses on the outside of a 3-cm-outer-diameter, 35-m-long tube at a rate of 130 kg/h. Determine the rate of heat transfer from the steam to the cooling water flowing through the pipe.

Problem 45P Water in a 5-cm-deep pan is observed to boil at 98°C. At what temperature will the water in a 40-cm-deep pan boil? Assume both pans are full of water.

Water initially at \(200 \mathrm{kPa}\) and \(300^{\circ} \mathrm{C}\) is contained in a piston-cylinder device fitted with stops. The water is allowed to cool at constant pressure until it exists as a saturated vapor and the piston rests on the stops. Then the water continues to cool until the pressure is \(100 \mathrm{kPa}\). On the \(T\)-v diagrams sketch, with respect to the saturation lines, the process curves passing through both the initial, intermediate, and final states of the water. Label the \(T, P\) and \(v\) values for end states on the process curves. Find the overall change in internal energy between the initial and final states per unit mass of water. FIGURE P3–43 Equation Transcription: 300? Text Transcription: 200 kPa 300? 100 kPa T-v T P v

Water is being heated in a vertical piston-cylinder device. The piston has a mass of \(40 \mathrm{~kg}\) and a cross-sectional area of \(150 \mathrm{~cm}^{2}\). If the local atmospheric pressure is \(100 \mathrm{kPa}\), determine the temperature at which the water starts boiling. Equation Transcription: Text Transcription: 40 kg 150 cm^2 100 kPa

A cooking pan whose inner diameter is \(20 \mathrm{~cm}\) is filled with water and covered with a 4-kg lid. If the local atmospheric pressure is \(101 \mathrm{kPa}\), determine the temperature at which the water starts boiling when it is heated. FIGURE P3–46 Equation Transcription: Text Transcription:

Problem 49P Water is boiled in a pan covered with a poorly fitting lid at a specified location. Heat is supplied to the pan by a 2-kW resistance heater. The amount of water in the pan is observed to decrease by 1.19 kg in 30 minutes. If it is estimated that 75 percent of electricity consumed by the heater is transferred to the water as heat, determine the local atmospheric pressure in that location.

Problem 50P A rigid tank with a volume of 1.8 m3 contains 15 kg of saturated liquid–vapor mixture of water at 90°C. Now the water is slowly heated. Determine the temperature at which the liquid in the tank is completely vaporized. Also, show the process on a T-v diagram with respect to saturation lines.

A piston-cylinder device contains \(0.005 \mathrm{~m}^{3}\) of (i) liquid water and \(0.9 \mathrm{~m}^{3}\) of water vapor in equi- librium at \(600 \mathrm{kPa}\). Heat is transferred at constant pressure until the temperature reaches \(200^{\circ} \mathrm{C}\). (a) What is the initial temperature of the water? (b) Determine the total mass of the water. (c) Calculate the final volume. (d) Show the process on a \(P-v\) diagram with respect to saturation lines. FIGURE P3–51 Equation Transcription: 200? Text Transcription: 0.9 m^3 600 kPa 200 degree celsius P-v

Problem 53P A 5 - ft3 rigid tank contains 5 lbm of water at 20 psia. Determine (a) the temperature, (b) the total enthalpy, and (c) the mass of each phase of water.

Reconsider Prob. 3–51. Using EES (or other) software, investigate the effect of pressure on the total mass of water in the tank. Let the pressure vary from \(0.1 \mathrm{MPa}\) to \(1 \mathrm{MPa}\). Plot the total mass of water against pressure, and discuss the results. Also, show the process in Prob. 3–51 on a \(P-v\) diagram using the property plot feature of EES. Equation Transcription: Text Transcription: 0.1 MPa 1 MPa P-v

Problem 54P A 5- ft3 rigid tank contains a saturated mixture of refrigerant-34a at 50 psia. If the saturated liquid occupies 20 percent of the volume, determine the quality and the total mass of the refrigerant in the tank.

Problem 55P Superheated water vapor at 180 psia and 500°F is allowed to cool at constant volume until the temperature drops to 250°F. At the final state, determine (a) the pressure, (b) the quality, and (c) the enthalpy. Also, show the process on a T-v diagram with respect to saturation lines.

Reconsider Prob. 3–55E. Using EES (or other) software, investigate the effect of initial pressure on the quality of water at the final state. Let the pressure vary from \(100 \mathrm{psia}\) to \(300 \mathrm{psia}\). Plot the quality against initial pressure, and discuss the results. Also, show the process in Prob. 3–55E on a \(T-v\) diagram using the property plot feature of EES. Equation Transcription: Text Transcription: 100 psi 300 psi T-v

Problem 57P A piston–cylinder device contains 0.6 kg of steam at 200°C and 0.5 MPa. Steam is cooled at constant pressure until one-half of the mass condenses. (a) Show the process on a T-v diagram. (b) Find the final temperature. (c) Determine the volume change.

Problem 58P A rigid tank contains water vapor at 250°C and an unknown pressure. When the tank is cooled to 124°C, the . vapor starts condensing. Estimate the initial pressure in the tank.

A piston-cylinder device initially contains \(1.4-\mathrm{kg}\) saturated liquid water at \(200^{\circ} \mathrm{C}\). Now heat is transferred to the water until the volume quadruples and the cylinder contains saturated vapor only. Determine (a) the volume of the tank, (b) the final temperature and pressure, and (c) the internal energy change of the water. FIGURE P3–59 Equation Transcription: 200? Text Transcription: 1.4-kg 200 degree celsius

Problem 60P How much error would one expect in determining the specific enthalpy by applying the incompressible-liquid approximation to water at 3000 psia and 400°F?

100 grams of \(R-134a\) initially fill a weighted piston cylinder device at \(60 \mathrm{kPa}\) and \(-20^{\circ} \mathrm{C}\). The device is then heated until the temperature is \(100^{\circ} \mathrm{C}\). Determine the change in the device's volume as a result of the heating. FIGURE P3–61 Equation Transcription: -20? 100? Text Transcription: 100 grams R-134a 60 kPa -20 degree celsius 100 degree celsius

Problem 62P A rigid vessel contains 8 kg of refrigerant-134a at 500 kPa and 120°C. Determine the volume of the vessel and the total internal energy.

A rigid tank initially contains \(1.4-\mathrm{kg}\) saturated liquid water at \(200^{\circ} \mathrm{C}\). At this state, 25 percent of the volume is occupied by water and the rest by air. Now heat is supplied to the water until the tank contains saturated vapor only. Determine \((a)\) the volume of the tank, \((b)\) the final temperature and pressure, and \((c)\) the internal energy change of the water. FIGURE P3–63 Equation Transcription: 200? Text Transcription: 1.4-kg 200 degree celsius

Problem 64P A piston-cylinder device initially contains 50 L of liquid water at 40°C and 200 kPa. Heat is transferred to the water at constant pressure until the entire liquid is vaporized. (a) What is the mass of the water? (b) What is the final temperature? (c) Determine the total enthalpy change. (d) Show the process on a T-v diagram with respect to saturation lines.

Problem 65P Under what conditions is the ideal-gas assumption suitable for real gases?

Problem 67P Propane 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. Which gas leakage do you think poses a greater risk for fire? Explain.

Problem 70P A 2-kg mass of helium is maintained at 300 kPa and 27°C in a rigid container. How large is the container, in m3?

Problem 68P A 400-L rigid tank contains 5 kg of air at 25°C. Determine the reading on the pressure gage if the atmospheric pressure is 97 kPa.

Problem 69P A 3-ft3 container is filled with 2-lbm of oxygen at a pressure of 80 psia. What is the temperature of the oxygen?

Problem 66P What is the difference between Rand Ru? How are these two related?

The pressure gage on a \(2.5-\mathrm{m}^{3}\) oxygen tank reads \(500 \mathrm{kPa}\). Determine the amount of oxygen in the tank if the temperature is \(28^{\circ} \mathrm{C}\) and the atmospheric pressure is \(97 \mathrm{kPa}\). FIGURE P3–71 Equation Transcription: 28? Text Transcription: 2.5-m^3 500 kPa 28 degree celsius 97 kPa

Reconsider Prob. 3-72. Using EES (or other) software, investigate the effect of the balloon diameter on the mass of helium contained in the balloon for the pressures of \((a) 100 \mathrm{kPa}\) and \((b) 200 \mathrm{kPa}\). Let the diameter vary from \(5 \mathrm{~m}\) to \(15 \mathrm{~m}\). Plot the mass of helium against the diameter for both cases. Equation Transcription: Text Transcription: 100 kPa 200 kPa 5 m 15 m

A \(1-\mathrm{m}^{3}\) tank containing air at \(10^{\circ} \mathrm{C}\) and \(350 \mathrm{kPa}\) is connected through a valve to another tank containing \(3 \mathrm{~kg}\) of air at \(35^{\circ} \mathrm{C}\) and \(200 \mathrm{kPa}\). Now the valve is opened, and the entire system is allowed to reach thermal equilibrium with the surroundings, which are at \(20^{\circ} \mathrm{C}\). Determine the volume of the second tank and the final equilibrium pressure of air. Equation Transcription: 10? 35? 20? Text Transcription: 1-m^3 10 degree celsius 350 kPa 3 kg 35 degree celsius 200 kPa 20 degree celsius

Problem 72P A spherical balloon with a diameter of 9 m is filled with helium at 27°C and 200 kPa. Determine the mole number and the mass of the helium in the balloon. Answers:30.6 kmol, 123 kg

The air in an automobile tire with a volume of \(0.53 \mathrm{ft}^{3}\) is at \(90^{\circ} \mathrm{F}\) and \(20 \mathrm{psig}\). Determine the amount of air that must be added to raise the pressure to the recommended value of 30 psig. Assume the atmospheric pressure to be \(14.6\) psia and the temperature and the volume to remain constant. Equation Transcription: 90? Text Transcription: 0.53 ft^3 90 degree fahrenheit 20 psig 30 psig

A rigid tank whose volume is unknown is divided into two parts by a partition. One side of the tank contains an ideal gas at \(927^{\circ} \mathrm{C}\). The other side is evacuated and has a volume twice the size of the part containing the gas. The partition is now removed and the gas expands to fill the entire tank. Heat is now applied to the gas until the pressure equals the initial pressure. Determine the final temperature of the gas. FIGURE P3–76 Equation Transcription: 927? Text Transcription: 927 degree celsius

Argon in the amount of \(1.5\ kg\) fills a \(0.04 \mathrm{m}^{3}\) piston-cylinder device at \(550\) kPa. The piston is now moved by changing the weights until the volume is twice its original size. During this process, argon’s temperature is maintained constant. Determine the final pressure in the device. Equation Transcription: Text Transcription: 1.5 kg 0.04-m^3 550 kPa

Problem 78P A rigid tank contains 20 lbm of air at 20 psia and 70°F. More air is added to the tank until the pressure and temperature rise to 35 psia and 90°F, respectively. Determine the amount of air added to the tank.

Problem 79P What is the principle of corresponding states?

Problem 81P Refrigerant-134a at 400 psia has a specific volume of 0.1384 ft3/lbm Determine the temperature of the refrigerant based on (a) the ideal-gas equation, (b) the generalized compressibility chart, and (c) the refrigerant tables.

Problem 80P How are the reduced pressure and reduced temperature defined?

Problem 84P Determine the specific volume of superheated water vapor at 3.5 MPa and 450°C based oh (a) the ideal-gas equation, (b) the generalized compressibility chart, and (c) the steam tables. Determine the error involved in the first two cases.

Reconsider Prob. 3-82. Solve the problem using the generalized compressibility factor feature of the EES software. Again using EES, compare the specific volume of water for the three cases at \(15 \mathrm{MPa}\) over the temperature range of 350 to \(600^{\circ} \mathrm{C}\) in \(25^{\circ} \mathrm{C}\) intervals. Plot the percent error involved in the ideal-gas approximation against temperature, and discuss the results. Equation Transcription: 600? 25? Text Transcription: 15 MPa 600 degree celsius 25 degree celsius

Problem 86P Ethane in a rigid vessel is to be heated from 50 psia and 100°F until its temperature is 540°F. What is the final pressure of the ethane as predicted by the compressibility chart?

Problem 85P Somebody claims that oxygen gas at 160 K and 3 MPa can be treated as an ideal gas with an error of less than 10 percent. Is this claim valid?

Problem 82P Determine the specific volume of superheated water vapor at 15 MPa and 350°C, using (a) the ideal-gas equation, (b) the generalized compressibility chart, and (c) the steam tables. Also determine the error involved in the first two cases.

Problem 87P Ethylene is heated at constant pressure from 5 MPa and 20°C to 200°C. Using the compressibility chart, determine the change in the ethylene specific volume as a result of this heating.

Problem 88P What is the percentage of error involved in treating a carbon dioxide at 7 MPa and 380 K as an ideal gas?

Problem 90P Methane at 10 MPa and 300 K is heated at constant pressure until its volume has increased by 80 percent. Determine the final temperature using the ideal gas equation of state and the compressibility factor. Which of these two results is more accurate?

Problem 89P Saturated water vapor at 350°C is heated at constant pressure until its volume has doubled. Determine the final temperature using the ideal gas equation of state, the compressibility charts, and the steam tables.

A \(0.016773-\mathrm{m}^{3}\) tank contains \(1 \mathrm{~kg}\) of refrigerant-134a at \(110^{\circ} \mathrm{C}\). Determine the pressure of the refrigerant, using (a) the ideal-gas equation, (b) the generalized compressibility chart, and (c) the refrigerant tables. Equation Transcription: 110? Text Transcription: 0.016773-m^3 1 kg 110 degree celsaius

Carbon dioxide gas enters a pipe at \(3 \mathrm{MPa}\) and \(500 \mathrm{~K}\) at a rate of \(2 \mathrm{~kg} / \mathrm{s} . \mathrm{CO}_{2}\) is cooled at constant pressure as it flows in the pipe and the temperature of \(\mathrm{CO}_{2}\) drops to \(450 \mathrm{~K}\) at the exit. Determine the volume flow rate and the density of carbon dioxide at the inlet and the volume flow rate at the exit of the pipe using (a) the ideal-gas equation and (b) the generalized compressibility chart. Also, determine (c) the error involved in the first case. FIGURE P3–91 Equation Transcription: Text Transcription: 3 MPa 500 K 2 kg/s CO_2 450 K

Problem 93P What is the physical significance of the two constants that appear in the van der Waals equation of state? On what basis are they determined?

Problem 95P Methane is heated in a rigid container from 80 kPa and 20°C to 300°C. Determine the final pressure of the methane treating it as (a) an ideal gas and (b) a Benedict-Webb-Rubin gas.

Problem 94P A 3.27-m3 tank contains 100 kg of nitrogen at 175 K. Determine the pressure in the tank, using (a) the ideal-gas equation, (b) the van der Waals equation, and (c) the Beattie- Bridgeman equation. Compare your results with the actual value of 1505 kPa.

Problem 96P Refrigerant-134a at 400 psia has a specific volume of 0.1144 ft3/lbm Determine the temperature of the refrigerant based on (a) the ideal-gas equation, (b) the van der Waals equation, and (c) the refrigerant tables.

Reconsider Prob. 3-97. Using EES (6f other) software, compare the pressure results of the ideal-gas and Beattie-Bridgeman equations with nitrogen data supplied by EES. Plot temperature versus specific volume for a pressure of \(1000 \mathrm{kPa}\) with respect to the saturated liquid and saturated vapor lines of nitrogen over the range of \(110 \mathrm{~K}<T<150 \mathrm{~K}\). Equation Transcription: Text Transcription: 1000 kPa 110 K?T ?150 K

Nitrogen at \(150 \mathrm{~K}\) has a specific volume of \(0.041884 \mathrm{~m}^{3} / \mathrm{kg}\). Determine the pressure of the nitrogen, using (a) the ideal-gas equation and (b) the BeattieBridgeman equation. Compare your results to the experimental value of \(1000 \mathrm{kPa}\). Equation Transcription: Text Transcription: 150 K 0.041884 m^3/kg 1000 kPa

Problem 99P 1-kg of, carbon dioxide is compressed from 1 MPa and 200°C to 3 MPa in a piston-cylinder device arranged to execute a poly tropic process for which PV1.2 = constant. Determine the final temperature treating the carbon dioxide as (a) an ideal gas and (b) a van der Waals gas.

Problem 102P During a hot summer day at the beach when the air temperature is 30°C, someone claims the vapor pressure in the air to be 5.2 kPa. Is this claim reasonable?

Problem 100P A 1-m3 tank contains 2.841 kg of steam at 0.6 MPa. Determine the temperature of the steam, using (a) the ideal gas equation, (b) the van der Waals equation, and (c) the steam tables.

Problem 103P Consider a glass of water in a room that is at 20°C and 40 percent relative humidity. If the water temperature is 15°C, determine the vapor pressure (a) at the free surface of the water and (b) at a location in the room far from the glass.

Problem 104P On a certain day, the temperature and relative humidity of air over a large swimming pool are measured to be 25°C and 60 percent, respectively. Determine the water temperature of the pool when phase equilibrium conditions are established between the water in the pool and the vapor in the air.

Problem 105P During a hot summer day when the air temperature is 35°C and the relative humidity is 70 percent, you buy a supposedly “cold” canned drink from a store. The store owner claims that the temperature of the drink is below 10°C. Yet the drink does not feel so cold and you are skeptical since you notice no condensation forming outside the can. Can the store owner be telling the truth?

Problem 106P Consider two rooms that are identical except that one is maintained at 25°C and 40 percent relative humidity while the other is maintained at 20°C and 55 percent relative humidity. Noting that the amount of moisture is proportional to the vapor pressure, determine which room contains more moisture.

Problem 107P A thermos bottle is half-filled with water and is left open to the atmospheric air at 60°F and 35 percent relative humidity. If heat transfer to the water through the thermos walls and the free surface is negligible, determine the temperature of water when phase equilibrium is established.

Problem 108P Water in a pressure cooker is observed to boil at 260°F. What is the absolute pressure in the pressure cooker, in psia?

Carbon-dioxide gas at \(3 \mathrm{MPa}\) and \(500 \mathrm{~K}\) flows steadily in a pipe at a rate of \90.4 \mathrm{kmol} / \mathrm{s}\). Determine (a) the volume and mass flow rates and the density of carbon dioxide at this state. If \(\mathrm{CO}_{2}\) is cooled at constant pressure as it flows in the pipe so that the temperature of \(\mathrm{CO}_{2}\) drops to \(450 \mathrm{~K}\) at the exit of the pipe, determine (b) the volume flow rate at the exit of the pipe. FIGURE P3–109 Equation Transcription: Text Transcription: 3 MPa 500 K 0.4 kmol/s CO_2 450 K

Problem 110P A tank contains argon at 600°C and 200 kPa gage. The argon is cooled in a process by heat transfer to the surroundings such that the argon reaches a final equilibrium state at 300°C. Determine the final gage pressure of the argon. Assume atmospheric pressure is 100 kPa.

The combustion in a gasoline engine may be approximated by a constant volume heat addition process. There exists the air-fuel mixture in the cylinder before the combustion and the combustion gases after it, and both may be approximated as air, an ideal gas. In a gasoline engine, the cylinder conditions are \(1.2 \mathrm{MPa}\) and \(450^{\circ} \mathrm{C}) before the combustion and \(1750^{\circ} \mathrm{C}\) after it. Determine the pressure at the end of the combustion process. FIGURE P3–111 Equation Transcription: 450? 1750? Text Transcription: 1.2 MPa 450 degree celsius 1750 degree celsius

Problem 112P One kilogram of R-134a fills a 0.090 m3 rigid container at an initial temperature of ?40°C. The container is then heated until the pressure is 280 kPa. Determine the initial pressure and final temperature. Answers:51.25 kPa, 50°C

Problem 113P A rigid tank with a volume of 0.117 m3 contains 1 kg of refrigerant-134a vapor at 240 kPa. The refrigerant is now allowed to cool. Determine the pressure when the refrigerant first starts condensing. Also, show the process on a P-v diagram with respect to saturation lines.

One pound-mass of water fills a \(2.649 \mathrm{ft}^{3}\) weighted piston-cylinder device at a temperature of \(400^{\circ} \mathrm{F}\). The piston cylinder device is now cooled until its temperature is \(100^{\circ} \mathrm{F}\). Determine the final pressure and volume of the water. FIGURE P3–114E Equation Transcription: 100? 400? Text Transcription: 2.649 ft^3 100 degree fahrenheit 400 degree fahrenheit

Problem 115P Ethane at 10 MPa and 100°C is heated at constant pressure until its volume has increased by 60 percent. Determine the final temperature using (a) the ideal gas equation of state and (b) the compressibility factor. Which of these two results is the more accurate?

Problem 116P A 13-m3 tank contains nitrogen at 17°C and 600 kPa. Some nitrogen is allowed to escape until the pressure in the tank drops to 400 kPa. If the temperature at this point is 15°C, determine the amount of nitrogen that has escaped.

Problem 117P A 10-kg mass of superheated refrigerant-134a at 1.2 MPa and 70°C is cooled at constant pressure until it exists as a compressed liquid at 20°C. (a) Show the process on a T-v diagram with respect to saturation lines. (b) Determine the change in volume. (c) Find the change in total internal energy.

Problem 119P The gage pressure of an automobile tire is measured to be 200 kPa before a trip and 220 kPa after the trip at a location where the atmospheric pressure is 90 kPa. Assuming the volume of the tire remains constant at 0.035 m3, determine the percent increase in the absolute temperature of the air in the tire.

A \(4 \mathrm{~L}\) rigid tank contains \(2 \mathrm{~kg}\) of saturated liquid vapor mixture of water at \(50^{\circ} \mathrm{C}\). The water is now slowly heated until it exists in a single phase. At the final state, will the water be in the liquid phase or the vapor phase? What would your answer be if the volume of the tank were \(400 \mathrm{~L}\) instead of \(4 \mathrm{~L}\) ? FIGURE P3–118 Equation Transcription: 50? Text Transcription: 4-L 2 kg 50 degree celsius 400 L

A piston-cylinder device initially contains \(0.2 \mathrm{~kg}\) of steam at \(200 \mathrm{kPa}\) and \(300^{\circ} \mathrm{C}\). Now, the steam is cooled at constant pressure until it is at \9150^{\circ} \mathrm{C}\). Determine the volume change of the cylinder during this process using the compressibility factor and compare the result to the actual value. FIGURE P3–120 Equation Transcription: 300? 150? Text Transcription: 0.2 kg 200 kPa 300 degree celsius 150 degree celsius

A tank whose volume is unknown is divided into two parts by a partition. One side of the tank contains \(0.03 \mathrm{~m}^{3}\) of refrigerant- \(134 \mathrm{a}\) that is a saturated liquid at \(0.9 \mathrm{MPa}\), while the other side is evacuated. The partition is now removed, and the refrigerant fills the entire tank. If the final state of the refrigerant is \(20^{\circ} \mathrm{C}\) and \(280 \mathrm{kPa}\), determine the volume of the tank. FIGURE P3–122 Equation Transcription: 20? Text Transcription: 0.03 m^3 134a 20 degree celsius 280 kPa 0.9 MPa

Problem 121P Steam at 400°C has a specific volume of 0.02 m3/kg. Determine the pressure of the steam based on (a) the ideal-gas equation, (b) the generalized compressibility chart, and (c) the steam tables.

Problem 125P Repeat Prob. 3–131 for isobutane.

Liquid propane is commonly used as a fuel for heating homes, powering vehicles such as forklifts, and filling portable picnic tanks. Consider a propane tank that initially contains \(5 \mathrm{~L}\) of liquid propane at the environment temperature of (20^{\circ} \mathrm{C}\). If a hole develops in the connecting tube of a propane tank and the propane starts to leak out, determine the temperature of propane when the pressure in the tank drops to \(1 \mathrm{~atm}\). Also, determine the total amount of heat transfer from the environment to the tank to vaporize the entire propane in the tank. FIGURE P3–124 Equation Transcription: 20? Text Transcription: 5 L 20 degree celsius

Problem 126P A tank contains helium at 37°C and 140 kPa gage. The helium is heated in a process by heat transfer from the surroundings such that the helium reaches a final equilibrium state at 200°C. Determine the final gage pressure of the helium. Assume atmospheric pressure is 100 kPa.

Problem 127P If sufficient data are provided, complete the blank cells in the following table of properties of water. In the last column describe the condition of water as compressed liquid, saturated mixture, superheated vapor, or insufficient information; and, if applicable, give the quality. P, kPa T,°C v,m3/kg u,kJ/kg Condition description and quality (if applicable) 250 2728.9 300 1560.0 101.42 100 3000 180

Problem 129P 0.5-lbm of argon is compressed from 1000 psia and 300°F to 2000 psia in a piston-cylinder device which executes a polytropic process for which PV1.6 = constant. Determine the final temperature treating the argon as (a) an ideal gas and (b) a Beattie-Bridgeman gas.

Water initially at \(300 \mathrm{kPa}\) and \(0.5 \mathrm{~m}^{3} / \mathrm{kg}\) is contained in a piston-cylinder device fitted with stops so that the water supports the weight of the piston and the force of the atmosphere. The water is heated until it reaches the saturated vapor state and the piston rests against the stops. With the piston against the stops, the water is further heated until the pressure is \(600 \mathrm{kPa}\). On the \(P-\mathrm{V}\) and \(T-v\) diagrams sketch, with respect to the saturation lines, the process curves passing through both the initial and final states of the water. Label the states on the process as 1,2 , and 3. On both the \(P\)-v and \(T\)-v diagrams, sketch the isotherms passing through the states and show their values, in \({ }^{\circ} \mathrm{C}\), on the isotherms. FIGURE P3–128 Equation Transcription: - - ? Text Transcription: 300 kPa 0.5 m3/kg 600 kPa P - v T - v degree celsius

Problem 130P Nitrogen is maintained at 400 psia and ?100°F. Compare the specific volume of this nitrogen as predicted by (?a?) the ideal gas equation of state, (?b?) the Benedict-Webb-Rubin equation of state, and (?c?) with the compressibility factor.

Problem 133P Consider an 18-m-diameter hot-air balloon that, together with its cage, has a mass of 120 kg when empty. The air in the balloon, which is now carrying two 70-kg people, is heated by propane burners at a location where the atmospheric pressure and temperature are 93 kPa and 12°C, respectively. Determine the average temperature of the air in the balloon when the balloon first starts rising. What would your response be if the atmospheric air temperature were 25°C?

Problem 134P 300-m3 rigid tank is filled with saturated liquid–vapor mixture of water at 200 kPa. If 25 percent of the mass is liquid and 75 percent of the mass is vapor, the total mass in the tank is (a) 451 kg ________________ (b) 556 kg ________________ (c) 300 kg ________________ (d) 331 kg ________________ (e) 195 kg

Although balloons have been around since 1783 when the first balloon took to the skies in France, a real breakthrough in ballooning occurred in 1960 with the design of the modern hot-air balloon fueled by inexpensive propane and constructed of lightweight nylon fabric. Over the years, ballooning has become a sport and a hobby for many people around the world. Unlike balloons filled with the light helium gas, hot-air balloons are open to the atmosphere. Therefore, the pressure in the balloon is always the same as the local atmospheric pressure, and the balloon is never in danger of exploding. Hot-air balloons range from about 15 to \(25 \mathrm{~m}\) in diameter. The air in the balloon cavity is heated by a propane burner located at the top of the passenger cage. The flames from the burner that shoot into the balloon heat the air in the balloon cavity, raising the air temperature at the top of the balloon from \(65^{\circ} \mathrm{C}\) to over \(120^{\circ} \mathrm{C}\). The air temperature is maintained at the desired levels by periodically firing the propane burner. The buoyancy force that pushes the balloon upward is proportional to the density of the cooler air outside the balloon and the volume of the balloon, and can be expressed as \(F_{B}=\rho_{\text {cool air }} g V_{\text {balloon }}\) where \(g\) is the gravitational acceleration. When air resistance is negligible, the buoyancy force is opposed by (1) the weight of the hot air in the balloon, (2) the weight of the cage, the ropes, and the balloon material, and (3) the weight of the people and other load in the cage. The operator of the balloon can control the height and the vertical motion of the balloon by firing the burner or by letting some hot air in the balloon escape, to be replaced by cooler air. The forward motion of the balloon is provided by the winds. Consider a 20-m-diameter hot-air balloon that, together with its cage, has a mass of \(80 \mathrm{~kg}\) when empty. This balloon is hanging still in the air at a location where the atmospheric pressure and temperature are \(90 \mathrm{kPa}\) and \(15^{\circ} \mathrm{C}\), respectively, while carrying three \(65-\mathrm{kg}\) people. Determine the average temperature of the air in the balloon. What would your response be if the atmospheric air temperature were \(30^{\circ} \mathrm{C}\) ? FIGURE P3–131 Equation Transcription: Text Transcription: 25 m 65 degree celsius 120 degree celsius F_B=rho_coel air gV_balloon 90 kPa 15 degree celsius 65-kg 30C degree celsius

Problem 135P Water is boiled at 1 atm pressure in a coffee maker equipped with an immersion-type electric heating element. The coffee maker initially contains 1 kg of water. Once boiling started, it is observed that half of the water in the coffee maker evaporated in 10 minutes. If the heat loss from the coffee maker is negligible, the power rating of the heating element is (a)3.8kW ________________ (b)2.2kW ________________ (c)1.9kW ________________ (d)1.6kW ________________ (e)0.8kW

Problem 136P 1-m3 rigid tank contains 10 kg of water (in any phase or phases) at 160°C. The pressure in the tank is (a)738kPa ________________ (b) 618 kPa ________________ (c)370kPa ________________ (d) 2000 MPa ________________ (e)1618kPa

Problem 137P Water is boiling at 1 atm pressure in a stainless steel pan on an electric range. It is observed that 2 kg of liquid water evaporates in 30 min. The rate of heat transfer to the water is (a)2.51kW ________________ (b) 2.32 kW ________________ (c)2.97kW ________________ (d) 00.47kW ________________ (e)3.12kW

Problem 138P Water is boiled in a pan on a stove at sea level. During 10 min of boiling, it is observed that 200 g of water has evaporated. Then the rate of heat transfer to the water is (a)0.84kJ/min ________________ (b) 45.1 kJ/min ________________ (c)41.8kJ/min ________________ (d) 53.5 kJ/min ________________ (e) 225.7 kJ/min

Problem 139P 3-m3 rigid vessel contains steam at 4 MPa. and 500°C. The mass of the steam is (a) 3 kg ________________ (b) 9 kg ________________ (c)26kg ________________ (d) 35 kg ________________ (e)52kg

Problem 140P Consider a sealed can that is filled with refrigerant-134a. The contents of the can are at the room temperature of 25°C. Now a leak develops, and the pressure in the can drops to the local atmospheric pressure of 90 kPa. The temperature of the refrigerant in the can is expected to drop to (rounded to the nearest integer) (a)0°C ________________ (b)-29°C ________________ (c)-16°C ________________ (d)5°C ________________ (e)25°C

Problem 141P A rigid tank contains 2 kg of an ideal gas at 5 atm and 40°C. Now a valve is opened, and half of mass of the gas is allowed to escape. If.the final pressure in the tank is 2.2 atm, the final temperature in the tank is (a)71°C ________________ (b)44°C ________________ (c)-100°C ________________ (d)20°C ________________ (e) 172°C

Problem 79P What is the principle of corresponding states?

Problem 107P A thermos bottle is half-filled with water and is left open to the atmospheric air at 60°F and 35 percent relative humidity. If heat transfer to the water through the thermos walls and the free surface is negligible, determine the temperature of water when phase equilibrium is established.

Problem 3.31 C 10-kg of R-134a fill a rigid container at an initial temperature of . The container is then heated until the pressure is . Determine the final temperature and the initial pressure.

Problem 3.32C A container is filled with 300 kg of R-134a at . What is the specific enthalpy of the R-134a in the container?

Problem 3.33C Refrigerant-134a at and flows through a refrigeration line. Determine its specific volume.

The average atmospheric pressure in Denver (elevation = 1610 m) is . Determine the temperature at which water in an uncovered pan boils in Denver.

The temperature in a pressure cooker during cooking at sea level is measured to be . Determine the absolute pressure inside the cooker in psia and in atm. Would you modify your answer if the place were at a higher elevation?

A spring-loaded piston-cylinder device is initially filled with of an liquid-vapor mixture whose temperature is and whose quality is 80 percent.The spring constant in the spring force relation is and the piston diameter is 12 in. The undergoes a process that increases its volume by 50 percent. Calculate the final temperature and enthalpy of the R-134a.

One pound-mass of water fills a weighted piston-cylinder device at a temperature of . The piston cylinder device is now cooled until its temperature is . Determine the final pressure of water, in psia, and the volume in . .

Three kilograms of water in a container have a pressure of and temperature of . What is the volume of this container?

Water is to be boiled at sea level in a 30-cm-diameter stainless steel pan placed on top of a 3-kW electric burner. If 60 percent of the heat generated by the burner is transferred to the water during boiling. Determine the rate of evaporation of water.

It is well known that warm air in a cooler environment rises. Now consider a warm mixture of air and gasoline on top of an open gasoline can. Do you think this gas mixture will rise in a cooler environment?

Does the amount of heat absorbed as 1 kg of saturated liquid water boils at have to be equal to the amount of heat released as 1 kg of saturated water vapor condenses at ?

Does the reference point selected for the properties of a substance have any effect on thermodynamic analysis? Why?

What is the physical significance of ? Can it be obtained from a knowledge of and ? How?

Does change with pressure? How?

Is it true that it takes more energy to vaporize 1 kg of saturated liquid water at than it would at

What is quality? Does it have any meaning in the superheated vapor region?

Which process requires more energy: completely vaporizing 1 kg of saturated liquid water at 1 atm pressure or completely vaporizing 1 kg of saturated liquid water at 8 atm pressure?

In the absence of compressed liquid tables, how is the specific volume of a compressed liquid at a given P and T determined?

In 1775, Dr. William Cullen made ice in Scotland by evacuating the air in a water tank. Explain how that device works, and discuss how the process can be made more efficient.

Complete this table for H2O: T, C P, kPa u, kJ/kg Phase description 400 1450 220 Saturated vapor 190 2500 4000 3040

Complete this table for H2O: T, 8C P, kPa v, m3/kg Phase description 50 7.72 400 Saturated vapor 250 500 110 350

Reconsider Prob. 321. Using EES (or other) software, determine the missing properties of water. Repeat the solution for refrigerant-134a, refrigerant-22, and ammonia.

Complete this table for H2O: T, 8C P, kPa v, m3/kg Phase description 140 0.05 550 Saturated liquid 125 750 500 0.140

Complete this table for H2O: T, 8F P, psia u, Btu/lbm Phase description 300 782 40 Saturated liquid 500 120 400 400

Reconsider Prob. 324E. Using EES (or other) software, determine the missing properties of water. Repeat the solution for refrigerant-134a, refrigerant-22, and ammonia.

Complete this table for refrigerant-134a: T, 8C P, kPa v, m3/kg Phase description 24 320 10 0.0065 850 Saturated vapor 90 600

Complete this table for refrigerant-134a: T, 8F P, psia h, Btu/lbm x Phase description 80 78 15 0.6 10 70 180 129.46 110 1.0

A 1.8-m3 rigid tank contains steam at 2208C. One-third of the volume is in the liquid phase and the rest is in the vapor form. Determine (a) the pressure of the steam, (b) the quality of the saturated mixture, and (c) the density of the mixture.

A pistoncylinder device contains 0.85 kg of refrigerant- 134a at 2108C. The piston that is free to move has a mass of 12 kg and a diameter of 25 cm. The local atmospheric pressure is 88 kPa. Now, heat is transferred to refrigerant-134a until the temperature is 158C. Determine (a) the final pressure, (b) the change in the volume of the cylinder, and (c) the change in the enthalpy of the refrigerant-134a.

R-134a, whose specific volume is 0.6243 ft3 /lbm, flows through a tube at 80 psia. What is the temperature in the tube?

10-kg of R-134a fill a 1.348-m3 rigid container at an initial temperature of 2408C. The container is then heated until the pressure is 200 kPa. Determine the final temperature and the initial pressure.

A 9-m3 container is filled with 300 kg of R-134a at 108C. What is the specific enthalpy of the R-134a in the container?

Refrigerant-134a at 200 kPa and 258C flows through a refrigeration line. Determine its specific volume.

The average atmospheric pressure in Denver (elevation 5 1610 m) is 83.4 kPa. Determine the temperature at which water in an uncovered pan boils in Denver.

The temperature in a pressure cooker during cooking at sea level is measured to be 2508F. Determine the absolute pressure inside the cooker in psia and in atm. Would you modifty your answer if the place were at a higher elevation?

A spring-loaded piston-cylinder device is initially filled with 0.13 lbm of an R-134a liquid-vapor mixture whose temperature is 2308F and whose quality is 80 percent. The spring constant in the spring force relation F 5 kx is 37 lbf/in, and the piston diameter is 12 in. The R-134a undergoes a process that increases its volume by 50 percent. Calculate the final temperature and enthalpy of the R-134a.

One pound-mass of water fills a 2.4264-ft3 weighted piston-cylinder device at a temperature of 6008F. The pistoncylinder device is now cooled until its temperature is 2008F. Determine the final pressure of water, in psia, and the volume, in ft3 .

Three kilograms of water in a container have a pressure of 100 kPa and temperature of 1508C. What is the volume of this container?

Water is to be boiled at sea level in a 30-cm-diameter stainless steel pan placed on top of a 3-kW electric burner. If 60 percent of the heat generated by the burner is transferred to the water during boiling, determine the rate of evaporation of water.

Repeat Prob, 339 for a location at an elevaion of 1500 m where the atmospheric pressure is 84.5 kPa and thus the boiling temperature of water is 958C.

10-kg of R-134a at 300 kPa fills a rigid container whose volume is 14 L. Determine the temperature and total enthalpy in the container. The container is now heated until the pressure is 600 kPa. Determine the temperature and total enthalpy when the heating is completed.

100-kg of R-134a at 200 kPa are contained in a pistoncylinder device whose volume is 12.322 m3 . The piston is now moved until the volume is one-half its original size. This is done such that the pressure of the R-134a does not change. Determine the final temperature and the change in the total internal energy of the R-134a.

Water initially at 200 kPa and 3008C is contained in a piston-cylinder device fitted with stops. The water is allowed to cool at constant pressure until it exists as a saturated vapor and the piston rests on the stops. Then the water continues to cool until the pressure is 100 kPa. On the T-v diagrams sketch, with respect to the saturation lines, the process curves passing through both the initial, intermediate, and final states of the water. Label the T, P and v values for end states on the process curves. Find the overall change in internal energy between the initial and final states per unit mass of water.

Saturated steam coming off the turbine of a steam power plant at 408C condenses on the outside of a 3-cmouter-diameter, 35-m-long tube at a rate of 130 kg/h. Determine the rate of heat transfer from the steam to the cooling water flowing through the pipe.

Water in a 5-cm-deep pan is observed to boil at 988C. At what temperature will the water in a 40-cm-deep pan boil? Assume both pans are full of water

A cooking pan whose inner diameter is 20 cm is filled with water and covered with a 4-kg lid. If the local atmospheric pressure is 101 kPa, determine the temperature at which the water starts boiling when it is heated.

Reconsider Prob. 346. Using EES (or other) software, investigate the effect of the mass of the lid on the boiling temperature of water in the pan. Let the mass vary from 1 kg to 10 kg. Plot the boiling temperature against the mass of the lid, and discuss the results

Water is being heated in a vertical pistoncylinder device. The piston has a mass of 40 kg and a cross-sectional area of 150 cm2 . If the local atmospheric pressure is 100 kPa, determine the temperature at which the water starts boiling.

Water is boiled in a pan covered with a poorly fitting lid at a specified location. Heat is supplied to the pan by a 2-kW resistance heater. The amount of water in the pan is observed to decrease by 1.19 kg in 30 minutes. If it is estimated that 75 percent of electricity consumed by the heater is transferred to the water as heat, determine the local atmospheric pressure in that location.

A rigid tank with a volume of 1.8 m3 contains 15 kg of saturated liquidvapor mixture of water at 908C. Now the water is slowly heated. Determine the temperature at which the liquid in the tank is completely vaporized. Also, show the process on a T-v diagram with respect to saturation lines.

A pistoncylinder device contains 0.005 m3 of liquid water and 0.9 m3 of water vapor in equilibrium at 600 kPa. Heat is transferred at constant pressure until the temperature reaches 2008C. (a) What is the initial temperature of the water? (b) Determine the total mass of the water. (c) Calculate the final volume. (d) Show the process on a P-v diagram with respect to saturation lines.

Reconsider Prob. 351. Using EES (or other) software, investigate the effect of pressure on the total mass of water in the tank. Let the pressure vary from 0.1 MPa to 1 MPa. Plot the total mass of water against pressure, and discuss the results. Also, show the process in Prob. 351 on a P-v diagram using the property plot feature of EES.

A 5-ft3 rigid tank contains 5 lbm of water at 20 psia. Determine (a) the temperature, (b) the total enthalpy, and (c) the mass of each phase of water

A 5-ft3 rigid tank contains a saturated mixture of refrigerant-34a at 50 psia. If the saturated liquid occupies 20 percent of the volume, determine the quality and the total mass of the refrigerant in the tank.

Superheated water vapor at 180 psia and 5008F is allowed to cool at constant volume until the temperature drops to 2508F. At the final state, determine (a) the pressure, (b) the quality, and (c) the enthalpy. Also, show the process on a T-v diagram with respect to saturation lines.

Reconsider Prob. 355E. Using EES (or other) software, investigate the effect of initial pressure on the quality of water at the final state. Let the pressure vary from 100 psi to 300 psi. Plot the quality against initial pressure, and discuss the results. Also, show the process in Prob. 355E on a T-v diagram using the property plot feature of EES.

A pistoncylinder device contains 0.6 kg of steam at 2008C and 0.5 MPa. Steam is cooled at constant pressure until one-half of the mass condenses. (a) Show the process on a T-v diagram. (b) Find the final temperature. (c) Determine the volume change.

A rigid tank contains water vapor at 2508C and an unknown pressure. When the tank is cooled to 1248C, the vapor starts condensing. Estimate the initial pressure in the tank.

A piston-cylinder device initially contains 1.4-kg saturated liquid water at 2008C. Now heat is transferred to the water until the volume quadruples and the cylinder contains saturated vapor only. Determine (a) the volume of the tank, (b) the final temperature and pressure, and (c) the internal energy change of the water.

How much error would one expect in determining the specific enthalpy by applying the incompressible-liquid approximation to water at 3000 psia and 4008F?

100 grams of R-134a initially fill a weighted pistoncylinder device at 60 kPa and 2208C. The device is then heated until the temperature is 1008C. Determine the change in the devices volume as a result of the heating.

A rigid vessel contains 8 kg of refrigerant-134a at 500 kPa and 1208C. Determine the volume of the vessel and the total internal energy.

A rigid tank initially contains 1.4-kg saturated liquid water at 2008C. At this state, 25 percent of the volume is occupied by water and the rest by air. Now heat is supplied to the water until the tank contains saturated vapor only. Determine (a) the volume of the tank, (b) the final temperature and pressure, and (c) the internal energy change of the water.

A piston-cylinder device initially contains 50 L of liquid water at 408C and 200 kPa. Heat is transferred to the water at constant pressure until the entire liquid is vaporized. (a) What is the mass of the water? (b) What is the final temperature? (c) Determine the total enthalpy change. (d) Show the process on a T-v diagram with respect to saturation lines.

Under what conditions is the ideal-gas assumption suitable for real gases?

What is the difference between R and Ru? How are these two related?

Propane 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. Which gas leakage do you think poses a greater risk for fire? Explain.

A 400-L rigid tank contains 5 kg of air at 258C. Determine the reading on the pressure gage if the atmospheric pressure is 97 kPa.

A 3-ft3 container is filled with 2-lbm of oxygen at a pressure of 80 psia. What is the temperature of the oxygen?

A 2-kg mass of helium is maintained at 300 kPa and 278C in a rigid container. How large is the container, in m3 ?

The pressure gage on a 2.5-m3 oxygen tank reads 500 kPa. Determine the amount of oxygen in the tank if the temperature is 288C and the atmospheric pressure is 97 kPa.

A spherical balloon with a diameter of 9 m is filled with helium at 278C and 200 kPa. Determine the mole number and the mass of the helium in the balloon.

Reconsider Prob. 372. Using EES (or other) software, investigate the effect of the balloon diameter on the mass of helium contained in the balloon for the pressures of (a) 100 kPa and (b) 200 kPa. Let the diameter vary from 5 m to 15 m. Plot the mass of helium against the diameter for both cases.

The air in an automobile tire with a volume of 0.53 ft3 is at 908F and 20 psig. Determine the amount of air that must be added to raise the pressure to the recommended value of 30 psig. Assume the atmospheric pressure to be 14.6 psia and the temperature and the volume to remain constant.

A 1-m3 tank containing air at 108C and 350 kPa is connected through a valve to another tank containing 3 kg of air at 358C and 200 kPa. Now the valve is opened, and the entire system is allowed to reach thermal equilibrium with the surroundings, which are at 208C. Determine the volume of the second tank and the final equilibrium pressure of air.

A rigid tank whose volume is unknown is divided into two parts by a partition. One side of the tank contains an ideal gas at 9278C. The other side is evacuated and has a volume twice the size of the part containing the gas. The partition is now removed and the gas expands to fill the entire tank. Heat is now applied to the gas until the pressure equals the initial pressure. Determine the final temperature of the gas.

Argon in the amount of 1.5 kg fills a 0.04-m3 pistoncylinder device at 550 kPa. The piston is now moved by changing the weights until the volume is twice its original size. During this process, argons temperature is maintained constant. Determine the final pressure in the device.

A rigid tank contains 20 lbm of air at 20 psia and 708F. More air is added to the tank until the pressure and temperature rise to 35 psia and 908F, respectively. Determine the amount of air added to the tank.

What is the principle of corresponding states?

How are the reduced pressure and reduced temperature defined?

Refrigerant-134a at 400 psia has a specific volume of 0.1384 ft3 /lbm. Determine the temperature of the refrigerant based on (a) the ideal-gas equation, (b) the generalized compressibility chart, and (c) the refrigerant tables.

Determine the specific volume of superheated water vapor at 15 MPa and 3508C, using (a) the ideal-gas equation, (b) the generalized compressibility chart, and (c) the steam tables. Also determine the error involved in the first two cases.

Reconsider Prob. 382. Solve the problem using the generalized compressibility factor feature of the EES software. Again using EES, compare the specific volume of water for the three cases at 15 MPa over the temperature range of 350 to 6008C in 258C intervals. Plot the percent error involved in the ideal-gas approximation against temperature, and discuss the results.

Determine the specific volume of superheated water vapor at 3.5 MPa and 4508C based on (a) the ideal-gas equation, (b) the generalized compressibility chart, and (c) the steam tables. Determine the error involved in the first two cases.

Somebody claims that oxygen gas at 160 K and 3 MPa can be treated as an ideal gas with an error of less than 10 percent. Is this claim valid?

Ethane in a rigid vessel is to be heated from 50 psia and 1008F until its temperature is 5408F. What is the final pressure of the ethane as predicted by the compressibility chart?

Ethylene is heated at constant pressure from 5 MPa and 208C to 2008C. Using the compressibility chart, determine the change in the ethylenes specific volume as a result of this heating.

What is the percentage of error involved in treating carbon dioxide at 7 MPa and 380 K as an ideal gas?

Saturated water vapor at 3508C is heated at constant pressure until its volume has doubled. Determine the final temperature using the ideal gas equation of state, the compressibility charts, and the steam tables.

Methane at 10 MPa and 300 K is heated at constant pressure until its volume has increased by 80 percent. Determine the final temperature using the ideal gas equation of state and the compressibility factor. Which of these two results is more accurate?

Carbon dioxide gas enters a pipe at 3 MPa and 500 K at a rate of 2 kg/s. CO2 is cooled at constant pressure as it flows in the pipe and the temperature of CO2 drops to 450 K at the exit. Determine the volume flow rate and the density of carbon dioxide at the inlet and the volume flow rate at the exit of the pipe using (a) the ideal-gas equation and (b) the generalized compressibility chart. Also, determine (c) the error involved in the first case.

A 0.016773-m3 tank contains 1 kg of refrigerant-134a at 1108C. Determine the pressure of the refrigerant, using (a) the ideal-gas equation, (b) the generalized compressibility chart, and (c) the refrigerant tables.

What is the physical significance of the two constants that appear in the van der Waals equation of state? On what basis are they determined?

A 3.27-m3 tank contains 100 kg of nitrogen at 175 K. Determine the pressure in the tank, using (a) the ideal-gas equation, (b) the van der Waals equation, and (c) the BeattieBridgeman equation. Compare your results with the actual value of 1505 kPa.

Methane is heated in a rigid container from 80 kPa and 208C to 3008C. Determine the final pressure of the methane treating it as (a) an ideal gas and (b) a Benedict-WebbRubin gas.

Refrigerant-134a at 400 psia has a specific volume of 0.1144 ft3 /lbm. Determine the temperature of the refrigerant based on (a) the ideal-gas equation, (b) the van der Waals equation, and (c) the refrigerant tables.

Nitrogen at 150 K has a specific volume of 0.041884 m3 /kg. Determine the pressure of the nitrogen, using (a) the ideal-gas equation and (b) the BeattieBridgeman equation. Compare your results to the experimental value of 1000 kPa.

Reconsider Prob. 397. Using EES (or other) software, compare the pressure results of the ideal-gas and Beattie-Bridgeman equations with nitrogen data supplied by EES. Plot temperature versus specific volume for a pressure of 1000 kPa with respect to the saturated liquid and saturated vapor lines of nitrogen over the range of 110 K , T , 150 K.

1-kg of carbon dioxide is compressed from 1 MPa and 2008C to 3 MPa in a piston-cylinder device arranged to execute a polytropic process for which PV 1.2 5 constant. Determine the final temperature treating the carbon dioxide as (a) an ideal gas and (b) a van der Waals gas.

A 1-m3 tank contains 2.841 kg of steam at 0.6 MPa. Determine the temperature of the steam, using (a) the idealgas equation, (b) the van der Waals equation, and (c) the steam tables.

Reconsider Prob. 3-100. Solve the problem using EES (or other) software. Again using the EES, compare the temperature of water for the three cases at constant specific volume over the pressure range of 0.1 MPa to 1 MPa in 0.1 MPa increments. Plot the percent error involved in the ideal-gas approximation against pressure, and discuss the results.

During a hot summer day at the beach when the air temperature is 308C, someone claims the vapor pressure in the air to be 5.2 kPa. Is this claim reasonable?

Consider a glass of water in a room that is at 208C and 40 percent relative humidity. If the water temperature is 158C, determine the vapor pressure (a) at the free surface of the water and (b) at a location in the room far from the glass.

On a certain day, the temperature and relative humidity of air over a large swimming pool are measured to be 258C and 60 percent, respectively. Determine the water temperature of the pool when phase equilibrium conditions are established between the water in the pool and the vapor in the air.

During a hot summer day when the air temperature is 358C and the relative humidity is 70 percent, you buy a supposedly cold canned drink from a store. The store owner claims that the temperature of the drink is below 108C. Yet the drink does not feel so cold and you are skeptical since you notice no condensation forming outside the can. Can the store owner be telling the truth?

Consider two rooms that are identical except that one is maintained at 258C and 40 percent relative humidity while the other is maintained at 208C and 55 percent relative humidity. Noting that the amount of moisture is proportional to the vapor pressure, determine which room contains more moisture.

A thermos bottle is half-filled with water and is left open to the atmospheric air at 608F and 35 percent relative humidity. If heat transfer to the water through the thermos walls and the free surface is negligible, determine the temperature of water when phase equilibrium is established.

Water in a pressure cooker is observed to boil at 2608F. What is the absolute pressure in the pressure cooker, in psia?

Carbon-dioxide gas at 3 MPa and 500 K flows steadily in a pipe at a rate of 0.4 kmol/s. Determine (a) the volume and mass flow rates and the density of carbon dioxide at this state. If CO2 is cooled at constant pressure as it flows in the pipe so that the temperature of CO2 drops to 450 K at the exit of the pipe, determine (b) the volume flow rate at the exit of the pipe.

A tank contains argon at 6008C and 200 kPa gage. The argon is cooled in a process by heat transfer to the surroundings such that the argon reaches a final equilibrium state at 3008C. Determine the final gage pressure of the argon. Assume atmospheric pressure is 100 kPa.

The combustion in a gasoline engine may be approximated by a constant volume heat addition process. There exists the airfuel mixture in the cylinder before the combustion and the combustion gases after it, and both may be approximated as air, an ideal gas. In a gasoline engine, the cylinder conditions are 1.2 MPa and 4508C before the combustion and 17508C after it. Determine the pressure at the end of the combustion process.

One kilogram of R-134a fills a 0.090 m3 rigid container at an initial temperature of 2408C. The container is then heated until the pressure is 280 kPa. Determine the initial pressure and final temperature.

A rigid tank with a volume of 0.117 m3 contains 1 kg of refrigerant-134a vapor at 240 kPa. The refrigerant is now allowed to cool. Determine the pressure when the refrigerant first starts condensing. Also, show the process on a P-v diagram with respect to saturation lines.

One pound-mass of water fills a 2.649 ft3 weighted piston-cylinder device at a temperature of 4008F. The pistoncylinder device is now cooled until its temperature is 1008F. Determine the final pressure and volume of the water.

Ethane at 10 MPa and 1008C is heated at constant pressure until its volume has increased by 60 percent. Determine the final temperature using (a) the ideal gas equation of state and (b) the compressibility factor. Which of these two results is the more accurate?

A 13-m3 tank contains nitrogen at 178C and 600 kPa. Some nitrogen is allowed to escape until the pressure in the tank drops to 400 kPa. If the temperature at this point is 158C, determine the amount of nitrogen that has escaped.

A 10-kg mass of superheated refrigerant-134a at 1.2 MPa and 708C is cooled at constant pressure until it exists as a compressed liquid at 208C. (a) Show the process on a T-v diagram with respect to saturation lines. (b) Determine the change in volume. (c) Find the change in total internal energy.

A 4-L rigid tank contains 2 kg of saturated liquid vapor mixture of water at 508C. The water is now slowly heated until it exists in a single phase. At the final state, will the water be in the liquid phase or the vapor phase? What would your answer be if the volume of the tank were 400 L instead of 4 L?

The gage pressure of an automobile tire is measured to be 200 kPa before a trip and 220 kPa after the trip at a location where the atmospheric pressure is 90 kPa. Assuming the volume of the tire remains constant at 0.035 m3 , determine the percent increase in the absolute temperature of the air in the tire.

A piston-cylinder device initially contains 0.2 kg of steam at 200 kPa and 3008C. Now, the steam is cooled at constant pressure until it is at 1508C. Determine the volume change of the cylinder during this process using the compressibility factor and compare the result to the actual value.

Steam at 4008C has a specific volume of 0.02 m3 /kg. Determine the pressure of the steam based on (a) the idealgas equation, (b) the generalized compressibility chart, and (c) the steam tables.

A tank whose volume is unknown is divided into two parts by a partition. One side of the tank contains 0.03 m3 of refrigerant-134a that is a saturated liquid at 0.9 MPa, while the other side is evacuated. The partition is now removed, and the refrigerant fills the entire tank. If the final state of the refrigerant is 208C and 280 kPa, determine the volume of the tank.

Reconsider Prob. 3122. Using EES (or other) software, investigate the effect of the initial pressure of refrigerant-134a on the volume of the tank. Let the initial pressure vary from 0.5 to 1.5 MPa. Plot the volume of the tank versus the initial pressure, and discuss the results.

Liquid propane is commonly used as a fuel for heating homes, powering vehicles such as forklifts, and filling portable picnic tanks. Consider a propane tank that initially contains 5 L of liquid propane at the environment temperature of 208C. If a hole develops in the connecting tube of a propane tank and the propane starts to leak out, determine the temperature of propane when the pressure in the tank drops to 1 atm. Also, determine the total amount of heat transfer from the environment to the tank to vaporize the entire propane in the tank.

Repeat Prob. 3124 for isobutane.

A tank contains helium at 378C and 140 kPa gage. The helium is heated in a process by heat transfer from the surroundings such that the helium reaches a final equilibrium state at 2008C. Determine the final gage pressure of the helium. Assume atmospheric pressure is 100 kPa.

If sufficient data are provided, complete the blank cells in the following table of properties of water. In the last column describe the condition of water as compressed liquid, saturated mixture, superheated vapor, or insufficient information; and, if applicable, give the quality.

Water initially at 300 kPa and 0.5 m3 /kg is contained in a piston-cylinder device fitted with stops so that the water supports the weight of the piston and the force of the atmosphere. The water is heated until it reaches the saturated vapor state and the piston rests against the stops. With the piston against the stops, the water is further heated until the pressure is 600 kPa. On the P-v and T-v diagrams sketch, with respect to the saturation lines, the process curves passing through both the initial and final states of the water. Label the states on the process as 1, 2, and 3. On both the P-v and T-v diagrams, sketch the isotherms passing through the states and show their values, in 8C, on the isotherms.

0.5-lbm of argon is compressed from 1000 psia and 3008F to 2000 psia in a piston-cylinder device which executes a polytropic process for which PV1.6 5 constant. Determine the final temperature treating the argon as (a) an ideal gas and (b) a Beattie-Bridgeman gas.

Nitrogen is maintained at 400 psia and 21008F. Compare the specific volume of this nitrogen as predicted by (a) the ideal gas equation of state, (b) the Benedict-WebbRubin equation of state, and (c) with the compressibility factor.

Although balloons have been around since 1783 when the first balloon took to the skies in France, a real breakthrough in ballooning occurred in 1960 with the design of the modern hot-air balloon fueled by inexpensive propane and constructed of lightweight nylon fabric. Over the years, ballooning has become a sport and a hobby for many people around the world. Unlike balloons filled with the light helium gas, hot-air balloons are open to the atmosphere. Therefore, the pressure in the balloon is always the same as the local atmospheric pressure, and the balloon is never in danger of exploding. Hot-air balloons range from about 15 to 25 m in diameter. The air in the balloon cavity is heated by a propane burner located at the top of the passenger cage. The flames from the burner that shoot into the balloon heat the air in the balloon cavity, raising the air temperature at the top of the balloon from 658C to over 1208C. The air temperature is maintained at the desired levels by periodically firing the propane burner. The buoyancy force that pushes the balloon upward is proportional to the density of the cooler air outside the balloon and the volume of the balloon, and can be expressed as FB 5 rcool air gVballoon where g is the gravitational acceleration. When air resistance is negligible, the buoyancy force is opposed by (1) the weight of the hot air in the balloon, (2) the weight of the cage, the ropes, and the balloon material, and (3) the weight of the people and other load in the cage. The operator of the balloon can control the height and the vertical motion of the balloon by firing the burner or by letting some hot air in the balloon escape, to be replaced by cooler air. The forward motion of the balloon is provided by the winds. Consider a 20-m-diameter hot-air balloon that, together with its cage, has a mass of 80 kg when empty. This balloon is hanging still in the air at a location where the atmospheric pressure and temperature are 90 kPa and 158C, respectively, while carrying three 65-kg people. Determine the average temperature of the air in the balloon. What would your response be if the atmospheric air temperature were 308C?

Reconsider Prob. 3-131. Using EES (or other) software, investigate the effect of the environment temperature on the average air temperature in the balloon when the balloon is suspended in the air. Assume the environment temperature varies from 210 to 308C. Plot the average air temperature in the balloon versus the environment temperature, and discuss the results. Investigate how the number of people carried affects the temperature of the air in the balloon.

Consider an 18-m-diameter hot-air balloon that, together with its cage, has a mass of 120 kg when empty. The air in the balloon, which is now carrying two 70-kg people, is heated by propane burners at a location where the atmo spheric pressure and temperature are 93 kPa and 128C, respectively. Determine the average temperature of the air in the balloon when the balloon first starts rising. What would your response be if the atmospheric air temperature were 258C?

A 300-m3 rigid tank is filled with saturated liquid vapor mixture of water at 200 kPa. If 25 percent of the mass is liquid and 75 percent of the mass is vapor, the total mass in the tank is (a) 451 kg (b) 556 kg (c) 300 kg (d) 331 kg (e) 195 kg

Water is boiled at 1 atm pressure in a coffee maker equipped with an immersion-type electric heating element. The coffee maker initially contains 1 kg of water. Once boiling started, it is observed that half of the water in the coffee maker evaporated in 10 minutes. If the heat loss from the coffee maker is negligible, the power rating of the heating element is (a) 3.8 kW (b) 2.2 kW (c) 1.9 kW (d) 1.6 kW (e) 0.8 kW

A 1-m3 rigid tank contains 10 kg of water (in any phase or phases) at 1608C. The pressure in the tank is (a) 738 kPa (b) 618 kPa (c) 370 kPa (d) 2000 kPa (e) 1618 kPa

Water is boiling at 1 atm pressure in a stainless steel pan on an electric range. It is observed that 2 kg of liquid water evaporates in 30 min. The rate of heat transfer to the water is (a) 2.51 kW (b) 2.32 kW (c) 2.97 kW (d) 0.47 kW (e) 3.12 kW

Water is boiled in a pan on a stove at sea level. During 10 min of boiling, it is observed that 200 g of water has evaporated. Then the rate of heat transfer to the water is (a) 0.84 kJ/min (b) 45.1 kJ/min (c) 41.8 kJ/min (d) 53.5 kJ/min (e) 225.7 kJ/min

A 3-m3 rigid vessel contains steam at 4 MPa and 5008C. The mass of the steam is (a) 3 kg (b) 9 kg (c) 26 kg (d) 35 kg (e) 52 kg

Consider a sealed can that is filled with refrigerant- 134a. The contents of the can are at the room temperature of 258C. Now a leak develops, and the pressure in the can drops to the local atmospheric pressure of 90 kPa. The temperature of the refrigerant in the can is expected to drop to (rounded to the nearest integer) (a) 08C (b) 2298C (c) 2168C (d) 58C (e) 258C

A rigid tank contains 2 kg of an ideal gas at 4 atm and 408C. Now a valve is opened, and half of mass of the gas is allowed to escape. If the final pressure in the tank is 2.2 atm, the final temperature in the tank is (a) 718C (b) 448C (c) 21008C (d) 208C (e) 1728C

The pressure of an automobile tire is measured to be 190 kPa (gage) before a trip and 215 kPa (gage) after the trip at a location where the atmospheric pressure is 95 kPa. If the temperature of air in the tire before the trip is 258C, the air temperature after the trip is (a) 51.18C (b) 64.28C (c) 27.28C (d) 28.38C (e) 25.08C

In an article on tire maintenance, it is stated that tires lose air over time, and pressure losses as high as 90 kPa (13 psi) per year are measured. The article recommends checking tire pressure at least once a month to avoid low tire pressure that hurts fuel efficiency and causes uneven thread wear on tires. Taking the beginning tire pressure to be 220 kPa (gage) and the atmospheric pressure to be 100 kPa, determine the fraction of air that can be lost from a tire per year.

It is well known that water freezes at 08C at atmospheric pressure. The mixture of liquid water and ice at 08C is said to be at stable equilibrium since it cannot undergo any changes when it is isolated from its surroundings. However, when water is free of impurities and the inner surfaces of the container are smooth, the temperature of water can be lowered to 228C or even lower without any formation of ice at atmospheric pressure. But at that state even a small disturbance can initiate the formation of ice abruptly, and the water temperature stabilizes at 08C following this sudden change. The water at 228C is said to be in a metastable state. Write an essay on metastable states and discuss how they differ from stable equilibrium states.

A solid normally absorbs heat as it melts, but there is a known exception at temperatures close to absolute zero. Find out which solid it is and give a physical explanation for it.