Thermodynamics: An Engineering Approach

Yunus A. Cengel, Michael A. Boles

Chapter 3

Properties of Pure Substances - all with Video Answers

Educators

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Chapter Questions

Problem 1

A propane tank is filled with a mixture of liquid and vapor propane. Can the contents of this tank be considered a pure substance? Explain.

Khoobchandra Agrawal

Khoobchandra Agrawal

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Problem 2

Is iced water a pure substance? Why?

Mayukh Banik

Numerade Educator

Problem 3

What is the difference between saturated vapor and superheated vapor?

Mayukh Banik

Numerade Educator

Problem 4

What is the difference between saturated liquid and compressed liquid?

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 5

If the pressure of a substance is increased during a boiling process, will the temperature also increase or will it remain constant? Why?

Khoobchandra Agrawal

Khoobchandra Agrawal

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Problem 6

Is it true that water boils at higher temperature at higher pressure? Explain.

Mayukh Banik

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Problem 7

What is the difference between the critical point and the triple point?

Mayukh Banik

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Problem 8

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?

Mayukh Banik

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Problem 9

How does a boiling process at supercritical pressures differ from the boiling process at subcritical pressures?

Khoobchandra Agrawal

Khoobchandra Agrawal

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Problem 10

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

Mayukh Banik

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Problem 11

Does the amount of heat absorbed as $1 \mathrm{~kg}$ of saturated liquid water boils at $100^{\circ} \mathrm{C}$ have to be equal to the amount of heat released as $1 \mathrm{~kg}$ of saturated water vapor condenses at $100^{\circ} \mathrm{C} ?$

Mayukh Banik

Numerade Educator

Problem 12

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

Mayukh Banik

Numerade Educator

Problem 13

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

Mayukh Banik

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Problem 14

Does $h_{f g}$ change with pressure? How?

Mayukh Banik

Numerade Educator

Problem 15

Is it true that it takes more energy to vaporize $1 \mathrm{~kg}$ of saturated liquid water at $100^{\circ} \mathrm{C}$ than it would at $120^{\circ} \mathrm{C} ?$

Mayukh Banik

Numerade Educator

Problem 16

Which process requires more energy: completely vaporizing $1 \mathrm{~kg}$ of saturated liquid water at 1 atm pressure or completely vaporizing $1 \mathrm{~kg}$ of saturated liquid water at $8 \mathrm{~atm}$ pressure?

Mayukh Banik

Numerade Educator

Problem 17

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.

Mayukh Banik

Numerade Educator

Problem 18

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?

Mayukh Banik

Numerade Educator

Problem 19

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

Mayukh Banik

Numerade Educator

Problem 20

A perfectly fitting pot and its lid often stick after cooking, and it becomes very difficult to open the lid when the pot cools down. Explain why this happens and what you would do to open the lid.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 21

Complete this table for $\mathrm{H}_{2} \mathrm{O}$ :
$$
\begin{array}{lccc}
\hline T,{ }^{\circ} \mathrm{C} & P, \mathrm{kPa} & u, \mathrm{~kJ} / \mathrm{kg} & \text { Phase description } \\
\hline & 400 & 1450 & \\
220 & & & \text { Saturated vapor } \\
190 & 2500 & & \\
& 4000 & 3040 & \\
\hline
\end{array}
$$

Mayukh Banik

Numerade Educator

Problem 22

Complete this table for $\mathrm{H}_{2} \mathrm{O}$ :
$$
\begin{array}{lccc}
\hline T,{ }^{\circ} \mathrm{C} & P, \mathrm{kPa} & \cup, \mathrm{m}^{3} / \mathrm{kg} & \text { Phase description } \\
\hline 140 & & 0.035 & \\
& 550 & & \text { Saturated liquid } \\
125 & 750 & & \\
300 & & 0.140 & \\
\hline
\end{array}
$$

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 23

Complete this table for $\mathrm{H}_{2} \mathrm{O}$
$$
\begin{array}{lccl}
\hline T,{ }^{\circ} \mathrm{F} & P \text { , psia } & u \text { , Btu/lbm } & \text { Phase description } \\
\hline 300 & & 782 & \\
& 40 & & \text { Saturated liquid } \\
500 & 120 & & \\
400 & 400 & &
\end{array}
$$

Mayukh Banik

Numerade Educator

Problem 24

Using appropriate software, determine the missing properties of water. Repeat the solution for refrigerant-134a, refrigerant- 22 and ammonia.

Khoobchandra Agrawal

Khoobchandra Agrawal

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Problem 25

Complete this table for $\mathrm{H}_{2} \mathrm{O}$ :
$$
\begin{array}{cccc}
\hline T,{ }^{\circ} \mathrm{C} & P, \mathrm{kPa} & h, \mathrm{~kJ} / \mathrm{kg} & x & \text { Phase description } \\
\hline & 200 & & 0.7 & \\
140 & & 1800 & & \\
& 950 & & 0.0 & \\
80 & 500 & & & \\
& 800 & 3162.2 & &
\end{array}
$$

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 26

Complete this table for refrigerant- $134 \mathrm{a}$ :
$$
\begin{array}{ccccc}
\hline T,{ }^{\circ} \mathrm{F} & P \text { , psia } & h \text { , Btu/lbm } & x & \text { Phase description } \\
\hline & 80 & 78 & & \\
15 & & & 0.6 & \\
10 & 70 & & & \\
& 180 & 129.46 & & \\
110 & & & 1.0 & \\
\hline
\end{array}
$$

Mayukh Banik

Numerade Educator

Problem 27

Complete this table for refrigerant-134a:
$$
\begin{array}{cccc}
\hline T,{ }^{\circ} \mathrm{C} & P, \mathrm{kPa} & u, \mathrm{~kJ} / \mathrm{kg} & \text { Phase description } \\
\hline 20 & & 95 & \\
-12 & & & \text { Saturated liquid } \\
& 400 & 300 & \\
8 & 600 & & \\
\hline
\end{array}
$$

Prabhat Tyagi

Numerade Educator

Problem 28

A $1.8-\mathrm{m}^{3}$ 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.

Anand Jangid

Numerade Educator

Problem 29

One pound-mass of water fills a container whose volume is $2 \mathrm{ft}^{3} .$ The pressure in the container is 100 psia. Calculate the total internal energy and enthalpy in the container.

Khoobchandra Agrawal

Khoobchandra Agrawal

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Problem 30

A piston-cylinder device contains $0.85 \mathrm{~kg}$ of refrigerant$134 a$ 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 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- $134 \mathrm{a} .$

Nicholas Mogoi

Numerade Educator

Problem 31

$10 \mathrm{~kg}$ of $\mathrm{R}-134 \mathrm{a}$ fill a $1.115-\mathrm{m}^{3}$ rigid container at an initial temperature of $-30^{\circ} \mathrm{C}$. The container is then heated until the pressure is $200 \mathrm{kPa}$. Determine the final temperature and the initial pressure.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 32

What is the specific internal energy of water at $50 \mathrm{kPa}$ and $200^{\circ} \mathrm{C}$ ?

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 33

What is the specific volume of water at $5 \mathrm{MPa}$ and $100^{\circ} \mathrm{C}$ ? What would it be if the incompressible liquid approximation were used? Determine the accuracy of this approximation.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 34

What is the specific volume of $\mathrm{R}-134 \mathrm{a}$ at $20^{\circ} \mathrm{C}$ and $700 \mathrm{kPa} ?$ What is the internal energy at that state?

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 35

Refrigerant-134a at $200 \mathrm{kPa}$ and $25^{\circ} \mathrm{C}$ flows through a refrigeration line. Determine its specific volume.

Mayukh Banik

Numerade Educator

Problem 36

One kilogram of R-134a fills a 0.14 -m $^{3}$ weighted piston-cylinder device at a temperature of $-26.4^{\circ} \mathrm{C}$. The container is now heated until the temperature is $100^{\circ} \mathrm{C}$. Determine the final volume of the R-134a.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 37

One kilogram of water vapor at $200 \mathrm{kPa}$ fills the $1.1989-\mathrm{m}^{3}$ left chamber of a partitioned system shown in Fig. $\mathrm{P} 3-37 .$ The right chamber has twice the volume of the left and is initially evacuated. Determine the pressure of the water after the partition has been removed and enough heat has been transferred so that the temperature of the water is $3^{\circ} \mathrm{C}$.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 38

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?

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 39

How much error would one expect in determining the specific enthalpy by applying the incompressible-liquid approximation to water at 3000 psia and $400^{\circ} \mathrm{F} ?$

Mayukh Banik

Numerade Educator

Problem 40

Water is to be boiled at sea level in a 30-cm-diameter stainless steel pan placed on top of a $3-\mathrm{kW}$ 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

Mayukh Banik

Numerade Educator

Problem 41

Repeat Prob. $3-40$ for a location at an elevation of $1500 \mathrm{~m}$ where the atmospheric pressure is $84.5 \mathrm{kPa}$ and thus the boiling temperature of water is $95^{\circ} \mathrm{C}$.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 42

$10 \mathrm{~kg}$ of $\mathrm{R}-134 \mathrm{a}$ 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 eating ic comnleted $d$

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 43

$100 \mathrm{~kg}$ of $\mathrm{R}-134 \mathrm{a}$ at $200 \mathrm{kPa}$ are contained in a piston-cylinder device whose volume $1 \mathrm{~s} 12.322 \mathrm{~m}^{3} .$ 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 $\mathrm{R}-134 \mathrm{a}$.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 44

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 $T$ -u diagram, sketch, with respect to the saturation lines, the process curves passing through the initial, intermediate, and final states of the water. Label the $T, P,$ and $\cup$ 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.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 45

Saturated steam coming off the turbine of a steam power plant at $40^{\circ} \mathrm{C}$ condenses on the outside of a $3-\mathrm{cm}$ -outerdiameter, $35-\mathrm{m}$ -long tube at a rate of $70 \mathrm{~kg} / \mathrm{h}$. Determine the rate of heat transfer from the steam to the cooling water flowing through the pipe.

Suman Saurav Thakur

Suman Saurav Thakur

Numerade Educator

Problem 46

A person cooks a meal in a 30 -cm-diameter pot that is covered with a well-fitting lid and lets the food cool to the room temperature of $20^{\circ} \mathrm{C}$. The total mass of the food and the pot is $8 \mathrm{~kg}$. Now the person tries to open the pan by lifting the lid up. Assuming no air has leaked into the pan during cooling, determine if the lid will open or if the pan will move up together with the lid.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 47

Water is boiled at 1 atm pressure in a 25 -cm-internaldiameter stainless steel pan on an electric range. If it is observed that the water level in the pan drops by $10 \mathrm{~cm}$ in 45 min, determine the rate of heat transfer to the pan.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 48

Repeat Prob. 3-47 for a location at 2000 -m elevation where the standard atmospheric pressure is $79.5 \mathrm{kPa}$.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 49

Water is boiled in a pan covered with a poorly fitting lid at a specified location. Heat is supplied to the pan by a $2-\mathrm{kW}$ resistance heater. The amount of water in the pan is observed to decrease by $1.19 \mathrm{~kg}$ in $30 \mathrm{~min}$. 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. Answer: $85.4 \mathrm{kPa}$

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 50

A rigid tank with a volume of $1.8 \mathrm{~m}^{3}$ contains $40 \mathrm{~kg}$ of saturated liquid-vapor mixture of water at $90^{\circ} \mathrm{C} .$ 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 $T$ -u diagram with respect to saturation lines.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 51

A piston-cylinder device contains $0.005 \mathrm{~m}^{3}$ of liquid water and $0.9 \mathrm{~m}^{3}$ of water vapor in equilibrium 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 $P$ -U diagram with respect to saturation lines.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 52

Appropriate 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. $3-51$ on a $P$ -U diagram using the property plot feature of the software.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 53

A $5-\mathrm{ft}^{3}$ rigid tank contains a saturated mixture of refrigerant-134a 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.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 54

Superheated water vapor at 180 psia and $500^{\circ} \mathrm{F}$ is allowed to cool at constant volume until the temperature drops to $250^{\circ} \mathrm{F}$. At the final state, determine $(a)$ the pressure, $(b)$ the quality, and $(c)$ the enthalpy. Also, show the process on a $T-U$ diagram with respect to saturation lines.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 55

Reconsider Prob. 3-54E. Using appropriate software, investigate the effect of initial pressure on the quality of water at the final state. Let the pressure vary from 100 psia to 300 psia. Plot the quality against initial pressure, and discuss the results. Also, show the process in Prob. $3-54 \mathrm{E}$ on a $T-U$ diagram using the property plot feature of the software.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 56

One kilogram of water fills a 150-L rigid container at an initial pressure of $2 \mathrm{MPa}$. The container is then cooled to $40^{\circ} \mathrm{C}$. Determine the initial temperature and the final pressure of the water.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 57

$10 \mathrm{~kg}$ of $\mathrm{R}-134 \mathrm{a}$ fill a $0.7-\mathrm{m}^{3}$ weighted piston-cylinder device at a pressure of $200 \mathrm{kPa}$. The container is now heated until the temperature is $30^{\circ} \mathrm{C}$. Determine the initial temperature and final volume of the R-134a.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 58

A piston-cylinder device contains $0.6 \mathrm{~kg}$ of steam at $300^{\circ} \mathrm{C}$ and $0.5 \mathrm{MPa}$. 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.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 59

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 cylinder, $(b)$ the final temperature and pressure, and $(c)$ the internal energy change of the water.

Anand Jangid

Numerade Educator

Problem 60

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.

Mayukh Banik

Numerade Educator

Problem 61

A rigid tank initially contains 1.4 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.

Mayukh Banik

Numerade Educator

Problem 62

A piston-cylinder device initially contains $50 \mathrm{~L}$ of liquid water at $40^{\circ} \mathrm{C}$ and $200 \mathrm{kPa}$. 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 $T$ -U diagram with respect to

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 63

The spring-loaded piston-cylinder device shown in Fig. $\mathrm{P} 3-63$ is filled with $0.5 \mathrm{~kg}$ of water vapor that is initially at $4 \mathrm{MPa}$ and $400^{\circ} \mathrm{C}$. Initially, the spring exerts no force against the piston. The spring constant in the spring force relation $F=k x$ is $k=0.9 \mathrm{kN} / \mathrm{cm}$ and the piston diameter is $D=20 \mathrm{~cm} .$ The water now undergoes a process until its volume is one-half of the original volume. Calculate the final temperature and the specitic enthalpy of the water.

Penny Riley

Numerade Educator

Problem 64

A piston-cylinder device initially contains steam at 3.5 MPa, superheated by $5^{\circ} \mathrm{C} .$ Now, steam loses heat to the surroundings and the piston moves down, hitting a set of stops, at which point the cylinder contains saturated liquid water. The cooling continues until the cylinder contains water at $200^{\circ} \mathrm{C}$. Determine $(a)$ the initial temperature, $(b)$ the enthalpy change per unit mass of the steam by the time the piston first hits the stops, and $(c)$ the final pressure and the quality (if mixture).

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 65

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

Mayukh Banik

Numerade Educator

Problem 66

What is the difference between mass and molar mass? How are these two related?

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 67

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.

Mayukh Banik

Numerade Educator

Problem 68

What is the specific volume of oxygen at 25 psia and $80^{\circ} \mathrm{F} ?$

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 69

A 100 - $L$ container is filled with $1 \mathrm{~kg}$ of air at a temperature of $27^{\circ} \mathrm{C}$. What is the pressure in the container?

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 70

A mass of 1 lbm of argon is maintained at 200 psia and $100^{\circ} \mathrm{F}$ in a tank. What is the volume of the tank?

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 71

A 400 - $L$ rigid tank contains $5 \mathrm{~kg}$ of air at $25^{\circ} \mathrm{C}$. Determine the reading on the pressure gage if the atmospheric pressure is 97 kPa.

Mayukh Banik

Numerade Educator

Problem 72

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 $97 \mathrm{kPa}$.

Mayukh Banik

Numerade Educator

Problem 73

A spherical balloon with a diameter of $9 \mathrm{~m}$ is filled with helium at $27^{\circ} \mathrm{C}$ and $200 \mathrm{kPa}$. Determine the mole number and the mass of the helium in the balloon.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 74

Reconsider Prob. 3-73. Using appropriate 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.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 75

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 $150 \mathrm{kPa}$. 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.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 76

A mass of $10 \mathrm{~g}$ of oxygen fill a weighted pistoncylinder device at $20 \mathrm{kPa}$ and $100^{\circ} \mathrm{C}$. The device is now cooled until the temperature is $0^{\circ} \mathrm{C}$. Determine the change of the volume of the device during this cooling.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 77

A mass of $0.1 \mathrm{~kg}$ of helium fills a $0.2 \mathrm{~m}^{3}$ rigid vessel at $350 \mathrm{kPa}$. The vessel is heated until the pressure is $700 \mathrm{kPa}$. Calculate the temperature change of helium (in ${ }^{\circ} \mathrm{C}$ and $\mathrm{K}$ ) as a result of this heating.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 78

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 transferred to the gas until the pressure equals the initial pressure. Determine the final temperature of the gas.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 79

A rigid tank contains 20 lbm of air at 20 psia and $70^{\circ} \mathrm{F}$. More air is added to the tank until the pressure and temperature rise to 25 psia and $90^{\circ} \mathrm{F}$, respectively. Determine the amount of air added to the tank.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 80

In an informative article in a magazine it is stated that tires lose roughly 1 psi of pressure for every $10^{\circ} \mathrm{F}$ drop in outside temperature. Investigate whether this is a valid statement.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 81

What is the physical significance of the compressibility factor $Z ?$

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 82

Determine the specific volume of refrigerant-134a vapor at $0.9 \mathrm{MPa}$ and $70^{\circ} \mathrm{C}$ based on $(a)$ the ideal-gas equation, (b) the generalized compressibility chart, and (c) data from tables. Also, determine the error involved in the first two cases.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 83

Refrigerant-134a at 400 psia has a specific volume of $0.1384 \mathrm{ft}^{3} / \mathrm{lbm} .$ Determine the temperature of the refrigerant based on $(a)$ the ideal-gas equation, $(b)$ the generalized compressibility chart, and $(c)$ the refrigerant tables.

Mayukh Banik

Numerade Educator

Problem 84

Determine the specific volume of superheated water vapor at $15 \mathrm{MPa}$ and $350^{\circ} \mathrm{C}$ 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.

Mayukh Banik

Numerade Educator

Problem 85

Reconsider Prob. 3-84. Solve the problem using appropriate software. Compare the specific volume of water for the three cases at 15 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.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 86

Determine the specific volume of superheated water vapor at $3.5 \mathrm{MPa}$ and $450^{\circ} \mathrm{C}$ 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.

Mayukh Banik

Numerade Educator

Problem 87

Determine the specific volume of nitrogen gas at $10 \mathrm{MPa}$ and $150 \mathrm{~K}$ based on $(a)$ the idea-gas equation and (b) the generalized compressibility chart. Compare these results with the experimental value of $0.002388 \mathrm{~m}^{3} / \mathrm{kg}$, and determine the error involved in each case.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 88

Ethylene is heated at constant pressure from 5 MPa and $20^{\circ} \mathrm{C}$ to $200^{\circ} \mathrm{C}$. Using the compressibility chart, determine the change in the ethylene's specific volume as a result of this heating.

Mayukh Banik

Numerade Educator

Problem 89

Carbon dioxide gas enters a pipe at 3 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 the $\mathrm{CO}_{2}$ 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.

Susan Hallstrom

Susan Hallstrom

Numerade Educator

Problem 90

Ethane in a rigid vessel is to be heated from $50 \mathrm{psia}$ and $100^{\circ} \mathrm{F}$ until its temperature is $540^{\circ} \mathrm{F}$. What is the final pressure of the ethane as predicted by the compressibility chart?

Mayukh Banik

Numerade Educator

Problem 91

A $0.016773-\mathrm{m}^{3}$ tank contains $1 \mathrm{~kg}$ of refrigerant- $134 \mathrm{a}$ 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.

Mayukh Banik

Numerade Educator

Problem 92

Saturated water vapor at $400^{\circ} \mathrm{F}$ 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.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 93

What is the percentage of error involved in treating carbon dioxide at $5 \mathrm{MPa}$ and $25^{\circ} \mathrm{C}$ as an ideal gas?

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 94

What is the percentage of error involved in treating carbon dioxide at $5 \mathrm{MPa}$ and $25^{\circ} \mathrm{C}$ as an ideal gas?

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 95

Refrigerant-134a at 400 psia has a specific volume of $0.1144 \mathrm{ft}^{3} / \mathrm{lbm} .$ Determine the temperature of the refrigerant based on $(a)$ the ideal-gas equation, $(b)$ the van der Waals equation, and $(c)$ the refrigerant tables.

Mayukh Banik

Numerade Educator

Problem 96

A $3.27-\mathrm{m}^{3}$ tank contains $100 \mathrm{~kg}$ of nitrogen at $175 \mathrm{~K}$. 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 $1505 \mathrm{kPa}$.

Mayukh Banik

Numerade Educator

Problem 97

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 Beattie-Bridgeman equation. Compare your results to the experimental value of 1000 kPa.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 98

Reconsider Prob. 3-97. Using appropriate software. compare the pressure results of the ideal-gas and Beattie-Bridgeman equations with nitrogen data supplied by the software. 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 $110 \mathrm{~K}<T<150 \mathrm{~K}$.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 99

100 grams of carbon monoxide are contained in a weighted piston-cylinder device. Initially the carbon monoxide is at $1000 \mathrm{kPa}$ and $200^{\circ} \mathrm{C} .$ It is then heated until its temperature is $500^{\circ} \mathrm{C}$. Determine the final volume of the carbon monoxide, treating it as $(a)$ an ideal gas and $(b)$ a BenedictWebb-Rubin gas.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 100

A $1-m^{3}$ tank contains $2.841 \mathrm{~kg}$ of steam at $0.6 \mathrm{MPa}$ Determine the temperature of the steam, using $(a)$ the ideal-gas equation, $(b)$ the van der Waals equation, and $(c)$ the steam tables.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 101

Reconsider Prob. 3-100. Solve the problem Ising appropriate software. Compare the temperature of water for the three cases at constant specific volume over the pressure range of $0.1 \mathrm{MPa}$ to $1 \mathrm{MPa}$ in 0.1 -MPa increments. Plot the percent error involved in the ideal-gas approximation against pressure, and discuss the results.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 102

1 lbm of carbon dioxide is heated in a constantpressure apparatus. Initially, the carbon dioxide is at 1000 psia and $200^{\circ} \mathrm{F}$, and it is heated until its temperature becomes $800^{\circ} \mathrm{F}$. Determine the final volume of the carbon dioxide, treating it as
(a) an ideal gas and ( $b$ ) a Benedict-Webb-Rubin gas.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 103

During a hot summer day at the beach when the air temperature is $30^{\circ} \mathrm{C}$, someone claims the vapor pressure in the air to be $5.2 \mathrm{kPa}$. Is this claim reasonable?

Mayukh Banik

Numerade Educator

Problem 104

Consider a glass of water in a room that is at $20^{\circ} \mathrm{C}$ and 40 percent relative humidity. If the water temperature is $15^{\circ} \mathrm{C},$ determine the vapor pressure $(a)$ at the free surface of the water and $(b)$ at a location in the room far from the glass.

Mayukh Banik

Numerade Educator

Problem 105

On a certain day, the temperature and relative humidity of air over a large swimming pool are measured to be $25^{\circ} \mathrm{C}$ 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.

Mayukh Banik

Numerade Educator

Problem 106

During a hot summer day when the air temperature is $35^{\circ} \mathrm{C}$ 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 $10^{\circ} \mathrm{C}$. 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?

Mayukh Banik

Numerade Educator

Problem 107

Consider two rooms that are identical except that one is maintained at $25^{\circ} \mathrm{C}$ and 40 percent relative humidity while the other is maintained at $20^{\circ} \mathrm{C}$ and 55 percent relative humidity. Noting that the amount of moisture is proportional to the vapor pressure, determine which room contains more moisture.

Mayukh Banik

Numerade Educator

Problem 108

A thermos bottle is half-filled with water and is left open to the atmospheric air at $60^{\circ} \mathrm{F}$ 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.

Mayukh Banik

Numerade Educator

Problem 109

Complete the blank cells in the following table of properties of steam. In the last column, describe the condition of steam as compressed liquid, saturated mixture, superheated vapor, or insufficient information, and, if applicable, give the quality.
$$
\begin{array}{lrlll}
\hline P, \mathrm{kPa} & T,{ }^{\circ} \mathrm{C} & \cup, \mathrm{m}^{3} / \mathrm{kg} & u, \mathrm{~kJ} / \mathrm{kg} & \begin{array}{l}
\text { Phase description and } \\
\text { quality (if applicable) }
\end{array} \\
& & & & \\
200 & 30 & & & \\
270.3 & 130 & & & \\
& 400 & 1.5493 & & \\
300 & & 0.500 & & \\
500 & & & 3084 & \\
\hline
\end{array}
$$

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 110

Complete the blank cells in the following table of properties of refrigerant-134a. In the last column, describe the condition of refrigerant-134a as compressed liquid, saturated mixture, superheated vapor, or insufficient information, and, if applicable, give the quality.
$$
\begin{array}{ccccc}
\hline P, \mathrm{kPa} & T,{ }^{\circ} \mathrm{C} & \cup, \mathrm{m}^{3} / \mathrm{kg} & u, \mathrm{~kJ} / \mathrm{kg} & \begin{array}{l}
\text { Phase description and } \\
\text { quality (if applicable) }
\end{array} \\
\hline 320 & -12 & & & \\
1000 & 39.37 & & & \\
& 40 & 1.17794 & & \\
180 & & 0.0700 & & \\
200 & & & 249 & \\
\hline
\end{array}
$$

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 111

A rigid tank contains an ideal gas at $300 \mathrm{kPa}$ and $600 \mathrm{~K}$. Now half of the gas is withdrawn from the tank and the gas is found at $100 \mathrm{kPa}$ at the end of the process. Determine $(a)$ the final temperature of the gas and $(b)$ the final pressure if no mass was withdrawn from the tank and the same final temperature was reached at the end of the process.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 112

Carbon dioxide gas at $3 \mathrm{MPa}$ and $500 \mathrm{~K}$ flows steadily in a pipe at a rate of $0.4 \mathrm{kmol} / \mathrm{s}$. 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.

Mayukh Banik

Numerade Educator

Problem 113

The gage pressure of an automobile tire is measured to be $200 \mathrm{kPa}$ before a trip and $220 \mathrm{kPa}$ after the trip at a location where the atmospheric pressure is $90 \mathrm{kPa}$. Assuming the volume of the tire remains constant at $0.035 \mathrm{~m}^{3}$, determine the percent increase in the absolute temperature of the air in the tire.

Mayukh Banik

Numerade Educator

Problem 114

A tank contains argon at $600^{\circ} \mathrm{C}$ and $200 \mathrm{kPa}$ gage. The argon is cooled in a process by heat transfer to the surroundings such that the argon reaches a final equilibrium state at $300^{\circ} \mathrm{C}$. Determine the final gage pressure of the argon. Assume atmospheric pressure is $100 \mathrm{kPa}$.

Mayukh Banik

Numerade Educator

Problem 115

The combustion in a gasoline engine may be approximated by a constant-volume heat addition process. The cylinder contains the air-fuel mixture before 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 $1900^{\circ} \mathrm{C}$
after it. Determine the pressure at the end of the combustion process.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 116

A rigid tank contains nitrogen gas at $227^{\circ} \mathrm{C}$ and 100 kPa gage. The gas is heated until the gage pressure reads $250 \mathrm{kPa}$. If the atmospheric pressure is $100 \mathrm{kPa}$, determine the final temperature of the gas, in ${ }^{\circ} \mathrm{C}$.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 117

One kilogram of $\mathrm{R}-134 \mathrm{a}$ fills a $0.090-\mathrm{m}^{3}$ rigid container at an initial temperature of $-40^{\circ} \mathrm{C}$. The container is then heated until the pressure is $280 \mathrm{kPa}$. Determine the initial pressure and final temperature.

Mayukh Banik

Numerade Educator

Problem 118

A rigid tank with a volume of $0.117 \mathrm{~m}^{3}$ contains $1 \mathrm{~kg}$ of refrigerant-134a vapor at $240 \mathrm{kPa}$. The refrigerant is now allowed to cool. Determine the pressure when the refrigerant first starts condensing. Also, show the process on a $P$ - $U$ diagram with respect to saturation lines.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 119

Water initially at $300 \mathrm{kPa}$ and $250^{\circ} \mathrm{C}$ is contained in a constant-volume tank. The water is allowed to cool until its pressure is $150 \mathrm{kPa}$. On the $P-U$ and $T$ -U diagrams, sketch, with respect to the saturation lines, the process curve passing through both the initial and final states of the water. Label the end states on the process curve. Also, on both the $P-U$ and $T-U$ diagrams, sketch the isotherms passing through both states and show their values, in ${ }^{\circ} \mathrm{C},$ on the isotherms.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 120

A $9-m^{3}$ tank contains nitrogen at $17^{\circ} \mathrm{C}$ and $600 \mathrm{kPa}$ Some nitrogen is allowed to escape until the pressure in the tank drops to $400 \mathrm{kPa}$. If the temperature at this point is $15^{\circ} \mathrm{C}$, determine the amount of nitrogen that has escaped. Answer: $20.6 \mathrm{~kg}$

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 121

A $10-\mathrm{kg}$ mass of superheated refrigerant-134a at 1.2 MPa and $70^{\circ} \mathrm{C}$ is cooled at constant pressure until it exists as a compressed liquid at $20^{\circ} \mathrm{C}$.
(a) Show the process on a $T$ -u diagram with respect to saturation lines.
(b) Determine the change in volume.
(c) Find the change in total internal energy.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 122

A 4-L rigid tank contains 2 kg of saturated liquidvapor 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 $4 \mathrm{~L} ?$

Mayukh Banik

Numerade Educator

Problem 123

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 $150^{\circ} \mathrm{C}$. Determine the volume change of the cylinder during this process using the compressibility factor, and compare the result to the actual value.

Mayukh Banik

Numerade Educator

Problem 124

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 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.

Mukesh Devi

Numerade Educator

Problem 125

Reconsider Prob. 3-124. Using appropriate 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 $1.5 \mathrm{MPa}$. Plot the volume of the tank versus the initial pressure, and discuss the results.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 126

A tank contains helium at $37^{\circ} \mathrm{C}$ and $140 \mathrm{kPa}$ gage. The helium is heated in a process by heat transfer from the surroundings such that the helium reaches a final equilibrium state at $200^{\circ} \mathrm{C}$. Determine the final gage pressure of the helium. Assume atmospheric pressure is $100 \mathrm{kPa}$.

Mayukh Banik

Numerade Educator

Problem 127

On the property diagrams indicated below, sketch (not to scale) with respect to the saturated liquid and saturated vapor lines and label the following processes and states for steam. Use arrows to indicate the direction of the process, and label the initial and final states:
(a) On the $P$ -u diagram, sketch the constant-temperature process through the state $P=300 \mathrm{kPa}, \cup=0.525 \mathrm{~m}^{3} / \mathrm{kg}$ as
pressure changes from $P_{1}=200 \mathrm{kPa}$ to $P_{2}=400 \mathrm{kPa} .$ Place the value of the temperature on the process curve on the $P$ - $\cup$ diagram.
(b) On the $T$ -u diagram, sketch the constant-specific-volume process through the state $T=120^{\circ} \mathrm{C}, \cup=0.7163 \mathrm{~m}^{3} / \mathrm{kg}$
from $P_{1}=100 \mathrm{kPa}$ to $P_{2}=300 \mathrm{kPa} .$ For this data set, place the temperature values at states 1 and 2 on its axis. Place the value of the specific volume on its axis.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 128

On the property diagrams indicated below, sketch (not to scale) with respect to the saturated liquid and saturated vapor lines and label the following processes and states for refrigerant-134a. Use arrows to indicate the direction of the process, and label the initial and final states:
(a) On the $P$ - $\cup$ diagram, sketch the constant-temperature process through the state $P=280 \mathrm{kPa}, \cup=0.06 \mathrm{~m}^{3} / \mathrm{kg}$ as pressure changes from $P_{1}=400 \mathrm{kPa}$ to $P_{2}=200 \mathrm{kPa} .$ Place the value of the temperature on the process curve on the $P$ - $\cup$ diagram.
(b) On the $T$ -u diagram, sketch the constant-specific-volume process through the state $T=20^{\circ} \mathrm{C}, \mathrm{U}=0.02 \mathrm{~m}^{3} / \mathrm{kg}$ from
$P_{1}=1200 \mathrm{kPa}$ to $P_{2}=300 \mathrm{kPa}$. For this data set, place the temperature values at states 1 and 2 on its axis. Place the value of the specific volume on its axis.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 129

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 $P-U$ and $T$ - $\cup$ 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 $P-U$ and $T-U$ diagrams, sketch the isotherms passing through the states and show their values, in ${ }^{\circ} \mathrm{C},$ on the isotherms.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 130

Ethane at $10 \mathrm{MPa}$ and $100^{\circ} \mathrm{C}$ 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?
$3-131$ Steam at $400^{\circ} \mathrm{C}$ has a specific volume of $0.02 \mathrm{~m}^{3} / \mathrm{kg}$. Determine the pressure of the steam based on $(a)$ the ideal-gas equation, $(b)$ the generalized compressibility chart, and $(c)$ the steam tables. Answers: (a) $15,529 \mathrm{kPa},$ (b) $12,574 \mathrm{kPa},$ (c) $12,515 \mathrm{kPa}$

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 131

Steam at $400^{\circ} \mathrm{C}$ has a specific volume of $0.02 \mathrm{~m}^{3} / \mathrm{kg}$. Determine the pressure of the steam based on ( $a$ ) the ideal-gas equation, $(b)$ the generalized compressibility chart, and $(c)$ the steam tables.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 132

Nitrogen is maintained at 400 psia and $-100^{\circ} \mathrm{F}$. 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 $(c)$ the compressibility factor.

Mayukh Banik

Numerade Educator

Problem 133

Consider an 18-m-diameter hot-air balloon that, together with its cage, has a mass of $120 \mathrm{~kg}$ when empty. The air in the balloon, which is now carrying two $85-\mathrm{kg}$ people, is heated by propane burners at a location where the atmospheric pressure and temperature are $93 \mathrm{kPa}$ and $12^{\circ} \mathrm{C},$ 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 $25^{\circ} \mathrm{C} ?$

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 134

Oxygen is maintained at $4 \mathrm{MPa}$ and $20^{\circ} \mathrm{C}$. Compare the specific volume of the oxygen under this condition as predicted by $(a)$ the ideal-gas equation of state, $(b)$ the Beattie-Bridgeman equation of state, and $(c)$ the compressibility factor.

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 135

A $1-\mathrm{m}^{3}$ rigid tank contains $10 \mathrm{~kg}$ of water (in any phase or phases) at $160^{\circ} \mathrm{C}$. The pressure in the tank is
$(a) 738 \mathrm{kPa}$
(b) $618 \mathrm{kPa}$
(c) $370 \mathrm{kPa}$
(d) $2000 \mathrm{kPa}$
(e) $1618 \mathrm{kPa}$

Mayukh Banik

Numerade Educator

Problem 136

A $3-\mathrm{m}^{3}$ rigid vessel contains steam at $2 \mathrm{MPa}$ and $500^{\circ} \mathrm{C} .$ The mass of the steam is
(a) $13 \mathrm{~kg}$
(b) $17 \mathrm{~kg}$
(c) $22 \mathrm{~kg}$
(d) $28 \mathrm{~kg}$
(e) $35 \mathrm{~kg}$

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 137

A $240-\mathrm{m}^{3}$ rigid tank is filled with a saturated liquidvapor mixture of water at $200 \mathrm{kPa}$. If 25 percent of the mass is liquid and 75 percent of the mass is vapor, the total mass in the tank is
(a) $240 \mathrm{~kg}$
(b) $265 \mathrm{~kg}$
(c) $307 \mathrm{~kg}$
(d) $361 \mathrm{~kg}$
(e) $450 \mathrm{~kg}$

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 138

Water is boiled at 1 atm pressure in a coffeemaker equipped with an immersion-type electric heating element. The coffeemaker initially contains $1 \mathrm{~kg}$ of water. Once boiling has begun, it is observed that half of the water in the coffeemaker evaporates in $10 \mathrm{~min}$. If the heat loss from the coffeemaker is negligible, the power rating of the heating element is
(a) $3.8 \mathrm{~kW}$
(b) $2.2 \mathrm{~kW}$
(c) $1.9 \mathrm{~kW}$
(d) $1.6 \mathrm{~kW}$
(e) $0.8 \mathrm{~kW}$

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 139

Water is boiling at 1 atm pressure in a stainless steel pan on an electric range. It is observed that $1.25 \mathrm{~kg}$ of liquid water evaporates in $30 \mathrm{~min}$. The rate of heat transfer to the water is
(a) $1.57 \mathrm{~kW}$
(b) $1.86 \mathrm{~kW}$
(c) $2.09 \mathrm{~kW}$
(d) $2.43 \mathrm{~kW}$
(e) $2.51 \mathrm{~kW}$

Khoobchandra Agrawal

Khoobchandra Agrawal

Numerade Educator

Problem 140

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

Prabhat Tyagi

Numerade Educator

Problem 141

A rigid tank contains $2 \mathrm{~kg}$ of an ideal gas at $4 \mathrm{~atm}$ and $40^{\circ} \mathrm{C}$. Now a valve is opened, and half of mass of the gas is allowed to escape. If the final pressure in the tank is $2.2 \mathrm{~atm},$ the final temperature in the tank is
(a) $71^{\circ} \mathrm{C}$
(b) $44^{\circ} \mathrm{C}$
(c) $-100^{\circ} \mathrm{C}$
(d) $20^{\circ} \mathrm{C}$
(e) $172^{\circ} \mathrm{C}$

Mayukh Banik

Numerade Educator

Problem 142

The pressure of an automobile tire is measured to be $190 \mathrm{kPa}$ (gage) before a trip and $215 \mathrm{kPa}$ (gage) after the trip at a location where the atmospheric pressure is $95 \mathrm{kPa}$. If the temperature of air in the tire before the trip is $25^{\circ} \mathrm{C},$ the air temperature after the trip is
(a) $51.1^{\circ} \mathrm{C}$
(b) $64.2^{\circ} \mathrm{C}$
(c) $27.2^{\circ} \mathrm{C}$
(d) $28.3^{\circ} \mathrm{C}$
(e) $25.0^{\circ} \mathrm{C}$

Mayukh Banik

Numerade Educator

Problem 143

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

Mayukh Banik

Numerade Educator

Problem 144

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.

Vidhi Bhatt

Numerade Educator

Problem 145

In an article on tire maintenance, it is stated that tires lose air over time, and pressure losses as high as $90 \mathrm{kPa}(13$ 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 $220 \mathrm{kPa}$ (gage) and the atmospheric pressure to be $100 \mathrm{kPa}$, determine the fraction of air that can be lost from a tire per year.

Vidhi Bhatt

Numerade Educator

Problem 146

It is well known that water freezes at $0^{\circ} \mathrm{C}$ at atmospheric pressure. The mixture of liquid water and ice at $0^{\circ} \mathrm{C}$ 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 $-2^{\circ} \mathrm{C}$ 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 $0^{\circ} \mathrm{C}$ following this sudden change. The water at $-2^{\circ} \mathrm{C}$ is said to be in a metastable state. Write an essay on metastable states, and discuss how they differ from stable equilibrium states.

Vidhi Bhatt

Numerade Educator