Thermodynamics: An Engineering Approach w/ Student Resources DVD

Yunus A. Cengel, Michael A. Boles

Chapter 3 PROPERTIES OF PURE SUBSTANCES - all with Video Answers

Educators

Chapter Questions

00:30

Problem 1

Is iced water a pure substance? Why?

Mayukh Banik

Numerade Educator

01:12

Problem 2

What is the difference between saturated liquid and compressed liquid?

Khoobchandra Agrawal

Numerade Educator

00:34

Problem 3

What is the difference between saturated vapor and superheated vapor?

Mayukh Banik

Numerade Educator

01:48

The atmospheric pressure at a location is usually specified at standard conditions, but it changes with the weather conditions. As the weather forecasters frequently state, the atmospheric pressure drops during stormy weather and it rises during clear and sunny days. If the pressure difference between the two extreme conditions is given to be 0.3 in of mercury, determine how much the boiling temperatures of water will vary as the weather changes from one extreme to the other.

Naman Kumar

Numerade Educator

00:46

Problem 4

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?

Mayukh Banik

Numerade Educator

03:41

Problem 4

Repeat Prob. 3-43 for a location at 2000-m elevation where the standard atmospheric pressure is $79.5 \mathrm{kPa}$.

Khoobchandra Agrawal

Numerade Educator

01:24

Problem 5

Is there any difference between the intensive properties of saturated liquid at a given temperature and the liquid of a saturated mixture at the same temperature?

Vysakh M

Numerade Educator

00:25

Problem 6

Is it true that water boils at higher temperatures at higher pressures? Explain.

Mayukh Banik

Numerade Educator

01:12

Problem 7

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

Numerade Educator

00:32

Problem 8

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

Mayukh Banik

Numerade Educator

00:14

Problem 9

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

Mayukh Banik

Numerade Educator

00:16

Problem 10

$ \mathrm{C}$ Is it possible to have water vapor at $-10^{\circ} \mathrm{C}$ ?

Mayukh Banik

Numerade Educator

03:02

Problem 10

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

00:37

Problem 11

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

Numerade Educator

01:57

Problem 12

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

Khoobchandra Agrawal

Numerade Educator

00:51

Problem 13

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

03:12

Problem 14

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

Numerade Educator

00:37

Problem 14

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

00:32

Problem 15

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

00:41

Problem 16

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.

Mayukh Banik

Numerade Educator

00:17

Problem 17

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

00:30

Problem 18

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

Mayukh Banik

Numerade Educator

00:46

Problem 19

What is the physical significance of $h_{f g}$ ? Can it be obtained from a knowledge of $h_f$ and $h_g$ ? How?

Mayukh Banik

Numerade Educator

00:42

Problem 20

$ \mathrm{C}$ 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

00:39

Problem 21

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

Mayukh Banik

Numerade Educator

00:33

Problem 22

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

Mayukh Banik

Numerade Educator

00:22

Problem 23

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

Mayukh Banik

Numerade Educator

01:51

Problem 24

Can quality be expressed as the ratio of the volume occupied by the vapor phase to the total volume? Explain.

Pronoy Sinha

Numerade Educator

00:24

Problem 25

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

01:15

Problem 26

Complete this table for $\mathrm{H}_2 \mathrm{O}$ :
$$
\begin{array}{llll}
\hline T,{ }^{\circ} \mathrm{C} & P, \mathrm{kPa} & \mathrm{V}, \mathrm{m}^3 / \mathrm{kg} & \text { Phase description } \\
\hline 50 & & 4.16 & \\
\hline & 200 & & \text { Saturated vapor } \\
\hline 250 & 400 & & \\
\hline 110 & 600 & & \\
\hline
\end{array}
$$

Mayukh Banik

Numerade Educator

01:00

Problem 27

↔\$ Reconsider Prob. 3-26. Using EES (or other) software, determine the missing properties of water. Repeat the solution for refrigerant-134a, refrigerant22 , and ammonia.

Mayukh Banik

Numerade Educator

01:12

Problem 28

Complete this table for $\mathrm{H}_2 \mathrm{O}$ :

$$
\begin{array}{lcll}
\hline T,{ }^{\circ} \mathrm{F} & P, \text { psia } & u, \text { Btu/lbm } & \text { Phase description } \\
\hline 300 & & 782 & \\
\hline & 40 & & \text { Saturated liquid } \\
\hline 500 & 120 & & \\
\hline 400 & 400 & & \\
\hline
\end{array}
$$

Mayukh Banik

Numerade Educator

01:00

Problem 29

$$
\mathrm{E}
$$

Reconsider Prob. 3-28E. Using EES (or other) software, determine the missing properties of water. Repeat the solution for refrigerant-134a, refrigerant22 , and ammonia.

Mayukh Banik

Numerade Educator

02:28

Problem 30

Complete this table for $\mathrm{H}_2 \mathrm{O}$ :

$$
\begin{array}{lllll}
\hline T,{ }^{\circ} \mathrm{C} & P, \mathrm{kPa} & h, \mathrm{~kJ} / \mathrm{kg} & x & \text { Phase description } \\
\hline & 200 & & 0.7 & \\
\hline 140 & & 1800 & & \\
\hline & 950 & & 0.0 & \\
\hline 80 & 500 & & & \\
\hline & 800 & 3162.2 & & \\
\hline
\end{array}
$$

Khoobchandra Agrawal

Numerade Educator

01:07

Problem 31

Complete this table for refrigerant-134a:

$$
\begin{array}{llll}
\hline T,{ }^{\circ} \mathrm{C} & P, \mathrm{kPa} & \mathrm{v}, \mathrm{m}^3 / \mathrm{kg} & \text { Phase description } \\
\hline-8 & 320 & & \\
\hline 30 & & 0.015 & \\
\hline & 180 & & \text { Saturated vapor } \\
\hline 80 & 600 & & \\
\hline
\end{array}
$$

Mayukh Banik

Numerade Educator

12:46

Problem 32

Complete this table for refrigerant-134a:

$$
\begin{array}{cccc}
\hline T,{ }^{\circ} \mathrm{C} & P, \mathrm{kPa} & U, \mathrm{~kJ} / \mathrm{kg} & \text { Phase description } \\
\hline 20 & & 95 & \\
\hline-12 & & & \text { Saturated liquid } \\
\hline & 400 & 300 & \\
\hline 8 & 600 & & \\
\hline
\end{array}
$$

Prabhat Tyagi

Numerade Educator

01:44

Problem 33

Complete this table for refrigerant-134a:

$$
\begin{array}{|c|c|c|c|c|}
\hline T \text {, }{ }^{\circ} \mathrm{F} & \text { P. psia } & \text { h. Btu/lbm } & x & \text { Phase description } \\
\hline & 80 & 78 & & \\
\hline 15 & & & 0.6 & \\
\hline 10 & 70 & & & \\
\hline & 180 & 129.46 & & \\
\hline 110 & & & 1.0 & \\
\hline
\end{array}
$$

Mayukh Banik

Numerade Educator

01:15

Problem 34

Complete this table for $\mathrm{H}_2 \mathrm{O}$ :

$$
\begin{array}{lccc}
\hline T_f{ }^{\circ} \mathrm{C} & P, \mathrm{kPa} & V, \mathrm{~m}^3 / \mathrm{kg} & \text { Phase description } \\
\hline 140 & & 0.05 & \\
\hline & 550 & & \text { Saturated liquid } \\
\hline 125 & 750 & & \\
\hline 500 & & 0.140 & \\
\hline
\end{array}
$$

Mayukh Banik

Numerade Educator

01:10

Problem 35

$$
\text { Complete this table for } \mathrm{H}_2 \mathrm{O} \text { : }
$$

$$
\begin{array}{lccl}
\hline T_{,}{ }^{\circ} \mathrm{C} & P, \mathrm{kPa} & u, \mathrm{~kJ} / \mathrm{kg} & \text { Phase description } \\
\hline & 400 & 1450 & \\
\hline 220 & & & \text { Saturated vapor } \\
\hline 190 & 2500 & & \\
\hline & 4000 & 3040 & \\
\hline
\end{array}
$$

Mayukh Banik

Numerade Educator

01:28

Problem 36

A $1.8-\mathrm{m}^3$ rigid tank contains steam at $220^{\circ} \mathrm{C}$. Onethird 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

01:54

Problem 37

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-134a

Anand Jangid

Numerade Educator

02:08

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

Numerade Educator

03:02

Problem 40

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 the pan will move up together with the lid.

Khoobchandra Agrawal

Numerade Educator

01:21

Problem 41

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

04:15

Problem 42

Repeat Prob. 3-41 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

Numerade Educator

01:43

Problem 43

Water is boiled at 1 atm pressure in a 25 -cm-internal diameter 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

Numerade Educator

01:39

Problem 45

Saturated steam coming off the turbine of a steam power plant at $30^{\circ} \mathrm{C}$ condenses on the outside of a $3-\mathrm{cm}$ outer-diameter, 35 -m-long tube at a rate of $45 \mathrm{~kg} / \mathrm{h}$. Determine the rate of heat transfer from the steam to the cooling water flowing through the pipe.

Mayukh Banik

Numerade Educator

00:27

Problem 46

The average atmospheric pressure in Denver (elevation $=1610 \mathrm{~m}$ ) is $83.4 \mathrm{kPa}$. Determine the temperature at which water in an uncovered pan boils in Denver.

Mayukh Banik

Numerade Educator

01:40

Problem 47

Water in a 5 -cm-deep pan is observed to boil at $98^{\circ} \mathrm{C}$. At what temperature will the water in a 40 -cm-deep pan boil? Assume both pans are full of water.

Mayukh Banik

Numerade Educator

01:31

Problem 48

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

Mayukh Banik

Numerade Educator

03:10

Problem 49

Reconsider Prob, 3-48. 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 $1 \mathrm{~kg}$ to $10 \mathrm{~kg}$. Plot the boiling temperature against the mass of the lid, and discuss the results.

Mayukh Banik

Numerade Educator

01:43

Problem 50

Water is being heated in a vertical piston-cylinder device. The piston has a mass of $20 \mathrm{~kg}$ and a cross-sectional area of $100 \mathrm{~cm}^2$. If the local atmospheric pressure is $100 \mathrm{kPa}$, determine the temperature at which the water starts boiling.

Mayukh Banik

Numerade Educator

02:22

Problem 51

A rigid tank with a volume of $2.5 \mathrm{~m}^3$ contains $15 \mathrm{~kg}$ of saturated liquid-vapor mixture of water at $75^{\circ} \mathrm{C}$. 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 $T-V$ diagram with respect to saturation lines.

Khoobchandra Agrawal

Numerade Educator

01:09

Problem 52

A rigid vessel contains $2 \mathrm{~kg}$ of refrigerant- $134 \mathrm{a}$ at 800 $\mathrm{kPa}$ and $120^{\circ} \mathrm{C}$. Determine the volume of the vessel and the total internal energy. Answers: $0.0753 \mathrm{~m}^3, 655.7 \mathrm{~kJ}$

Mayukh Banik

Numerade Educator

02:55

Problem 53

E A 5 - $\mathrm{ft}^3$ rigid tank contains $5 \mathrm{lbm}$ of water at 20 psia. Determine $(a)$ the temperature, $(b)$ the total enthalpy, and $(c)$ the mass of each phase of water.

Mayukh Banik

Numerade Educator

01:15

Problem 54

A $0.5-\mathrm{m}^3$ vessel contains $10 \mathrm{~kg}$ of refrigerant $-134 \mathrm{a}$ at $-20^{\circ} \mathrm{C}$. Determine $(a)$ the pressure, $(b)$ the total internal energy, and $(c)$ the volume occupied by the liquid phase. Answers: (a) $132.82 \mathrm{kPa}$, (b) $904.2 \mathrm{~kJ}$, (c) $0.00489 \mathrm{~m}^3$

Mayukh Banik

Numerade Educator

03:33

Problem 55

A piston-cylinder device contains $0.1 \mathrm{~m}^3$ of liquid water and $0.9 \mathrm{~m}^3$ of water vapor in equilibrium at $800 \mathrm{kPa}$. Heat is transferred at constant pressure until the temperature reaches $350^{\circ} \mathrm{C}$.
(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.

Khoobchandra Agrawal

Numerade Educator

05:25

Problem 56

Reconsider Prob. 3-55. 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 $1 \mathrm{MPa}$. Plot the total mass of water against pressure, and discuss the results. Also, show the process in Prob. 3-55 on a $P$ - $V$ diagram using the property plot feature of EES.

Vidhi Bhatt

Numerade Educator

01:55

Problem 57

Superheated water vapor at $180 \mathrm{psia}$ 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 $T-v$ diagram with respect to saturation lines.

Mayukh Banik

Numerade Educator

03:12

Problem 58

$\mathbb{6}$ Reconsider Prob, 3-57E. 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 $100 \mathrm{psi}$ to $300 \mathrm{psi}$. Plot the quality against initial pressure, and discuss the results. Also, show the process in Prob. $3-57 \mathrm{E}$ on a $T-v$ diagram using the property plot feature of EES.

Khoobchandra Agrawal

Numerade Educator

02:02

Problem 59

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 $T$ - $V$ diagram with respect to saturation lines.

Mayukh Banik

Numerade Educator

06:58

Problem 60

A $0.3-\mathrm{m}^3$ rigid vessel initially contains saturated liquid vapor mixture of water at $150^{\circ} \mathrm{C}$. The water is now heated until it reaches the critical state. Determine the mass of the liquid water and the volume occupied by the liquid at the initial state. Answers: $96.10 \mathrm{~kg}, 0.105 \mathrm{~m}^3$

Shahab Ullah

Numerade Educator

01:14

Problem 61

Determine the specific volume, internal energy, and enthalpy of compressed liquid water at $100^{\circ} \mathrm{C}$ and 15 MPa using the saturated liquid approximation. Compare these values to the ones obtained from the compressed liquid tables.

Manik Pulyani

Numerade Educator

01:10

Problem 62

Reconsider Prob. 3-61. Using EES (or other) software, determine the indicated properties of compressed liquid, and compare them to those obtained using the saturated liquid approximation.

Mayukh Banik

Numerade Educator

02:26

Problem 63

A $15-\mathrm{ft}^3$ rigid tank contains a saturated mixture of refrigerant-134a at $50 \mathrm{psia}$. 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

Numerade Educator

03:05

Problem 64

A piston-cylinder device contains $0.8 \mathrm{~kg}$ of steam at $300^{\circ} \mathrm{C}$ and $1 \mathrm{MPa}$. 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

Numerade Educator

00:28

Problem 65

A rigid tank contains water vapor at $250^{\circ} \mathrm{C}$ and an unknown pressure. When the tank is cooled to $150^{\circ} \mathrm{C}$, the vapor starts condensing. Estimate the initial pressure in the tank. Answer: $0.60 \mathrm{MPa}$

Mayukh Banik

Numerade Educator

01:54

Problem 66

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

Khoobchandra Agrawal

Numerade Educator

02:28

Problem 67

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.

Mayukh Banik

Numerade Educator

05:18

Problem 68

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

Numerade Educator

01:02

Problem 69

Propane and methane are commonly used for heating in winter, and the leakage of these fuels, even for short periods, poses a tire danger for homes. Which gas leakage do you think poses a greater risk for fire? Explain.

Mayukh Banik

Numerade Educator

00:25

Problem 70

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

Mayukh Banik

Numerade Educator

00:56

Problem 71

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

Mayukh Banik

Numerade Educator

01:09

Problem 72

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

Khoobchandra Agrawal

Numerade Educator

02:04

Problem 73

A spherical balloon with a diameter of $6 \mathrm{~m}$ is filled with helium at $20^{\circ} \mathrm{C}$ and $200 \mathrm{kPa}$. Determine the mole number and the mass of the helium in the balloon.

Khoobchandra Agrawal

Numerade Educator

01:34

Problem 74

Reconsider Prob, 3-73. 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.

Mayukh Banik

Numerade Educator

01:07

Problem 75

The pressure in an automobile tire depends on the temperature of the air in the tire. When the air temperature is $25^{\circ} \mathrm{C}$, the pressure gage reads $210 \mathrm{kPa}$. If the volume of the tire is $0.025 \mathrm{~m}^3$, determine the pressure rise in the tire when the air temperature in the tire rises to $50^{\circ} \mathrm{C}$. Also, determine the amount of air that must be bled off to restore pressure to its original value at this temperature. Assume the atmospheric pressure is $100 \mathrm{kPa}$.

Mayukh Banik

Numerade Educator

02:17

Problem 76

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 $30 \mathrm{psig}$. Assume the atmospheric pressure to be 14.6 psia and the temperature and the volume to remain constant.

Mayukh Banik

Numerade Educator

00:56

Problem 77

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

02:05

Problem 78

A rigid tank contains $20 \mathrm{lbm}$ of air at $20 \mathrm{psia}$ and $70^{\circ} \mathrm{F}$. More air is added to the tank until the pressure and temperature rise to $35 \mathrm{psia}$ and $90^{\circ} \mathrm{F}$, respectively. Determine the amount of air added to the tank.

Mayukh Banik

Numerade Educator

00:58

Problem 79

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 $97 \mathrm{kPa}$.

Mayukh Banik

Numerade Educator

02:40

Problem 80

A $1-\mathrm{m}^3$ tank containing air at $25^{\circ} \mathrm{C}$ and $500 \mathrm{kPa}$ is connected through a valve to another tank containing $5 \mathrm{~kg}$ 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.

Khoobchandra Agrawal

Numerade Educator

01:45

Problem 81

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

Khoobchandra Agrawal

Numerade Educator

00:42

Problem 82

What is the principle of corresponding states?

Mayukh Banik

Numerade Educator

00:51

Problem 83

How are the reduced pressure and reduced temperature defined?

Mayukh Banik

Numerade Educator

03:22

Problem 84

Determine the specific volume of superheated water vapor at $10 \mathrm{MPa}$ and $400^{\circ} \mathrm{C}$, 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

02:38

Problem 85

$\in$ Reconsider Prob. 3-84. 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 $10 \mathrm{MPa}$ over the temperature range of 325 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.

Mayukh Banik

Numerade Educator

03:31

Problem 86

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

Numerade Educator

03:09

Problem 87

Determine the specific volume of nitrogen gas at $10 \mathrm{MPa}$ and $150 \mathrm{~K}$ based on $(a)$ the ideal-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

Numerade Educator

01:54

Problem 88

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

02:46

Problem 89

Refrigerant-134a at 400 psia has a specific volume of $0.13853 \mathrm{ft}^3 / \mathrm{lbm}$. 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

03:20

Problem 90

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.

Mayukh Banik

Numerade Educator

03:34

Problem 91

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

Mayukh Banik

Numerade Educator

03:27

Problem 92

What is the percentage of error involved in treating carbon dioxide at $3 \mathrm{MPa}$ and $10^{\circ} \mathrm{C}$ as an ideal gas?

Khoobchandra Agrawal

Numerade Educator

01:03

Problem 93

What is the percentage of error involved in treating carbon dioxide at $7 \mathrm{MPa}$ and $380 \mathrm{~K}$ as an ideal gas?

Mayukh Banik

Numerade Educator

04:25

Problem 94

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 $\mathrm{CO}_2$ 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 each case.

Mayukh Banik

Numerade Educator

00:37

Problem 95

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?

Mayukh Banik

Numerade Educator

00:53

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

02:57

Problem 97

A $1-\mathrm{m}^3$ tank contains $2.841 \mathrm{~kg}$ of steam at $0.6 \mathrm{MPa}$. Determine the temperature of the steam, using (a) the idealgas equation, $(b)$ the van der Waals equation, and $(c)$ the steam tables. Answers: (a) $457.6 \mathrm{~K}$, (b) $465.9 \mathrm{~K}$, (c) $473 \mathrm{~K}$

Mayukh Banik

Numerade Educator

01:10

Problem 98

$\mathbb{E S 3}$ Reconsider Prob. 3-97. 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 $0.1 \mathrm{MPa}$ to $1 \mathrm{MPa}$ in $0.1 \mathrm{MPa}$ increments. Plot the percent error involved in the ideal-gas approximation against pressure, and discuss the results.

Mayukh Banik

Numerade Educator

00:50

Problem 99

Refrigerant-134a at 100 psia has a specific volume of $0.54022 \mathrm{ft}^3 / \mathrm{lbm}$. 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

00:35

Problem 100

Nitrogen at $150 \mathrm{~K}$ has a specific volume of (6) $0.041884 \mathrm{~m}^3 / \mathrm{kg}$. 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 $1000 \mathrm{kPa}$. Answers: (a) $1063 \mathrm{kPa}$, (b) $1000.4 \mathrm{kPa}$

Mayukh Banik

Numerade Educator

01:40

Problem 101

(ङ) Reconsider Prob. 3-100. 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 $1000 \mathrm{kPa}$ with respect to the saturated liquid and saturated vapor lines of nitrogen over the range of $110 \mathrm{~K}<T<150 \mathrm{~K}$.

Jincy M Saji

Numerade Educator

01:03

Problem 102

Consider a glass of water in a room that is at $20^{\circ} \mathrm{C}$ and 60 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

01:02

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

00:47

Problem 104

On a certain day, the temperature and relative humidity of air over a large swimming pool are measured to be $20^{\circ} \mathrm{C}$ and 40 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

01:31

Problem 105

Consider two rooms that are identical except that one is maintained at $30^{\circ} \mathrm{C}$ and 40 percent relative humidity while the other is maintained at $20^{\circ} \mathrm{C}$ and 70 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

01:13

Problem 106

A thermos bottle is half-filled with water and is left open to the atmospheric air at $70^{\circ} \mathrm{F}$ 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

01:29

Problem 107

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

00:44

Problem 108

3-108 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 $1.8 \mathrm{MPa}$ and $450^{\circ} \mathrm{C}$ before the combustion and $1300^{\circ} \mathrm{C}$ after it. Determine the pressure at the end of the combustion process.

Khoobchandra Agrawal

Numerade Educator

01:41

Problem 109

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

Numerade Educator

03:57

Problem 111

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

00:44

Problem 112

Combustion in a diesel engine may be modeled as a constant-pressure heat addition process with air in the cylinder before and after combustion. Consider a diesel engine with cylinder conditions of $950 \mathrm{~K}$ and $75 \mathrm{~cm}^3$ before combustion, and $150 \mathrm{~cm}^3$ after it. The engine operates with an air-fuel ratio of $22 \mathrm{~kg}$ air $/ \mathrm{kg}$ fuel (the mass of the air divided by the mass of the fuel). Determine the temperature after the combustion process.

Mayukh Banik

Numerade Educator

05:00

Problem 113

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 $P-V$ diagram sketch the constant temperature process through the state $P=300 \mathrm{kPa}, v=0.525 \mathrm{~m}^3 / \mathrm{kg}$ 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 $P$-V diagram.

(b) On the $T$-V diagram sketch the constant specific volume process through the state $T=120^{\circ} \mathrm{C}, V=0.7163 \mathrm{~m}^3 / \mathrm{kg}$ 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

Numerade Educator

01:07

Problem 114

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

08:44

Problem 115

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
$$
F_B=\rho_{\text {cool 2ir }} g V_{\text {balloon }}
$$
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 $30^{\circ} \mathrm{C}$ ?

Vidhi Bhatt

Numerade Educator

01:34

Problem 116

Reconsider Prob, 3-115, Using EES (or other)
software, investigate the effect of the environ-
ment temperature on the average air temperature in the bal-
loon when the balloon is suspended in the air. Assume the
environment temperature varies from -10 to $30^{\circ} \mathrm{C}$. 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.

Mayukh Banik

Numerade Educator

06:47

Problem 117

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 $70-\mathrm{kg}$ 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 $25^{\circ} \mathrm{C}$ ?

Vidhi Bhatt

Numerade Educator

00:22

Problem 118

Water in a pressure cooker is observed to boil at $260^{\circ} \mathrm{F}$. What is the absolute pressure in the pressure cooker, in psia?

Mayukh Banik

Numerade Educator

00:57

Problem 119

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 $P$ - $v$ diagram with respect to saturation lines.

Mayukh Banik

Numerade Educator

01:31

Problem 120

A 4-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 $4 \mathrm{~L}$ ?

Mayukh Banik

Numerade Educator

01:15

Problem 121

A 10-kg mass of superheated refrigerant-134a at 1.2 $\mathrm{MPa}$ 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 $T-V$ diagram with respect to saturation lines.
(b) Determine the change in volume.
(c) Find the change in total internal energy.

Mayukh Banik

Numerade Educator

02:40

Problem 122

A $0.5-\mathrm{m}^3$ rigid tank containing hydrogen at $20^{\circ} \mathrm{C}$ and $600 \mathrm{kPa}$ is connected by a valve to another $0.5-\mathrm{m}^3$ rigid tank that holds hydrogen at $30^{\circ} \mathrm{C}$ and $150 \mathrm{kPa}$. Now the valve is opened and the system is allowed to reach thermal equilibrium with the surroundings, which are at $15^{\circ} \mathrm{C}$. Determine the final pressure in the tank.

Khoobchandra Agrawal

Numerade Educator

02:43

Problem 123

Reconsider Prob. 3-122. Using EES (or other) software, investigate the effect of the surroundings temperature on the final equilibrium pressure in the tanks. Assume the surroundings temperature to vary from -10 to $30^{\circ} \mathrm{C}$. Plot the final pressure in the tanks versus the surroundings temperature, and discuss the results.

Jincy M Saji

Numerade Educator

01:11

Problem 124

A $20-\mathrm{m}^3$ tank contains nitrogen at $23^{\circ} \mathrm{C}$ 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 $20^{\circ} \mathrm{C}$, determine the amount of nitrogen that has escaped.

Mayukh Banik

Numerade Educator

01:54

Problem 125

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 idealgas equation, (b) the generalized compressibility chart, and (c) the steam tables. Answers: (a) $15,529 \mathrm{kPa}$, (b) $12,576 \mathrm{kPa}$, (c) $12,500 \mathrm{kPa}$

Mayukh Banik

Numerade Educator

01:37

Problem 126

A tank whose volume is unknown is divided into two parts by a partition. One side of the tank contains $0.01 \mathrm{~m}^3$
of refrigerant-134a that is a saturated liquid at $0.8 \mathrm{MPa}$, 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 $400 \mathrm{kPa}$, determine the volume of the tank.

Mayukh Banik

Numerade Educator

01:46

Problem 127

$\in \mathbb{S}$ Reconsider Prob. 3-126. 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 $1.5 \mathrm{MPa}$. Plot the volume of the tank versus the initial pressure, and discuss the results.

Mayukh Banik

Numerade Educator

00:42

Problem 128

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.

Mayukh Banik

Numerade Educator

00:45

Problem 129

Repeat Prob. 3-128 for isobutane.

Mayukh Banik

Numerade Educator

01:45

Problem 130

A tank contains helium at $100^{\circ} \mathrm{C}$ and $10 \mathrm{kPa}$ gage. The helium is heated in a process by heat transfer from the surroundings such that the helium reaches a final equilibrium state at $300^{\circ} \mathrm{C}$. Determine the final gage pressure of the helium. Assume atmospheric pressure is $100 \mathrm{kPa}$.

Mayukh Banik

Numerade Educator

01:27

Problem 131

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

01:33

Problem 132

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.
(table cant copy)

Khoobchandra Agrawal

Numerade Educator

01:45

Problem 133

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.

Khoobchandra Agrawal

Numerade Educator

01:49

Problem 134

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 $P-V$ diagram sketch the constant temperature process through the state $P=280 \mathrm{kPa}, V=0.06 \mathrm{~m}^3 / \mathrm{kg}$ 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 $P$ - $V$ diagram.
(b) On the $T$ - $V$ diagram sketch the constant specific volume process through the state $T=20^{\circ} \mathrm{C}, V=0.02 \mathrm{~m}^3 / \mathrm{kg}$ 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

Numerade Educator

00:19

Problem 135

A rigid tank contains $6 \mathrm{~kg}$ of an ideal gas at $3 \mathrm{~atm}$ 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) $186^{\circ} \mathrm{C}$
(b) $59^{\circ}$
(c) $-43^{\circ} \mathrm{C}$
(d) $20^{\circ} \mathrm{C}$
(e) $230^{\circ} \mathrm{C}$

Mayukh Banik

Numerade Educator

01:09

Problem 136

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

02:33

Problem 137

A $300-\mathrm{m}^3$ rigid tank is filled with 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) $451 \mathrm{~kg}$
(b) $556 \mathrm{~kg}$
(c) $300 \mathrm{~kg}$
(d) $331 \mathrm{~kg}$
(e) $195 \mathrm{~kg}$

Mayukh Banik

Numerade Educator

01:53

Problem 138

Water is boiled at $1 \mathrm{~atm}$ pressure in a coffee maker equipped with an immersion-type electric heating element. The coffee maker initially contains $1 \mathrm{~kg}$ of water. Once boiling started, it is observed that half of the water in the coffee maker evaporated in 18 minutes. If the heat loss from the coffee maker is negligible, the power rating of the heating element is
(a) $0.90 \mathrm{~kW}$
(d) $1.05 \mathrm{~kW}$
(b) $1.52 \mathrm{~kW}$
(e) $1.24 \mathrm{~kW}$
(c) $2.09 \mathrm{~kW}$

Mayukh Banik

Numerade Educator

01:14

Problem 139

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) $738 \mathrm{kPa}$
(d) $2000 \mathrm{MPa}$
(b) $618 \mathrm{kPa}$
(e) $1618 \mathrm{kPa}$
(c) $370 \mathrm{kPa}$

Mayukh Banik

Numerade Educator

00:35

Problem 140

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

Mayukh Banik

Numerade Educator

01:35

Problem 141

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

Mayukh Banik

Numerade Educator

02:11

Problem 142

A 3- $\mathrm{m}^3$ rigid vessel contains steam at $10 \mathrm{MPa}$ and $500^{\circ} \mathrm{C}$. The mass of the steam is
(a) $3.0 \mathrm{~kg}$
(b) $19 \mathrm{~kg}$
(c) $84 \mathrm{~kg}$
(d) $91 \mathrm{~kg}$
(e) $130 \mathrm{~kg}$
3-143

Mayukh Banik

Numerade Educator

00:54

Problem 143

Consider a sealed can that is filled with refrigerant134a. 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

03:14

Problem 145

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

05:10

Problem 146

Enthalpy of Fusion for Water Experiment. The enthalpy of fusion for water (also known as latent heat of fusion) is obtained with an ice calorimeter that is constructed from a copper tube with closed ends and two access ports. Inside the calorimeter is coiled thermocouple wire that serves as electric heater wire. The calorimeter is filled with water, placed in a freezer and removed after the water is frozen. The calorimeter is insulated with Styrofoam and placed in a chamber with double walls that hold crushed ice and water providing a $0^{\circ} \mathrm{C}$ air environment. Electrical power input into the heater causes the solid ice at $0^{\circ} \mathrm{C}$ to melt to liquid water at $0^{\circ} \mathrm{C}$ - the energy supplied for this phase-change is the enthalpy of fusion. Obtain the enthalpy of fusion for water using the video clip, the complete write-up, and the data provided on the DVD accompanying this book.

Matthew Baker

Numerade Educator