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Chemistry A Molecular Approach

Nivaldo J. Tro

Chapter 12

Liquids, Solids, and Intermolecular Forces - all with Video Answers

Educators

Chapter Questions

01:21

Problem 1

Explain why water drops are spherical in the absence of gravity.

Vysakh M
Vysakh M
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00:41

Problem 2

Why are intermolecular forces important?

Nicholas White
Nicholas White
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01:18

Problem 3

What are the main properties of liquids (in contrast to gases and solids)?

Lizabeth Tumminello
Lizabeth Tumminello
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01:09

Problem 4

What are the main properties of solids (in contrast to liquids and gases)?

Nicholas White
Nicholas White
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01:04

Problem 5

What is the fundamental difference between an amorphous solid and a crystalline solid?

Lizabeth Tumminello
Lizabeth Tumminello
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07:10

Problem 6

What factors cause transitions between the solid and liquid state? The liquid and gas state?

RD
Ryan Daly
Numerade Educator
00:36

Problem 7

Describe the relationship between the state of a substance, its temperature, and the strength of its intermolecular forces.

Lizabeth Tumminello
Lizabeth Tumminello
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09:26

Problem 8

From what kinds of interactions do intermolecular forces originate?

RD
Ryan Daly
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03:34

Problem 9

Why are intermolecular forces generally much weaker than bonding forces?

Ahmed Ali
Ahmed Ali
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08:05

Problem 10

What is the dispersion force? What does the magnitude of the dispersion force depend on? How can you predict the magnitude of the dispersion force for closely related elements or compounds?

RD
Ryan Daly
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02:05

Problem 11

What is the dipole-dipole force? How can you predict the presence of dipole-dipole forces in a compound?

Ahmed Ali
Ahmed Ali
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05:38

Problem 12

How is the polarity of a liquid generally related to its miscibility with water?

RD
Ryan Daly
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02:55

Problem 13

What is hydrogen bonding? How can you predict the presence of hydrogen bonding in a compound?

Ahmed Ali
Ahmed Ali
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03:55

Problem 14

What is the ion-dipole force? Why is it important?

RD
Ryan Daly
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00:32

Problem 15

What is surface tension? How does surface tension result from
intermolecular forces? How is it related to the strength of intermolecular forces?

Lizabeth Tumminello
Lizabeth Tumminello
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02:59

Problem 16

What is viscosity? How does viscosity depend on intermolecular forces? What other factors affect viscosity?

Nicholas White
Nicholas White
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04:00

Problem 17

What is capillary action? How does it depend on the relative strengths of adhesive and cohesive forces?

Ahmed Ali
Ahmed Ali
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07:47

Problem 18

Explain what happens in the processes of vaporization and condensation. Why does the rate of vaporization increase with increasing temperature and surface area?

RD
Ryan Daly
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03:16

Problem 19

Why is vaporization endothermic? Why is condensation exothermic?

Ahmed Ali
Ahmed Ali
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01:16

Problem 20

How is the volatility of a substance related to the intermolecular forces present within the substance?

Nicholas White
Nicholas White
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02:09

Problem 21

What is the heat of vaporization for a liquid, and why is it useful?

Ahmed Ali
Ahmed Ali
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01:57

Problem 22

Explain the process of dynamic equilibrium. How is dynamic equilibrium related to vapor pressure?

Nicholas White
Nicholas White
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03:06

Problem 23

What happens to a system in dynamic equilibrium when it is disturbed in some way?

Ahmed Ali
Ahmed Ali
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03:00

Problem 24

How is vapor pressure related to temperature? What happens to the vapor pressure of a substance when the temperature is increased? Decreased?

Ahmed Ali
Ahmed Ali
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00:49

Problem 25

Define the terms boiling point and normal boiling point.

Lizabeth Tumminello
Lizabeth Tumminello
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01:17

Problem 26

What is the Clausius-Clapeyron equation, and why is it important?

Nicholas White
Nicholas White
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00:41

Problem 27

Explain what happens to a substance when it is heated in a closed container to its critical temperature.

Lizabeth Tumminello
Lizabeth Tumminello
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01:28

Problem 28

What is sublimation? Give a common example of sublimation.

Ahmed Ali
Ahmed Ali
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00:31

Problem 29

What is fusion? Is fusion exothermic or endothermic? Why?

Lizabeth Tumminello
Lizabeth Tumminello
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01:23

Problem 30

What is the heat of fusion, and why is it important?

Nicholas White
Nicholas White
Numerade Educator
01:22

Problem 31

Examine the heating curve for water in Section 12.7 (Figure 12.36 ). Explain why the curve has two segments in which heat is added to the water but the temperature does not rise.

Catherine Lemar
Catherine Lemar
Numerade Educator
02:10

Problem 32

Examine the heating curve for water in Section 12.7 (Figure 12.36). Explain the significance of the slopes of each of the three rising segments. Why are the slopes different?

Catherine Lemar
Catherine Lemar
Numerade Educator
03:10

Problem 33

What is a phase diagram? Draw a generic phase diagram and label its important features. What is the significance of crossing a line in a phase diagram?

Ahmed Ali
Ahmed Ali
Numerade Educator
06:21

Problem 34

How do the properties of water differ from those of most other substances?

Ahmed Ali
Ahmed Ali
Numerade Educator
04:20

Problem 35

Determine the kinds of intermolecular forces that are present in each element or compound. MISSED THIS?
a. $\mathrm{N}_{2}$
b. $\mathrm{NH}_{3}$
c. CO
d. $\mathrm{CCl}_{4}$

Shahina -
Shahina -
Numerade Educator
07:44

Problem 36

Determine the kinds of intermolecular forces that are present in
each element or compound.
a. $\mathrm{Kr}$
b. $\mathrm{NCl}_{3}$
c. $\mathrm{SiH}_{4}$
d. HF

RD
Ryan Daly
Numerade Educator
04:13

Problem 37

Determine the kinds of intermolecular forces that are present in each element or compound. MISSED THIS?
a. HCl
b. $\mathrm{H}_{2} \mathrm{O}$
c. $\mathrm{Br}_{2}$
d. He

Shahina -
Shahina -
Numerade Educator
01:20

Problem 38

Determine the kinds of intermolecular forces that are present in each element or compound.
a. $\mathrm{PH}_{3}$
b. HBr
c. $\mathrm{CH}_{3} \mathrm{OH}$
d. $\mathrm{I}_{2}$

Catherine Lemar
Catherine Lemar
Numerade Educator
03:21

Problem 39

Arrange these compounds in order of increasing boiling point. Explain your reasoning. MISSED THIS?
a. $\mathrm{CH}_{4}$
b. $\mathrm{CH}_{3} \mathrm{CH}_{3}$
c. $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{Cl}$
d. $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}$

Susan Hallstrom
Susan Hallstrom
Numerade Educator
02:39

Problem 40

Arrange these compounds in order of increasing boiling point. Explain your reasoning.
a. $\mathrm{H}_{2} \mathrm{~S}$
b. $\mathrm{H}_{2} \mathrm{Se}$
c. $\mathrm{H}_{2} \mathrm{O}$

Ahmed Ali
Ahmed Ali
Numerade Educator
06:32

Problem 41

In each pair of compounds, pick the one with the higher boiling point. Explain your reasoning. MISSED THIS? Read Section 12.3; Watch $\mathrm{KCV} 12.3,$ IWE 12.2
a. $\mathrm{CH}_{3} \mathrm{OH}$ or $\mathrm{CH}_{3} \mathrm{SH}$
b. $\mathrm{CH}_{3} \mathrm{OCH}_{3}$ or $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}$
c. $\mathrm{CH}_{4}$ or $\mathrm{CH}_{3} \mathrm{CH}_{3}$

Shahina -
Shahina -
Numerade Educator
03:07

Problem 42

In each pair of compounds, pick the one with the higher boiling point. Explain your reasoning.
a. $\mathrm{NH}_{3}$ or $\mathrm{CH}_{4}$
b. $\mathrm{CS}_{2}$ or $\mathrm{CO}_{2}$
c. $\mathrm{CO}_{2}$ or $\mathrm{NO}_{2}$

Ahmed Ali
Ahmed Ali
Numerade Educator
07:58

Problem 43

In each pair of compounds, pick the one with the higher vapor pressure at a given temperature. Explain your reasoning. MISSED THIS?
a. $\mathrm{Br}_{2}$ or $\mathrm{I}_{2}$
b. $\mathrm{H}_{2} \mathrm{~S}$ or $\mathrm{H}_{2} \mathrm{O}$
c. $\mathrm{NH}_{3}$ or $\mathrm{PH}_{3}$

Shahina -
Shahina -
Numerade Educator
05:22

Problem 44

In each pair of compounds, pick the one with the higher vapor pressure at a given temperature. Explain your reasoning.
a. $\mathrm{CH}_{4}$ or $\mathrm{CH}_{3} \mathrm{Cl}$
b. $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{OH}$ or $\mathrm{CH}_{3} \mathrm{OH}$
c. $\mathrm{CH}_{3} \mathrm{OH}$ or $\mathrm{H}_{2} \mathrm{CO}$

Ahmed Ali
Ahmed Ali
Numerade Educator
04:24

Problem 45

Determine whether each pair of compounds forms a homogeneous solution when combined. For those that form homogeneous solutions, indicate the type of forces that are involved. MISSED THIS?
a. $\mathrm{CCl}_{4}$ and $\mathrm{H}_{2} \mathrm{O}$
b. $\mathrm{KCl}$ and $\mathrm{H}_{2} \mathrm{O}$
c. $\mathrm{Br}_{2}$ and $\mathrm{CCl}_{4}$
d. $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}$ and $\mathrm{H}_{2} \mathrm{O}$

Shahina -
Shahina -
Numerade Educator
04:12

Problem 46

Determine whether each pair of compounds forms a homogeneous solution when combined. For those that form homogeneous solutions, indicate the type of forces that are involved.
a. $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{3}$ and $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{3}$
b. $\mathrm{CBr}_{4}$ and $\mathrm{H}_{2} \mathrm{O}$
c. $\mathrm{LiNO}_{3}$ and $\mathrm{H}_{2} \mathrm{O}$
d. $\mathrm{CH}_{3} \mathrm{OH}$ and $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{3}$

Ahmed Ali
Ahmed Ali
Numerade Educator
01:41

Problem 47

Which compound would you expect to have greater surface tension: acetone $\left[\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CO}\right]$ or water $\left(\mathrm{H}_{2} \mathrm{O}\right)$ ? Explain.

Ahmed Ali
Ahmed Ali
Numerade Educator
04:37

Problem 48

Water (a) "wets" some surfaces and beads up on others. Mercury
(b), in contrast, beads up on almost all surfaces. Explain this difference.

Ahmed Ali
Ahmed Ali
Numerade Educator
03:28

Problem 49

The structures of two isomers of heptane are shown. Which of these two compounds would you expect to have the greater viscosity? MISSED THIS?

Shahina -
Shahina -
Numerade Educator
06:00

Problem 50

Explain why the viscosity of multigrade motor oils is less temperature-dependent than that of single-grade motor oils.

Ahmed Ali
Ahmed Ali
Numerade Educator
02:47

Problem 51

Water in a glass tube that contains grease or oil residue displays a flat meniscus (left), whereas water in a clean glass tube displays a concave meniscus (right). Explain this observation.

Ahmed Ali
Ahmed Ali
Numerade Educator
04:51

Problem 52

When a thin glass tube is put into water, the water rises $1.4 \mathrm{~cm} .$ When the same tube is put into hexane, the hexane rises only $0.4 \mathrm{~cm} .$ Explain.

RD
Ryan Daly
Numerade Educator
00:38

Problem 53

Which evaporates more quickly: $55 \mathrm{~mL}$ of water in a beaker with a diameter of $4.5 \mathrm{~cm}$ or $55 \mathrm{~mL}$ of water in a dish with a diameter of $12 \mathrm{~cm} ?$ Is the vapor pressure of the water different in the two containers? Explain.

Lizabeth Tumminello
Lizabeth Tumminello
Numerade Educator
05:27

Problem 54

Which evaporates more quickly: $55 \mathrm{~mL}$ of water $\left(\mathrm{H}_{2} \mathrm{O}\right)$ in a beaker or $55 \mathrm{~mL}$ of acetone $\left[\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CO}\right]$ in an identical beaker under identical conditions? Is the vapor pressure of the two substances different? Explain.

RD
Ryan Daly
Numerade Educator
00:39

Problem 55

Spilling room-temperature water over your skin on a hot day cools you down. Spilling room-temperature vegetable oil over your skin on a hot day does not. Explain the difference.

Lizabeth Tumminello
Lizabeth Tumminello
Numerade Educator
01:15

Problem 56

Why is the heat of vaporization of water greater at room temperature than it is at its boiling point?

Nicholas White
Nicholas White
Numerade Educator
04:47

Problem 57

The human body obtains 915 kJ of energy from a candy bar. If this energy were used to vaporize water at $100.0{ }^{\circ} \mathrm{C},$ how much water (in liters) could be vaporized? (Assume the density of water is $1.00 \mathrm{~g} / \mathrm{mL} .$ )

Ahmed Ali
Ahmed Ali
Numerade Educator
03:14

Problem 58

A 100.0 -mL sample of water is heated to its boiling point. How much heat (in kj) is required to vaporize it? (Assume a density of $1.00 \mathrm{~g} / \mathrm{mL}$

Ahmed Ali
Ahmed Ali
Numerade Educator
04:39

Problem 59

Suppose that $0.95 \mathrm{~g}$ of water condenses on a $75.0-\mathrm{g}$ block of iron that is initially at $22^{\circ} \mathrm{C}$. If the heat released during condensation goes only to warming the iron block, what is the final temperature (in ${ }^{\circ} \mathrm{C}$ ) of the iron block? (Assume a constant enthalpy of vaporization for water of $44.0 \mathrm{~kJ} / \mathrm{mol} .)$

Ahmed Ali
Ahmed Ali
Numerade Educator
06:40

Problem 60

Suppose that $1.15 \mathrm{~g}$ of rubbing alcohol $\left(\mathrm{C}_{3} \mathrm{H}_{8} \mathrm{O}\right)$ evaporates from a $65.0-\mathrm{g}$ aluminum block. If the aluminum block is initially at $25^{\circ} \mathrm{C},$ what is the final temperature of the block after the evaporation of the alcohol? Assume that the heat required for the vaporization of the alcohol comes only from the aluminum block and that the alcohol
vaporizes at $25^{\circ} \mathrm{C}$

Ahmed Ali
Ahmed Ali
Numerade Educator
04:36

Problem 61

This table displays the vapor pressure of ammonia at several different temperatures. Use the data to determine the heat of
vaporization and normal boiling point of ammonia.

Ahmed Ali
Ahmed Ali
Numerade Educator
04:57

Problem 62

This table displays the vapor pressure of nitrogen at several different temperatures. Use the data to determine the heat of vaporization and normal boiling point of nitrogen.

Nicholas White
Nicholas White
Numerade Educator
03:29

Problem 63

Ethanol has a heat of vaporization of $38.56 \mathrm{~kJ} / \mathrm{mol}$ and a normal boiling point of $78.4^{\circ} \mathrm{C}$. What is the vapor pressure of ethanol at $15^{\circ} \mathrm{C} ?$

Ahmed Ali
Ahmed Ali
Numerade Educator
03:13

Problem 64

Benzene has a heat of vaporization of $30.72 \mathrm{~kJ} / \mathrm{mol}$ and a normal boiling point of $80.1^{\circ} \mathrm{C}$. At what temperature does benzene boil when the external pressure is 445 torr?

Ahmed Ali
Ahmed Ali
Numerade Educator
02:53

Problem 65

Carbon disulfide has a vapor pressure of 363 torr at $25^{\circ} \mathrm{C}$ and a normal boiling point of $46.3^{\circ} \mathrm{C}$. Find $\Delta H_{\text {vap }}$ for carbon disulfide.

Ahmed Ali
Ahmed Ali
Numerade Educator
15:34

Problem 66

Methylamine has a vapor pressure of 344 torr at $-25^{\circ} \mathrm{C}$ and a boiling point of $-6.4^{\circ} \mathrm{C}$. Find $\Delta H_{\mathrm{vap}}$ for methylamine.

RD
Ryan Daly
Numerade Educator
01:21

Problem 67

How much energy is released when 65.8 g of water freezes?

Lizabeth Tumminello
Lizabeth Tumminello
Numerade Educator
02:50

Problem 68

Calculate the amount of heat required to completely sublime $50.0 \mathrm{~g}$ of solid dry ice $\left(\mathrm{CO}_{2}\right)$ at its sublimation temperature. The heat of sublimation for carbon dioxide is $32.3 \mathrm{~kJ} / \mathrm{mol}$.

Ahmed Ali
Ahmed Ali
Numerade Educator
01:26

Problem 69

An $8.5-\mathrm{g}$ ice cube is placed into $255 \mathrm{~g}$ of water. Calculate the temperature change in the water upon the complete melting of the ice. Assume that all of the energy required to melt the ice comes from the water.

Lizabeth Tumminello
Lizabeth Tumminello
Numerade Educator
14:22

Problem 70

How much ice (in grams) would have to melt to lower the temperature of $352 \mathrm{~mL}$ of water from $25^{\circ} \mathrm{C}$ to $5^{\circ} \mathrm{C}$ ? (Assume the density of water is $1.0 \mathrm{~g} / \mathrm{mL} .$.)

RD
Ryan Daly
Numerade Educator
05:17

Problem 71

How much heat (in kj) is required to warm $10.0 \mathrm{~g}$ of ice, initially at $-10.0^{\circ} \mathrm{C},$ to steam at $110.0^{\circ} \mathrm{C} ?$ The heat capacity of ice is $2.09 \mathrm{~J} / \mathrm{g} \cdot{ }^{\circ} \mathrm{C},$ and that of steam is $2.01 \mathrm{~J} / \mathrm{g} \cdot{ }^{\circ} \mathrm{C}$

Catherine Lemar
Catherine Lemar
Numerade Educator
03:55

Problem 72

How much heat (in kJ) is evolved in converting $1.00 \mathrm{~mol}$ of steam at $145^{\circ} \mathrm{C}$ to ice at $-50^{\circ} \mathrm{C}$ ? The heat capacity of steam is $2.01 \mathrm{~J} / \mathrm{g} \cdot{ }^{\circ} \mathrm{C},$ and that of ice is $2.09 \mathrm{~J} / \mathrm{g} \cdot{ }^{\circ} \mathrm{C}$

Catherine Lemar
Catherine Lemar
Numerade Educator
01:19

Problem 73

Consider the phase diagram shown here. Identify the states present at points $a$ through $g$.

Ahmed Ali
Ahmed Ali
Numerade Educator
02:59

Problem 74

Consider the phase diagram for iodine shown here.
a. What is the normal boiling point for iodine?
b. What is the melting point for iodine at 1 atm?
c. What state is present at room temperature and normal atmospheric pressure?
d. What state is present at $186^{\circ} \mathrm{C}$ and $1.0 \mathrm{~atm} ?$

Shahina -
Shahina -
Numerade Educator
03:40

Problem 75

Nitrogen has a normal boiling point of $77.3 \mathrm{~K}$ and a melting point (at 1 atm) of 63.1 K. Its critical temperature is $126.2 \mathrm{~K}$, and its critical pressure is $2.55 \times 10^{4}$ torr. It has a triple point at $63.1 \mathrm{~K}$ and 94.0 torr. Sketch the phase diagram for nitrogen. Does nitrogen have a stable liquid state at 1 atm?

Ahmed Ali
Ahmed Ali
Numerade Educator
03:18

Problem 76

Argon has a normal boiling point of $87.2 \mathrm{~K}$ and a melting point (at 1 atm) of 84.1 K. Its critical temperature is $150.8 \mathrm{~K},$ and its critical pressure is 48.3 atm. It has a triple point at $83.7 \mathrm{~K}$ and 0.68 atm. Sketch the phase diagram for argon. Which has the greater density, solid argon or liquid argon?

Nicholas White
Nicholas White
Numerade Educator
03:25

Problem 77

The phase diagram for sulfur is shown here. The rhombic and monoclinic states are two solid states with different structures.
a. Below what pressure does solid sulfur sublime?
b. Which of the two solid states of sulfur is more dense?

Ahmed Ali
Ahmed Ali
Numerade Educator
01:17

Problem 78

The high-pressure phase diagram of ice is shown here. Notice that, under high pressure, ice can exist in several different solid forms. What three forms of ice are present at the triple point marked O? How does the density of ice II compare to ice I (the familiar form of ice)? Would ice III sink or float in liquid water?

Christina Sanchez
Christina Sanchez
Numerade Educator
01:07

Problem 79

Water has a high boiling point given its relatively low molar mass. Why?

Ahmed Ali
Ahmed Ali
Numerade Educator
01:53

Problem 80

Water is a good solvent for many substances. What is the molecular basis for this property, and why is it significant?

Ahmed Ali
Ahmed Ali
Numerade Educator
01:12

Problem 81

Explain the role of water in moderating Earth's climate.

Ahmed Ali
Ahmed Ali
Numerade Educator
01:45

Problem 82

How is the density of solid water compared to that of liquid water atypical among substances? Why is this significant?

Nicholas White
Nicholas White
Numerade Educator
01:51

Problem 83

Explain the observed trend in the melting points of the hydrogen halides.
$$
\begin{array}{ll}
\text { HI } & -50.8^{\circ} \mathrm{C} \\
\mathrm{HBr} & -88.5^{\circ} \mathrm{C} \\
\mathrm{HCl} & -114.8^{\circ} \mathrm{C} \\
\mathrm{HF} & -83.1^{\circ} \mathrm{C}
\end{array}
$$

Ahmed Ali
Ahmed Ali
Numerade Educator
02:11

Problem 84

Explain the observed trend in the boiling points of these compounds.
$$
\begin{array}{ll}
\mathrm{H}_{2} \mathrm{Te} & -2{ }^{\circ} \mathrm{C} \\
\mathrm{H}_{2} \mathrm{Se} & -41.5{ }^{\circ} \mathrm{C} \\
\mathrm{H}_{2} \mathrm{~S} & -60.7{ }^{\circ} \mathrm{C} \\
\mathrm{H}_{2} \mathrm{O} & 100^{\circ} \mathrm{C}
\end{array}
$$

Ahmed Ali
Ahmed Ali
Numerade Educator
02:33

Problem 85

The vapor pressure of water at $25^{\circ} \mathrm{C}$ is 23.76 torr. If $1.25 \mathrm{~g}$ of water is enclosed in a 1.5 -L container, will any liquid be present? If so, what mass of liquid?

Ahmed Ali
Ahmed Ali
Numerade Educator
02:26

Problem 86

The vapor pressure of $\mathrm{CCl}_{3} \mathrm{~F}$ at $300 \mathrm{~K}$ is 856 torr. If $11.5 \mathrm{~g}$ of $\mathrm{CCl}_{3} \mathrm{~F}$ is enclosed in a 1.0 - $\mathrm{L}$ container, will any liquid be present? If so, what mass of liquid?

Ahmed Ali
Ahmed Ali
Numerade Educator
02:25

Problem 87

Examine the phase diagram for iodine shown in Figure 12.39 (a). What state transitions occur as we uniformly increase the pressure on a gaseous sample of iodine from 0.010 atm at $185^{\circ} \mathrm{C}$ to 100 atm at $185^{\circ} \mathrm{C}$ ? Make a graph, analogous to the heating curve for water shown in Figure $12.36 .$ Plot pressure versus time during the pressure increase.

Jenna Nikles
Jenna Nikles
Numerade Educator
01:08

Problem 88

Carbon tetrachloride displays a triple point at $249.0 \mathrm{~K}$ and a melting point (at 1 atm) of $250.3 \mathrm{~K}$. Which state of carbon tetrachloride is more dense, the solid or the liquid? Explain.

Ahmed Ali
Ahmed Ali
Numerade Educator
01:54

Problem 89

Four ice cubes at exactly $0^{\circ} \mathrm{C}$ with a total mass of $53.5 \mathrm{~g}$ are combined with $115 \mathrm{~g}$ of water at $75^{\circ} \mathrm{C}$ in an insulated container. If no heat is lost to the surroundings, what is the final temperature of the mixture?

Ahmed Ali
Ahmed Ali
Numerade Educator
01:32

Problem 90

A sample of steam with a mass of $0.552 \mathrm{~g}$ and at a temperature of $100^{\circ} \mathrm{C}$ condenses into an insulated container holding $4.25 \mathrm{~g}$ of water at $5.0^{\circ} \mathrm{C}$. Assuming that no heat is lost to the surroundings, what is the final temperature of the mixture?

Ahmed Ali
Ahmed Ali
Numerade Educator
05:07

Problem 91

Draw a heating curve (such as the one in Figure 12.36 ) for 1 mole of methanol beginning at $170 \mathrm{~K}$ and ending at $350 \mathrm{~K}$. Assume that the values given here are constant over the relevant temperature ranges.
$$
\begin{array}{ll}
\hline \text { Melting point } & 176 \mathrm{~K} \\
\text { Boiling point } & 338 \mathrm{~K} \\
\Delta \mathrm{H}_{\text {fus }} & 2.2 \mathrm{~kJ} / \mathrm{mol} \\
\Delta \mathrm{H}_{\text {vap }} & 35.2 \mathrm{~kJ} / \mathrm{mol} \\
\mathrm{C}_{\mathrm{s}, \text { solid }} & 105 \mathrm{~J} / \mathrm{K} \\
\mathrm{C}_{\mathrm{s}} \text { , liquid } & 81.3 \mathrm{~J} / \mathrm{mol} \cdot \mathrm{K} \\
\mathrm{C}_{\mathrm{s}, \text { gas }} & 48 \mathrm{~J} / \mathrm{mol} \cdot \mathrm{K} \\
\hline
\end{array}
$$

Jenna Nikles
Jenna Nikles
Numerade Educator
04:08

Problem 92

Draw a heating curve (such as the one in Figure 12.36 ) for $1 \mathrm{~mol}$ of benzene beginning at $0^{\circ} \mathrm{C}$ and ending at $100^{\circ} \mathrm{C}$. Assume that the values given here are constant over the relevant tempera-
ture ranges.
$$
\begin{array}{ll}
\hline \text { Melting point } & 5.4^{\circ} \mathrm{C} \\
\text { Boiling point } & 80.1^{\circ} \mathrm{C} \\
\Delta \mathrm{H}_{\text {fus }} & 9.9 \mathrm{~kJ} / \mathrm{mol} \\
\Delta H_{\text {vap }} & 30.7 \mathrm{~kJ} / \mathrm{mol} \\
C_{\text {s, solid }} & 118 \mathrm{~J} / \mathrm{mol} \cdot \mathrm{K} \\
\mathrm{C}_{\text {s, liquid }} & 135 \mathrm{~J} / \mathrm{mol} \cdot \mathrm{K} \\
\mathrm{C}_{\mathrm{s}, \text { gas }} & 104 \mathrm{~J} / \mathrm{mol} \cdot \mathrm{K} \\
\hline
\end{array}
$$

Jenna Nikles
Jenna Nikles
Numerade Educator
09:16

Problem 93

Air conditioners not only cool air but dry it as well. A room in a home measures $6.0 \mathrm{~m} \times 10.0 \mathrm{~m} \times 2.2 \mathrm{~m} .$ If the outdoor tem-
perature is $30^{\circ} \mathrm{C}$ and the partial pressure of water in the air is $85 \%$ of the vapor pressure of water at this temperature, what mass of water must be removed from the air each time the vol-
ume of air in the room is cycled through the air conditioner? (Assume that all of the water must be removed from the air.) The vapor pressure for water at $30^{\circ} \mathrm{C}$ is 31.8 torr.

Shahina -
Shahina -
Numerade Educator
14:11

Problem 94

A sealed flask contains $0.55 \mathrm{~g}$ of water at $28^{\circ} \mathrm{C}$. The vapor pressure of water at this temperature is $28.35 \mathrm{mmHg}$. What is the minimum volume of the flask in order that no liquid water be present in the flask?

RD
Ryan Daly
Numerade Educator
View

Problem 95

Based on the phase diagram of $\mathrm{CO}_{2}$ shown in Figure 12.39 (b), describe the state changes that occur when the temperature of $\mathrm{CO}_{2}$ is increased from $190 \mathrm{~K}$ to $350 \mathrm{~K}$ at a constant pressure of
(a) $1 \mathrm{~atm},$ (b) $5.1 \mathrm{~atm},$ (c) $10 \mathrm{~atm},$ and
(d) $100 \mathrm{~atm} .$

Qusai Hassan
Qusai Hassan
Numerade Educator
00:49

Problem 96

Consider a planet where the pressure of the atmosphere at sea level is $2500 \mathrm{mmHg}$. Does water behave in a way that can sustain life on the planet?

Christina Sanchez
Christina Sanchez
Numerade Educator
06:00

Problem 97

Liquid nitrogen can be used as a cryogenic substance to obtain low temperatures. Under atmospheric pressure, liquid nitrogen boils at $77 \mathrm{~K},$ allowing low temperatures to be reached. However, if the nitrogen is placed in a sealed, insulated container connected to a vacuum pump, even lower temperatures can be reached. Why? If the vacuum pump has sufficient capacity and is left on for an extended period of time, the liquid nitrogen will start to freeze. Explain.

Noah Barguez-Arias
Noah Barguez-Arias
Numerade Educator
02:45

Problem 98

Given that the heat of fusion of water is $-6.02 \mathrm{~kJ} / \mathrm{mol}$, the heat capacity of $\mathrm{H}_{2} \mathrm{O}(l)$ is $75.2 \mathrm{~J} / \mathrm{mol} \cdot \mathrm{K},$ and the heat capacity of $\mathrm{H}_{2} \mathrm{O}(s)$ is $37.7 \mathrm{~J} / \mathrm{mol} \cdot \mathrm{K},$ calculate the heat of fusion of water at $-10^{\circ} \mathrm{C}$

Catherine Lemar
Catherine Lemar
Numerade Educator
04:35

Problem 99

The heat of combustion of $\mathrm{CH}_{4}$ is $890.4 \mathrm{~kJ} / \mathrm{mol},$ and the heat capacity of $\mathrm{H}_{2} \mathrm{O}$ is $75.2 \mathrm{~J} / \mathrm{mol} \cdot \mathrm{K}$. Find the volume of methane measured at $298 \mathrm{~K}$ and 1.00 atm required to convert $1.00 \mathrm{~L}$ of water at $298 \mathrm{~K}$ to water vapor at $373 \mathrm{~K}$.

Catherine Lemar
Catherine Lemar
Numerade Educator
05:20

Problem 100

Two liquids, $\mathrm{A}$ and $\mathrm{B}$, have vapor pressures at a given temperature of $24 \mathrm{mmHg}$ and $36 \mathrm{mmHg}$, respectively. We prepare solutions of $\mathrm{A}$ and $\mathrm{B}$ at a given temperature and measure the total pressures above the solutions. We obtain these data:
$$
\begin{array}{cccc}
\text { Solution } & \text { Amt A (mol) } & \text { Amt B (mol) } & \text { P(mmHg) } \\
\hline 1 & 1 & 1 & 30 \\
\hline 2 & 2 & 1 & 28 \\
\hline 3 & 1 & 2 & 32 \\
\hline 4 & 1 & 3 & 33 \\
\hline
\end{array}
$$
$$
\text { Predict the total pressure above a solution of } 5 \mathrm{~mol} \text { A and } 1 \mathrm{~mol} \text { B. }
$$

Shahina -
Shahina -
Numerade Educator
02:42

Problem 101

Three $1.0-\mathrm{L}$ flasks, maintained at $308 \mathrm{~K},$ are connected to each other with stopcocks. Initially, the stopcocks are closed. One of the flasks contains $1.0 \mathrm{~atm}$ of $\mathrm{N}_{2} ;$ the second, $2.0 \mathrm{~g}$ of $\mathrm{H}_{2} \mathrm{O} ;$ and the third, $0.50 \mathrm{~g}$ of ethanol, $\mathrm{C}_{2} \mathrm{H}_{6} \mathrm{O}$. The vapor pressure of $\mathrm{H}_{2} \mathrm{O}$ at $308 \mathrm{~K}$ is $42 \mathrm{mmHg},$ and that of ethanol is $102 \mathrm{mmHg} .$ The stopcocks are then opened and the contents mix freely. What is the pressure?

Jenna Nikles
Jenna Nikles
Numerade Educator
08:18

Problem 102

Butane $\left(\mathrm{C}_{4} \mathrm{H}_{10}\right)$ has a heat of vaporization of $22.44 \mathrm{~kJ} / \mathrm{mol}$ and a normal boiling point of $-0.4^{\circ} \mathrm{C} .$ A $250-\mathrm{mL}$ sealed flask contains $0.55 \mathrm{~g}$ of butane at $-22^{\circ} \mathrm{C} .$ How much butane is present as a liquid? If the butane is warmed to $25^{\circ} \mathrm{C},$ how much is present as a liquid?

Adriano Chikande
Adriano Chikande
Numerade Educator
04:19

Problem 103

The following image is an electrostatic potential map for ethylene oxide, $\left(\mathrm{CH}_{2}\right)_{2} \mathrm{O},$ a polar molecule. Use the electrostatic potential map to predict the geometry for how one ethylene oxide molecule interacts with another. Draw structural formu-
las, using the $3 \mathrm{D}$ bond notation introduced in Section $11.4,$ to
show the geometry of the interaction.

Shahina -
Shahina -
Numerade Educator
00:51

Problem 104

One prediction of global warming is the melting of global ice, which may result in coastal flooding. A criticism of this prediction is that the melting of icebergs does not increase ocean levels any more than the melting of ice in a glass of water increases the level of liquid in the glass. Is this a valid criticism? Does the melting of an ice cube in a cup of water raise the level of the liquid in the cup? Why or why not? In response to this criticism, scientists have asserted that they are not worried about melting icebergs, but rather the melting of ice sheets that sit on the continent of Antarctica. Would the melting of this ice increase ocean levels? Why or why not?

Lizabeth Tumminello
Lizabeth Tumminello
Numerade Educator
01:28

Problem 105

The rate of vaporization depends on the surface area of the liquid. However, the vapor pressure of a liquid does not depend on the surface area. Explain.

Nicholas White
Nicholas White
Numerade Educator
02:02

Problem 106

Substance A has a smaller heat of vaporization than substance $\mathrm{B}$. Which of the two substances will undergo a larger change in vapor pressure for a given change in temperature?

Ahmed Ali
Ahmed Ali
Numerade Educator
01:37

Problem 107

The density of a substance is greater in its solid state than in its liquid state. If the triple point in the phase diagram of the substance is below 1.0 atm, which will necessarily be at a lower temperature, the triple point or the normal melting point?

Ahmed Ali
Ahmed Ali
Numerade Educator
01:28

Problem 108

A substance has a heat of vaporization of $\Delta H_{\text {vap }}$ and a heat of fusion of $\Delta H_{\text {fus. }}$ Express the heat of sublimation in terms of $\Delta H_{\text {vap }}$ and $\Delta H_{\text {fus }}$

Ahmed Ali
Ahmed Ali
Numerade Educator
00:51

Problem 109

Examine the heating curve for water in Section 12.7 (Figure 12.36 ). If heat is added to the water at a constant rate, which of the three segments in which temperature is rising will have the least steep slope? Why?

Catherine Lemar
Catherine Lemar
Numerade Educator
01:40

Problem 110

A root cellar is an underground chamber used to store fruits, vegetables, and even meats. In extreme cold, farmers put large vats of water into the root cellar to prevent the fruits and vegetables from freezing. Explain why this works.

Christina Sanchez
Christina Sanchez
Numerade Educator
00:36

Problem 111

Suggest an explanation for the observation that the heat of fusion of a substance is always smaller than its heat of vaporization.

Lizabeth Tumminello
Lizabeth Tumminello
Numerade Educator
05:13

Problem 112

Refer to Figure 12.36 to answer each question.
a. A sample of steam begins on the line segment labeled 5 on the graph. Is heat absorbed or released in moving from the line segment labeled 5 to the line segment labeled $3 ?$ What is the sign of $q$ for this change?
b. In moving from left to right along the line segment labeled 2 on the graph, heat is absorbed, but the temperature remains constant. Where does the heat go?
c. How would the graph change if it were for another substance (other than water)?

Nicholas White
Nicholas White
Numerade Educator
04:17

Problem 113

The boiling points of three compounds are tabulated here.
$$
\begin{array}{lcc}
& \text { Molar Mass } & \text { Boiling Point } \\
\hline \text { 2-hexanone } & 100.16 & 128^{\circ} \mathrm{C} \\
\hline \text { heptane } & 100.20 & 98^{\circ} \mathrm{C} \\
\hline \text { 1-hexanol } & 102.17 & 156^{\circ} \mathrm{C} \\
\hline
\end{array}
$$
Answer the following questions without looking up the structures for these molecules: Which compound experiences hydrogen bonding? Which compound is polar but is unable to experience hydrogen bonding? Which is neither polar nor capable of hydrogen bonding? Explain your answers.

Shahina -
Shahina -
Numerade Educator
03:39

Problem 114

The vapor pressure for pure water and pure acetone is measured as a function of temperature. In each case, a graph of the log of the vapor pressure versus $1 / T$ is found to be a straight line. The slope of the line for water is $-4895 \mathrm{~K},$ and the slope of the line for acetone is $-3765 \mathrm{~K}$. Determine $\Delta H_{\text {vap }}$ for each substance. Account for the difference by discussing the molecular structure of the two molecules.

Ahmed Ali
Ahmed Ali
Numerade Educator
00:55

Problem 115

Based on the heating curve for water, does it take more energy to melt a mole of water or to boil a mole of water? Does it take
more energy to warm the solid, the liquid, or the gas by $10^{\circ} \mathrm{C} ?$ Explain your answers clearly.

Christina Sanchez
Christina Sanchez
Numerade Educator
03:39

Problem 116

Sketch the phase diagram for carbon dioxide. If you have carbon dioxide at 1.0 atm and $25^{\circ} \mathrm{C}$, could you make it a liquid by cooling it down? How could you make it a liquid at $25^{\circ} \mathrm{C}$ ? If you increase the pressure of carbon dioxide that is at body temperature $\left(37^{\circ} \mathrm{C}\right),$ will it ever liquefy?

Ahmed Ali
Ahmed Ali
Numerade Educator
01:35

Problem 117

We have seen that molar mass and molecular structure influ-
ence the boiling point of a substance. We can see these two factors at work in the boiling points of the group 6 A hydrides shown in the following graph.

Lottie Adams
Lottie Adams
Numerade Educator