Chemistry Principles and Reactions

William L. Masterton, Cecile N. Hurley

Chapter 9

Liquids and Solids - all with Video Answers

Educators

Chapter Questions

Problem 1

1. Methyl alcohol can be used as a fuel instead of, or combined with, gasoline. A sample of methyl alcohol, $\mathrm{CH}_{3} \mathrm{OH}$, in a flask of constant volume exerts a pressure of $254 \mathrm{~mm} \mathrm{Hg}$ at $57^{\circ} \mathrm{C}$. The flask is slowly cooled.
(a) Assuming no condensation, use the ideal gas law to calculate the pressure of the vapor at $35^{\circ} \mathrm{C} ;$ at $45^{\circ} \mathrm{C}$.
(b) Compare your answers in (a) with the equilibrium vapor pressures of methyl alcohol: $203 \mathrm{~mm} \mathrm{Hg}$ at $35^{\circ} \mathrm{C}$; $325 \mathrm{~mm} \mathrm{Hg}$ at $45^{\circ} \mathrm{C}$
(c) On the basis of your answers to (a) and (b), predict the pressure exerted by the methyl alcohol in the flask at $35^{\circ} \mathrm{C} ;$ at $45^{\circ} \mathrm{C}$
(d) What physical states of methyl alcohol are present in the flask at $35^{\circ} \mathrm{C}$ ? at $45^{\circ} \mathrm{C} ?$

Eileen Sullivan

Eileen Sullivan

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Problem 2

Benzene, a known carcinogen, was once widely used as a solvent. A sample of benzene vapor in a flask of constant volume exerts a pressure of $325 \mathrm{~mm} \mathrm{Hg}$ at $80^{\circ} \mathrm{C}$. The flask is slowly cooled.
(a) Assuming no condensation, use the ideal gas law to calculate the pressure of the vapor at $50^{\circ} \mathrm{C} ;$ at $60^{\circ} \mathrm{C}$.
(b) Compare your answers in (a) to the equilibrium vapor pressures of benzene: $269 \mathrm{~mm} \mathrm{Hg}$ at $50^{\circ} \mathrm{C}$, $389 \mathrm{~mm} \mathrm{Hg}$ at $60^{\circ} \mathrm{C}$
(c) On the basis of your answers to (a) and (b), predict the pressure exerted by the benzene at $50^{\circ} \mathrm{C}$; at $60^{\circ} \mathrm{C}$.

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 3

The vapor pressure of $\mathrm{I}_{2}(s)$ at $30^{\circ} \mathrm{C}$ is $0.466 \mathrm{~mm} \mathrm{Hg}$.
(a) How many milligrams of iodine will sublime into an evacuated 750.0 -mL flask?
(b) If $3.00 \mathrm{mg}$ of $\mathrm{I}_{2}$ are used, what will the final pressure in the flask be?
(c) If $7.85 \mathrm{mg}$ of $\mathrm{I}_{2}$ are used, what will the final pressure in the flask be?

Susan Hallstrom

Susan Hallstrom

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Problem 4

Camphor, $\mathrm{C}_{10} \mathrm{H}_{16} \mathrm{O},$ is the active ingredient in vaporsteam products like Vicks VapoRub $^{\oplus}$. Its vapor pressure at $20^{\circ} \mathrm{C}$ is $0.18 \mathrm{~mm} \mathrm{Hg}$
(a) How many milligrams of camphor will sublime into an evacuated 0.500 -L flask?
(b) A $125-\mathrm{mL}$ flask contains $0.15 \mathrm{mg}$ of camphor at $20^{\circ} \mathrm{C}$. What is the pressure in the flask?

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 5

Trichloroethane, $\mathrm{C}_{2} \mathrm{H}_{3} \mathrm{Cl}_{3}$ is used as a degreaser (solvent for waxes and oils). Its density is $1.435 \mathrm{~g} / \mathrm{mL}$ and its vapor pressure at $20^{\circ} \mathrm{C}$ is $124 \mathrm{~mm} \mathrm{Hg}$.
(a) How many mL will vaporize in an evacuated $1.50-\mathrm{L}$ flask at $20^{\circ} \mathrm{C} ?$
(b) A 3.00-mL sample is poured into an evacuated 1.5 - $\mathrm{L}$ flask at $20^{\circ} \mathrm{C}$. Will all the liquid vaporize? If not, what is the pressure in the flask?
(c) A similar 3.00 -mL sample is poured into an evacuated $20.00-\mathrm{L}$ flask at $20^{\circ} \mathrm{C}$. What physical state(s) is/are in the flask?

Eileen Sullivan

Eileen Sullivan

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Problem 6

$p$ -Dichlorobenzene, $\mathrm{C}_{6} \mathrm{H}_{4} \mathrm{Cl}_{2},$ can be one of the ingredients in mothballs. Its vapor pressure at $20^{\circ} \mathrm{C}$ is $0.40 \mathrm{~mm} \mathrm{Hg}$.
(a) How many milligrams of $\mathrm{C}_{6} \mathrm{H}_{4} \mathrm{Cl}_{2}$ will sublime into an evacuated 750 -mL flask at $20^{\circ} \mathrm{C}$ ?
(b) If $5.0 \mathrm{mg}$ of $p$ -dichlorobenzene were put into an evacuated 750 -mL flask, how many milligrams would remain in the solid phase?
(c) What is the final pressure in an evacuated $500-\mathrm{mL}$ flask at $20^{\circ} \mathrm{C}$ that contains $2.00 \mathrm{mg}$ of $p$ -dichlorobenzene? Will there be any solid in the flask?

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 7

Chloroform, $\mathrm{CHCl}_{3},$ was once used as an anesthetic. In spy movies it is the liquid put in handkerchiefs to render victims unconscious. Its vapor pressure is $197 \mathrm{~mm} \mathrm{Hg}$ at $23^{\circ} \mathrm{C}$ and $448 \mathrm{~mm} \mathrm{Hg}$ at $45^{\circ} \mathrm{C}$. Estimate its
(a) heat of vaporization.
(b) normal boiling point.

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 8

Dichloromethane, $\mathrm{CH}_{2} \mathrm{Cl}_{2}$, is widely used as a "degreaser" and paint stripper. Its vapor pressure is $381.0 \mathrm{~mm} \mathrm{Hg}$ at $21.9^{\circ} \mathrm{C}$ and $465.8 \mathrm{~mm} \mathrm{Hg}$ at $26.9^{\circ} \mathrm{C}$. Estimate
(a) its heat of vaporization $\left(\Delta H_{\text {vap }}\right)$.
(b) its normal boiling point.

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 9

Winter Park, a town in the Rocky Mountains of Colorado, has an altitude of 9100 (2 significant figures) feet. Water $\left(\Delta H_{\text {vap }}=40.7 \mathrm{~kJ} / \mathrm{mol}\right)$ boils at $91^{\circ} \mathrm{C}$ in Winter Park. What is the normal atmospheric pressure in Winter Park?

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 10

Glacier National Park in Montana is a favorite vacation spot for backpackers. It is about $4100 \mathrm{ft}$ above sea level with an atmospheric pressure of $681 \mathrm{~mm} \mathrm{Hg} .$ At what temperature does water $\left(\Delta H_{\text {vap }}=40.7 \mathrm{~kJ} / \mathrm{mol}\right)$ boil in Glacier National Park?

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 11

At a resort in Sante Fe, New Mexico, the barometric pressure is $625 \mathrm{~mm} \mathrm{Hg}$. Water boils in an open pot at $94.5^{\circ} \mathrm{C}$. A pressure cooker is set for 1.75 atm.
(a) At what temperature will water boil in that pressure cooker? (For water, $\left.\Delta H_{\text {vap }}=40.7 \mathrm{~kJ} / \mathrm{mol} .\right)$
(b) What is the difference between the boiling point in the open pot and in the pressure cooker?

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 12

At sea level, the barometric pressure is $760 \mathrm{~mm}$ Hg. Calculate the difference in the normal boiling point for water boiled in an open pot and water boiled in a pressure cooker set for 1.75 atm. $\left(\Delta H_{\text {vap }}\right.$ for water $\left.=40.7 \mathrm{~kJ} / \mathrm{mol}\right)$

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 13

The data below give the vapor pressure of octane, a major component of gasoline.
$$
\begin{array}{lllcl}
\mathrm{vp}(\mathrm{mm} \mathrm{Hg}) & 10 & 40 & 100 & 400 \\
t\left({ }^{\circ} \mathrm{C}\right) & 19.2 & 45.1 & 65.7 & 104.0
\end{array}
$$
Plot $\ln (\mathrm{vp})$ versus $1 / T$. Use your graph to estimate the heat of vaporization of octane. $\left(\ln P=A-\frac{\Delta H_{\mathrm{vap}}}{R}\left(\frac{1}{T}\right),\right.$ where $A$ is the $y$ -intercept and $\Delta H_{\text {vap }}$ is the slope.)

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 14

Consider the following data for the vapor pressure of diethyl ether, a widely used anesthetic in the early days of surgery.
$\begin{array}{lrrrr}\mathrm{vp}(\mathrm{mm} \mathrm{Hg}) & 146 & 231 & 355 & 531 \\ t\left({ }^{\circ} \mathrm{C}\right) & -5 & 5 & 15 & 2\end{array}$
$$
25
$$
Follow the instructions in Question 13 to estimate the heat of vaporization of diethyl ether.

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 15

Referring to Figure $9.7,$ state what phase(s) is/are present at
(a) $1 \mathrm{~atm}, 100^{\circ} \mathrm{C}$.
(b) $0.5 \mathrm{~atm}, 100^{\circ} \mathrm{C}$.
(c) $0.8 \mathrm{~atm}, 50^{\circ} \mathrm{C}$.

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 16

Referring to Figure $9.7,$ state what phase(s) is (are) present at
(a) $1 \mathrm{~atm}, 10^{\circ} \mathrm{C}$.
(b) $3 \mathrm{~mm} \mathrm{Hg}, 20^{\circ} \mathrm{C}$
(c) $1000 \mathrm{~mm} \mathrm{Hg}, 75^{\circ} \mathrm{C}$.

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 17

Consider the phase diagram of the compound $\mathrm{X}$ below. Use the phase diagram to answer the following questions.(a) What is the physical state of the compound at $35 \mathrm{~mm} \mathrm{Hg}$ and $-50^{\circ} \mathrm{C}$ ?
(b) What is the normal boiling point of the compound?
(c) Where is the critical point?
(d) Where is the triple point?
(e) What change occurs when at a constant pressure of $30 \mathrm{~mm} \mathrm{Hg}$, the temperature is decreased from $120^{\circ} \mathrm{C}$ to $20^{\circ} \mathrm{C}$ ?
(f) Which phase is the densest phase?

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 18

Consider the phase diagram of the compound in Problem 17 to answer the following questions.
(a) What is the physical state of the compound at $35 \mathrm{~mm} \mathrm{Hg}$ and $120^{\circ} \mathrm{C}$ ?
(b) What is the normal freezing point of the compound?
(c) What is the point $A$ called?
(d) What is the point $B$ called?
(e) What is the point $C$ called?
(f) What change occurs when at a constant pressure of $33 \mathrm{~mm} \mathrm{Hg},$ the temperature is decreased from $40^{\circ} \mathrm{C}$ to $-20^{\circ} \mathrm{C}$ ?
(g) Will the solid float on the liquid?
(h) Can the compound exist as a liquid at $180^{\circ} \mathrm{C}$ and 2 atm pressure?

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 19

Argon gas has its triple point at $-189.3^{\circ} \mathrm{C}$ and $516 \mathrm{~mm} \mathrm{Hg} .$ It has a critical point at $-122{ }^{\circ} \mathrm{C}$ and 48 atm. The density of the solid is $1.65 \mathrm{~g} / \mathrm{cm}^{3}$, whereas that of the liquid is $1.40 \mathrm{~g} / \mathrm{cm}^{3}$. Sketch the phase diagram for argon and use it to fill in the blanks below with the words "boils," "melts," "sublimes," or "condenses."
(a) Solid argon at $500 \mathrm{~mm} \mathrm{Hg}$ __________ when the temperature is increased.
(b) Solid argon at 2 atm _________ when the temperature is increased.
(c) Argon gas at $-150^{\circ} \mathrm{C}$ _____________when the pressure is increased.
(d) Argon gas at $-165^{\circ} \mathrm{C}$ _____________ when the pressure is increased.

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 20

Iodine has a triple point at $114^{\circ} \mathrm{C}, 90 \mathrm{~mm} \mathrm{Hg} .$ Its critical temperature is $535^{\circ} \mathrm{C}$. The density of the solid is $4.93 \mathrm{~g} / \mathrm{cm}^{3},$ and that of the liquid is $4.00 \mathrm{~g} / \mathrm{cm}^{3} .$ Sketch the phase diagram for iodine and use it to fill in the blanks using either "liquid" or "solid."
(a) Iodine vapor at $80 \mathrm{~mm}$ Hg condenses to the __________ when cooled sufficiently.
(b) Iodine vapor at $125^{\circ} \mathrm{C}$ condenses to the _________ when enough pressure is applied.
(c) Iodine vapor at $700 \mathrm{~mm}$ Hg condenses to the ____________ when cooled above the triple point temperature.

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 21

Given the following data about xenon,
$$
\begin{array}{l}
\text { normal boiling point }=-108^{\circ} \mathrm{C} \\
\text { normal melting point }=-112^{\circ} \mathrm{C} \\
\text { triple point }=-121^{\circ} \mathrm{C} \text { at } 281 \mathrm{~mm} \mathrm{Hg} \\
\text { critical point }=16.6^{\circ} \mathrm{C} \text { at } 58 \mathrm{~atm}
\end{array}
$$
(a) Construct an approximate phase diagram for xenon.
(b) Estimate the vapor pressure of xenon at $-115^{\circ} \mathrm{C}$.
(c) Is the density of solid Xe larger than that for liquid Xe?

Nicole Smina

Numerade Educator

Problem 22

Given the following data about $\mathrm{CO}_{2}$ :
triple point: $-57^{\circ} \mathrm{C}, 5.11 \mathrm{~atm}$
critical point: $31^{\circ} \mathrm{C}, 73$ atm
sublimes at $-78.5^{\circ} \mathrm{C}, 1 \mathrm{~atm}$
The solid is the denser phase.
(a) Construct a simplified (not to scale) phase diagram for $\mathrm{CO}_{2}$
(b) Estimate the vapor pressure of $\mathrm{CO}_{2}$ at $0^{\circ} \mathrm{C}$.
(c) At 10 atm pressure and $-50^{\circ} \mathrm{C},$ is $\mathrm{CO}_{2}$ a liquid?

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 23

A pure substance $X$ has the following properties: $\mathrm{mp}=90^{\circ} \mathrm{C}$, increasing slightly as pressure increases; normal $\mathrm{bp}=120^{\circ} \mathrm{C} ;$ liquid $\mathrm{vp}=65 \mathrm{~mm} \mathrm{Hg}$ at $100^{\circ} \mathrm{C}, 20 \mathrm{~mm} \mathrm{Hg}$ at the triple point.
(a) Draw a phase diagram for $\mathrm{X}$.
(b) Label solid, liquid, and vapor regions of the diagram.
(c) What changes occur if, at a constant pressure of $100 \mathrm{~mm} \mathrm{Hg}$, the temperature is raised from $100^{\circ} \mathrm{C}$ to $150^{\circ} \mathrm{C} ?$

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 23

A pure substance $X$ has the following properties: $\mathrm{mp}=90^{\circ} \mathrm{C}$, increasing slightly as pressure increases; normal $\mathrm{bp}=120^{\circ} \mathrm{C} ;$ liquid $\mathrm{vp}=65 \mathrm{~mm} \mathrm{Hg}$ at $100^{\circ} \mathrm{C}, 20 \mathrm{~mm} \mathrm{Hg}$ at the triple point.
(a) Draw a phase diagram for $\mathrm{X}$.
(b) Label solid, liquid, and vapor regions of the diagram.
(c) What changes occur if, at a constant pressure of $100 \mathrm{~mm} \mathrm{Hg}$, the temperature is raised from $100^{\circ} \mathrm{C}$ to $150^{\circ} \mathrm{C} ?$

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 24

A pure substance A has a liquid vapor pressure of 6 atm at $550^{\circ} \mathrm{C}$. Its triple point is at $5 \mathrm{~atm}, 350^{\circ} \mathrm{C}$. The solid phase is denser than the liquid phase.
(a) Sketch the phase diagram for compound $A$.
(b) From the phase diagram, estimate the temperature at which the compound boils when 6.3 atm of pressure are applied.
(c) What changes occur when, at a constant pressure of 4 atm, the temperature drops from $400^{\circ} \mathrm{C}$ to $100^{\circ} \mathrm{C} ?$

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 25

Arrange the following in order of decreasing boiling point.
(a) $\mathrm{I}_{2}$
(b) $\mathrm{F}_{2}$
(c) $\mathrm{Cl}_{2}$
(d) $\mathrm{Br}_{2}$

Nicole Smina

Numerade Educator

Problem 26

Arrange the following compounds in order of increasing boiling point.
(a) $\mathrm{Ar}$
(b) $\mathrm{He}$
(c) $\mathrm{Ne}$
(d) $\mathrm{Xe}$

Nicole Smina

Numerade Educator

Problem 27

Which of the following would you expect to show dispersion forces? dipole forces?
(a) $\mathrm{GeBr}_{4}$
(b) $\mathrm{C}_{2} \mathrm{H}_{2}$
(c) $\mathrm{HF}(g)$
(d) $\mathrm{TeCl}_{2}$

Nicole Smina

Numerade Educator

Problem 28

Which of the following compounds would you expect to show dispersion forces? Dipole forces?
(a) $\mathrm{F}_{2}$
(b) $\mathrm{CO}$
(c) $\mathrm{CO}_{2}$
(d) $\mathrm{H}_{2} \mathrm{CO}$

Nicole Smina

Numerade Educator

Problem 29

Which of the following would show hydrogen bonding?
(a) $\mathrm{CH}_{3} \mathrm{OH}$
(b)
(c) $\mathrm{CH}_{3} \mathrm{NH}_{2}$
(d) HF

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 30

Which of the following compounds show hydrogen bonding?
(a) $\mathrm{CH}_{3} \mathrm{~F}$
(b) $\mathrm{HO}-\mathrm{OH}$
(c) $\mathrm{NH}_{3} \mathrm{~F}$
(d) $\mathrm{H}_{3} \mathrm{C}-\mathrm{O}-\mathrm{CH}_{3}$

Nicole Smina

Numerade Educator

Problem 31

Explain in terms of forces between structural units why
(a) HI has a higher boiling point than HBr.
(b) $\mathrm{GeH}_{4}$ has a higher boiling point than $\mathrm{SiH}_{4}$.
(c) $\mathrm{H}_{2} \mathrm{O}_{2}$ has a higher melting point than $\mathrm{C}_{3} \mathrm{H}_{8}$.
(d) $\mathrm{NaCl}$ has a higher boiling point than $\mathrm{CH}_{3} \mathrm{OH}$.

Nicole Smina

Numerade Educator

Problem 32

Explain in terms of structural units why
(a) $\mathrm{CO}_{2}$ has a lower boiling point than $\mathrm{Na}_{2} \mathrm{CO}_{3}$.
(b) $\mathrm{N}_{2} \mathrm{H}_{4}$ has a higher boiling point than $\mathrm{C}_{2} \mathrm{H}_{6}$.
(c) formic acid, has a lower boiling point than benzoic acid,
(d) CO has a higher boiling point than $\mathrm{N}_{2}$.

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 33

In which of the following processes is it necessary to break covalent bonds as opposed to simply overcoming intermolecular forces?
(a) melting mothballs made of naphthalene
(b) dissolving HBr gas in water to form hydrobromic acid
(c) vaporizing ethyl alcohol, $\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}$
(d) changing ozone, $\mathrm{O}_{3},$ to oxygen gas, $\mathrm{O}_{2}$

Nicole Smina

Numerade Educator

Problem 34

In which of the following processes is it necessary to break covalent bonds as opposed to simply overcoming intermolecular forces?
(a) Decomposing HCl to $\mathrm{H}_{2}$ and $\mathrm{Cl}_{2}$
(b) Dissolving $\mathrm{NaCl}$ in water
(c) Freezing ethyl alcohol
(d) Subliming iodine

Nicole Smina

Numerade Educator

Problem 35

For each of the following pairs, choose the member with the lower boiling point. Explain your reason in each case.
(a) $\mathrm{NaCl}$ or $\mathrm{PCl}_{3}$
(b) $\mathrm{NH}_{3}$ or $\mathrm{AsH}_{3}$
(c) $\mathrm{C}_{3} \mathrm{H}_{7} \mathrm{OH}$ or $\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OCH}_{3}$
(d) $\mathrm{HI}(g)$ or $\mathrm{HCl}(g)$

Nicole Smina

Numerade Educator

Problem 36

Follow the directions for Question 35 for the following substances.
(a) $\mathrm{LiCl}$ or $\mathrm{CCl}_{4}$
(b) $\mathrm{CH}_{3} \mathrm{OH}$ or $\mathrm{CH}_{3} \mathrm{~F}$
(c) $\mathrm{H}_{2} \mathrm{O}$ or $\mathrm{SO}_{2}$
(d) $\mathrm{N}_{2}$ or $\mathrm{Cl}_{2}$

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 37

What are the strongest attractive forces that must be overcome to
(a) boil silicon hydride, $\mathrm{SiH}_{4}$ ?
(b) vaporize calcium chloride?
(c) dissolve $\mathrm{Cl}_{2}$ in carbon tetrachloride, $\mathrm{CCl}_{4}$ ?
(d) melt iodine?

Nicole Smina

Numerade Educator

Problem 38

What are the strongest attractive forces that must be overcome to
(a) melt ice?
(b) sublime bromine?
(c) boil chloroform $\left(\mathrm{CHCl}_{3}\right)$ ?
(d) vaporize benzene $\left(\mathrm{C}_{6} \mathrm{H}_{6}\right)$ ?

Lottie Adams

Numerade Educator

Problem 39

Classify each of the following solids as metallic, network covalent, ionic, or molecular.
(a) It is insoluble in water, melts above $500^{\circ} \mathrm{C},$ and does not conduct electricity either as a solid, dissolved in water, or molten.
(b) It dissolves in water but does not conduct electricity as an aqueous solution, as a solid, or when molten.
(c) It dissolves in water, melts above $100^{\circ} \mathrm{C},$ and conducts electricity when present in an aqueous solution.

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 40

Classify each of the following solids as metallic, network covalent, ionic, or molecular.
(a) It melts below $100^{\circ} \mathrm{C}$ and is insoluble in water.
(b) It conducts electricity only when melted.
(c) Mostly insoluble in water and conducts electricity.

Nicole Smina

Numerade Educator

Problem 41

Of the four general types of solids, which one(s)
(a) are generally low-boiling?
(b) are ductile and malleable?
(c) are generally soluble in nonpolar solvents?

Tianyu Li

Numerade Educator

Problem 42

Of the four general types of solids, which one(s)
(a) are generally insoluble in water?
(b) have very high melting points?
(c) conduct electricity as solids?

Nicole Smina

Numerade Educator

Problem 43

Classify each of the following species as molecular, network covalent, ionic, or metallic.
(a) $\mathrm{Na}$
(b) $\mathrm{Na}_{2} \mathrm{SO}_{4}$
(c) $\mathrm{C}_{6} \mathrm{H}_{6}$
(d) $\mathrm{C}_{60}$
(e) $\mathrm{HCl}(a q)$

Nicole Smina

Numerade Educator

Problem 44

Classify each of the following species as metallic, network covalent, ionic, or molecular.
(a) W
(b) $\mathrm{NO}_{2}$
(c) C (diamond)
(d) $\mathrm{FeCl}_{2}$
(e) $\mathrm{C}_{2} \mathrm{H}_{2}$

Nicole Smina

Numerade Educator

Problem 45

Give the formula of a solid containing Si that is
(a) molecular
(b) ionic
(c) network covalent

Nicole Smina

Numerade Educator

Problem 46

Give the formula of a solid containing oxygen that is
(a) a polar molecule
(b) ionic
(c) network covalent
(d) a nonpolar molecule

Nicole Smina

Numerade Educator

Problem 47

Describe the structural units in
(a) NaI
(b) $\mathrm{N}_{2}$
(c) $\mathrm{KO}_{2}$
(d) $\mathrm{Au}$

Nicole Smina

Numerade Educator

Problem 48

Describe the structural units in
(a) C (graphite)
(b) $S_{i} C$
(c) $\mathrm{FeCl}_{2}$
(d) $\mathrm{C}_{2} \mathrm{H}_{2}$

Nicole Smina

Numerade Educator

Problem 49

Molybdenum has an atomic radius of $0.145 \mathrm{nm}$. The volume of its cubic unit cell is $0.0375 \mathrm{~mm}^{3} .$ What is the geometry of the molybdenum unit cell?

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 50

Nickel has an atomic radius of $0.162 \mathrm{nm}$. The edge of its cubic unit cell is $0.458 \mathrm{nm}$. What is the geometry of the nickel unit cell?

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 51

Lead (atomic radius $=0.181 \mathrm{nm})$ crystallizes with a face-centered cubic unit cell. What is the length of a side of the cell?

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 52

Iridium crystallizes in a face-centered unit cell. The side of the cell is $0.3833 \mathrm{nm} .$ Calculate the volume of the cell and the radius of an iridium atom.

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 53

In the LiCl structure shown in Figure 9.21 , the chloride ions form a face-centered cubic unit cell $0.513 \mathrm{nm}$ on an edge. The ionic radius of $\mathrm{Cl}^{-}$ is $0.181 \mathrm{nm} .$
(a) Along a cell edge, how much space is between the $\mathrm{Cl}^{-}$ ions?
(b) Would an $\mathrm{Na}^{+}$ ion $(r=0.095 \mathrm{nm})$ fit into this space? a $\mathrm{K}^{+}$ ion $(r=0.133 \mathrm{nm}) ?$

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 54

Potassium iodide has a unit cell similar to that of sodium chloride (Figure 9.21$) .$ The ionic radii of $\mathrm{K}^{+}$ and $\mathrm{I}^{-}$ are $0.133 \mathrm{nm}$ and $0.216 \mathrm{nm},$ respectively. How long is
(a) one side of the cube?
(b) the face diagonal of the cube?

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 55

For a cell of the CsCl type (Figure 9.21 ), how is the length of one side of the cell, $s$, related to the sum of the radii of the ions, $r_{\text {cation }}+r_{\text {anion }}$ ?

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 56

Consider the CsCl cell (Figure 9.21). The ionic radii of $\mathrm{Cs}^{+}$ and $\mathrm{Cl}^{-}$ are 0.169 and $0.181 \mathrm{nm}$, respectively. What is the length of
(a) the body diagonal?
(b) the side of the cell?

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 57

Consider the sodium chloride unit cell shown in Figure 9.21. Looking only at the front face (five large Clions, four small $\mathrm{Na}^{+}$ ions $)$,
(a) how many cubes share each of the $\mathrm{Na}^{+}$ ions in this face?
(b) how many cubes share each of the $\mathrm{Cl}^{-}$ ions in this face?

Aadit Sharma

Numerade Educator

Problem 58

Consider the CsCl unit shown in Figure 9.21. How many Cs $^{+}$ ions are there per unit cell? How many $\mathrm{Cl}^{-}$ ions? (Note that each $\mathrm{Cl}^{-}$ ion is shared by eight cubes.)

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 59

A $1.25-\mathrm{L}$ clean and dry flask is sealed. The air in the flask is at $27^{\circ} \mathrm{C}$ and $38 \%$ relative humidity. The flask is put in a cooler at $5^{\circ} \mathrm{C}$. How many grams of water will condense in the flask? (Use the table in Appendix 1 for the vapor pressure of water at various temperatures.)

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 60

Aluminum metal crystallizes with a face-centered cubic unit cell. The volume of the cell is $0.0662 \mathrm{nm}^{3}$.
(a) What is the atomic radius of aluminum in $\mathrm{cm}$ ?
(b) What is the volume of a single aluminum atom?
(c) What is the density of a single aluminum atom?
(d) In face-centered cubic cell packing, the fraction of empty space is $26.0 \%$. When this is factored in, what is the calculated density of aluminum?

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 61

Consider a sealed flask with a movable piston that contains $5.25 \mathrm{~L}$ of $\mathrm{O}_{2}$ saturated with water vapor at $25^{\circ} \mathrm{C}$. The piston is depressed at constant temperature so that the gas is compressed to a volume of $2.00 \mathrm{~L}$. (Use the table in Appendix 1 for the vapor pressure of water at various temperatures.)
(a) What is the vapor pressure of water in the compressed gas mixture?
(b) How many grams of water condense when the gas mixture is compressed?

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 62

Packing efficiency is defined as the percent of the total volume of a solid occupied by (spherical) atoms. The formula is packing efficiency $=\frac{\text { volume of the atom(s) in the cell }}{\text { volume of the cell }} \times 100$ The volume of one atom is $\frac{4}{3} \pi r^{3}$ and the volume of the cell is
$s^{3} .$ Calculate the packing efficiency of
(a) a simple cubic cell (1 atom/cell).
(b) a face-centered cubic cell $(4$ atoms/cell).
(c) a body-centered cubic cell $(2$ atoms/cell). Use Table 9.6 to relate $r$ to $s$.

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 63

Mercury is an extremely toxic substance. Inhalation of the vapor is just as dangerous as swallowing the liquid. How many milliliters of mercury will saturate a room that is $15 \times 12 \times 8.0 \mathrm{ft}$ with mercury vapor at $25^{\circ} \mathrm{C}$ ? The vapor pressure of $\mathrm{Hg}$ at $25^{\circ} \mathrm{C}$ is $0.00163 \mathrm{~mm} \mathrm{Hg}$ and its density is $13 \mathrm{~g} / \mathrm{mL}$.

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 64

An experiment is performed to determine the vapor pressure of formic acid. A 30.0-L volume of helium gas at $20.0^{\circ} \mathrm{C}$ is passed through $10.00 \mathrm{~g}$ of liquid formic acid $(\mathrm{HCOOH})$ at $20.0^{\circ} \mathrm{C}$. After the experiment, $7.50 \mathrm{~g}$ of liquid formic acid remains. Assume that the helium gas becomes saturated with formic acid vapor and the total gas volume and temperature remain constant. What is the vapor pressure of formic acid at $20.0^{\circ} \mathrm{C}$ ?

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 65

Chloroform, $\mathrm{CHCl}_{3}$, has a normal boiling point of $61^{\circ} \mathrm{C}$. Its vapor pressure at $43^{\circ} \mathrm{C}$ is $0.526 \mathrm{~atm} .$ What is the concentration (in $\mathrm{g} / \mathrm{L}$ ) of $\mathrm{CHCl}_{3}$ when it saturates the air at $27^{\circ} \mathrm{C}$ ?

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 66

Which of the following statements are true?
(a) The critical temperature must be reached to change liquid to gas.
(b) To melt a solid at constant pressure, the temperature must be above the triple point.
(c) $\mathrm{CHF}_{3}$ can be expected to have a higher boiling point than $\mathrm{CHCl}_{3}$ because $\mathrm{CHF}_{3}$ has hydrogen bonding.
(d) One metal crystallizes in a body-centered cubic cell and another in a face-centered cubic cell of the same volume. The two atomic radii are related by the factor $\sqrt{1.5}$

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 67

Write the letter(s) corresponding to the bond(s) and/or force(s) associated with each species below. A - dispersion forces
$\mathrm{B}-$ dipole-dipole interaction C - ionic bond
$\mathrm{D}-$ metallic bond
$\mathrm{E}-$ covalent bond within a network covalent solid $\mathrm{F}$ - hydrogen bond.
(a) C (diamond)
(b) $\mathrm{CH}_{3}$
(c) $\mathrm{Au}$
(d) $\mathrm{SO}_{3}$
(e) $\mathrm{NH}_{3}$
(f) $\mathrm{KCl}$

Nicole Smina

Numerade Educator

Problem 68

In the blanks provided, answer the questions below, using LT (for is less than), GT (for is greater than), $\mathrm{EQ}$ (for is equal to), or MI (for more information required).
(a) The boiling point of $\mathrm{C}_{3} \mathrm{H}_{7} \mathrm{OH}(\mathrm{MM}=60.0 \mathrm{~g} / \mathrm{mol})$ _______
the boiling point of $\mathrm{C}_{2} \mathrm{H}_{6} \mathrm{C}=\mathrm{O} \quad(\mathrm{MM}=$
$58.0 \mathrm{~g} / \mathrm{mol})$
(b) The vapor pressure of $X$ is $250 \mathrm{~mm} \mathrm{Hg}$ at $57^{\circ} \mathrm{C}$. Given a sealed flask ________ at $57^{\circ} \mathrm{C}$ that contains only gas, the pressure in the flask $245 \mathrm{~mm} \mathrm{Hg}$.
(c) The melting-point curve for $Y$ tilts to the right of a straight line. The density of $Y(l)$ _______ the density of $\mathrm{Y}(s)$
(d) The normal boiling point of $A$ is $85^{\circ} \mathrm{C},$ while the normal boiling point of $\mathrm{B}$ is $45^{\circ} \mathrm{C}$. The vapor pressure of A at $85^{\circ} \mathrm{C}$ ______ the vapor pressure of $\mathrm{B}$ at $45^{\circ} \mathrm{C}$.
(e) The triple point of $\mathrm{A}$ is $25 \mathrm{~mm} \mathrm{Hg}$ and $5^{\circ} \mathrm{C}$. The melting point of $\mathrm{A}$ _______ $5^{\circ} \mathrm{C}$.

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 69

Answer the questions below, by filling in the blanks with LT for is less than, GT for is greater than, $\mathrm{EQ}$ for is equal to, or MI for more information required.
(a) At $50^{\circ} \mathrm{C},$ benzene has a vapor pressure of $269 \mathrm{~mm} \mathrm{Hg}$. A flask that contains both benzene liquid and vapor at $50^{\circ} \mathrm{C}$ has a pressure _______________ $269 \mathrm{~mm} \mathrm{Hg} .$
(b) Ether has a vapor pressure of $537 \mathrm{~mm} \mathrm{Hg}$ at $25^{\circ} \mathrm{C}$. A flask that contains only ether vapor at $37^{\circ} \mathrm{C}$ has a pressure ______________ $537 \mathrm{~mm} \mathrm{Hg} .$
(c) The boiling point of $\mathrm{H}_{2} \mathrm{O} $ ________ the boiling point of $\mathrm{C}_{3} \mathrm{H}_{8}$.
(e) The dispersion forces present in naphthalene, $\mathrm{C}_{10} \mathrm{H}_{8}$, ____________ the dispersion forces present in butane, $\mathrm{C}_{4} \mathrm{H}_{10}$.

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 70

A liquid has a vapor pressure of $159 \mathrm{~mm} \mathrm{Hg}$ at $20^{\circ} \mathrm{C}$ and $165 \mathrm{~mm} \mathrm{Hg}$ at $30^{\circ} \mathrm{C} .$ Different amounts of the liquid are added to three identical evacuated steel tanks kept at $20^{\circ} \mathrm{C}$. The tanks are all fitted with pressure gauges. For each part, write
$\mathrm{L} / \mathrm{G}$ if both liquid and gas are present. G if only gas is present. I if the situation is impossible.
(a) The pressure gauge in Flask I registers a pressure of $256 \mathrm{~mm} \mathrm{Hg}$
(b) The pressure gauge in Flask II registers a pressure of $135 \mathrm{~mm} \mathrm{Hg}$
(c) The pressure gauge in Flask III registers a pressure of $165 \mathrm{~mm} \mathrm{Hg}$ at $30^{\circ} \mathrm{C}$. The temperature is lowered to $20^{\circ} \mathrm{C},$ and the gauge registers a pressure of $159 \mathrm{~mm} \mathrm{Hg}$.

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 71

Indicate whether the following statements are true or false.
(a) The triple point in the phase diagram of a pure substance is the temperature and pressure at which the substance can boil, freeze, and sublime at the same time.
(b) $\mathrm{CHF}_{3}$ can be expected to have a higher boiling point than $\mathrm{CHCl}_{3}$ because $\mathrm{CHCl}_{3}$ has hydrogen bonds.
(c) The strength of covalent bonds within a molecule has no effect on the melting or boiling points of the compound made up of that molecule.
(d) As the gas from a condensable gas (e.g., propane) in a tank is used up, the pressure gradually decreases.
(e) The critical temperature is the temperature above which only the gaseous phase can exist.

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 72

What is the difference between
(a) a covalent bond and an ionic bond?
(b) boiling point and critical point?
(c) deposition and sublimation?
(d) freezing point and triple point?

Nicole Smina

Numerade Educator

Problem 73

Four shiny solids are labeled $A, B, C,$ and $D$. Given the following information about the solids, deduce the identity of $\mathrm{A}, \mathrm{B}, \mathrm{C},$ and $\mathrm{D} .$
(1) The solids are a graphite rod, a silver bar, a lump of "fool's gold" (iron sulfide), and iodine crystals.
(2) $\mathrm{B}, \mathrm{C},$ and $\mathrm{D}$ are insoluble in water. $\mathrm{A}$ is slightly soluble.
(3) Only C can be hammered into a sheet.
(4) $\mathrm{C}$ and $\mathrm{D}$ conduct electricity as solids; $\mathrm{B}$ conducts when melted; A does not conduct as a solid, melted, or dissolved in water.

Nicole Smina

Numerade Educator

Problem 74

Consider the vapor pressure curves of molecules $\mathrm{A}, \mathrm{B}$, and C shown below.
(a) Which compound $(\mathrm{A}, \mathrm{B},$ or $\mathrm{C})$ has the weakest forces between molecules?
(b) Which compound $(\mathrm{A}, \mathrm{B},$ or $\mathrm{C})$ has a normal boiling point at about $15^{\circ} \mathrm{C} ?$
(c) At what temperature will $\mathrm{B}$ boil if the atmospheric pressure is $500 \mathrm{~mm} \mathrm{Hg}$ ?
(d) At $25^{\circ} \mathrm{C}$ and $400 \mathrm{~mm} \mathrm{Hg}$, what is the physical state of $\mathrm{A}$ ?
(e) At what pressure will C boil at $40^{\circ} \mathrm{C}$ ?

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 75

The following data are given for $\mathrm{CCl}_{4}:$ normal melting point $=-23^{\circ} \mathrm{C}$ normal boiling point $=77^{\circ} \mathrm{C}$ density of liquid $=1.59 \mathrm{~g} / \mathrm{mL}$ vapor pressure at $25^{\circ} \mathrm{C}=110 \mathrm{~mm} \mathrm{Hg}$ How much heat is required to vaporize $20.0 \mathrm{~L}$ of $\mathrm{CCl}_{4}$ at its normal boiling point?

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 76

Iron crystallizes in a body-centered unit cell. Its atomic radius is $0.124 \mathrm{nm}$. Its density is $7.86 \mathrm{~g} / \mathrm{cm}^{3}$. Using this information, estimate Avogadro's number.

Tianyu Li

Numerade Educator

Problem 77

A flask with a volume of $10.0 \mathrm{~L}$ contains $0.400 \mathrm{~g}$ of hydrogen gas and $3.20 \mathrm{~g}$ of oxygen gas. The mixture is ignited and the reaction
$$
2 \mathrm{H}_{2}(g)+\mathrm{O}_{2}(g) \longrightarrow 2 \mathrm{H}_{2} \mathrm{O}
$$
goes to completion. The mixture is cooled to $27^{\circ} \mathrm{C}$. Assuming $100 \%$ yield,
(a) What physical state(s) of water is (are) present in the flask?
(b) What is the final pressure in the flask?
(c) What is the pressure in the flask if $3.2 \mathrm{~g}$ of each gas is used?

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 78

Trichloroethane, $\mathrm{C}_{2} \mathrm{H}_{3} \mathrm{Cl}_{3},$ is the active ingredient in aerosols that claim to stain-proof men's ties. Trichloroethane has a vapor pressure of $100.0 \mathrm{~mm} \mathrm{Hg}$ at $20.0^{\circ} \mathrm{C}$ and boils at $74.1^{\circ} \mathrm{C}$. An uncovered $\operatorname{cup}\left(\frac{1}{2}\right.$ pint $)$ of trichloroethane $(d=$ $1.325 \mathrm{~g} / \mathrm{mL})$ is kept in an $18-\mathrm{ft}^{3}$ refrigerator at $39^{\circ} \mathrm{F} .$ What percentage (by mass) of the trichloroethane is left as a liquid when equilibrium is established?

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 79

It has been suggested that the pressure exerted on a skate blade is sufficient to melt the ice beneath it and form a thin film of water, which makes it easier for the blade to slide over the ice. Assume that a skater weighs $120 \mathrm{lb}$ and the blade has an area of 0.10 in $^{2}$. Calculate the pressure exerted on the blade $\left(1\right.$ atm $\left.=15 \mathrm{lb} / \mathrm{in}^{2}\right) .$ From information in the text, calculate the decrease in melting point at this pressure. Comment on the plausibility of this explanation and suggest another mechanism by which the water film might be formed.

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 80

As shown in Figure $9.20, \mathrm{Li}^{+}$ ions fit into a closely packed array of $\mathrm{Cl}^{-}$ ions, but $\mathrm{Na}^{+}$ ions do not. What is the value of the $r_{\text {cation }} / r_{\text {anion }}$ ratio at which a cation just fits into a structure of this type?

Eileen Sullivan

Eileen Sullivan

Numerade Educator

Problem 81

When the temperature drops from $20^{\circ} \mathrm{C}$ to $10^{\circ} \mathrm{C},$ the pressure of a cylinder of compressed $\mathrm{N}_{2}$ drops by $3.4 \%$. The same temperature change decreases the pressure of a propane $\left(\mathrm{C}_{3} \mathrm{H}_{8}\right)$ cylinder by $42 \% .$ Explain the difference in behavior.

Nicole Smina

Numerade Educator