• Home
  • Textbooks
  • Chemistry
  • Properties of Solutions

Chemistry

Steven S. Zumdahl, Susan A. Zumdahl

Chapter 11

Properties of Solutions - all with Video Answers

Educators

Chapter Questions

02:40

Problem 1

The four most common ways to describe solution composition are mass percent, mole fraction, molarity, and molality. Define each of these solution composition terms. Why is molarity temperature-dependent, whereas the other three solution composition terms are temperature-independent?

Ronald Prasad
Ronald Prasad
Numerade Educator
View

Problem 1

Consider Fig. 11.9. According to the caption and picture, water seems to go from one beaker to another.
a. Explain why this occurs.
b. The explanation in the text uses terms such as vapor pressure and equilibrium. Explain what these have to do with the phenomenon. For example, what is coming to equilibrium?
c. Does all the water end up in the second beaker?
d. Is water evaporating from the beaker containing the solution? If so, is the rate of evaporation increasing, decreasing, or staying constant? Draw pictures to illustrate your explanations.

Ronald Prasad
Ronald Prasad
Numerade Educator
05:36

Problem 2

Using KF as an example, write equations that refer to $\Delta H_{\text {soln }}$ and $\Delta H_{\text {byd }}$. Lattice energy was defined in Chapter 8 as $\Delta H$ for the reaction $\mathrm{K}^{+}(g)+\mathrm{F}^{-}(g) \longrightarrow \mathrm{KF}(s)$.
Show how you would utilize Hess's law to calculate $\Delta H_{\text {soln }}$ from $\Delta H_{\text {hyd }}$ and $\Delta H_{\mathrm{LE}}$ for $\mathrm{KF}$, where $\Delta H_{\mathrm{LE}}=$ lattice energy. $\Delta H_{\text {soln }}$ for $\mathrm{KF}$, as for other soluble ionic compounds, is a relatively small number. How can this be since $\Delta H_{\text {tyd }}$ and $\Delta H_{\mathrm{LE}}$ are relatively large negative numbers?

Susan Hallstrom
Susan Hallstrom
Numerade Educator
04:34

Problem 2

Once again, consider Fig. 11.9. Suppose instead of having a nonvolatile solute in the solvent in one beaker, the two beakers contain different volatile liquids. That is, suppose one beaker contains liquid $\mathrm{A}\left(P_{\text {vap }}=50\right.$ torr $)$ and the other beaker contains liquid B $\left(P_{\text {vap }}=100\right.$ torr $)$. Explain what happens as time passes. How is this similar to the first case (shown in the figure)? How is it different?

James Irizarry
James Irizarry
Numerade Educator
06:17

Problem 3

What does the axiom "like dissolves like" mean? There are four types of solute/solvent combinations: polar solutes in polar solvents, nonpolar solutes in polar solvents, and so on. For each type of solution, discuss the magnitude of $\Delta H_{\text {soln }}$

Shazia Naz
Shazia Naz
Numerade Educator
07:38

Problem 3

Assume that you place a freshwater plant into a saltwater solution and examine it under a microscope. What happens to the plant cells? What if you placed a saltwater plant in pure water? Explain. Draw pictures to illustrate your explanations.

Margaret Calhoun
Margaret Calhoun
Numerade Educator
00:38

Problem 4

Structure, pressure, and temperature all have an effect on solubility. Discuss each of their effects. What isHenry's law? Why does Henry's law not work for $\mathrm{HCl}(g) ?$ What do the terms $h y d r o p h o b i c$ and $h y d r o$ philic mean?

Amy Jiang
Amy Jiang
Numerade Educator
03:16

Problem 4

How does $\Delta H_{\text {soln }}$ relate to deviations from Raoult's law? Explain.

Crystal Wang
Crystal Wang
Numerade Educator
04:53

Problem 5

Define the terms in Raoult's law. Figure $11.9$ illustrates the net transfer of water molecules from pure water to an aqueous solution of a nonvolatile solute. Explain why eventually all of the water from the beaker of pure water will transfer to the aqueous solution. If the experiment illustrated in Fig. $11.9$ was performed using a volatile solute, what would happen? How do you calculate the total vapor pressure when both the solute and solvent are volatile?

Shazia Naz
Shazia Naz
Numerade Educator
05:44

Problem 5

You have read that adding a solute to a solvent can both increase the boiling point and decrease the freezing point. $A$ friend of yours explains it to you like this: "The solute and solvent can be like salt in water. The salt gets in the way of freezing in that it blocks the water molecules from joining together. The salt acts like a strong bond holding the water molecules together so that it is harder to boil." What do you say to your friend?

Ronald Prasad
Ronald Prasad
Numerade Educator
01:02

Problem 6

In terms of Raoult's law, distinguish between an ideal liquid-liquid solution and a nonideal liquid-liquid solution. If a solution is ideal, what is true about $\Delta H_{\text {soln }}$, $\Delta T$ for the solution formation, and the interactive forces within the pure solute and pure solvent as compared to the interactive forces within the solution? Give an example of an ideal solution. Answer the previous two questions for solutions that exhibit either negative or positive deviations from Raoult's law.

Narayan Hari
Narayan Hari
Numerade Educator
01:05

Problem 6

You drop an ice cube (made from pure water) into a saltwater solution at $0^{\circ} \mathrm{C}$. Explain what happens and why.

James Irizarry
James Irizarry
Numerade Educator
01:00

Problem 7

Vapor-pressure lowering is a colligative property, as are freezing-point depression and boiling-point elevation. What is a colligative property? Why is the freezing point depressed for a solution as compared to the pure solvent? Why is the boiling point elevated for a solution as compared to the pure solvent? Explain how to calculate $\Delta T$ for a freezing-point depression problem or ? boiling-point elevation problem. Of the solvents listed in Table $11.5$, which would have the largest freezing-point depression for a $0.50$ molal solution? Which would have the smallest boiling-point elevation for a $0.50$ molal solution?

A common application of freezing-point depression and boiling-point elevation experiments is to provide a means to calculate the molar mass of a nonvolatile solute. What data are needed to calculate the molar mass of a nonvolatile solute? Explain how you would manipulate these data to calculate the molar mass of the nonvolatile solute.

Mari Davey
Mari Davey
Numerade Educator
05:32

Problem 7

Using the phase diagram for water and Raoult's law, explain why salt is spread on the roads in winter (even when it is below freezing).

Crystal Wang
Crystal Wang
Numerade Educator
04:52

Problem 8

What is osmotic pressure? How is osmotic pressure calculated? Molarity units are used in the osmotic

Jekaterina Viktorova
Jekaterina Viktorova
Numerade Educator
02:55

Problem 8

You and your friend are each drinking cola from separate $2-\mathrm{L}$ bottles. Both colas are equally carbonated. You are able to drink $1 \mathrm{~L}$ of cola, but your friend can drink only about half a liter. You each close the bottles and place them in the refrigerator. The next day when you each go to get the colas, whose will be more carbonated and why?

James Irizarry
James Irizarry
Numerade Educator
02:24

Problem 9

Distinguish between a strong electrolyte, a weak electrolyte, and a nonelectrolyte. How can colligative properties be used to distinguish between them? What is the van't Hoff factor? Why is the observed freezingpoint depression for electrolyte solutions sometimes less than the calculated value? Is the discrepancy greater for concentrated or dilute solutions?

Keenan Mintz
Keenan Mintz
University of Miami
01:36

Problem 9

Is molality or molarity dependent on temperature? Explain your answer. Why is molality, and not molarity, used in the equations describing freezing-point depression and boilingpoint elevation?

Crystal Wang
Crystal Wang
Numerade Educator
01:27

Problem 10

What is a colloidal dispersion? Give some examples of colloids. The Tyndall effect is often used to distinguish between a colloidal suspension and a true solution. Explain. The destruction of a colloid is done through a process called coagulation. What is coagulation?

Qiao Ruan
Qiao Ruan
Numerade Educator
01:03

Problem 10

Consider a beaker of salt water sitting open in a room. Over time, does the vapor pressure increase, decrease, or stay the same? Explain.

Ronald Prasad
Ronald Prasad
Numerade Educator
02:16

Problem 11

Rubbing alcohol contains $585 \mathrm{~g}$ isopropanol $\left(\mathrm{C}_{3} \mathrm{H}_{7} \mathrm{OH}\right)$ per liter (aqueous solution). Calculate the molarity.

Teresa Elam
Teresa Elam
Numerade Educator
00:55

Problem 12

\begin{aligned}
&\text { What mass of sodium oxalate }\left(\mathrm{Na}_{2} \mathrm{C}_{2} \mathrm{O}_{4}\right) \text { is needed to prepare }\\
&0.250 \mathrm{~L} \text { of a } 0.100-M \text { solution? }
\end{aligned}

Ronald Prasad
Ronald Prasad
Numerade Educator
00:52

Problem 13

What yolume of $0.25 M \mathrm{HCl}$ solution must be diluted to prepare $1.00 \mathrm{~L}$ of $0.040 \mathrm{M} \mathrm{HCl}$ ?

Lizabeth Tumminello
Lizabeth Tumminello
Numerade Educator
01:53

Problem 14

What volume of a $0.580-M$ solution of $\mathrm{CaCl}_{2}$ contains $1.28 \mathrm{~g}$ solute?

James Irizarry
James Irizarry
Numerade Educator
01:45

Problem 15

Calculate the sodium ion concentration when $70.0 \mathrm{~mL}$ of 3.0 $M$ sodium carbonate is added to $30.0 \mathrm{~mL}$ of $1.0 \mathrm{M}$ sodium
bicarbonate.

Ronald Prasad
Ronald Prasad
Numerade Educator
01:39

Problem 16

Write equations showing the ions present after the following strong electrolytes are dissolved in water.
a. $\mathrm{HNO}_{3}$
f. $\mathrm{NH}_{4} \mathrm{Br}$
b. $\mathrm{Na}_{2} \mathrm{SO}_{4}$
g. $\mathrm{NH}_{4} \mathrm{NO}_{3}$
c. $\mathrm{Al}\left(\mathrm{NO}_{3}\right)_{3}$
h. $\mathrm{CuSO}_{4}$
d. $\mathrm{SrBr}_{2}$
i. $\mathrm{NaOH}$
e. $\mathrm{KClO}_{4}$

Crystal Wang
Crystal Wang
Numerade Educator
01:04

Problem 17

Rationalize the temperature dependence of the solubility of a gas in water in terms of the kinetic molecular theory.

Ronald Prasad
Ronald Prasad
Numerade Educator
05:26

Problem 18

The weak electrolyte $\mathrm{NH}_{3}(g)$ does not obey Henry's law. Why? $\mathrm{O}_{2}(g)$ obeys Henry's law in water but not in blood (an aqueous solution). Why?

James Irizarry
James Irizarry
Numerade Educator
03:31

Problem 19

The two beakers in the sealed container illustrated below contain pure water and an aqueous solution of a volatile solute.

Crystal Wang
Crystal Wang
Numerade Educator
02:27

Problem 20

The following plot shows the vapor pressure of various solutions of components $\mathrm{A}$ and $\mathrm{B}$ at some temperature.

Crystal Wang
Crystal Wang
Numerade Educator
00:47

Problem 21

When pure methanol is mixed with water, the resulting solution feels warm. Would you expect this solution to be ideal? Explain.

Ronald Prasad
Ronald Prasad
Numerade Educator
03:55

Problem 22

Detergent molecules can stabilize the emulsion of oil in water as well as remove dirt from soiled clothes. A typical detergent is sodium dodecylsulfate, or $\mathrm{SDS}$, and it has a formula of $\mathrm{CH}_{3}\left(\mathrm{CH}_{2}\right)_{10} \mathrm{CH}_{2} \mathrm{SO}_{4}^{-} \mathrm{Na}^{+} .$ In aqueous solution, SDS suspends
oil or dirt by forming small aggregates of detergent anions called micelles. Propose a structure for micelles.

Ronald Prasad
Ronald Prasad
Numerade Educator
04:25

Problem 23

For an acid or a base, when is the normality of a solution equal to the molarity of the solution and when are the two concentration units different?

James Irizarry
James Irizarry
Numerade Educator
02:37

Problem 24

In order for sodium chloride to dissolve in water, a small
amount of energy must be added during solution formation. This is not energetically favorable. Why is $\mathrm{NaCl}$ so soluble in water?

James Irizarry
James Irizarry
Numerade Educator
02:35

Problem 25

Which of the following statements is(are) true? Correct the false statements.
a. The vapor pressure of a solution is directly related to the mole fraction of solute.
b. When a solute is added to water, the water in solution has a lower vapor pressure than that of pure ice at $0^{\circ} \mathrm{C}$.
c. Colligative properties depend only on the identity of the solute and not on the number of solute particles present.
d. When sugar is added to water, the boiling point of the solution increases above $100^{\circ} \mathrm{C}$ because sugar has a higher boiling point than water.

Ronald Prasad
Ronald Prasad
Numerade Educator
03:21

Problem 26

Is the following statement true or false? Explain your answer. When determining the molar mass of a solute using boilingpoint or freezing-point data, camphor would be the best solvent choice of all of the solvents listed in Table $11.5$.

James Irizarry
James Irizarry
Numerade Educator
01:45

Problem 27

Explain the terms isotonic solution, crenation, and hemolysis.

Ronald Prasad
Ronald Prasad
Numerade Educator
01:15

Problem 28

What is ion pairing?

Ronald Prasad
Ronald Prasad
Numerade Educator
04:08

Problem 29

A solution of phosphoric acid was made by dissolving $10.0 \mathrm{~g}$ $\mathrm{H}_{3} \mathrm{PO}_{4}$ in $100.0 \mathrm{~mL}$ water. The resulting volume was $104 \mathrm{~mL}$. Calculate the density, mole fraction, molarity, and molality of the solution. Assume water has a density of $1.00 \mathrm{~g} / \mathrm{cm}^{3}$.

Ronald Prasad
Ronald Prasad
Numerade Educator
03:41

Problem 30

An aqueous antifreeze solution is $40.0 \%$ ethylene glycol $\left(\mathrm{C}_{2} \mathrm{H}_{6} \mathrm{O}_{2}\right)$ by mass. The density of the solution is $1.05 \mathrm{~g} / \mathrm{cm}^{3}$.
Calculate the molality, molarity, and mole fraction of the ethylene glycol.

Ronald Prasad
Ronald Prasad
Numerade Educator
02:11

Problem 31

Common commercial acids and bases are aqueous solutions with the following properties:

Crystal Wang
Crystal Wang
Numerade Educator
View

Problem 32

In lab you need to prepare at least $100 \mathrm{~mL}$ of each of the following solutions. Explain how you would proceed using the given information.
a. $2.0 \mathrm{~m} \mathrm{KCl}$ in water (density of $\mathrm{H}_{2} \mathrm{O}=1.00 \mathrm{~g} / \mathrm{cm}^{3}$ )
b. $15 \% \mathrm{NaOH}$ by mass in water $\left(d=1.00 \mathrm{~g} / \mathrm{cm}^{3}\right)$
c. $25 \% \mathrm{NaOH}$ by mass in $\mathrm{CH}_{3} \mathrm{OH}\left(d=0.79 \mathrm{~g} / \mathrm{cm}^{3}\right)$
d. 0. 10 mole fraction of $\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}$ in water $\left(d=1.00 \mathrm{~g} / \mathrm{cm}^{3}\right)$

Susan Hallstrom
Susan Hallstrom
Numerade Educator
04:00

Problem 33

A solution is prepared by mixing $25 \mathrm{~mL}$ pentane $\left(\mathrm{C}_{5} \mathrm{H}_{12}, d=\right.$ $0.63 \mathrm{~g} / \mathrm{cm}^{3}$ ) with $45 \mathrm{~mL}$ hexane $\left(\mathrm{C}_{6} \mathrm{H}_{14}, d=0.66 \mathrm{~g} / \mathrm{cm}^{3}\right)$.
Assuming that the volumes add on mixing, calculate the mass percent, mole fraction, molality, and molarity of the pentane.

Ronald Prasad
Ronald Prasad
Numerade Educator
06:20

Problem 34

A solution is prepared by mixing $50.0 \mathrm{~mL}$ toluene $\left(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CH}_{3}\right.$ $d=0.867 \mathrm{~g} / \mathrm{cm}^{3}$ ) with $125 \mathrm{~mL}$ benzene $\left(\mathrm{C}_{6} \mathrm{H}_{6}, d=0.874 \mathrm{~g} / \mathrm{cm}^{3}\right)$.
Assuming that the volumes add on mixing, calculate the mass percent, mole fraction, molality, and molarity of the toluene.

James Irizarry
James Irizarry
Numerade Educator
04:21

Problem 35

A bottle of wine contains $12.5 \%$ ethanol by volume. The density of ethanol $\left(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}\right)$ is $0.789 \mathrm{~g} / \mathrm{cm}^{3} .$ Calculate the concentration of ethanol in wine in terms of mass percent and molality.

Ronald Prasad
Ronald Prasad
Numerade Educator
06:24

Problem 36

Calculate the molarity and mole fraction of acetone in a $1.00-m$ solution of acetone $\left(\mathrm{CH}_{3} \mathrm{COCH}_{3}\right)$ in ethanol $\left(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}\right)$.
(Density of acetone $=0.788 \mathrm{~g} / \mathrm{cm}^{3} ;$ density of ethanol $=$ $0.789 \mathrm{~g} / \mathrm{cm}^{3}$.) Assume that the volumes of acetone and ethanol add.

James Irizarry
James Irizarry
Numerade Educator
04:02

Problem 37

A $1.37-M$ solution of citric acid $\left(\mathrm{H}_{3} \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{O}_{7}\right)$ in water has a density of $1.10 \mathrm{~g} / \mathrm{cm}^{3}$. Calculate the mass percent, molality, mole fraction, and normality of the citric acid. Citric acid has three acidic protons.

Ronald Prasad
Ronald Prasad
Numerade Educator
02:24

Problem 38

Calculate the normality of each of the following solutions.
a. $0.250 \mathrm{M} \mathrm{HCl}$
b. $0.105 \mathrm{M} \mathrm{H}_{2} \mathrm{SO}_{4}$
c. $5.3 \times 10^{-2} \mathrm{M} \mathrm{H}_{3} \mathrm{PO}_{4}$
d. $0.134 M \mathrm{NaOH}$
e. $0.00521 \mathrm{M} \mathrm{Ca}(\mathrm{OH})_{2}$
What is the equivalent mass for each of the acids or bases listed above?

Crystal Wang
Crystal Wang
Numerade Educator
02:10

Problem 39

The lattice energy" of NaI is $-686 \mathrm{~kJ} / \mathrm{mol}$, and the enthalpy of hydration is $-694 \mathrm{~kJ} / \mathrm{mol}$. Calculate the enthalpy of solution per mole of solid NaI. Describe the process to which this enthalpy change applies.

Shazia Naz
Shazia Naz
Numerade Educator
02:26

Problem 40

a. Use the following data to calculate the enthalpy of hydration for calcium chloride and calcium iodide.b. Based on your answers to part a, which ion, $\mathrm{Cl}^{-}$ or $\mathrm{I}^{-}$, is more strongly attracted to water?

Crystal Wang
Crystal Wang
Numerade Educator
03:09

Problem 41

Although $\mathrm{Al}(\mathrm{OH})_{3}$ is insoluble in water, $\mathrm{NaOH}$ is very soluble. Explain in terms of lattice energies.

Ronald Prasad
Ronald Prasad
Numerade Educator
03:46

Problem 42

The high melting points of ionic solids indicate that a lot of energy must be supplied to separate the ions from one another. How is it possible that the ions can separate from one another when soluble ionic compounds are dissolved in water, often with essentially no temperature change?

James Irizarry
James Irizarry
Numerade Educator
00:41

Problem 43

Which solvent, water or carbon tetrachloride, would you choose to dissolve each of the following?
a. $\mathrm{KrF}_{2}$
e. $\mathrm{MgF}_{2}$
b. $\mathrm{SF}_{2}$
f. $\mathrm{CH}_{2} \mathrm{O}$
c. $\mathrm{SO}_{2}$
g. $\mathrm{CH}_{2}=\mathrm{CH}_{2}$
d. $\mathrm{CO}$

Lizabeth Tumminello
Lizabeth Tumminello
Numerade Educator
00:33

Problem 44

Which solvent, water or hexane $\left(\mathrm{C}_{6} \mathrm{H}_{14}\right)$, would you choose to dissolve each of the following?
a. $\mathrm{Cu}\left(\mathrm{NO}_{3}\right)_{2}$
d. $\mathrm{CH}_{3}\left(\mathrm{CH}_{2}\right)_{16} \mathrm{CH}_{2} \mathrm{OH}$
b. $\mathrm{CS}_{2}$
e. $\mathrm{HCl}$
c. $\mathrm{CH}_{3} \mathrm{OH}$
f. $\mathrm{C}_{6} \mathrm{H}_{6}$

Lizabeth Tumminello
Lizabeth Tumminello
Numerade Educator
01:10

Problem 45

For each of the following pairs, predict which substance would be more soluble in water.

Ronald Prasad
Ronald Prasad
Numerade Educator
03:44

Problem 46

Which ion in each of the following pairs would you expect to be more strongly hydrated? Why?
a. $\mathrm{Na}^{+}$ or $\mathrm{Mg}^{2+}$
d. $\mathrm{F}^{-}$ or $\mathrm{Br}^{-}$
b. $\mathrm{Mg}^{2+}$ or $\mathrm{Be}^{2+}$
e. $\mathrm{Cl}^{-}$ or $\mathrm{ClO}_{4}^{-}$
c. $\mathrm{Fe}^{2+}$ or $\mathrm{Fe}^{3+}$
f. $\mathrm{ClO}_{4}^{-}$ or $\mathrm{SO}_{4}^{2-}$

Crystal Wang
Crystal Wang
Numerade Educator
01:27

Problem 47

Rationalize the trend in water solubility for the following $\operatorname{sim}-$ ple alcohols:

Crystal Wang
Crystal Wang
Numerade Educator
02:34

Problem 48

In flushing and cleaning columns used in liquid chromatography to remove adsorbed contaminants, a series of solvents is used. Hexane $\left(\mathrm{C}_{6} \mathrm{H}_{14}\right)$, chloroform $\left(\mathrm{CHCl}_{3}\right)$, methanol $\left(\mathrm{CH}_{3} \mathrm{OH}\right)$, and water are passed through the column in that order. Rationalize the order in terms of intermolecular forces and the mutual
solubility (miscibility) of the solvents.

James Irizarry
James Irizarry
Numerade Educator
01:22

Problem 49

The solubility of nitrogen in water is $8.21 \times 10^{-4} \mathrm{~mol} / \mathrm{L}$ at $0^{\circ} \mathrm{C}$ when the $\mathrm{N}_{2}$ pressure above water is $0.790 \mathrm{~atm} .$ Calculate the Henry's law constant for $\mathrm{N}_{2}$ in units of $\mathrm{mol} / \mathrm{L} \cdot \mathrm{atm}$ for Henry's law in the form $C=k P$, where $C$ is the gas concentration in mol/L. Calculate the solubility of $\mathrm{N}_{2}$ in water when the partial pressure of nitrogen above water is $1.10 \mathrm{~atm}$ at $0^{\circ} \mathrm{C}$.

Crystal Wang
Crystal Wang
Numerade Educator
01:53

Problem 50

Calculate the solubility of $\mathrm{O}_{2}$ in water a partial pressure of $\mathrm{O}_{2}$ of 120 torr at $25^{\circ} \mathrm{C}$. The Henry's law constant for $\mathrm{O}_{2}$ is $1.3 \times 10^{-3} \mathrm{~mol} / \mathrm{L} \cdot$ atm for Henry's law in the form $C=k P$, where $C$ is the gas concentration $(\mathrm{mol} / \mathrm{L})$.

James Irizarry
James Irizarry
Numerade Educator
02:25

Problem 51

Glycerin, $\mathrm{C}_{3} \mathrm{H}_{8} \mathrm{O}_{3}$, is a nonvolatile liquid. What is the vapor pressure of a solution made by adding $164 \mathrm{~g}$ glycerin to $338 \mathrm{~mL} \mathrm{H}_{2} \mathrm{O}$ at $39.8^{\circ} \mathrm{C}$ ? The vapor pressure of pure water at $39.8^{\circ} \mathrm{C}$ is $54.74$ torr and its density is $0.992 \mathrm{~g} / \mathrm{cm}^{3}$.

Ronald Prasad
Ronald Prasad
Numerade Educator
02:15

Problem 52

The vapor pressure of a solution containing $53.6 \mathrm{~g}$ glycerin $\left(\mathrm{C}_{3} \mathrm{H}_{8} \mathrm{O}_{3}\right)$ in $133.7 \mathrm{~g}$ ethanol $\left(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}\right)$ is 113 torr at $40^{\circ} \mathrm{C} .$
Calculate the vapor pressure of pure ethanol at $40^{\circ} \mathrm{C}$ assuming that glycerin is a nonvolatile, nonelectrolyte solute in ethanol.

Ronald Prasad
Ronald Prasad
Numerade Educator
01:12

Problem 53

The normal boiling point of diethyl ether is $34.5^{\circ} \mathrm{C}$. A solution containing a nonvolatile solute dissolved in diethyl ether has a vapor pressure of 698 torr at $34.5^{\circ} \mathrm{C}$. What is the mole fraction of diethyl ether in this solution?

Ronald Prasad
Ronald Prasad
Numerade Educator
07:53

Problem 54

At a certain temperature, the vapor pressure of pure benzene $\left(\mathrm{C}_{6} \mathrm{H}_{6}\right)$ is $0.930$ atm. A solution was prepared by dissolving $10.0 \mathrm{~g}$ of a nondissociating, nonvolatile solute in $78.11 \mathrm{~g}$ of benzene at that temperature. The vapor pressure of the solution was found to be $0.900$ atm. Assuming the solution behaves ideally, determine the molar mass of the solute.

James Irizarry
James Irizarry
Numerade Educator
02:35

Problem 55

A solution is made by dissolving $25.8 \mathrm{~g}$ urea $\left(\mathrm{CH}_{4} \mathrm{~N}_{2} \mathrm{O}\right)$, a nonelectrolyte, in $275 \mathrm{~g}$ water. Calculate the vapor pressures of this solution at $25^{\circ} \mathrm{C}$ and $45^{\circ} \mathrm{C}$. (The vapor pressure of pure water is $23.8$ torr at $25^{\circ} \mathrm{C}$ and $71.9$ torr at $45^{\circ} \mathrm{C}$.)

Ronald Prasad
Ronald Prasad
Numerade Educator
02:26

Problem 56

A solution of sodium chloride in water has a vapor pressure of $19.6$ torr at $25^{\circ} \mathrm{C}$. What is the mole fraction of solute particles in this solution? What would be the vapor pressure of this solution at $45^{\circ} \mathrm{C} ?$ The vapor pressure of pure water is $23.8$ torr at $25^{\circ} \mathrm{C}$ and $71.9$ torr at $45^{\circ} \mathrm{C}$, and assume sodium chloride exists as $\mathrm{Na}^{+}$ and $\mathrm{Cl}^{-}$ ions in solution.

Ronald Prasad
Ronald Prasad
Numerade Educator
02:35

Problem 57

Pentane $\left(\mathrm{C}_{5} \mathrm{H}_{12}\right)$ and hexane $\left(\mathrm{C}_{6} \mathrm{H}_{14}\right)$ form an ideal solution. At $25^{\circ} \mathrm{C}$ the vapor pressures of pentane and hexane are 511 and $150 .$ torr, respectively. A solution is prepared by mixing $25 \mathrm{~mL}$ pentane (density, $0.63 \mathrm{~g} / \mathrm{mL}$ ) with $45 \mathrm{~mL}$ hexane (density, $0.66 \mathrm{~g} / \mathrm{mL}$ ).
a. What is the vapor pressure of the resulting solution?
b. What is the composition by mole fraction of pentane in the vapor that is in equilibrium with this solution?

Ronald Prasad
Ronald Prasad
Numerade Educator
04:10

Problem 58

A solution is prepared by mixing $0.0300$ mole of $\mathrm{CH}_{2} \mathrm{Cl}_{2}$ and $0.0500$ mole of $\mathrm{CH}_{2} \mathrm{Br}_{2}$ at $25^{\circ} \mathrm{C}$. Assuming the solution is ideal, calculate the composition of the vapor (in terms of mole fractions) at $25^{\circ} \mathrm{C}$. At $25^{\circ} \mathrm{C}$, the vapor pressures of pure $\mathrm{CH}_{2} \mathrm{Cl}_{2}$ and pure $\mathrm{CH}_{2} \mathrm{Br}_{2}$ are 133 and $11.4$ torr, respectively.

James Irizarry
James Irizarry
Numerade Educator
02:25

Problem 59

What is the composition of a methanol $\left(\mathrm{CH}_{3} \mathrm{OH}\right)$ -propanol $\left(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{OH}\right)$ solution that has a vapor pressure of
174 torr at $40^{\circ} \mathrm{C} ?$ At $40^{\circ} \mathrm{C}$, the vapor pressures of pure methanol and pure propanol are 303 and $44.6$ torr, respectively. Assume the solution is ideal.

Ronald Prasad
Ronald Prasad
Numerade Educator
02:00

Problem 60

Benzene and toluene form an ideal solution. Consider a solution of benzene and toluene prepared at $25^{\circ} \mathrm{C}$. Assuming the mole fractions of benzene and toluene in the vapor phase are equal, calculate the composition of the solution. At $25^{\circ} \mathrm{C}$ the vapor pressures of benzene and toluene are 95 and 28 torr, respectively.

James Irizarry
James Irizarry
Numerade Educator
02:03

Problem 61

Which of the following will have the lowest total vapor pressure at $25^{\circ} \mathrm{C}$ ?
a. pure water (vapor pressure $=23.8$ torr at $25^{\circ} \mathrm{C}$ )
b. a solution of glucose in water with $\chi_{\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}}=0.01$
c. a solution of sodium chloride in water with $\chi_{\mathrm{NaCl}}=0.01$
d. a solution of methanol in water with $\chi_{\mathrm{CH}_{3} \mathrm{OH}}=0.2$ (Consider the vapor pressure of both methanol [ 143 torr at $\left.25^{\circ} \mathrm{C}\right]$ and water. $)$

Crystal Wang
Crystal Wang
Numerade Educator
01:19

Problem 62

Which of the choices in Exercise 61 has the highest vapor pressure?

Ronald Prasad
Ronald Prasad
Numerade Educator
03:13

Problem 63

Match the vapor pressure diagrams with the solute-solvent combinations and explain your answers.

Crystal Wang
Crystal Wang
Numerade Educator
02:50

Problem 64

The vapor pressures of several solutions of water-propanol $\left(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{OH}\right)$ were determined at various compositions, with the following data collected at $45^{\circ} \mathrm{C}$ :a. Are solutions of water and propanol ideal? Explain.
b. Predict the sign of $\Delta H_{\text {soln }}$ for water-propanol solutions.

Crystal Wang
Crystal Wang
Numerade Educator
01:25

Problem 65

A solution is prepared by dissolving $27.0 \mathrm{~g}$ urea, $\left(\mathrm{NH}_{2}\right)_{2} \mathrm{CO}$, in $150.0 \mathrm{~g}$ water. Calculate the boiling point of the solution. Urea is a nonelectrolyte.

Ronald Prasad
Ronald Prasad
Numerade Educator
01:48

Problem 66

A $2.00-\mathrm{g}$ sample of a large biomolecule was dissolved in $15.0 \mathrm{~g}$ carbon tetrachloride. The boiling point of this solution was determined to be $77.85^{\circ} \mathrm{C}$. Calculate the molar mass of the biomolecule. For carbon tetrachloride, the boiling-point constant is $5.03^{\circ} \mathrm{C} \cdot \mathrm{kg} / \mathrm{mol}$, and the boiling point of pure carbon tetrachloride is $76.50^{\circ} \mathrm{C}$.

Ronald Prasad
Ronald Prasad
Numerade Educator
01:16

Problem 67

What mass of glycerin $\left(\mathrm{C}_{3} \mathrm{H}_{8} \mathrm{O}_{3}\right)$, a nonelectrolyte, must be dissolved in $200.0 \mathrm{~g}$ water to give a solution with a freezing point of $-1.50^{\circ} \mathrm{C}$ ?

Ronald Prasad
Ronald Prasad
Numerade Educator
03:47

Problem 68

The freezing point of $t$ -butanol is $25.50^{\circ} \mathrm{C}$ and $K_{\mathrm{f}}$ is $9.1^{\circ} \mathrm{C} \cdot \mathrm{kg} /$ mol. Usually $t$ -butanol absorbs water on exposure to air. If the freezing point of a $10.0$ -g sample of $t$ -butanol is $24.59^{\circ} \mathrm{C}$, how many grams of water are present in the sample?

James Irizarry
James Irizarry
Numerade Educator
03:26

Problem 69

Calculate the freezing point and boiling point of an antifreeze solution that is $50.0 \%$ by mass of ethylene glycol $\left(\mathrm{HOCH}_{2} \mathrm{CH}_{2} \mathrm{OH}\right)$ in water. Ethylene glycol is a nonelectrolyte.

Ronald Prasad
Ronald Prasad
Numerade Educator
09:22

Problem 70

What volume of ethylene glycol $\left(\mathrm{C}_{2} \mathrm{H}_{6} \mathrm{O}_{2}\right)$, a nonelectrolyte, must be added to $15.0 \mathrm{~L}$ water to produce an antifreeze solution with a freezing point of $-25.0^{\circ} \mathrm{C}$ ? What is the boiling point of this solution? (The density of ethylene glycol is $1.11$ $\mathrm{g} / \mathrm{cm}^{3}$, and the density of water is $1.00 \mathrm{~g} / \mathrm{cm}^{3} .$ )

James Irizarry
James Irizarry
Numerade Educator
02:11

Problem 71

Reserpine is a natural product isolated from the roots of the shrub Rauwolfia serpentina. It was first synthesized in 1956 by Nobel Prize winner $\mathrm{R} . \mathrm{B}$. Woodward. It is used as a tranquilizer and sedative. When $1.00 \mathrm{~g}$ reserpine is dissolved in $25.0 \mathrm{~g}$ camphor, the freezing-point depression is $2.63^{\circ} \mathrm{C}\left(K_{\mathrm{f}}\right.$ for camphor is $40 .{ }^{\circ} \mathrm{C} \cdot \mathrm{kg} / \mathrm{mol}$ ). Calculate the molality of the solution and the molar mass of reserpine.

Ronald Prasad
Ronald Prasad
Numerade Educator
03:29

Problem 72

A solution contains $3.75 \mathrm{~g}$ of a nonvolatile pure hydrocarbon in $95 \mathrm{~g}$ acetone. The boiling points of pure acetone and the solution are $55.95^{\circ} \mathrm{C}$ and $56.50^{\circ} \mathrm{C}$, respectively. The molal boiling-point constant of acetone is $1.71^{\circ} \mathrm{C} \cdot \mathrm{kg} / \mathrm{mol}$. What is the molar mass of the hydrocarbon?

James Irizarry
James Irizarry
Numerade Educator
02:58

Problem 73

a. Calculate the freezing-point depression and osmotic pressure at $25^{\circ} \mathrm{C}$ of an aqueous solution containing 1.0 $\mathrm{g} / \mathrm{L}$ of a protein (molar mass $=9.0 \times 10^{4} \mathrm{~g} / \mathrm{mol}$ ) if the density of the solution is $1.0 \mathrm{~g} / \mathrm{cm}^{3}$.
b. Considering your answer to part a, which colligative property, freezing-point depression or osmotic pressure, would be better used to determine the molar masses of large molecules? Explain.

David Collins
David Collins
Numerade Educator
01:55

Problem 74

Erythrocytes are red blood cells containing hemoglobin. In a saline solution they shrivel when the salt concentration is high and swell when the salt concentration is low. In a $25^{\circ} \mathrm{C}$ aqueous solution of $\mathrm{NaCl}$, whose freezing point is $-0.406^{\circ} \mathrm{C}$, erythrocytes neither swell nor shrink. If we want to calculate the osmotic pressure of the solution inside the erythrocytes under these conditions, what do we need to assume? Why? Estimate how good (or poor) of an assumption this is. Make this assumption and calculate the osmotic pressure of the solution inside the erythrocytes.

Ronald Prasad
Ronald Prasad
Numerade Educator
01:56

Problem 75

An aqueous solution of $10.00 \mathrm{~g}$ of catalase, an enzyme found in the liver, has a volume of $1.00 \mathrm{~L}$ at $27^{\circ} \mathrm{C}$. The solution's osmotic pressure at $27^{\circ} \mathrm{C}$ is found to be $0.745$ torr. Calculate the molar mass of catalase.

Ronald Prasad
Ronald Prasad
Numerade Educator
01:58

Problem 76

A $0.15-\mathrm{g}$ sample of a purified protein is dissolved in water to give $2.0 \mathrm{~mL}$ of solution. The osmotic pressure is found to be $18.6$ torr at $25^{\circ} \mathrm{C}$. Calculate the protein's molar mass.

Ronald Prasad
Ronald Prasad
Numerade Educator
01:41

Problem 77

How would you prepare $1.0 \mathrm{~L}$ of an aqueous solution of sucrose $\left(\mathrm{C}_{12} \mathrm{H}_{22} \mathrm{O}_{11}\right)$ having an osmotic pressure of $15 \mathrm{~atm}$ at a temperature of $22^{\circ} \mathrm{C} ?$ Sucrose is a nonelectrolyte.

Ronald Prasad
Ronald Prasad
Numerade Educator
01:52

Problem 78

How would you prepare $1.0 \mathrm{~L}$ of an aqueous solution of sodium chloride having an osmotic pressure of 15 atm at $22^{\circ} \mathrm{C}$ ? Assume sodium chloride exists as $\mathrm{Na}^{+}$ and $\mathrm{Cl}^{-}$ ions in solution.

Ronald Prasad
Ronald Prasad
Numerade Educator
03:26

Problem 79

Consider the following solutions:
$0.010 \mathrm{~m} \mathrm{Na}_{3} \mathrm{PO}_{4}$ in water
$0.020 \mathrm{~m} \mathrm{CaBr}_{2}$ in water
$0.020 \mathrm{~m} \mathrm{KCl}$ in water
$0.020 \mathrm{~m} \mathrm{HF}$ in water $(\mathrm{HF}$ is a weak acid. $)$
a. Assuming complete dissociation of the soluble salts, which solution(s) would have the same boiling point as $0.040 \mathrm{~m} \mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}$ in water? $\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}$ is a nonelectrolyte.
b. Which solution would have the highest vapor pressure at $28^{\circ} \mathrm{C}$ ?
c. Which solution would have the largest freezing-point depression?

Crystal Wang
Crystal Wang
Numerade Educator
07:24

Problem 80

From the following:
pure water solution of $\mathrm{C}_{12} \mathrm{H}_{22} \mathrm{O}_{11}(m=0.01)$ in water
solution of $\mathrm{NaCl}(m=0.01)$ in water solution of $\mathrm{CaCl}_{2}(m=0.01)$ in water Choose the one with the
a. highest freezing point.
b. lowest freezing point.
c. highest boiling point.
d. lowest boiling point.
e. highest osmotic pressure.

James Irizarry
James Irizarry
Numerade Educator
06:23

Problem 81

Calculate the freezing point and the boiling point of each of the following solutions. (Assume complete dissociation.)
a. $5.0 \mathrm{~g} \mathrm{NaCl}$ in $25 \mathrm{~g} \mathrm{H}_{2} \mathrm{O}$
b. $2.0 \mathrm{~g} \mathrm{Al}\left(\mathrm{NO}_{3}\right)_{3}$ in $15 \mathrm{~g} \mathrm{H}_{2} \mathrm{O}$

Ronald Prasad
Ronald Prasad
Numerade Educator
01:01

Problem 82

A water desalination plant is set up near a salt marsh containing water that is $0.10 \mathrm{M} \mathrm{NaCl}$. Calculate the minimum pressure that must be applied at $20 .{ }^{\circ} \mathrm{C}$ to purify the water by reverse osmosis. Assume $\mathrm{NaCl}$ is completely dissociated.

Ronald Prasad
Ronald Prasad
Numerade Educator
00:30

Problem 83

Determine the van't Hoff factor for the following ionic solute dissolved in water.

Ronald Prasad
Ronald Prasad
Numerade Educator
02:22

Problem 84

Consider the following representations of an ionic solute in water. Which flask contains $\mathrm{MgSO}_{4}$, and which flask contains $\mathrm{NaCl} ?$ How can you tell?

James Irizarry
James Irizarry
Numerade Educator
03:01

Problem 85

Calculate the freezing point and the boiling point of each of the following aqueous solutions. (Assume complete dissociation.)
a. $0.050 \mathrm{~m} \mathrm{MgCl}_{2}$
b. $0.050 \mathrm{~m} \mathrm{FeCl}_{3}$

Lizabeth Tumminello
Lizabeth Tumminello
Numerade Educator
01:33

Problem 86

Calculate the freezing point and the boiling point of each of the following solutions using the observed van't Hoff factors in Table $11.6$.
a. $0.050 \mathrm{~m} \mathrm{MgCl}_{2}$
b. $0.050 \mathrm{~m} \mathrm{FeCl}_{3}$

Lizabeth Tumminello
Lizabeth Tumminello
Numerade Educator
01:15

Problem 87

Use the following data for three aqueous solutions of $\mathrm{CaCl}_{2}$ to calculate the apparent value of the van't Hoff factor.

Crystal Wang
Crystal Wang
Numerade Educator
03:27

Problem 88

The freezing-point depression of a $0.091-m$ solution of $\mathrm{CsCl}$ is $0.320^{\circ} \mathrm{C}$. The freezing-point depression of a $0.091-\mathrm{m}$ solution of $\mathrm{CaCl}_{2}$ is $0.440^{\circ} \mathrm{C}$. In which solution does ion association appear to be greater? Explain.

Ronald Prasad
Ronald Prasad
Numerade Educator
02:45

Problem 89

In the winter of 1994 , record low temperatures were registered throughout the United States. For example, in Champaign, Illinois, a record low of $-29^{\circ} \mathrm{F}$ was registered. At this temperature can salting icy roads with $\mathrm{CaCl}_{2}$ be effective in melting the ice?
a. Assume $i=3.00$ for $\mathrm{CaCl}_{2}$.
b. Assume the average value of $i$ from Exercise 87 . (The solubility of $\mathrm{CaCl}_{2}$ in cold water is $74.5 \mathrm{~g}$ per $100.0 \mathrm{~g}$ water.)

Ronald Prasad
Ronald Prasad
Numerade Educator
01:29

Problem 90

A $0.500-\mathrm{g}$ sample of a compound is dissolved in enough water to form $100.0 \mathrm{~mL}$ of solution. This solution has an osmotic pressure of $2.50 \mathrm{~atm}$ at $25^{\circ} \mathrm{C}$. If each molecule of the solute dissociates into two particles (in this solvent), what is the molar mass of this solute?

Ronald Prasad
Ronald Prasad
Numerade Educator
01:58

Problem 91

The solubility of benzoic acid $\left(\mathrm{HC}_{7} \mathrm{H}_{5} \mathrm{O}_{2}\right)$,is $0.34 \mathrm{~g} / 100 \mathrm{~mL}$ in water at $25^{\circ} \mathrm{C}$ and is $10.0 \mathrm{~g} / 100 \mathrm{~mL}$ in
benzene $\left(\mathrm{C}_{6} \mathrm{H}_{6}\right)$ at $25^{\circ} \mathrm{C}$. Rationalize this solubility behavior. (Hint: Benzoic acid forms a dimer in benzene.) Would benzoic acid be more or less soluble in a 0.1-M $\mathrm{NaOH}$ solution than it is in water? Explain.

Ronald Prasad
Ronald Prasad
Numerade Educator
03:11

Problem 92

Given the following electrostatic potential diagrams, comment on the expected solubility of $\mathrm{CH}_{4}$ in water and $\mathrm{NH}_{3}$ in water.

Ronald Prasad
Ronald Prasad
Numerade Educator
03:25

Problem 93

In a coffee-cup calorimeter, $1.60 \mathrm{~g} \mathrm{NH}_{4} \mathrm{NO}_{3}$ was mixed with $75.0 \mathrm{~g}$ water at an initial temperature $25.00^{\circ} \mathrm{C}$. After dissolution of the salt, the final temperature of the calorimeter contents was $23.34^{\circ} \mathrm{C}$.
a. Assuming the solution has a heat capacity of $4.18 \mathrm{~J} / \mathrm{g} \cdot{ }^{\circ} \mathrm{C}$, and assuming no heat loss to the calorimeter, calculate the enthalpy of solution $\left(\Delta H_{\text {soln }}\right)$ for the dissolution of $\mathrm{NH}_{4} \mathrm{NO}_{3}$ in units of $\mathrm{kJ} / \mathrm{mol}$.
b. If the enthalpy of hydration for $\mathrm{NH}_{4} \mathrm{NO}_{3}$ is $-630 . \mathrm{kJ} / \mathrm{mol}$, calculate the lattice energy of $\mathrm{NH}_{4} \mathrm{NO}_{3} .$

Ronald Prasad
Ronald Prasad
Numerade Educator
07:37

Problem 94

In Exercise 96 in Chapter 5, the pressure of $\mathrm{CO}_{2}$ in a bottle of sparkling wine was calculated assuming that the $\mathrm{CO}_{2}$ was insoluble in water. This was a bad assumption. Redo this problem by assuming that $\mathrm{CO}_{2}$ obeys Henry's law. Use the data given in that problem to calculate the partial pressure of $\mathrm{CO}_{2}$ in the gas phase and the solubility of $\mathrm{CO}_{2}$ in the wine at $25^{\circ} \mathrm{C}$. The Henry's law constant for $\mathrm{CO}_{2}$ is $3.1 \times 10^{-2} \mathrm{~mol} / \mathrm{L} \cdot$ atm at $25^{\circ} \mathrm{C}$ with Henry's law in the form $C=k P$, where $C$ is the concentration of the gas in $\mathrm{mol} / \mathrm{L}$.

James Irizarry
James Irizarry
Numerade Educator
09:22

Problem 95

Explain the following on the basis of the behavior of atoms and/or ions.
a. Cooking with water is faster in a pressure cooker than in an open pan.
b. Salt is used on icy roads.
c. Melted sea ice from the Arctic Ocean produces fresh water.
d. $\mathrm{CO}_{2}(s)$ (dry ice) does not have a normal boiling point under normal atmospheric conditions, even though $\mathrm{CO}_{2}$ is a liquid in fire extinguishers.
e. Adding a solute to a solvent extends the liquid phase over a larger temperature range.

Ronald Prasad
Ronald Prasad
Numerade Educator
02:05

Problem 96

The term proof is defined as twice the percent by volume of pure ethanol in solution. Thus, a solution that is $95 \%$ (by volume) ethanol is 190 proof. What is the molarity of ethanol in a 92 proof ethanol-water solution? Assume the density ofethanol, $\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}$, is $0.79 \mathrm{~g} / \mathrm{cm}^{3}$ and the density of water is $1.0 \mathrm{~g} / \mathrm{cm}^{3}$

Lizabeth Tumminello
Lizabeth Tumminello
Numerade Educator
01:12

Problem 97

At $25^{\circ} \mathrm{C}$, the vapor in equilibrium with a solution containing carbon disulfide and acetonitrile has a total pressure of 263 torr and is $85.5$ mole percent carbon disulfide. What is the mole fraction of carbon disulfide in the solution? At $25^{\circ} \mathrm{C}$, the vapor pressure of carbon disulfide is 375 torr. Assume the solution and vapor exhibit ideal behavior.

Ronald Prasad
Ronald Prasad
Numerade Educator
14:11

Problem 98

For each of the following solute-solvent combinations, state the sign and relative magnitudes for $\Delta H_{1}, \Delta H_{2}, \Delta H_{3}$, and $\Delta H_{\text {soln }}$ (as defined in Fig. $11.1$ of the text). Explain your answers.

James Irizarry
James Irizarry
Numerade Educator
05:20

Problem 99

A solution is made by mixing $50.0$ g acetone $\left(\mathrm{CH}_{3} \mathrm{COCH}_{3}\right)$ and 50.0 $\mathrm{g}$ methanol $\left(\mathrm{CH}_{3} \mathrm{OH}\right)$. What is the vapor pressure of this solution at $25^{\circ} \mathrm{C} ?$ What is the composition of the vapor expressed as a mole fraction? Assume ideal solution and gas behavior. (At $25^{\circ} \mathrm{C}$ the vapor pressures of pure acetone and pure methanol are 271 and 143 torr, respectively.) The actual vapor pressure of this solution is 161 torr. Explain any discrepancies.

Ronald Prasad
Ronald Prasad
Numerade Educator
01:36

Problem 100

If the fluid inside a tree is about $0.1 M$ more concentrated in solute than the groundwater that bathes the roots, how highwill a column of fluid rise in the tree at $25^{\circ} \mathrm{C}$ ? Assume that the density of the fluid is $1.0 \mathrm{~g} / \mathrm{cm}^{3}$. (The density of mercury is $\left.13.6 \mathrm{~g} / \mathrm{cm}^{3} .\right)$

Ronald Prasad
Ronald Prasad
Numerade Educator
01:44

Problem 101

Thyroxine, an important hormone that controls the rate of metabolism in the body, can be isolated from the thyroid gland. When $0.455 \mathrm{~g}$ thyroxine is dissolved in $10.0 \mathrm{~g}$ benzene, the freezing point of the solution is depressed by $0.300^{\circ} \mathrm{C}$. What is the molar mass of thyroxine? See Table $11.5$.

Ronald Prasad
Ronald Prasad
Numerade Educator
01:54

Problem 102

If the human eye has an osmotic pressure of $8.00$ atm at $25^{\circ} \mathrm{C}$, what concentration of solute particles in water will provide an isotonic eyedrop solution (a solution with equal osmotic pressure)?

James Irizarry
James Irizarry
Numerade Educator
05:00

Problem 103

An unknown compound contains only carbon, hydrogen, and oxygen. Combustion analysis of the compound gives mass percents of $31.57 \% \mathrm{C}$ and $5.30 \% \mathrm{H}$. The molar mass is determined by measuring the freezing-point depression of an aqueous solution. A freezing point of $-5.20^{\circ} \mathrm{C}$ is recorded for a solution made by dissolving $10.56 \mathrm{~g}$ of the compound in $25.0 \mathrm{~g}$ water. Determine the empirical formula, molar mass, and molecular formula of the compound. Assume that the compound is a nonelectrolyte.

Ronald Prasad
Ronald Prasad
Numerade Educator
03:06

Problem 104

Consider the following:What would happen to the level of liquid in the two arms if the semipermeable membrane separating the two liquids were permeable to
a. $\mathrm{H}_{2} \mathrm{O}$ (the solvent) only?
b. $\mathrm{H}_{2} \mathrm{O}$ and solute?

James Irizarry
James Irizarry
Numerade Educator
02:00

Problem 105

Consider an aqueous solution containing sodium chloride that has a density of $1.01 \mathrm{~g} / \mathrm{mL}$. Assume the solution behaves ideally. The freezing point of this solution at $1.0 \mathrm{~atm}$ is $-1.28^{\circ} \mathrm{C}$. Calculate the percent composition of this solution (by mass).

Ronald Prasad
Ronald Prasad
Numerade Educator
02:09

Problem 106

What stabilizes a colloidal suspension? Explain why adding heat or adding an electrolyte can cause the suspended particles to settle out.

David Collins
David Collins
Numerade Educator
06:40

Problem 107

The freezing point of an aqueous solution is $-2.79^{\circ} \mathrm{C}$.
a. Determine the boiling point of this solution.
b. Determine the vapor pressure (in $\mathrm{mm} \mathrm{Hg}$ ) of this solution at $25^{\circ} \mathrm{C}$ (the vapor pressure of pure water at $25^{\circ} \mathrm{C}$ is $23.76 \mathrm{~mm} \mathrm{Hg}$ ).
c. Explain any assumptions you make in solving parts a and $\mathrm{b}$.

Shazia Naz
Shazia Naz
Numerade Educator
16:53

Problem 108

Specifications for lactated Ringer's solution, which is used for intravenous (IV) injections, are as follows to reach $100 . \mathrm{mL}$ of solution:
$285-315 \mathrm{mg} \mathrm{Na}^{+}$
$14.1-17.3 \mathrm{mg} \mathrm{K}^{+}$
4.9-6.0 $\mathrm{mg} \mathrm{Ca}^{2+}$
$368-408 \mathrm{mg} \mathrm{Cl}^{-}$
231-261 mg lactate, $\mathrm{C}_{3} \mathrm{H}_{5} \mathrm{O}_{3}^{-}$
a. Specify the amount of $\mathrm{NaCl}, \mathrm{KCl}, \mathrm{CaCl}_{2} \cdot 2 \mathrm{H}_{2} \mathrm{O}$, and
$\mathrm{NaC}_{3} \mathrm{H}_{5} \mathrm{O}_{3}$ needed to prepare 100. mL lactated Ringer's solution.
b. What is the range of the osmotic pressure of the solution at $37^{\circ} \mathrm{C}$, given the preceding specifications?

Ronald Prasad
Ronald Prasad
Numerade Educator
02:00

Problem 111

The lattice energy of $\mathrm{NaCl}$ is $-786 \mathrm{~kJ} / \mathrm{mol}$, and the enthalpy of hydration of 1 mole of gaseous $\mathrm{Na}^{+}$ and 1 mole of gaseous $\mathrm{Cl}^{-}$ ions is $-783 \mathrm{~kJ} / \mathrm{mol}$. Calculate the enthalpy of solution per mole of solid $\mathrm{NaCl}$.

Ronald Prasad
Ronald Prasad
Numerade Educator
05:20

Problem 112

For each of the following pairs, predict which substance is more soluble in water.
a. $\mathrm{CH}_{3} \mathrm{NH}_{2}$ or $\mathrm{NH}_{3}$
b. $\mathrm{CH}_{3} \mathrm{CN}$ or $\mathrm{CH}_{3} \mathrm{OCH}_{3}$
c. $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}$ or $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{3}$
d. $\mathrm{CH}_{3} \mathrm{OH}$ or $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}$
e. $\left(\mathrm{CH}_{3}\right)_{3} \mathrm{CCH}_{2} \mathrm{OH}$ or $\mathrm{CH}_{3}\left(\mathrm{CH}_{2}\right)_{6} \mathrm{OH}$
f. $\mathrm{CH}_{3} \mathrm{OCH}_{3}$ or $\mathrm{CH}_{3} \mathrm{CO}_{2} \mathrm{H}$

James Irizarry
James Irizarry
Numerade Educator
01:05

Problem 113

The normal boiling point of methanol is $64.7^{\circ} \mathrm{C}$. A solution containing a nonvolatile solute dissolved in methanol has a vapor pressure of $556.0$ torr at $64.7^{\circ} \mathrm{C}$. What is the mole fraction of methanol in this solution?

Ronald Prasad
Ronald Prasad
Numerade Educator
04:00

Problem 114

A solution is prepared by mixing $1.000$ mole of methanol $\left(\mathrm{CH}_{3} \mathrm{OH}\right)$ and $3.18$ moles of propanol $\left(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{OH}\right) .$ What
is the composition of the vapor (in mole fractions) at $40^{\circ} \mathrm{C}$ ? At $40^{\circ} \mathrm{C}$, the vapor pressure of pure methanol is 303 torr, and the vapor pressure of pure propanol is $44.6$ torr.

James Irizarry
James Irizarry
Numerade Educator
01:41

Problem 115

The molar mass of a nonelectrolyte is $58.0 \mathrm{~g} / \mathrm{mol}$. Determine the boiling point of a solution containing $35.0 \mathrm{~g}$ of this compound and $600.0 \mathrm{~g}$ of water. The barometric pressure during the experiment was such that the boiling point of pure water was $99.725^{\circ} \mathrm{C}$.

Ronald Prasad
Ronald Prasad
Numerade Educator
03:41

Problem 116

A $4.7 \times 10^{-2} \mathrm{mg}$ sample of a protein is dissolved in water to make $0.25 \mathrm{~mL}$ of solution. The osmotic pressure of the solution is $0.56$ torr at $25^{\circ} \mathrm{C}$. What is the molar mass of the protein?

James Irizarry
James Irizarry
Numerade Educator
07:09

Problem 117

A solid consists of a mixture of $\mathrm{NaNO}_{3}$ and $\mathrm{Mg}\left(\mathrm{NO}_{3}\right)_{2} .$ When $6.50 \mathrm{~g}$ of the solid is dissolved in $50.0 \mathrm{~g}$ of water, the freezing point of the solution is lowered by $5.23^{\circ} \mathrm{C}$. What is the composition by mass of the solid mixture?

Ronald Prasad
Ronald Prasad
Numerade Educator
05:18

Problem 118

The vapor pressure of pure benzene is $750.0$ torr and the vapor pressure of toluene is $300.0$ torr at a certain temperature. You make a solution by pouring "some" benzene with "some" toluene. You then place this solution in a closed container and wait for the vapor to come into equilibrium with the solution. Next, you condense the vapor. You put this liquid (the condensed vapor) in a closed container and wait for the vapor to come into equilibrium with the solution. You then condense this vapor and find the mole fraction of benzene in this vapor to be $0.714 .$ Determine the mole fraction of benzene in the original solution assuming the solution behaves ideally.

Ronald Prasad
Ronald Prasad
Numerade Educator
06:29

Problem 119

Liquid A has vapor pressure $x$, and liquid B has vapor pressure $y$. What is the mole fraction of the liquid mixture if the vapor above the solution is $30 . \%$ A by moles? $50 . \%$ A? $80 . \%$ A? (Calculate in terms of $x$ and $y .)$

Liquid A has vapor pressure $x$, liquid B has vapor pressure
$y$. What is the mole fraction of the vapor above the solution if the liquid mixture is $30 . \%$ A by moles? $50 . \%$ A? $80 . \% \mathrm{~A}$ ? (Calculate in terms of $x$ and $y .$ )

Ronald Prasad
Ronald Prasad
Numerade Educator
07:45

Problem 120

Plants that thrive in salt water must have internal solutions (inside the plant cells) that are isotonic with (have the same osmotic pressure as) the surrounding solution. A leaf of a saltwater plant is able to thrive in an aqueous salt solution (at $25^{\circ} \mathrm{C}$ ) that has a freezing point equal to $-0.621^{\circ} \mathrm{C}$. You would like to use this information to calculate the osmotic pressure of the solution in the cell.
a. In order to use the freezing-point depression to calculate osmotic pressure, what assumption must you make (in addition to ideal behavior of the solutions, which we will assume)?
b. Under what conditions is the assumption (in part a) reasonable?
c. Solve for the osmotic pressure (at $25^{\circ} \mathrm{C}$ ) of the solution in the plant cell.
d. The plant leaf is placed in an aqueous salt solution (at $25^{\circ} \mathrm{C}$ ) that has a boiling point of $102.0^{\circ} \mathrm{C}$. What will happen to the plant cells in the leaf?

James Irizarry
James Irizarry
Numerade Educator
05:10

Problem 121

You make $20.0 \mathrm{~g}$ of a sucrose $\left(\mathrm{C}_{12} \mathrm{H}_{22} \mathrm{O}_{11}\right)$ and $\mathrm{NaCl}$ mixture and dissolve it in $1.00 \mathrm{~kg}$ water. The freezing point of this solution is found to be $-0.426^{\circ} \mathrm{C}$. Assuming ideal behavior, calculate the mass percent composition of the original mixture, and the mole fraction of sucrose in the original mixture.

Ronald Prasad
Ronald Prasad
Numerade Educator
03:10

Problem 122

An aqueous solution is $1.00 \% \mathrm{NaCl}$ by mass and has a density of $1.071 \mathrm{~g} / \mathrm{cm}^{3}$ at $25^{\circ} \mathrm{C}$. The observed osmotic pressure of this solution is $7.83$ atm at $25^{\circ} \mathrm{C}$.

Crystal Wang
Crystal Wang
Numerade Educator
04:24

Problem 123

The vapor in equilibrium with a pentane-hexane solution at $25^{\circ} \mathrm{C}$ has a mole fraction of pentane equal to $0.15$ at $25^{\circ} \mathrm{C}$. What is the mole fraction of pentane in the solution? (See Exercise 57 for the vapor pressures of the pure liquids.)

Ronald Prasad
Ronald Prasad
Numerade Educator
04:50

Problem 124

A forensic chemist is given a white solid that is suspected of being pure cocaine $\left(\mathrm{C}_{17} \mathrm{H}_{21} \mathrm{NO}_{4}\right.$, molar mass $=303.35 \mathrm{~g} / \mathrm{mol}$ ).
She dissolves $1.22 \pm 0.01 \mathrm{~g}$ of the solid in $15.60 \pm 0.01 \mathrm{~g}$ benzene. The freezing point is lowered by $1.32 \pm 0.04^{\circ} \mathrm{C}$.
a. What is the molar mass of the substance? Assuming that the percent uncertainty in the calculated molar mass is the same as the percent uncertainty in the temperature change, calculate the uncertainty in the molar mass.
b. Could the chemist unequivocally state that the substance is cocaine? For example, is the uncertainty small enough to distinguish cocaine from codeine $\left(\mathrm{C}_{18} \mathrm{H}_{21} \mathrm{NO}_{3}\right.$, molar mass $=299.36 \mathrm{~g} / \mathrm{mol}$ )?
c. Assuming that the absolute uncertainties in the measurements of temperature and mass remain unchanged, how could the chemist improve the precision of her results?

Ronald Prasad
Ronald Prasad
Numerade Educator
05:49

Problem 125

A $1.60-\mathrm{g}$ sample of a mixture of naphthalene $\left(\mathrm{C}_{10} \mathrm{H}_{8}\right)$ and anthracene $\left(\mathrm{C}_{14} \mathrm{H}_{10}\right)$ is dissolved in $20.0 \mathrm{~g}$ benzene $\left(\mathrm{C}_{6} \mathrm{H}_{\mathrm{b}}\right)$. The freezing point of the solution is $2.81^{\circ} \mathrm{C}$. What is the composition as mass percent of the sample mixture? The freezing point of benzene is $5.51^{\circ} \mathrm{C}$ and $K_{\mathrm{f}}$ is $5.12^{\circ} \mathrm{C} \cdot \mathrm{kg} / \mathrm{mol}$.

Ronald Prasad
Ronald Prasad
Numerade Educator
11:59

Problem 126

A solid mixture contains $\mathrm{MgCl}_{2}$ and NaCl. When $0.5000 \mathrm{~g}$ of this solid is dissolved in enough water to form $1.000 \mathrm{~L}$ of solution, the osmotic pressure at $25.0^{\circ} \mathrm{C}$ is observed to be $0.3950$ atm. What is the mass percent of $\mathrm{MgCl}_{2}$ in the solid? (Assume ideal behavior for the solution.)

James Irizarry
James Irizarry
Numerade Educator
09:09

Problem 127

Formic acid $\left(\mathrm{HCO}_{2} \mathrm{H}\right)$ is a monoprotic acid that ionizes only partially in aqueous solutions. A $0.10-M$ formic acid solution is $4.2 \%$ ionized. Assuming that the molarity and molality of the solution are the same, calculate the freezing point and the boiling point of $0.10 M$ formic acid.

Shalini Tyagi
Shalini Tyagi
Numerade Educator
08:15

Problem 128

You have a solution of two volatile liquids, $\mathrm{A}$ and $\mathrm{B}$ (assume ideal behavior). Pure liquid A has a vapor pressure of $350.0$ torr and pure liquid $\mathrm{B}$ has a vapor pressure of $100.0$ torr at thetemperature of the solution. The vapor at equilibrium above the solution has double the mole fraction of substance A that
the solution does. What is the mole fraction of liquid $\mathrm{A}$ in the solution?

Tianyu Li
Tianyu Li
Numerade Educator
View

Problem 129

In some regions of the southwest United States, the water is very hard. For example, in Las Cruces, New Mexico, the tap water contains about $560 \mu \mathrm{g}$ of dissolved solids per milliliter. Reverse osmosis units are marketed in this area to soften water. A typical unit exerts a pressure of $8.0 \mathrm{~atm}$ and can produce $45 \mathrm{~L}$ water per day.
a. Assuming all of the dissolved solids are $\mathrm{MgCO}_{3}$ and assuming a temperature of $27^{\circ} \mathrm{C}$, what total volume of water must be processed to produce $45 \mathrm{~L}$ pure water?
b. Would the same system work for purifying seawater? (Assume seawater is $0.60 \mathrm{M} \mathrm{NaCl}$.)

Susan Hallstrom
Susan Hallstrom
Numerade Educator
08:55

Problem 130

Creatinine, $\mathrm{C}_{4} \mathrm{H}_{7} \mathrm{~N}_{3} \mathrm{O}$, is a by-product of muscle metabolism, and creatinine levels in the body are known to be a fairly reliable indicator of kidney function. The normal level of creatinine in the blood for adults is approximately $1.0 \mathrm{mg}$ per deciliter (dL) of blood. If the density of blood is $1.025 \mathrm{~g} / \mathrm{mL}$, calculate the molality of a normal creatinine level in a $10.0-\mathrm{mL}$ blood sample. What is the osmotic pressure of this solution at $25.0^{\circ} \mathrm{C} ?$

James Irizarry
James Irizarry
Numerade Educator
04:53

Problem 131

An aqueous solution containing $0.250$ mole of $\mathrm{Q}$, a strong electrolyte, in $5.00 \times 10^{2} \mathrm{~g}$ water freezes at $-2.79^{\circ} \mathrm{C}$. What is the van't Hoff factor for Q? The molal freezing-point depression constant for water is $1.86^{\circ} \mathrm{C} \cdot \mathrm{kg} / \mathrm{mol}$. What is the formula of $\mathrm{Q}$ if it is $38.68 \%$ chlorine by mass and there are twice as many anions as cations in one formula unit of $\mathrm{Q}$ ?

Ronald Prasad
Ronald Prasad
Numerade Educator
10:58

Problem 132

Anthraquinone contains only carbon, hydrogen, and oxygen. When $4.80 \mathrm{mg}$ anthraquinone is burned, $14.2 \mathrm{mg} \mathrm{CO}_{2}$ and $1.65 \mathrm{mg} \mathrm{H}_{2} \mathrm{O}$ are produced. The freezing point of camphor is lowered by $22.3^{\circ} \mathrm{C}$ when $1.32 \mathrm{~g}$ anthraquinone is dissolved in $11.4 \mathrm{~g}$ camphor. Determine the empirical and molecular formulas of anthraquinone.

James Irizarry
James Irizarry
Numerade Educator