Conductivity of Solutions
Use the results of the demonstration to determine whether the substances and mixtures below are
a strong electrolyte (SE), a weak electrolyte (WE), or a nonelectrolyte (NE). A strong
electrolyte will light the bulb as bright as it can be lit, a weak electrolyte will not light up the
bulb to full brightness, and a nonelectrolyte will not light the bulb at all.
1. Distilled water _____
2. Tap water _____
3. Magnesium sulfate in distilled water
_____
4. Ethanol _____
5. Solid sodium chloride _____
6. Sodium chloride in distilled water _____
7. Sodium chloride in ethanol _____
8. Sucrose in distilled water _____
9. Sucrose in ethanol _____
10. Hydrochloric acid ____
11. Sodium hydroxide in distilled water
_____
12. Ammonia _____
13. Acetic acid (vinegar) _____
14. Pepsi: Predict _____ Actual ____
15. Gatorade: Predict _____ Actual _____
16. Pickle: Predict _____ Actual _____
Questions:
1. What two criteria must be met for something to be an electrolyte?
a)____________________________________________________________________________
b)____________________________________________________________________________
2. What can be inferred about tap water versus distilled water? __________________________
______________________________________________________________________________
3. Explain why solid sodium chloride and sodium chloride in ethanol are nonelectrolytes, but
sodium chloride in water is a strong electrolyte. ______________________________________
_____________________________________________________________________________
_____________________________________________________________________________
4. Explain why sucrose is a nonelectrolyte in ethanol and is still a nonelectrolyte in water.
_____________________________________________________________________________
_____________________________________________________________________________
5. Compare and contrast the electrolytic behavior of sodium chloride in water and sucrose in
water. _______________________________________________________________________
_____________________________________________________________________________
6. In general, what types of mixtures make strong electrolytes? _________________________
_____________________________________________________________________________
7. In general, what types of mixtures make weak electrolytes? __________________________
_____________________________________________________________________________
Name
Date
15
CHAPTER
Class
STUDY GUIDE FOR CONTENT MASTERY
Solutions
Section 15.1
What are solutions?
In your textbook, read about the characteristics of solutions.
Use each of the terms below just once to complete the passage.
immiscible
liquid
soluble
solution
insoluble
miscible
solute
solvent
Air is a(n) (1)
of oxygen gas dissolved in nitrogen
, and nitrogen is the
gas. The oxygen in air is the (2)
. Because oxygen gas dissolves in a solvent, oxygen gas
(3)
substance. A substance that does not dissolve is
is a(n) (4)
. (6)
(5)
solutions are the most common
type of solutions. If one liquid is soluble in another liquid, such as acetic acid in water, the
. However, if one liquid is insoluble in another,
two liquids are (7)
.
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
the liquids are (8)
Read about solvation in aqueous solutions in your textbook.
The diagram shows the hydration of solid sodium chloride to form an aqueous solution.
Use the diagram to answer the following questions.
Na
Cl
Cl
Cl
Na Cl
Na Cl Na
Cl
Na
H H
O
Cl
9. Hydration is solvation in which the solvent is water. What is solvation?
Study Guide for Content Mastery
Chemistry: Matter and Change • Chapter 15
85
Name
Date
CHAPTER
15
Class
CHAPTER ASSESSMENT
Understanding Main Ideas (Part A)
In the space at the left, write true if the statement is true; if the statement is false,
change the italicized word or phrase to make it true.
1. A solution may exist as a gas, a liquid, or a solid depending on the
state of the solvent.
2. Molar solutions are calculated and expressed in grams per liter.
3. The most common solvent among liquid solutions is ethanol.
4. Nonpolar solutes are more soluble in nonpolar solvents.
5. A supersaturated solution contains less dissolved solute than a
saturated solution at the same temperature.
6. The lowering of the vapor pressure of a pure solvent when a
solution is formed is a colligative property.
7. A 1m solution of a nonelectrolyte will have a lesser effect on the
colligative properties of its solution than a 1m solution of an
electrolyte will have on the colligative properties of its solution.
8. In an aerosol, the dispersing medium is a liquid.
9. A dilute solution contains a small amount of solute relative to the
10. Attractions between the dispersed particles and the particles of the
dispersing medium of a colloid produce magnetic layers that keep
the dispersed particles from settling out.
11. Boiling point depression is the temperature difference between a
solution’s and a pure solvent’s boiling point.
Circle the letter of the response that best answers the question.
12. What term describes a solution in which the dissolved solute is in equilibrium with the
undissolved solute?
a. dilute solution
b. saturated solution
c. supersaturated solution
d. unsaturated solution
13. Which of the following statements explains the solubility of ionic substances in water?
a. The molar mass of water is 18.02 g/mol.
b. An oxygen atom has six electrons in its outermost energy level.
c. Water molecules are polar.
d. Water is a covalent substance.
14. Which of the following compounds provides the most solute particles when completely
dissociated in water?
a. MgCl2
86
b. KBr
Chemistry: Matter and Change • Chapter 15
c. NaCl
d. Na3PO4
Chapter Assessment
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
solute’s solubility.
Name
Date
Directed Reading for
Content Mastery
Class
Overview
Solutions
Chapter
23
Directions: Use the words listed below to complete the paragraphs. Some words will be used more than once.
solute
decreases
electrolyte
solvent
temperature
nonelectrolyte
increases
nonpolar
higher
polar
lower
2. ____________________ is the substance being dissolved. For solids dissolving in
liquids, the speed of dissolving 3. ____________________ with increased surface
area, with increased temperature, and with stirring. For gases in liquids, the speed of
solubility 4. ____________________ with increased temperature but 5.
____________________ with increased pressure.
In general, polar solutes dissolve in polar solvents and do not dissolve in
6. ____________________ solvents. Usually, nonpolar solvents dissolve nonpolar
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
solutes and do not dissolve 7. ____________________ solutes.
Solubility is usually expressed as the maximum number of grams of
8. ____________________ that will dissolve in 100 grams of solvent at a certain
9. ____________________.
A substance that forms charged ions in solution and can conduct electricity is
called a(n) 10. ____________________. A(n) 11. ____________________ does not
ionize in water and cannot conduct electricity. The boiling point of a water solution
of any substance is 12. ____________________ than the boiling point of water.
The freezing point of a water solution of any substance is 13. ____________________
than the freezing point of water.
Solutions
19
Meeting Individual Needs
In a solution, the 1. ____________________ does the dissolving and the
Name
Date
Directed Reading for
Content Mastery
Class
Section 1 How Solutions Form
Section 3 Solubility and
Concentration
Section 4 Particles in Solution
■
■
Chapter
23
■
1. In a solution of sugar and water, the water is the _____.
a. solvent
b. solute
2. In the dissolving process, negative polar ends are attracted to _____
polar ends.
a. negative
b. positive
3. Grinding a solute increases its surface area, making it dissolve more _____.
a. slowly
b. quickly
4. A gas’s solubility is best in a liquid solvent when the solution is under
_____ pressure.
a. high
b. low
5. Different substances have _____ solubilities.
a. different
b. the same
6. The concentration of a solution of two or more liquids is expressed as a
percentage by _____.
a. area
b. volume
7. As the temperature of a liquid solvent increases, the amount of solid
solute that can be dissolved in the solvent usually _____.
a. increases
b. decreases
8. Lines on a graph that show how much solute a solvent can hold at a
given temperature are called _____.
a. solution graph
b. solubility curves
9. In the ionization process, water pulls the molecules of a polar substance
apart into _____.
a. crystals
b. ions
10. If a solute is a(n) _____, the solution can conduct electricity.
a. electrolyte
b. nonelectrolyte
11. The more particles of a solute that are added to a solution, the _____
the freezing point of the solution.
a. lower
b. higher
20 Solutions
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
Directions: For each of the following, write the letter of the term or phrase that best completes the sentence.
Name
Date
Chapter
Review
Class
Chapter
Solutions
23
Part A. Vocabulary Review
Directions: Match the description in Column I with the items in Column II by writing the correct letter in the
space provided.
Column I
Column II
1. a mixture that has the same composition,
color, density and taste throughout
a. unsaturated solution
2. the substance being dissolved
b. ion
3. the substance doing the dissolving
c. alloy
4. solid solution
5. molecules with a positive and negative area
d. dissociation
6. molecules with no separated positive and
negative areas
e. nonpolar
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
8. a solution that contains all the solute it can
hold at a given temperature
9. any solution that can dissolve more solute at
a given temperature
10. a solution that contains more solute than
a saturated one at the same temperature
f. nonelectrolytes
g. polar
h. solubility
i. supersaturated solution
j. electrolytes
11. charged particles
12. solutions of ions that conduct electricity
in water
13. substances that form no ions in water and
cannot conduct electricity
14. molecules broken apart in such a way that
the atoms take on a charge; the process of
forming ions
15. the process in which an ionic solid separates
into positive and negative ions
k. ionization
l. solution
m. saturated solution
n. solute
o. solvent
Solutions
39
Assessment
7. the maximum amount of solute that can be
dissolved in a given amount of solvent at
a given temperature
Name
Date
3
Reinforcement
Class
Solubility and Concentration
Chapter
23
Directions: Use the information in the table to graph the solubility curves for barium hydroxide, Ba(OH)2 ;
copper(II) sulfate, CuSO4 ; potassium chloride, KCl ; and sodium nitrate, NaNO3 . Use a different colored pencil for
each compound.
Solubility in g /100 g Water
Temperature
0˚C
Ba(OH)
20˚C
1.67
2
3.89
60˚C
100˚C
20.94
101.40
CuSO
23.10
32.0
61.8
114.0
KCl
28.0
34.2
45.8
56.3
73.0
87.6
122.0
180.0
4
NaNO
3
Meeting Individual Needs
Compound
Solubility (g/100 g of water)
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
180
160
140
120
100
80
60
40
20
0
0
20
40
60
80
100
120
Temperature ˚C
Directions: Use the information in the table and your graph to answer the following questions.
1. At about what temperature will 100 g of water dissolve equal amounts of potassium chloride
and barium hydroxide?
2. At about what temperature will 37 g of both copper(II) sulfate and potassium chloride dissolve
in 100 g of water?
3. If 100 g of sodium nitrate are dissolved in 100 g of water at 60°C, is the solution formed
saturated, unsaturated, or supersaturated?
4. If 32 g of copper (II) sulfate are dissolved in 100 g of water at 20°C, is the solution produced
saturated, unsaturated, or supersaturated?
Solutions
29
Name
Date
4
Reinforcement
Class
Chapter
Particles in Solution
23
Directions: Study the diagram. Then answer the following questions on the lines provided.
O
O
H
H
H
H
O
Cl
H
H
+
H
O
Cl
H
H
1. What is the name of the process taking place in the diagram? Describe the process.
2. What is an ion?
3. What is the solute in the diagram? Is the solute an electrolyte or a nonelectrolyte?
4. Will the solution conduct electricity? Explain.
30 Solutions
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
Meeting Individual Needs
H
Name
1
Date
Enrichment
Class
Chapter
Surface Area and Speed
of Dissolving
23
Figure 1
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
20 cm
Figure 2
20 cm
10 cm
Figure 3
2 cm
2 cm
2 cm
Meeting Individual Needs
Why does a crushed solute dissolve faster than a large chunk? In the following
activity you will observe and analyze how the surface area of a solute affects the
speed at which it dissolves.
Look at the cube in Figure 1; the length of each side is 20 cm. The area of one
side of this cube is 400 cm2 (length ✕ width = 20 cm ✕ 20 cm). Because there are
six sides on a cube, the surface area of the cube is 6 ✕ 400 cm2 = 2400 cm2.
Now cut the cube into eight 10-cm cubes as in Figure 2. The area of each
side of these cubes is 10 cm ✕ 10 cm = 100 cm2.
Multiply by six to get the surface area of one cube: 6 ✕ 100 cm2 = 600 cm2.
There are eight cubes, so the total surface area of all of the 10-cm cubes is now
600 cm2 ✕ 8 = 4800 cm2.
Next, divide the 20-cm cube into many cubes. In your mind, cut the cube
into one thousand 2-cm cubes, as in Figure 3. The area of each side of each of
these small cubes is 2 cm ✕ 2 cm = 4 cm2. The surface area of each cube is 4
cm2 ✕ 6 = 24 cm2. The surface area of all of the 2-cm cubes is 1,000 ✕ 24 cm2 =
24,000 cm2.
Figure 4
1 cm
1 cm
1 cm
10 cm
20 cm
10 cm
1. What would the total surface area be if our large cube were divided into 8000 cubes with each
side having a length of 1 cm?
2. What formula can you write for finding the total surface area of the divided cubes?
3. Using the formula from question 2, find the total surface area of the following:
a. a 4-cm cube
b. 8 2-cm cubes
c. 64 1-cm cubes
4. The large cube in Figure 4 is divided into 12 cubes on each side. Find the total surface area of
the divided cube.
Solutions
31
Name
Date
Class
Chapter Review (continued)
Part B. Concept Review
Directions: Determine whether the italicized word makes each statement true or false. If the statement is true, write
the word true in the blank. If the statement is false, write in the blank the word that makes the statement true.
1. Adding a solute to a solvent raises the freezing point of the solvent.
2. Adding a solute to a solvent raises the boiling point of a solvent.
3. A supersaturated solution is more stable than a saturated solution.
4. A substance that produces ions in water is a nonelectrolyte.
5. The ocean is a solution because it is a mixture of salts and water.
6. A gas dissolves in a liquid most rapidly when under low pressure.
7. Sugar dissolves in water because the positive ends of the sugar
molecules are pulled off the solute surface by the negative ends of the
water molecules.
8. A solid dissolves faster when it is ground because grinding decreases
surface area.
9. Generally, the concentration of a liquid dissolved in a liquid can be
expressed as a percentage by mass.
Assessment
11. A general statement that describes which substances dissolve which is
“like dissolves unlike.”.
12. Because grease is polar, it cannot be dissolved in water.
13. An alloy is a solid solution.
14. Hydrocarbons are nonpolar because they have an unequal
distribution of electrons.
15. Nail polish can be dissolved by the nonpolar solvent acetone.
16. The process called dissociation separates ionic crystals into ions.
40 Solutions
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
10. Adding antifreeze to a car radiator increases the boiling point of the
water in the radiator.
Name
Date
Chapter
Test
Class
Chapter
Solutions
23
I. Testing Concepts
Directions: For each of the following, write the letter of the term or phrase that best completes the sentence or
answers the question.
1. In a solution, the substance that is being dissolved is the _____.
a. solute
b. solvent
c. liquid
d. gas
2. The air that you breathe is an example of a(n) _____ solution.
a. gaseous
b. solid
c. liquid
d. amalgam
3. In soda pop, the solvent would be the _____.
a. water
b. carbon dioxide c. sugar
d. flavoring
4. A substance that does not conduct an electric current when it forms a solution
is a(n) _____.
a. electrolyte
c. polar substance
b. nonelectrolyte
d. salt
5. A solution that contains all of the solute it can normally hold at a given temperature
is _____.
a. dilute
b. unsaturated
c. supersaturated
d. saturated
7. Increasing the surface area of a solid _____.
a. slows the speed of dissolving
b. has no effect on the speed of dissolving
c. increases the speed of dissolving
d. causes the solid to ionize
Assessment
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
6. The process by which the particles in a crystal are separated and drawn into solution
by water is called _____.
a. ionization
b. dissociation
c. polarity
d. saturation
8. The solubility of a gas in a liquid occurs faster if the liquid is _____.
a. heated
c. under low pressure
b. cooled
d. an electrolyte
9. Which of the following types of solutes dissolves well in water?
a. hydrocarbons
c. nonpolar molecules
b. polar molecules
d. oil
10. The concentration of a solution that contains a large amount of solute in the solvent
could be described as _____.
a. unsaturated
b. polar
c. concentrated
d. dilute
11. Which of the following substances would dissolve iodine?
a. water
b. ethanol
c. polar solvent
d. vinegar
12. An alloy is an example of a _____ solution.
a. gaseous
b. liquid
c. solid
d. dilute
Solutions
41
Name
Date
Class
Chapter Test (continued)
13. Adding more solute to a solvent _____.
a. raises its freezing point
b. lowers its boiling point
c. raises its boiling point
d. does not affect its boiling point
14. What is the first step of the dissolving process?
a. The molecules of the solvent pull the molecules of the solute into solution.
b. The molecules of the solute pull the molecules of the solvent into solution.
c. The moving molecules of the solvent spread the molecules of the solute equally
throughout the solution.
d. The moving molecules of the solvent surround the molecules of the solute.
15. Which of the following combinations would increase the solubility of a gas in a liquid?
a. Increase the pressure and decrease the temperature.
b. Increase the pressure and temperature.
c. Decrease the pressure and temperature.
d. Decrease the pressure and increase the temperature.
16. Which of the following will speed up the dissolving of a solid solute in water?
a. Stir the solution.
c. Grind up the solvent.
b. Cool the solution.
d. Freeze the solute.
Assessment
18. One commonly used precise way to describe concentrations of solutions is to
state _____.
a. that the solution is dilute or concentrated
b. the percentage by area of the solute.
c. the percentage by volume of the solute
d. the percentage by volume of the solvent
19. A molecule with a positive and a negative area is
a. polar
b. nonpolar
c. ionic
d. radioactive
20. The maximum amount of a solute that can be dissolved in a given amount of solvent
is its ______ .
a. concentration
b. density
c. solubility
d. dilution
21. Soap has a(n) ______ end that will dissolve in water and a long hydrocarbon proton
that will dissolve in oily dirt.
a. ethanol
b. dry
c. toxic
d. ionic
42 Solutions
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
17. Water is sometimes referred to as the universal solvent because _____.
a. it has no separated positive and negative areas
b. it is a small molecule and can fit easily among the molecules of many solutes.
c. it has a polar and a nonpolar end
d. its molecules can slip easily among molecules of a nonpolar solvent
Name
Date
Class
Chapter Test (continued)
II. Understanding Concepts
Skill: Making and Using Graphs
Directions: Use the line graph to complete questions 1 through 8.
240
KNO3
Solubility (g/100 g of water)
220
200
180
160
NaClO3
140
120
KBr
100
80
60
NaCl
40
20
0
0 10 20 30 40 50 60 70 80 90 100
Temperature ˚C
2. In terms of saturation, how would you classify a KBr solution with a concentration of 90 g/100 g
of water at 50°C?
3. Use the information in the following table to add the solubility curve of potassium chloride
(KCl) to the graph above.
Solubility of KCl (g per 100 g of water)
Temperature
0˚C
20˚C
60˚C
100˚C
Solubility
28.0
34.0
46.0
56.0
4. At what temperature is the solubility of KBr the same as that of KNO3?
5. The solubility of which salt is least affected by temperature?
6. How many grams of KCl will form a saturated solution in 100 g of water at 60°C?
7. If 10 g of KCl were placed in 100 g of water at 0° C, what kind of solution would be formed?
8. Which is more soluble in water, KCl or KBr?
Solutions
43
Assessment
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
1. How many grams of KBr are needed to make a saturated solution in 100 g of water at 30°C?
CHAPTER 15
Solutions
Name:
1
Date:
A beaker contains a saturated solution of water and
NaCl at 25ºC. How could the amount of NaCl that
can be dissolved in the solution be increased?
A
Add more NaCl.
B
Heat the solution.
C
Add a second salt.
4
D Transfer the solution to a larger beaker.
This question covers TEKS 12A This question tests
the material that was covered in the textbook on
pages 458–459.
Which of the following is the most unstable type of
solution?
A
Saturated
B
Supersaturated
C
Unsaturated
D
Concentrated
This question covers TEKS 13A. This question tests
the material that was covered in the textbook on
page 459.
Use the table below to answer question 5.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
2
Which of these decreases as the amount of solute
particles in a solution increases?
A
Boiling point
Solute
B
Osmotic pressure
C
Freezing point
D
Molality
NaCl
KMnO4
Na2CO3
C6H12O6
This question covers TEKS 13B. This question tests
the material that was covered in the textbook on
pages 472–473.
3
Solute Effect on Water’s Boiling Point
Breaking a large solid into smaller pieces increases
its rate of solvation in a solvent. This process
accelerates the rate because —
A
greater surface area increases the likelihood of
collisions
B
it makes the solid immiscible
C
greater surface area decreases the likelihood of
collisions
D
it creates an adiabatic environment
This question covers TEKS 12A. This question tests
the material that was covered in the textbook on
page 456.
Reviewing Chemistry: Mastering the TEKS
5
point
Quantity Boiling
elevation
1 mol
?
1 mol
?
1 mol
?
1 mol
?
The table above shows the effects of various solutes
in a given volume of water. Without knowing the
actual values, which of these is the most likely
reason that the Na2CO3 will cause the greatest
boiling point elevation?
A
Na2CO3 is the only solute that exhibits the
Tyndall effect.
B
Na2CO3 produces the smallest number of moles
in solution.
C
Na2CO3 has the greatest heat of enthalpy.
D
Na2CO3 produces the largest number of moles
in solution.
This question covers TEKS 13B. This question tests
the material that was covered in the textbook on
pages 472–473.
Chemistry: Matter and Change
29
CHAPTER 15
Solutions, continued
Name:
6
Date:
A red blood cell’s shriveling in a cup of pure water
is its response to —
A
decreased rate of solvation
B
increased osmotic pressure
C
decreased osmotic pressure
D
increased ionic concentration
9
This question covers TEKS 12C and 13B. This
question tests the material that was covered in the
textbook on pages 474–475.
7
decreasing the temperature and increasing the
pressure
B
increasing the temperature and decreasing the
pressure
C
B
The colligative properties of the solute must be
at a maximum.
C
The solvation rate must exceed the rate
of crystallization.
D
Seed crystals must be added to
the solvent.
10
Ionic solutes readily interact with water molecules
because —
A
the forces of attraction between the ionic
particles are nonexistent
B
the forces of attraction between the ions and the
water are greater than those between the ions in
the solute
C
solvation only occurs between unlike solutes
and solvents
D
the surface area of ionic solutes is greater than
that of water molecules
increasing the temperature and increasing the
pressure
This question covers TEKS 12B. This question tests
the material that was covered in the textbook on
pages 458–460.
8
The crystallization rate must exceed the rate of
solvation.
If the molality of a solute is increased, the freezing
point of the solution will —
A
be increased
B
remain constant
C
fluctuate
D
be depressed
This question covers TEKS 13B. This question tests
the material that was covered in the textbook on
pages 454–455.
This question covers TEKS 4C and 13B. This
question tests the material that was covered in the
textbook on page 473.
30
Chemistry: Matter and Change
Reviewing Chemistry: Mastering the TEKS
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
D
decreasing the temperature and decreasing the
pressure
A
This question covers TEKS 12B. This question tests
the material that was covered in the textbook on
pages 457–458.
Janet wants to dissolve carbon dioxide in water. The
rate of solvation could be most improved by —
A
Which of the following is required in order for a
solute to achieve maximum solubility in a solvent?