Name ________________________________________ Class _________________ Date _______________
17.1
LIQUID WATER AND ITS PROPERTIES
SECTION REVIEW
Objectives
• Describe the hydrogen bonding that occurs in water
• Explain the high surface tension and low vapor pressure of water in terms of
hydrogen bonding
Key Terms
• surface tension
• surfactant
Part A Completion
Use this completion exercise to check your understanding of the concepts and terms
that are introduced in this section. Each blank can be completed with a term, short
phrase, or number.
Each O—H bond in a water molecule is highly
2
acquires a slightly
slightly
3
1
. Oxygen 1.
charge, while hydrogen acquires a
2.
charge. Since the H—O—H bond angle is 105 8, the
water molecule as a whole is
4
.
4.
Water molecules are attracted to each other as a result of
intermolecular
5
6.
7
7.
boiling point. Hydrogen bonding is also responsible for the high
8.
properties of water, such as its
8
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5.
bonds. This bonding accounts for many
6
3.
vapor pressure and
tension of water. Liquids tend to minimize their surface
area and form
9
droplets because of their surface tension.
The surface tension of water can be reduced by adding a
Water has a high
the air
12
9.
11
10
10.
.
capacity, which helps to moderate
11.
12.
around large bodies of water.
Part B True-False
Classify each of these statements as always true, AT; sometimes true, ST; or never true, NT.
________ 13. Hydrogen bonding is responsible for the polar nature of the water
molecule.
________ 14. The water molecule is a straight molecule.
Review Module / Chapters 17–20
7
Name ________________________________________ Class _________________ Date _______________
________ 15. Detergents lower the surface tension of water by interfering with the
formation of hydrogen bonds.
________ 16. Polar molecules are attracted to one another by dipole interactions.
Part C Matching
Match each description in Column B to the correct term in Column A.
Column A
Column B
________ 17. surface tension
a. inward force that tends to minimize the surface area of a
liquid
________ 18. surfactant
b. the amount of heat required to raise the temperature of
1 gram of a substance by 1 8C
________ 19. hydrogen bond
c. a wetting agent
________ 20. specific heat capacity
d. intermolecular attraction between a hydrogen atom
and a highly electronegative atom such as oxygen, on
an adjacent molecule
Part D Questions and Problems
Answer the following in the space provided.
21. State whether each of the following properties of water is higher or lower than
compounds of similar size and molecular mass.
a. vapor pressure
b. surface tension
d. boiling point
e. heat of vaporization
22. Calculate the amount of energy necessary to raise the temperature of 100.0 g of
water by 2.0 8C.
23. Calculate the amount of energy necessary to raise the temperature of 100.0 g of
iron by 20.0 8C.
8
Review Module / Chapters 17–20
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c. specific heat capacity
Name ________________________________________ Class _________________ Date _______________
WATER VAPOR AND ICE
17.2
SECTION REVIEW
Objectives
• Account for the high heat of vaporization and the high boiling point of water in
terms of hydrogen bonding
• Explain why ice floats in water
Part A Completion
Use this completion exercise to check your understanding of the concepts and terms
that are introduced in this section. Each blank can be completed with a term, short
phrase, or number.
Water absorbs a large amount of heat as it evaporates because
1
of
. The heat of vaporization is the amount of
2
2.
needed to convert 1 g of a substance from a liquid to a gas at the
3.
boiling point. The large amount of heat is necessary to break the
4.
hydrogen bonds that hold the
3
condensation of a substance is
of liquid water together.
4
The reverse of vaporization is
5
are usually
7
due to
6.
to its heat of vaporization.
or low boiling liquids. Water is an important
. Its high boiling point is due to
9
10
6
5.
. The heat of
Molecular compounds with molar masses similar to water
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1.
8
.
floats in liquid water. This is because it is less
7.
8.
9.
10.
11.
than water. Ice has a rigid open structure, which is also
11
.
Part B True-False
Classify each of these statements as always true, AT; sometimes true, ST; or never true, NT.
________ 12. Ice is more dense than water.
________ 13. Molecular compounds of low molar mass are gases at normal
atmospheric pressure.
________ 14. Hydrogen bonding accounts for water’s high boiling point.
________ 15. Water becomes more dense as it is cooled.
Review Module / Chapters 17-20
9
Name ________________________________________ Class _________________ Date _______________
Part C Questions and Problems
Answer the following questions or problems in the space provided. Show your work.
16. How much energy is required to change 86.0 g of water at 100 8C to 86.0 g of
steam at 100 8C? Express your answer in kilojoules.
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17. Methane, CH4, has a formula mass of 16 amu, a melting point of 2183 8C, and a
boiling point of 2164 8C. Water, H2O, has a formula mass of 18 amu, a melting
point of 0 8C, and a boiling point of 100 8C. Explain why there is such a
difference in the melting and boiling points when the formula masses of the
two compounds are so close.
10
Review Module / Chapters 17–20
Name ________________________________________ Class _________________ Date _______________
17.3
AQUEOUS SOLUTIONS
SECTION REVIEW
Objectives
• Explain the significance of the statement “like dissolves like”
• Distinguish among strong electrolytes, weak electrolytes, and nonelectrolytes,
giving examples of each
Key Terms
•
•
•
•
•
•
•
•
•
aqueous solutions
solvent
solute
solvation
•
•
•
•
nonelectrolytes
weak electrolyte
strong electrolyte
water of hydration
effloresce
hygroscopic
dessicants
deliquescent
electrolytes
Key Equation
mass water
mass of hydrate
• Percent H2O 5 }} 3 100%
Part A Completion
Use this completion exercise to check your understanding of the concepts and terms
that are introduced in this section. Each blank can be completed with a term, short
phrase, or number.
Water is a polar liquid and an excellent
substances. Aqueous solutions are
2
1
for many
1.
mixtures of ions or
2.
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molecules in water. The solubility of a solute depends on solutesolvent interactions. A good rule to remember is
3
4
Substances that dissolve as ions are known as
solute that is completely ionized in solution is a
electrolyte. A weak electrolyte is only
7
of an electrolyte will
solution of a
8
4.
.A
5.
5
6.
ionized. A solution
an electric current, whereas a
9
10
7.
8.
is nonconducting.
Many crystals are
In the process called
6
.
3.
9.
; they contain water of hydration.
10.
, the water of hydration is lost from a
hydrate that is exposed to the air.
Review Module / Chapters 17–20
11
Name ________________________________________ Class _________________ Date _______________
Part B True-False
Classify each of these statements as always true, AT; sometimes true, ST; or never true, NT.
________ 11. Carbon tetrafluoride is a nonelectrolyte.
________ 12. Hydrates are crystals that contain a fixed quantity of water within their
structure.
________ 13. Covalent solutes are very soluble in water.
________ 14. Solutions are always homogeneous.
Part C Matching
Match each description in Column B to the correct term in Column A.
Column A
Column B
________ 15. aqueous solutions
a. the dissolved particles in a solution
________ 16. solute
b. compounds that conduct electric current in aqueous
solution
________ 17. solvation
c. able to remove moisture from air
________ 18. electrolyte
d. water samples containing dissolved substances
________ 19. nonelectrolytes
e. drying agents
________ 20. water of hydration
f. compounds that do not conduct electric current in
aqueous solution
________ 21. hygroscopic
g. water contained in the crystal structure of a compound
________ 22. dessicants
h. process that occurs when a solute dissolves
Answer the following questions or problems in the space provided. Show your work.
23. Calculate the percent by mass of water in Glauber’s salt (Na2SO4?10H2O).
24. Which of the following substances dissolve to a significant extent in water?
12
a. C6H6
c. Na2SO4
b. NaCl
d. N2
Review Module / Chapters 17–20
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Part D Questions and Problems
Name ________________________________________ Class _________________ Date _______________
HETEROGENEOUS AQUEOUS SYSTEMS
17.4
SECTION REVIEW
Objectives
• Explain how colloids and suspensions differ from solutions
• Describe the Tyndall effect
Key Terms
• suspension
• colloids
• Tyndall effect
• Brownian motion
• emulsions
Part A Completion
Use this completion exercise to check your understanding of the concepts and terms
that are introduced in this section. Each blank can be completed with a term, short
phrase, or number.
The component particles of a suspension are much
2
than those of a solution. Gravity or
1.
will separate the
2.
suspended particles from a suspension. The particles in a colloid
3.
generally do not settle under gravity, and they pass through
4.
ordinary filter paper unchanged.
3
are good at scattering
light, as are suspensions, as evidenced by the
5
dispersions also exhibit
are small
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1
6
or
7
4
. Colloidal
motion. The particles in solutions
. They cannot be trapped by filter
the formation of
10
9
7.
9.
are colloidal dispersions of liquids in liquids.
Emulsifying agents maintain the
6.
8.
paper, nor do they exhibit the Tyndall effect.
8
5.
10
of an emulsion and allow
for liquids that do not ordinarily mix.
Part B True-False
Classify each of these statements as always true, AT; sometimes true, ST; or never true, NT.
________ 11. The scattering of light by colloidal particles is called Brownian
motion.
________ 12. Heterogeneous aqueous systems can be separated by filtration.
Review Module / Chapters 17–20
13
Name ________________________________________ Class _________________ Date _______________
________ 13. Emulsifying agents are essential to forming and maintaining
emulsions.
________ 14. Colloids are dispersions of liquids in liquids.
________ 15. The random motion of particles is known as the Tyndall effect.
Part C Matching
Match each description in Column B to the correct term in Column A.
Column A
Column B
________ 16. suspensions
a. chaotic movement of colloidal particles
________ 17. colloids
b. heterogeneous mixtures containing particles intermediate
in size between those of suspensions and solutions
________ 18. Tyndall effect
c. substance necessary to the formation and stability of an
emulsion
________ 19. Brownian motion
d. scattering of visible light by colloidal particles
________ 20. emulsions
e. mixtures from which particles settle on standing
________ 21. emulsifying agent
f. dispersions of liquids in liquids
Part D Questions and Problems
Answer the following questions in the space provided.
22. What is the typical particle size in a colloidal dispersion?
a. greater than 100 nm
b. 1 nm to 100 nm
c. less than 1 nm
23. What is the typical particle size in a suspension?
a. greater than 100 nm
b. 1 nm to 100 nm
c. less than 1 nm
d. There are no particles in a suspension.
14
Review Module / Chapters 17–20
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d. There are no particles in a colloidal dispersion.