Chapter 9 Review
Vocabulary
Section 9.2
Match each word to the sentence where it best
fits.
Section 9.1
concentration
dilute
solubility
concentrated
insoluble
Molarity
saturated
dissolved
solute
aqueous equilibrium
solvent
polar
supersaturation
hydrogen bond
surface tension
hydration
distilled water
tap water
deionized water
aqueous
12. A solution that contains more dissolved solute
that it can “hold” is called __________.
13. An _________________ has been achieved
when the amount of dissolved solute becomes
constant over time.
1.
The biggest percentage of a solution is made up of
the _______________. Often this is a liquid.
14. A solution is ___________ when it is holding the
maximum amount of solute that it can hold.
2.
A molecule with a charge separation is called
_____________.
15. A solution that has very little solute dissolved in
it is said to be ______________.
3.
A substance is said to be ______________ when
it completely separates and disperses into the
solution.
16. If a solution is called ____________ then it has a
large amount of dissolved solute.
4.
The _________ is the substance dissolved in the
solvent.
17. When the concentration of a solution is measured
as moles solute divided by liters of solution the
concentration unit is called ___________.
5.
A property named _____________ describes
when intermolecular forces pull a liquid surface
into the smallest possible area.
18. When a substance will not dissolve it is said to be
______________.
6.
A _____________ is a type of intermolecular
attraction formed when a hydrogen atom bonded
to an N, O or F atom is attracted to a negative
charge on another molecule or even the same
molecule.
7.
8.
9.
The process known as ____________ describes
the surrounding of water molecules around a
charged ion or polar molecule.
Water that comes from the sink is called ______
water, and conducts electricity.
19. The amount of solute that will dissolve in a
particular solvent is called its __________. (at a
given temperature and pressure)
Section 9.3
suspension
heat of solution
enthalpy
colloid
entropy
colligative property
electrolyte
molality
An ______________ solution is one that has
water as its solvent.
20. An ___________ is a solute capable of
conducting electricity when it is dissolved.
10. Water that is condensed after boiling to separate
solute particles from the water is called
_________________.
21. When a liquid mixture can be separated by
filtration it is called a ___________.
11. Water that does not contain ions is called
__________________.
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22. A uniform mixture that contains particles that are
too small to filter and do not settle is called a
______________.
A NATURAL APPROACH TO CHEMISTRY
23. The _______________________ is the energy
released or absorbed when a solute dissolves in a
solution.
24. ____________ is the concentration unit that does
not vary with temperature. It is measured as
moles solute per kilogram of solvent.
25. The heat energy of a chemical change is called
________________, or ΔH.
26. The ___________ of a system is a measure of the
disorder or randomness.
water molecules orient themselves around
potassium.
38. Sometimes we use distilled water to iron or to
soak our contact lenses in. Why don’t we use tap
water?
39. Describe the difference between distilled water
and deionized water.
40. Give 3 reasons why aqueous solutions are
important.
27. A ___________________ is a property that
depends on the number of solute particles in
solution and not the type of solute particle.
41. Write out a chemical equation that represents
salt, NaCl(s) dissolving in water. On the products
side of your arrow show the appropriate state of
matter for the ions.
Conceptual Questions
42. Write the chemical formula for mineral spirits.
Would this substance be soluble in water?
Section 9.2
Section 9.1
28. Suppose you make a solution of ice tea using a
mix, what are the solute and solvent. Explain.
29. Describe what happens to the ice tea mix when
you mix it.
30. Give an example of a common solid that
dissolves in water. Can you explain how it does
this?
31. Draw a picture of a water molecule. Label the
positive ends and the negative ends of the
molecule.
32. Now draw 3 water molecules and show how they
form hydrogen bonds to each other. Label the
hydrogen bonds with a different color pen.
33. Describe why hydrogen bonding is important to
life on earth.
34. Look up hydrogen bonding on the internet. Write
down the definition.
35. Give an example of surface tension that you have
witnessed in your everyday life. If you have not
seen this in your everyday life ask some friends.
43. If you were to mix water and chalk, would the
chalk dissolve? Explain. Give an example of
something that would dissolve (for comparison).
44. Describe how you would make a concentrated
solution of lemonade.
45. There are several ways to calculate
concentration. List 3 of them.
46. Pretend you are sitting at the kitchen table with a
glass of water and a sugar bowl:
a. You take a teaspoon of sugar and add it to the
water. What happens?
b. You add two more teaspoons of sugar to the
water and stir. What happens now?
c. Slowly you keep adding small amounts of
sugar, what will eventually happen?
47. Refer to the previous question - What would
happen if your glass of water was hot?
Would this affect what you observe? Explain.
48. Can gases “dissolve” in water? If so, give an
example.
36. When we are told to “stay hydrated” during
exercise, what does that actually mean? Explain.
49. Explain why the fish swim deeper during the
summer months?
37. Draw a picture of a potassium ion, K+
surrounded by water molecules. Show how the
50. Describe how you would prepare a 1.0 M
solution of copper(II) chloride, CuCl2. List each
step and explain as necessary.
A NATURAL APPROACH TO CHEMISTRY
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Chapter 9 Review.
51. What would be the difference between a 1.0 M
solution of potassium chloride, KCl and a 6.0M
solution of potassium chloride, KCl?
52. Explain why it is important to be very accurate
when preparing a solution of known
concentration?
53. Do you think it would be easy to measure a
drinking water supply that contained 1 ppb of
lead? Is it important to be able to measure such
small amounts accurately?
54. Explain what would happen if you dropped a
sugar cube in a cup of water and did not stir. How
would this compare to the same amount of
granular sugar added to water?
55. What is the density of water? How does this
compare with the density of ice? Briefly explain.
Section 9.3
two practical applications that take advantage of
this phenomena.
63. In a case where a salt dissolves and the solution
absorbs heat, is the heat written on the products
side of the arrow or the reactants side? Explain.
64. Why are styrofoam coffee cups good to use when
we are investigating chemical changes in solution?
65. When a chemical change takes place in a solution
the water molecules either absorb heat or give heat
to the chemical solute. What are these two
processes called?
66. Based on the law of conservation of energy, we
can say that ΔHsoltn = - ΔHrxn. Explain why.
67. In your own words describe what entropy means.
68. Why does spreading salt on icy roads make the
salt melt, when the temperature is still at the
freezing point for ice? Explain to the best of your
ability.
56. If you added a piece of chalk, CaCO3(s) to a
solution of 1.0 M carbonic acid, H2CO3(aq) and
another piece of chalk to a 3.0 M solution of
carbonic acid, would you expect there to be a
difference in what you see? Explain. Describe
what you think would be different at the
microscopic or molecular level.
69. Compare molality(m) to molarity(M).
57. Describe why sugar dissolves better in hot tea
than in cold ice tea. Be sure to discuss the water
molecules involved.
73. Which solution would be a better conductor, a 1.0
M solution of NaCl or a 1.0 M solution of CaCl2.
Explain your answer.
58. The ocean does not “freeze-over” as easily as a
lake or pond. What does an ocean have in it that
could describe this behavior? Explain.
74. Which substance listed below would you expect
to give the lowest freezing point when added to
water? Assume that the same mass of each solute
is added to 1.0 L of water. Explain your choice.
a) NaCl b) Sugar, C12H22O11 c) MgCl2 d) KI
59. When we add y 2.0 grams of a solute to a
solution, the mass of the solution always increases
by 2.0 grams as well, but if we add 2.0 mL or 2.0
cm3 the volume does not increase by the same
amount. Why not? Briefly explain.
60. How does the density of a solution change with
the addition of a solute? Explain.
61. How is the Tyndall effect used to identify a
colloid from a suspension? Explain.
62. Sometimes there is a change in temperature in a
solution when as solute is added to it. For
example the temperature can either increase or
decrease when a salt is dissolved in water. Give
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70. What is the formula for calculating molality?
71. Why is it important to use molality when applying
the principles of colligative properties?
72. Why can electrolyte solutions conduct
electricity?
75. Look at table 9.4 and compare the 0.1 m solution
of CaCl2 to the 0.001 m solution of CaCl2. Why
do you think the molarity goes up in a more dilute
solution?
Quantitative Problems
Section 9.2
76.
If you dissolve 12.0 g of sugar in 120.0 g of
water.
A NATURAL APPROACH TO CHEMISTRY
a) Calculate the concentration, in percent by mass,
of sugar in the solution.
b) If the density of water is 1.0 g/mL, calculate the
concentration in grams /liter.
c) Calculate the molarity of this solution.
77. You need to prepare a solution with 20.0 g of
MgCl2 in 500 mL of water.
a. Calculate the percent by mass of MgCl2 in the
solution.
b. Calculate the concentration in grams/L,
assume density of water is 1.0g/m.
c. Calculate the molarity of this solution.
78. What is the molarity of a solution that contains 8.5
g of NaCl in 250mL of water?
79. If there is 30 g of CaCO3 dissolved in a 2.0 L of
solution what is the percent by mass of CaCO3 in
the solution (assume density of water is 1.0 g/
mL)?
80. Calculate the number of moles of potassium
iodide (KI) needed to make one liter of a 0.75 M
solution.
81. When a student mixes 50.0 mL of 1.0 M NaOH
and 50.0 mL of 1.0M HCl in a coffee cup
calorimeter, the final temperature of the mixture
rises from 21.0oC to 25.0oC. Calculate the
enthalpy change for the reaction of hydrochloric
acid (HCl) with sodium hydroxide (NaOH).
Assume that the coffee cup calorimeter loses
negligible heat, that the density of the solution is
that of pure water 1.0 g/mL , and assume the
specific heat of the solution is the same as that of
pure water. NaOH(aq) + HCl(aq)→ NaCl(aq) +
H2O(l) ΔH = ?
82. In one experiment a student mixed 100.0mL of
water with 2.60 g of ammonium nitrate,
NH4NO3(s), in a coffee cup calorimeter. The
initial temperature of the water was 24.5oC. After
the ammonium nitrate was added the solution was
A NATURAL APPROACH TO CHEMISTRY
stirred and the final temperature of the mixed
solution was 20.2oC. Calculate the heat change
(enthalpy) for the dissolving of NH4NO3(s), in
kilojoules per mole of solid dissolved. Assume the
specific heat of the solution is the same as that of
pure water.
NH4NO3(s) + H2O(l) → NH4+(aq) + NO3-(aq)
ΔH = ?
83. In a coffee cup calorimetry experiment 1.75 g of
Zn(s) is added to 100.0 mL of 1.0M HCl initially
at 21.0oC. The temperature rises to 30.1oC. What
is the heat of the reaction per mole of Zn? Assume
that the specific heat of the acid is the same as that
of pure water.
Zn(s) + 2HCl(aq) → ZnCl2(aq) + H2(g) ΔH = ?
84. Calculate the molality of the following solutions:
a. A solution containing 2.0 g of NaCl in 500.0g
of water.
b. A solution containing 6.5 g of CaBr2 in
1200 g of water.
c. A solution prepared by adding 100 g of sugar
(C12H22O11) to 2.0 L of water.
85. Calculate the freezing point of a 2.20 m aqueous
solution of antifreeze which contains ethylene
glycol (C2H6O2) as the solute. Kf = 1.86oC/m for
water.
86. Adding 1.50 g of benzene, C6H6, to 80.70 g of
cyclohexane (C6H12) causes a decrease in the
freezing point of the cylcohexane from 7.0 to
3.8oC. What is the Kf (freezing point depression
constant) for cyclohexane?
87. Determine the freezing point of a solution
containing 0.750 kg of chloroform, CHCl3 and
48.0 g of eucalyptol (C10H18O) a compound
found in eucalyptus trees. The Kf for CHCl3 is
4.68oC/m and the normal freezing point of CHCl3
is -63.5 oC.
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