Chapter 14 Review.
Vocabulary
13. How does a gas exert a pressure if there is lots of
empty space between its molecules?
Match each word to the sentence where it best
fits.
Section 14.1
kinetic molecular
theory
14. Why is it better to lie down on ice that is cracking
beneath your feet than to remain in a standing
position?
15. What causes atmospheric pressure?
Brownian motion
barometer
16. Why does atmospheric pressure on top of a
mountain less than at the base of that same
mountain?
Bernoulli principle
1. If you view tiny particles in a liquid or gas using a
microscope you can see ________.
2. Using a ________ you can measure atmospheric
pressure.
3. Whenever you fly in an airplane you rely on the
________.
4. ________ describes our basic understanding of
substances at the molecular level.
Section 14.2
molar volume
ideal gas
5. At standard temperature and pressure you will find
6.02 x 1023 molecules in a ________.
6. The gas laws are only 100% accurate for an
________.
Conceptual Questions
Section 14.1
7. Compare a gas, liquid, and solid on a molecular
level.
8. What are some common properties of gases?
9. What is kinetic molecular theory.
10. Describe how kinetic molecular theory explains
why gases have the properties you mentioned in
question 8.
11. How was Brownian motion discovered and what
was it caused by?
12. What is the difference between force and
pressure?
468
Section 14.2
17. Many aerosol cans have warning labels on the side
that say to keep away from heat and fire. Why?
18. One of the first thermometers was made from
sealing a gas in a container that would allow the
gas to expand or contract. Explain how this could
be used as a thermometer.
19. Why does it makes sense that if you squeeze the
air in a sealed syringe, that the pressure will go
up? Explain on a molecular level?
20. When you drive a car the tires heat up because of
friction with the road and internal friction between
the molecules of the rubber. What will happen to
the gas pressure in the tire as the tire heats up?
Explain on a molecular level.
21. When pumping up a bicycle tire with a hand pump
it gets harder and harder as you continue pumping.
Explain the connection of this phenomenon with
Avogadro’s Law.
22. Explain why weather balloons, sealed latex
balloons filled with helium, eventually pop when
they reach extremely high altitudes.
23. Explain why it makes sense to use a temperature
scale that starts at zero like the Kelvin temperature
scale?
24. What is the relationship between temperature and
kinetic energy?
25. Gay-Lussac gave us another law which states that
pressure and temperature are directly proportional
to each other if volume and moles are constant.
Using this law what do you predict will happen to
the temperature of a gas with an increase in its
pressure? Explain.
26. Plants breathe through the stomata on their leaves,
small pores that can be opened or closed as
A NATURAL APPROACH TO CHEMISTRY
needed. Plants grown in an environment with a
high partial pressure of CO2 have fewer stomata.
Why does this make sense?
27. Describe everything you can about the molecules
of two different gases that are at the same
temperature.
28. How can the molar volume of ALL gases be the
same 22.4 L volume at standard temperature and
pressure? Why doesn’t the size of the molecule
have any affect?
29. What is meant by an ideal gas?
30. Ideal gases have molecules that take up no space.
However, real molecules do take up some space.
How does fact affect the volume predicted by
Boyle’s Law and Charles’ Law? Will it be larger
or smaller than predicted for an ideal gas?
Explain.
31. Ideal gases have molecule that don’t interact with
each other. However, real molecules feel the weak
intermolecular attractions felt by all molecules.
How does fact affect the volume predicted by
Boyle’s Law and Charles’ Law? Will it be larger
or smaller than predicted for an ideal gas?
Explain.
Section 14.3
32. If you run an electric current through water it goes
through a dissociation reaction, breaking back
down into hydrogen and oxygen gas via this
reaction: 2 H2O(l) → 2 H2(g) + O2(g)
If you measure the masses of the hydrogen and
oxygen produced you will find a mass ratio of
2 H2 :16 O2. If you measure the volume of the
hydrogen and oxygen you will get a volume ratio
of 2 H2 :1 O2, the same as the molar ratio in the
balanced chemical equation. Why does the
volume ratio match the molar ratio, but not the
mass ratio?
Quantitative Problems
Section 14.1
33. What is the pressure exerted by an elephant
weighing 8,000 lbs if the total area of the bottom
of its four feet equals 312 in2 ?
A NATURAL APPROACH TO CHEMISTRY
34. What is the weight of a car that has its tires
lbsinflated to 35 -----and is touching the ground over
2
in
an area equal to 285 in2?
35. Perform the following conversions:
a. 3.50 psi to Pa
b. 200435 Pa to atm
c. 5.67 atm to mmHg
d. 0.89 atm to inHg (inches of mercury). You will
need the following equalities to help: 1 in =
2.54 cm and 10 mm = 1 cm.
Section 14.2
36. Draw a graph of two variables that are directly
proportional to each other.
37. Draw a graph of two variables that are inversely
proportional to each other.
38. You decide to climb to the tops of some of the
tallest mountains. Before you are about to leave on
your epic journey, a friend gives you a balloon
with a volume of 800.0 cm3 that was inflated
under standard atmospheric pressure.
You climbed two different mountains with this
balloon: Mt. Everest 29,028 ft above sea level
which has an average atmospheric pressure of
221 mmHg, and Mt. McKinley 20,320 ft above
sea level which has an average atmospheric
pressure of 345 mmHg.
What was the size of the balloon on each mountain
top?
39. A 50.0 mL soap bubble is blown at standard
pressure. When a thunder storm passes later in the
day, the pressure becomes 700.0 mmHg. Will the
bubble get bigger or smaller? What is its new
volume?
40. A balloon was inflated to a volume of 5.0 liters at
a pressure of 0.90 atm. It rises to an altitude where
its volume becomes 25.0 liters. Will the pressure
around the balloon increase or decrease? What
was the new pressure?
41. A SCUBA diver inflates a balloon to 10.0 liters at
the surface and takes it on a dive. At a depth of
100.0 feet the pressure is 4.0 ‘atm. Will the
volume of the balloon increase or decrease? What
was the new volume of the balloon?
469
Chapter 14 Review.
42. The living quarters of the space shuttle has a
volume of 20,000 liters (2.00 x 104 L) and is kept
lbsat 12.0 -----. If all the air were lost, it would have to
2
in
be replaced from a compressed air cylinder which
has a volume of 50.0 liters. What is the pressure in
that tank? (In other words: How much pressure
would it take to compress all the air in the shuttle
into a 50.0 liter space?)
43. Back to the space shuttle. the living quarters have
a volume of 20,000 liters (2.00 x 104 L) at
500.0 mmHg. The shuttle docks with a space-lab
which has a volume of 230,000 liters
(2.30 x 105 L) and no air in it. What does the air
pressure in both become when the hatch is opened
between the two?
44. A fountain pen which has a total volume
of 2.4 cm3 is half full with ink at the
surface where the pressure is
780.0 mmHg. It is put in a pilot's pocket
who flies to an altitude where the pressure
is 520.0 mmHg. How much ink leaks out
of the pen?
45. A 50.0 mL soap bubble is blown in a
27.0 °C room. It drifts out an open window and
lands in a snow bank at -3.0 °C. What is its new
volume?
46. A balloon was inflated to a volume of 5.0 liters at
a temperature of 7.0 °C. It landed in an oven and
was heated to 147 °C. What is its new volume?
47. During the day at 27 °C a cylinder with a sliding
top contains 20.0 liters of air. At night it only
holds 19 liters. What is the temperature at night?
Give the answer in Kelvin and °C?
48. A 113 L sample of Helium at 27 °C is cooled to 78 °C. Calculate the new volume of the Helium.
49. On all aerosol cans you see a warning that tells
you to keep the can away from heat because of the
danger of explosion. What is the potential volume
of the gas contained in a 500.0 mL can at 25 °C if
it were heated to 54 °C. In other words if the can
could expand to allow the gas to take up a greater
volume, what would be the new volume of the gas
when heated as previously described?
50. A 0.20 ml CO2 bubble in a cake batter is at 27 °C.
In the oven it gets heated to 177 °C.
a. What is its new volume?
470
b. If the cake had 5,000 bubbles, by how many
mL would the cake rise when it was cooked?
c. What common baking ingredient was used to
create the original CO2 bubble?
51. A 500.0 mL glass filled with air is placed into
water up-side-down while at 7.0 °C. The water is
heated to 77 °C. How much air bubbles out from
under the glass?
52. At one point in history people could measure
temperature by looking at the volume of a sample
of gas. Suppose a sample in a gas thermometer has
a volume of 135 mL at 11.0 °C. Indicate what
temperature would correspond to each of the
following volumes: 113 mL, 142 mL, 155 mL, and
127 mL.
53. A balloon is filled with helium to a volume of
4.0 liters when the pressure is 1.0 atm and the
temperature is 27.0 °C. It escapes and rises until
the pressure is 0.25 atm. and the temperature is 23.0 °C. What is the new volume?
54. When a bubble escapes form a sunken ship, it has
a volume of 12.0 cm3 at a pressure of 400.0 atm
and a temperature of -3.00 °C. It reaches the
surface where the pressure is 1.10 atm and the
temperature is 27.0 °C. What is its new volume?
55. A CO2 bubble in some bread dough had an
original volume of 0.30 mL when it formed at
27.0 °C and 750 mmHg of pressure. While baking,
its temperature rose to 177.0 °C and a
thunderstorm moved in, dropping the pressure to
725 mmHg. What is the new volume of the
bubble?
56. If a hot air balloon holds 3000 liters (3.00 x 103 L)
of air at 17.0 °C and standard pressure, how much
air will escape as the balloon is heated to 67.0 °C
lbsand rises to where the pressure is 13.5 -----?
2
in
57. “A SCUBA diver's tank holds 200.0 liters of air at
27.0 °C and 150.0 atm. How many 1.50 liter
breaths can the diver take where the pressure is
4.00 atm and the temperature is 7.00 °C?
58. You drive to school in a hurricane where the
pressure is an abnormally low 720.0 mmHg.
However, when you get out of your car you notice
that the volume of your tires seems to be a normal
29 L. During the day a high pressure, bright
sunshine system moves overhead changing the
pressure to 780.0 mmHg. When you come back
A NATURAL APPROACH TO CHEMISTRY
outside you notice your tires seem a little flat.
What is the new volume of your tires?
70. What mass of CO2 is needed to fill an 80.0 L tank
to a pressure of 150.0 atm at 27.0 °C?
59. During the day at 25.0 °C a cylinder with a sliding
top contains 20.0 liters of air. At night it only
holds 18.0 liters of air. None of the air leaked out.
What is the temperature at night? Give the answer
in Kelvins and in °C.
71. At what temperature does 5.00 g of H2 occupy a
volume of 50.0 L at a pressure of 1.01 atm?
72. How many moles of gas would you have if you
had a volume of 38.0 L under a pressure of
1432 mmHg at standard temperature?
60. At what temperature would 2.10 moles of N2 gas
have a pressure of 1.25 atm in a 25.0 L tank?
Section 14.3
61. When filling a weather balloon with gas you have
to consider that the gas will expand greatly as it
rises and the pressure decreases. Let’s say you put
about 10.0 moles of He gas into a balloon that can
inflate to hold 5000.0 L. Currently, the balloon is
not full because of the high pressure on the
ground. What is the pressure when the balloon
rises to a point where the temperature is -10.0 °C
and the balloon has completely filled with the gas.
62. What volume is occupied by 5.03 g of O2 at 28 °C
and a pressure of 0.998 atm?
63. Calculate the pressure in a 212 Liter tank
containing 23.3 kg of argon gas at 25°C?
64. If you were to take a volleyball scuba diving with
you what would be its new volume if it started at
the surface with a volume of 2.00 L, under a
pressure of 752.0 mmHg and a temperature of
20.0 °C? On your dive you take it to a place where
the pressure is 2943 mmHg, and the temperature is
0.245 °C.
65. What is the volume of 1.00 mole of a gas at
standard temperature and pressure?
66. A 113L sample of helium at 27 °C is cooled at
constant pressure to -78.0 °C. Calculate the new
volume of the helium.
73. Use the following chemical equation to answer
questions 73 through 76.
2 C8H18 + 25 O2 → 16 CO2 + 18 H2O
74. If 4.00 moles of gasoline are burned, what volume
of oxygen is needed if the pressure is 0.953 atm,
and the temperature is 35.0 °C?
75. How many grams of water would be produced if
20.0 liters of oxygen were burned at a temperature
of -10.0 °C and a pressure of 1.3 atm?
76. If you burned one gallon of gas (approximately
4000 grams), how many liters of carbon dioxide
would be produced at a temperature of 21.0 °C
and a pressure of 1.00 atm?
77. How many liters of oxygen would be needed to
produced 45.0 liters of carbon dioxide if the
temperature and pressure for both are 0.00 °C and
5.02 atm?
78. Use the following chemical equation, which
shows the acetylene combustion reaction used in
acetylene welding torches, to answer questions 78
through:
2 C2H2 + 5 O2 → 4 CO2 + 2 H2O
67. What volume is occupied by 2.35 mol of He at
25 °C and a pressure of 0.980 atm?
79. If you had 0.564 moles of acetylene, what volume
of oxygen would be needed to react with it, if the
pressure was 13.9 psi and the temperature was
23 °C?
68. An aerosol can contains 400.0 ml of compressed
gas at 5.2 atm pressure. When the gas is sprayed
into a large plastic bag, the bag inflates to a
volume of 2.14 L. What is the pressure of gas
inside the plastic bag?
80. What volume of acetylene did you use if
10.5 grams of water were produced and the
pressure was 12.0 atm and the temperature was
18 °C?
69. At what temperature does 16.3 g of nitrogen gas
have a pressure of 1.25 atm in a 25.0 L tank?
81. What is the temperature of the reaction if
3.65 moles of oxygen are used and 500.0 Liters of
CO2 are produced under a pressure of 1.04 atm?
A NATURAL APPROACH TO CHEMISTRY
471