Name: __________________
Unit 7
Gases and the Kinetic
Molecular Theory
-1-
Name: __________________
Chemistry: Unit 7 Outline: Gas Las
Assignment
WB Page Number
Score Out of
Podcast 7.1 (CB 1-5)
Online

Demo: Two Balloons
In Class

Lab: Boyles Law-technology
Teacher Handout
100
Worksheet A
Pg 12-13

Podcast 7.2 (CB 7-9)
Online

Take Home Lab: Pressure and
Pg 4-5
100
Balloons
Lab: Charles’ Law
Pg 6-8
100
Worksheet B
Pg 14-15
100
Podcast 7.3 (CB 11-17)
Online

Demo: Graham’s Law
Teacher Demo

Worksheet C
Pg 16

Worksheet D
Pg 17-18

Podcast 7.4 (19-21)
Online

Lab: Stoichiometry and Gas
Pg 9-11
100
Laws
Worksheet E
Pg 19-21

Worksheet F
Pg 22

Worksheet G
Pg 23-25

Lab Test: MM of Butane
In class
100
Unit 7 Exam
In class
100
(You must score 85/100 on all assignments with a number to move to the next unit. For those
assignments with a check, you need to do it to the satisfaction of your teacher)
-2-
Name: __________________
Unit 7: Gas Laws
Section 12.1: The Properties of Gases
1
Gases Introduction (pg 326-330)
Define, Compressibility
List: four variables that describe a gas
Explain: What does it mean when the book says that gas particles are not affected by attractive or repulsive forces?
Section 12.2: Factors Affecting Gas Pressure
3
Properties of Gases (pg 330-332)
Sketch: Figure 12.4, Figure 12.7, Figure 12.8, Figure 12.9
Describe: (Use the diagrams to help explain this—you should write the explanations next to the diagrams)
Why does pressure increase as you pump up a bicycle tire? (Fig 12.4)
Why does an aerosol can work? (Fig 12.7)
Why does the pressure in a can increase when you push down the plunger (Fig 12.8)
Why does a sealed can explode when it is heated? (Fig 12.9)
Section 12.3: The Gas Laws
5
Boyles, Charles’, Gay-Lussac Laws (pg 333-337)
 Define Boyles’ Law and write down its equation
 Define Charles’ Law and write down its equation
 Define Gay-Lussac Law and write down its equation
Sketch: For each law sketch a graph the illustrates how each varies
7
9
Simple Gas Law Problems
Leave Blank for teacher notes
Combined Gas Law (pg 339-340)
Copy down: the Combined Gas Law Equation
Section 12.4: The Ideal Gas Law
11 The Ideal Gas Las (pg 341-343)
Copy: the Ideal Gas Law found on the bottom of page 341
Write down: what each variable in the equation represents
Write down: the value for R and include units
13 Deviations from Ideal Behavior (pg 344-346)
Sketch: Figure 12.19
Sketch: Figure 12.20
Question:
Under what conditions of pressure and temperature (high or low) does a gas act in an ideal fashion?
Section 12.5: Gas Molecules: Mixtures and Movements
15 Avogadro’s Hypothesis (pg 347-349)
Define: Avogadro’s Hypothesis
Sketch: Figure 12.21
17 Daltons & Grahams Laws (pg 350-353)
Define: Partial Pressure, Daltons Law of Partial Pressures.
Sketch: Figure 12.22
Define: Diffusion, effusion, Graham’s law of effusion:
Copy: Equation for Graham’s Law
19 Stoichiometry and Gas Laws
Leave Blank for podcast notes
21 Molar Mass of a Gas
Leave Blank for podcast notes
-3-
Name: __________________
Take Home Lab: Gas Laws
Purpose: To determine the atmospheric pressure at a location that has a different altitude than
Woodland Park.
Materials: A balloon, a tape measure, and a string
Procedure:
1. Blow up a balloon either at a lower altitude (Colorado Springs) or a higher altitude
(Woodand Park), and take the balloon to the other location. You could also fill the
balloon up in Woodland Park and then go skiing and measure the diameter of the balloon
at the top of Hosier Pass.
2. Measure the circumference of the balloon in the first location. This is probably best done
with a string.
3. Drive to location 2 and measure the circumference of the balloon.
Calculations:
1. In the interest of making the calculations simple, we will assume that the balloon is a
sphere.
2. Using the equation C=2πr, determine the radius of the balloon in both locations.
3. Using the equation V=4/3πr3, determine the volume of the balloon in both locations.
4. Assuming that the pressure in Woodland Park is 571 torr, determine, using Boyles Law,
the pressure in location 2.
5. Use the table on the next page to determine your percent error. You may need to use a
program like google earth to determine the altitude for your two samples. The graph
below only shows form about 6500 feet up to 15,000 feet. The pressure unit is in
millibars: 1mb = 0.75 torr
Data Table
Circumference of Balloon at lower Altitude
Radius of balloon at lower altitude
Volume of balloon at lower altitude
Circumference of Balloon at higher
Altitude
Radius of balloon at higher altitude
Volume of balloon at higher altitude
Pressure in Woodland Park
571 torr
Pressure at Location 2
-4-
Name: __________________
Questions
1. Discuss, using the kinetic molecular theory, why the balloon shrunk or grew at different
altitudes. Use a picture in your explanation.
2. What would happen if you took your balloon to the top of Mt. Everest (average pressure
= 253torr), the tallest point on the earth?
3. Explain why air pressure goes down the higher you are in altitude.
For Credit: You must have a signed note from your parent/guardian explaining two things:
1. Why does air pressure go down as you go up in altitude
2. Why does a bag of potato chips purchased in Colorado Springs expand (and
sometimes, blow up) when brought to Woodland Park?
-5-
Name: __________________
Charles’ Law Lab
Purpose: To determine the relationship between Temperature and volume of a gas.
Procedure
1. Obtain an empty 250 mL Erlenmeyer flask with a one hole stopper and use crucible tongs
to hold it in a boiling how water bath.
2. After 5 min quickly invert the flask (holding your finger over the one hole) and move it
into a vat of ice cold water.
3. Remove your finger from the stopper and allow water to move into the flask.
4. Hold the flask under the water for 5 minutes
5. Measure the amount of water in the flask using a graduated cylinder
6. Measure the total amount of water in the flask using a graduated cylinder.
7. Measure the temperature of both the ice water and the boiling water.
Safety
There is a danger of the flask imploding. You need to make sure that your flask has no chips or
cracks. If so report this to your teacher immediately and don’t use that flask.
-6-
Name: __________________
Data
Total Volume of water in flask
Volume of water in flask after the
experiment
Volume of air in the flask when hot
Volume of air in the flask when cold
Temperature of the hot gas (˚C)
Temperature of the cold gas (˚C)
Data Analysis
 Plot a graph of temperature (x axis) verses Volume (y axis). Set your such that the
temperature goes from –400˚C to 200˚C. Set your volume (y axis) to be from 0 to 300
mL
 Place two points on your graph and draw the line back to where volume is equal to zero.
Questions
1. At what point did your line cross the x axis? What is the significance of this
point?
2. What happens to molecules at absolute zero?
3. What would really happen to your gas if you cooled it down to a really low
temperature? (HINT: Think about attractive forces)
4. What is your percentage error for the determination of absolute zero?
-7-
Name: __________________
-8-
Name: __________________
Stoichiometry and Gas Law Lab
Purpose: To determine the volume of H2 that will be liberated when a sample of
magnesium is completely reacted with excess hydrochloric acid (HCl). This is a single
replacement reaction.
Material: Magnesium ribbon--untarnished, thread, hydrochloric acid--concentrated.
Procedure:
Fill a plastic tub with water. Roll a
length of magnesium ribbon of
known mass into a loose coil. Tie it
with one end of a piece of thread,
approx 25 cm. in length, in such
manner that all the loops of
coil are tied together. Obtain 5ml. of
concentrated hydrochloric acid
(DANGER) from your instructor in
the eudiometer. Slowly fill it
completely with water, being careful
not to mix the water and the acid.
Lower the magnesium coil into the
water in the gas measuring tube to a
depth of about 5 cm. Close the tube
with your thumb so that the thread is
held firmly against the edge of the
tube. Taking care that no air enters,
invert the eudiometer in the tub and
allow it to rest against the bottom to
hold the thread. It may be clamped
in this position on the ring stand, as
shown.
When the magnesium has completely
reacted (no more metal present and
the bubbles have stopped), go to the
big bucket of water and insert your
tube in the water. Adjust the tube
until the liquid levels inside and
outside are the same. Read the
volume of hydrogen gas liberated as
precisely as possible. Take the temperature of the water in the tub and assume this to be
temperature of the hydrogen gas collected. Record the barometric pressure from the
board.
-9-
Name: __________________
Procedure:
Turn the paragraphs above into a stepwise procedure. Place an * next to each step
whenever a measurement must be recorded in your data table,
Data & Calculations:
1. Record all data in the provided table.
2. The mass of one meter of magnesium is ____________. Determine the mass of
your sample.
3. Calculate the expected volume of hydrogen gas from your data. Begin with the
balanced equation and use the ideal gas law to determine the volume of H2 that
should have been collected from the mass of magnesium you started with.
4. Calculate the % error using the calculated volume from question (2) above as the
accepted value and your measured volume as the experimental value.
Questions:
1. What type of reaction occurred? (single, double, synthesis, decomposition,
combustion)
2. Why is it necessary to make a water-vapor correction of the barometer reading in this
experiment?
3. If this same experiment were done in Florida, how would the experimental volume
(would it be higher or lower) of the gas have changed? Explain thoroughly.
4. Complete a cause-effect error analysis to explain your observed % error. Include a
minimum of 4 specific errors.
Data Table
Length of Mg obtained (cm)
Mass of Mg (g)
Volume of H2 Actual (mL)
Temperature of H2O=THydrogen
Atmospheric Pressure (mmHg)
Vapor Pressure of H2O (mmHg)
Pressure of H2
Volume of H2 Predicted (mL)
Percentage Error
- 10 -
Name: __________________
Water Vapor Pressure
Temp VP
Temp VP
ºC
mm ºC
mm
Hg
Hg
4
6.1
27
26.7
5
6.5
28
28.3
6
7.0
29
30.0
7
7.5
30
31.8
8
8.0
31
33.6
9
8.6
32
35.6
10
9.2
33
37.7
11
9.8
34
39.8
12
10.5 35
42.1
13
11.2 36
44.5
14
12.0 37
47.0
15
12.8 38
49.7
16
13.6 39
52.4
17
14.5 40
55.3
18
15.5 41
58.3
19
16.5 42
61.5
20
17.5 43
64.8
21
18.6 44
68.3
22
19.8 45
71.9
23
21.0 46
75.6
24
22.3 47
79.6
25
23.7 48
83.7
26
25.2 49
88.0
- 11 -
Name: __________________
Gas Laws Worksheet A: Boyles-Charles-Gay-Lussac
1. You are now wearing scuba gear and swimming under water at a depth of 66.0 ft. You are
breathing air at 3.00 atm and your lung volume is 10.0 L. Your scuba gauge indicates that your
air supply is low so, to conserve air, you make a terrible and fatal mistake: you hold your breath
while you surface. What happens to your lungs? Why?
2. A gas with a volume of 4.0 L at a pressure of 0.90-atm is allowed to expand until the pressure
drops to 0.20-atm. What is the new volume?
3. A given mass of air has a volume of 6.0 L at 1.0-atm. What volume will it occupy at 190
mm Hg if the temperature does not change?
4. The pressure of air in an automobile tire is 2.0-atm at 27˚ C. At the end of a journey on a
hot sunny day the pressure has risen to 2.2-atm. What is the temperature of the air in the tire?
(Assume that the volume of the tire has not changed.)
5. Five liters of air at -50˚C is warmed to 100˚C. What is the new volume if the pressure
remains constant?
6. A gas cylinder contains nitrogen gas at 10-atm pressure and a temperature of 20˚C. The
cylinder is left in the sun, and the temperature of the gas increases to 50˚C. What is the pressure
in the cylinder?
- 12 -
Name: __________________
7. A bike tire has a volume of 0.850L at a pressure of 40 psi and 0˚C. What will be the pressure
of the tire at 35˚C?
8. A hot air balloon has a volume of 10,000-L when at 25˚C. What will be the new volume if
the air is heated up to 65˚C?
9. A student holds the end of a bicycle pump and pumps the air in the pump. He holds on for as
long as possible. Before pumping the pressure was 20-psi The pressure gauge on the pump
reads 80psi right before air escaped. By what fraction did he reduce the volume in the pump.
Hint: Assume that you have 1-L of air and use Boyle’s law to determine the number.
10. A tire pressure gauge is used to determine that the pressure in an automobile tire is 25 psi on
a cold winter day (-10˚C). After the car has driven a considerable distance the pressure was 30
psi. What is the temperature of the gas inside of the car tire?
- 13 -
Name: __________________
Gas Laws Worksheet B
The Combined Gas Law Worksheet
1. A 5.0L balloon in a freezer is at a temperature of -50˚C has a pressure of 800 mm Hg. What
will be the new pressure if the balloon is taken out and placed in a warm room (Temperature
37˚C) and the volume expands to 7.0 L?
2. A 2.0 L bag of potato chips in Denver is at 15˚C and 0.82 atm. The same bag is brought to
the top of Longs Peak on a cold winter day. If the bag can only expand to 2.5 L before
exploding and Longs Peak has a temperature of -5˚C and a pressure of 0.45 atm, will the bag
explode? Use the combined gas law to prove this to yourself.
3. A gas has a volume of 0.50 L, a pressure of 0.5 atm, and a temperature of 40˚C. What will be
the new temperature if the gas is expanded to 5.0L L and a pressure of 0.10atm atm?
4. Convert 44.5 L of oxygen at 32˚C and 654 mm Hg to STP. Hint: when STP is stated this
gives you a specific temperature and a specific pressure.
5. A gas bubble has a volume of 0.650 mL at the bottom of a lake, where the pressure is 3.46atm. What is the volume of the bubble at the surface of the lake, where the pressure is 1.00atm? Assume that the temperature is constant. Will the new volume be bigger or smaller?
- 14 -
Name: __________________
6.
A balloon filled with air has a volume of 3.25 L at 30°C. It is placed in a freezer at
-10°C. What is the volume of the balloon at this temperature? Assume that the pressure is
constant. What are the temperatures in Kelvin? Should V2 be bigger or smaller?
7.
A .500 L container contains nitrogen gas at 0.800-atm and 0°C. If the highest pressure
the container can withstand before exploding is 3.0-atm, what is the highest temperature to which
the gas can be heated? Assume the volume is constant. What is the original temperature in
Kelvin? Should T2 be bigger or smaller from the change in pressure?
8.
A weather balloon is partially filled with helium at 20°C to a volume of 31.5 L and a
pressure of 1.3 atm. The balloon rises to the stratosphere, where the temperature is -23°C and
pressure is .00300 atm. Calculate the volume of the balloon in the stratosphere. What are the
temperatures in Kelvin? What effect does the change in temperature have on V2? What effect
does the change in pressure have on V2? Does temperature or pressure have more influence on
volume in this balloon?
- 15 -
Name: __________________
Gas Laws Worksheet #C: Ideal Gas Law Worksheet
1. What pressure will be exerted by 0.450 mol of a gas at 25˚C if it is contained in a vessel
whose volume is 650mL?
2. What volume will 12.0 g of oxygen gas (O2) occupy at 25˚C and a pressure of 0.520 atm?
3. If 4.5 g of methane (CH4) is introduced to an evacuated 2.00L container at 35˚C, what is the
pressure in the container in atmospheres?
4. A 5.00 L flask at 25˚ C contains 0.200 mol of Cl2. What is the pressure in the flask?
5. What is the pressure exerted by 32 g of O2 in a 20-L container at 30.0˚C?
6. How many moles of N2 are in a flask with a volume of 250 mL at a pressure of 0.56 atm and a
temperature of 300 K?
- 16 -
Name: __________________
WS D: Gas Law Worksheet D: Daltons and Graham’s Law
Dalton’s Law Questions
1. A container holds three gases: oxygen, carbon dioxide, and helium. The partial pressures
of the three gases are 2.00 atm, 3.00 atm, and 4.00 atm, respectively. What is the total
pressure inside the container?
2. A container with two gases, helium and argon, is 30.0% by volume helium. Calculate the
partial pressure of helium and argon if the total pressure inside the container is 4.00 atm.
3. If 60.0 L of nitrogen is collected over water at 40.0 °C when the atmospheric pressure is
760.0 mm Hg, what is the partial pressure of the nitrogen?
4. 80.0 liters of oxygen is collected over water at 50.0 °C. The atmospheric pressure in the
room is 96.00 kPa. What is the partial pressure of the oxygen?
5. A tank contains 480.0 grams of oxygen and 80.00 grams of helium at a total pressure of
7.00 atmospheres. Calculate the following.
- 17 -
Name: __________________
Graham’s Law Questions
6. If equal amounts of helium and argon are placed in a porous container and allowed to
escape, which gas will escape faster and how much faster?
7. What is the molecular weight of a gas which diffuses 1/50 as fast as hydrogen?
8. Two porous containers are filled with hydrogen and neon respectively. Under identical
conditions, 2/3 of the hydrogen escapes in 6 hours. How long will it take for half the neon
to escape?
9. If the density of hydrogen is 0.090 g/L and its rate of diffusion is 6 times that of chlorine,
what is the density of chlorine?
10. How much faster does hydrogen escape through a porous container than sulfur dioxide?
- 18 -
Name: __________________
Gas Laws Worksheet E: Gas Laws and Stoichiometry Questions
1.
Solid potassium chlorate (KClO3) decomposes to produce solid potassium chloride and
oxygen gas. What volume of oxygen gas, measured at 40°C and 655 mmHg, will be produced
when 13.5 g of potassium chlorate is decomposed?
2.
What volume of chlorine gas, measured at 71.7°C and 1.31 atm, will be produced when
98.4 g of iron(II) chloride is decomposed into its elements?
3.
How many grams of water are produced when 500 L of hydrogen gas measured at 25°C
and 0.97-atm is ignited with oxygen?
4.
If 500 g of carbon disulfide burns in the presence of oxygen to produce carbon dioxide
and sulfur dioxide, how many liters of sulfur dioxide collected over water measured at 27°C and
740-mmHg, are produced?
- 19 -
Name: __________________
5. Given the following reaction:
5C(s) +
2SO2(g) -----> CS2(s)
+
4CO(g)
How many liters of CO(g) at 23˚C and 623 mmHg will be formed if 5.0 g of Carbon completely
reacts?
6.
C6H12O6 (s) + 6 O2 (g)
--------->
6CO2(g)
+
6H2O(g)
Given the above reaction, How many grams of C6H12O6 (s) will be needed to make 54 mL of
CO2 at 550˚C and 8 atm?
7. When the following reaction occurs:
4P(s)
+
5O2(g)
---------->
2P2O5(s)
How many grams of P2O5 is produced when 82.54 mL of oxygen at 6000 K and 45-atm is
completely consumed?
- 20 -
Name: __________________
8. How many Liters of carbon dioxide is produced at 300 K and 99.2-kPa when 43.65 grams of
acetylene, C2H2 is burned?
9. When silicon dioxide reacts with carbon by heating, the following reaction occurs:
SiO2(s) +
3C(s) ----- -----> SiC(s)
+
2CO(g)
What will be the volume of carbon monoxide collected over water will be produced at 22.0˚C
and 657mm when 96.25 grams of SiO2 completely reacts?96.25 grams of SiO2 completely
reacts?
10··. Nitroglycerine explodes violently to form several gasses according to the following
equation:
4 C3H5O9N3 ----------> 12 CO2(g) +
O2(g) +
6N2(g) + 10 H2O(g)
A sealed 1.00 mL container filled with 2.8 g of nitroglycerine is detonated. If the Temperature
inside the container is 300˚C and assuming that the container would not break upon detonation,
what is the pressure inside the container right after detonation? (Put your answer in atm's)
- 21 -
Name: __________________
Gas Law Worksheet F: Molar Mass of a Gas
1. A 256 mL sample of an unknown gas was collecte over water at 23˚C and 750 mmHg. The
gas has a mass of 0.80 grams. What is the molar mass of the gas? (The vapor pressure of water
at 23˚C is 21.0 mmHg)
2. 0.235 grams of magnesium reacts with excess hydrochloric acid to make 309 mL of hydrogen
gas at 28˚C and 615 mmHg. (The vapor pressure of water at 28˚C is 28.3 mmHg). From the
experimental data what is the molar mass of magnesium? What is the percentage error?
3. 0.855 grams of Potassium chlorate decomposes into oxygen gas and potassium chloride. A
350 mL sample of oxygen gas was collected at 65˚C and 810 mmHg over water. (The vapor
pressure of water at 65˚C is 187.5 mmHg). According to experimental data, what is the molar
mass of potassium chlorate? What is the percentage of error?
4. A compound contains only nitrogen and hydrogen and is 87.4% nitrogen by mass. A one liter
sample of gas has a mass of 0.977 grams at 710 mm Hg and 100˚C. What is the molecular
formula of the gas?
- 22 -
Name: __________________
Gas Laws Worksheet G: Mixed Gas Law Problems--Review
1. 0.322-g of an unknown gas was collected. The gas had a volume of 59.8-mL a pressure of
655mm Hg and a temperature of 52˚C. What is the molar mass of the gas?
2. A 6.2-L balloon at 55˚C and 615mm Hg is taken to the top of Mt. Everest (-35˚C and 400mmHg). What is the size of the balloon?
3. 2.5-g of oxygen is at 56˚C and 45.3-atm. What is the volume of the gas?
4. 23.5-g of sodium carbonate is reacted with hydrochloric acid to make water, carbon dioxide
and sodium chloride. The gas is collected over water at 24˚C and 615-mmHg. What volume is
produced?
- 23 -
Name: __________________
5. 0.21-grams of an unknown gas is collected over water. That gas had a volume of 325-mL and
was collected at 744-mm Hg and 21˚C. What is the molar mass of the gas?
6. A bicycle tire that has a volume of 0.85-L is inflated to 140 pounds per square inch. What
will be the pressure in the tire if the number of moles of gas is doubled?
7. 324-mL of oxygen is collected over water at 685-mmHg and 18˚C. It is released when
hydrogen peroxide (H2O2) decomposes. It also forms water. How many grams of hydrogen
peroxide decomposed?
8. Convert 23.5-mL of N2 gas at 220-kPa and 98.7˚C to STP.
- 24 -
Name: __________________
9. What is the density of oxygen gas at 40˚C and 615-mmHg. Hint: Find the grams per mL.
Assume that you have a given amount of grams (You choose) and then convert to volume. Then
divide.
10. What is the temperature of a gas that has a volume of 555-mL and 43.5-atm that was initially
at 20˚ , 885-mL, and 2.9-atm?
11. At 298 K O2 travels at 1200 miles per hour. What is the speed of Helium at the same
temperature?
- 25 -
Name: __________________
Gas Laws Worksheet A
Boyles-Charles-Gay--Lussac
1. A gas with a volume of 4.0 L at a pressure of 0.90-atm is allowed to expand until the pressure
drops to 0.20-atm. What is the new volume?
P1V1  P2V2
(0.90atm)(4.0L)  (0.20atm)(V2 )
(0.90atm)(4.0L) (0.20atm)(V2 )

0.20atm
0.20atm
V2  18L
2. A given mass of air has a volume of 6.0 L at 1.0-atm. What volume will it occupy at 190 mm
Hg if the temperature does not change?


P1V1  P2V2
1.0atm 760mmHg
x
 760mmHg
1
1atm
(760mmHg)(6.0L)  (190mmHg)(V2 )
(760mmHg)(6.0L) (190mmHg)(V2 )

190mmHg
190mmHg
V2  24L
P1 
3. The pressure of air in an automobile tire is 2.0-atm at 27˚ C. At the end of a journey on a hot
sunny day the pressure has risen to 2.2-atm. What is the temperature of the air in the tire?
(Assume that the volume of the tire has not changed.)
P1 P2
 :: P1  2.0atm :: T1  27˚273  300 K
T1 T2
P2  2.2atm :: T2  ?
2.0atm 2.2atm

:: CrossMulti ply
300 K
T2
(2.0atm)(T2 )  (2.2atm)(300 K )
(2.0atm)(T2 ) (2.2atm)(300 K )

2.0atm
2.0atm
T2  330 K  57˚C
- 26 -
Name: __________________
4. Five liters of air at -50˚C is warmed to 100˚C. What is the new volume if the pressure
remains constant?
V1 V2

:: V1  5.0L :: T1  50Þ273  223K
T1 T2
V2  ? :: T2  100Þ273  373K
5.0L
V
 2 :: CrossMultiply
223K 373
(5.0L )(373K )  (223K )(V2 )
DivideBothSidesBy 223K
V2  8.36L
5. A gas cylinder contains nitrogen gas at 10-atm pressure and a temperature of 20˚C. The
cylinder is left in the sun, and the temperature of the gas increases to 50˚C. What is the pressure
in the cylinder?
P1 P2
 :: P1  10atm :: T1  20Þ273  293K
T1 T2
P2  ? :: T2  50Þ273  323K
10atm
P
 2 :: CrossMultiply
293K 323K
(10.0atm)(323K)  (P2 )(293K)
DivideBy 293K
P2  11.0atm

6. A bike tire has a volume of 0..850L at a pressure of 40 psi and 0˚C. What will be the
pressure of the tire at 35˚C?
P1 P2

:: P1  40 psi :: T1  0˚273  273K
T1 T2
P2  ? :: T2  35˚273  308 K
P2
40 psi

:: CrossMulti ply
273K 308 K
(40 psi )(308 K )  ( P2 )( 273K )
DivideBy 273K
P2  45 psi
- 27 -
Name: __________________
7. A hot air balloon has a volume of 10,000-L when at 25˚C. What will be the new volume if
the air is heated up to 65˚C?
V1 V2
 :: V1  10,000L :: T1  25Þ273  298K
T1 T2
V2  ? :: T2  65Þ273  338K
10,000L V2

:: CrossMultiply
298K
338
(10,000L)(338K)  (298K)(V2 )
DivideBothSidesBy 298K
V2  11342L

8. An aerosol can has a fixed volume of gas at 4.0-atm of pressure and room temperature (25˚C).
If the pressure inside the can reaches 5.9-atm the can will explode. The can is thrown into a fire
that is 400˚C. Will the can explode? Show all calculations to support your answer.
P1 P2
 :: P1  4.0atm :: T1  25Þ273  298K
T1 T2
P2  ? :: T2  400Þ273  673K
4.0atm
P
 2 :: CrossMultiply
298K
673K
(4.0atm)(673K)  (P2 )(298K)
DivideBy 298K
P2  9.0atm : This pressure is greater than 5.9atm so YES it
will explode

9. A student holds the end of a bicycle pump and pumps the air in the pump. He holds on for as
long as possible. Before pumping the pressure was 20-psi The pressure gauge on the pump
reads 80psi right before air escaped. By what fraction did he reduce the volume in the pump.
Hint: Assume that you have 1-L of air and use the Gay-Lussac law to determine the number.
P1  20 psi :: V1  1.0L :: P2  80 psi
P1V1  P2V2
(20 psi)(1.0L)  (80 psi)(V2 )
DivideBothSidesBy 80 psi
V2  0.25L
1.0L
Fraction 
 4Times
0.25L
- 28 -

Name: __________________
10. A tire pressure gauge is used to determine that the pressure in an automobile tire is 25 psi on
a cold winter day (-10˚C). After the car has driven a considerable distance the pressure was 30
psi. What is the temperature of the gas inside of the car tire?
P1 P2
 :: P1  25 psi :: T1  10Þ273  263K
T1 T2
P2  30atm :: T2  ?
25 psi 30 psi

:: CrossMultiply
263K
T2
(25 psi)(T2 )  (30 psi)(263K)
(25 psi)(T2 ) (30 psi)(263K)

25 psi
25 psi
T2  315K  42.6ÞC

- 29 -
Worksheet B: The Combined Gas Law Worksheet Answers
Answer on your own paper
1. A 5.0L balloon in a freezer is at a temperature of -50˚C has a pressure of 800 mm Hg.
What will be the new pressure if the balloon is taken out and placed in a warm room
(Temperature 37˚C) and the volume expands to 7.0 L?
P1 V1 P2 V2

T1
T2
(800)(5.0) P2 (7.0)

223
310
P2  794mmHg
2. A 2.0 L bag of potato chips in Denver is at 15˚C and 0.82 atm. The same bag is
brought to the top of Longs Peak on a cold winter day. If the bag can only expand to
2.5 L before exploding and Longs Peak has a temperature of -5˚C and a pressure of
0.45 atm, will the bag explode? Use the combined gas law to prove this to yourself.
P1 V1 P2 V2

T1
T2
(0.82)(2.0) (0.45)(V2 )

288
268
V2  3.4L bigger than 2.5L so it will explode
3. Freon gas is is used in a freezer to cool the food down. The gas travels at a volume of
0.50 L, a pressure of 0.5 atm, and a temperature of 40˚C. What will be the new
temperature if the gas is expanded to 5.0L L and a pressure of 0.10atm atm?
P1V1 P2V2

T1
T2
(0.50atm)(0.50 L) (0.1atm)(5.0 L)

313
T2
T2 = 626K = 353C : doesnt make sense
I wrote the question w rong
4. Convert 44.5 L of oxygen at 32˚C and 654 mm Hg to STP.
P1 V1 P2 V2

T1
T2
(654)(44.5) (760)(V2 )

305
273
V2  34.3L
5. A gas bubble has a volume of 0.650 mL at the bottom of a lake, where the pressure is
3.46 atm. What is the volume of the bubble at the surface of the lake, where the
pressure is 1.00 atm? Assume that the temperature is constant. Will the new volume
be bigger or smaller?
P1 V1 P2 V2

T1
T2
(3.46)(0.65) (1.0)(V2 )

T
T
V2  2.24mL the bubble is bigger
6. A balloon filled with air has a volume of 3.25 L at 30°C. It is placed in a freezer at 10°C. What is the volume of the balloon at this temperature? Assume that the
pressure is constant. What are the temperatures in kelvin? Should V2 be bigger or
smaller?
P1 V1 P2 V2

T1
T2
P(3.25) P(V2 )

303
263
V2  2.82L smaller because the Temp went down
7. A .500 L container contains nitrogen gas at 0.800 atm and 0°C. If the highest
pressure the container can withstand before exploding is 3.0 atm, what is the highest
temperature to which the gas can be heated? Assume the volume is constant. What is
the original temperature in kelvin? Should T2 be bigger or smaller from the change in
pressure?
P1 V1 P2 V2

T1
T2
0.800atm(0.50L) 3.00atm(0.50L)

273
T2
T2  1023K = 751 C
8. A weather balloon is partially filled with helium at 20°C to a volume of 31.5 L and a
pressure of 1.3 atm. The balloon rises to the stratosphere, where the temperature is 23°C and pressure is .00300 atm. Calculate the volume of the balloon in the
stratosphere. What are the temperatures in kelvin? What effect does the change in
temperature have on V2? What effect does the change in pressure have on V2? Does
temperature or pressure have more influence on volume in this balloon?
P1 V1 P2 V2

T1
T2
(1.3atm)(31.5L) 0.0030atm(V2 )

293
250
V2  11646L
9.
A gas occupied 550 cm3 at a pressure of 100.8 kPa and a temperature of 21°C.
Several days later it was measured at a pressure of 106.4 kPa and a temperature of
15°C. What volume did the gas have under the new conditions? What are the
temperatures in kelvin? What effect does the change in pressure have on V2? What
effect does the change in temperature have on V2?
P1 V1 P2 V2

T1
T2
(100.8kPa)(550cm3 ) (106.4kPa)(V2 )

294K
288K
V2  510cm3
WS C: Ideal Gas Law Worksheet
Name: ______________
Period: __
1. What pressure will be exerted by 0.450 mol of a gas at 25˚C if it is contained in a vessel
whose volume is 650mL?
PV  nRT
P?
V  650mL  0.650L
n  0.450mol
Latm
R  O.08206 molK
T  25C  298K
nRT (o.450mol)(O.08206 Latm
)(298K)
molK
P

 16.9atm
V
(0.650L)
2. What volume will 12.0 g of oxygen gas (O2) occupy at 25˚C and a pressure of 0.520 atm?
PV  nRT
P  0.520atm
V ?
12.0g 1mol
n
x
 0.375mol
1
32g
Latm
R  O.08206 molK
T  25C  298K
V
nRT (0.375mol)(O.08206 Latm
molK )(298K)

 17.6L
P
(0.520atm)
3. If 4.5 g of methane (CH4) is introduced to an evacuated 2.00L container at 35˚C, what is
the pressure in the container in atmospheres?
PV  nRT
P?
V  2.00L
4.5g 1mol
n
x
 0.281mol
1
16g
Latm
R  O.08206 molK
T  35C  308K
P
nRT (0.281mol)(O.08206 Latm
molK )(308K)

 3.6atm
V
(2.00L)
4. A 5.00 L flask at 25˚ C contains 0.200 mol of Cl2. What is the pressure in the flask?
PV  nRT
P?
V  5.00L
n  0.200mol
Latm
R  O.08206 molK
T  25C  298K
nRT (0.200mol)(O.08206 Latm
)(298K)
molK
P

 0.98atm
V
(5.00L)
4. What is the pressure exerted by 32 g of O2 in a 20-L container at 30.0˚C?
PV  nRT
P?
V  20.L
32g 1mol
n
x
 1.0mol
1
32g
Latm
R  O.08206 molK
T  30C  303K
P
nRT (1.0mol)(O.08206 Latm
molK )(303K)

 1.24atm
V
(20.0L)
5. How many moles of N2 are in a flask with a volume of 250 mL at a pressure of 0.56 atm
and a temperature of 300 K?
PV  nRT
P  0.56atm
V  250mL  0.250L
n?
Latm
R  O.08206 molK
T  300K
PV
(0.56atm)(0.250L)
n

 0.0057mol
RT (O.08206 Latm
)(300K)
molK
WS D: Gas Law Worksheet D: Daltons and Graham’s Law
Dalton’s Law Questions
1. A container holds three gases: oxygen, carbon dioxide, and helium. The partial pressures
of the three gases are 2.00 atm, 3.00 atm, and 4.00 atm, respectively. What is the total
pressure inside the container?
2.00 atm + 3.00 atm + 4.00 atm = 9.0 atm
2. A container with two gases, helium and argon, is 30.0% by volume helium. Calculate the
partial pressure of helium and argon if the total pressure inside the container is 4.00 atm.
PHe  (0.30)( 4.0atm)  1.2atm
PAr  (0.70)( 4.0atm)  2.8atm
6.
If 60.0 L of nitrogen is collected over water at 40.0 °C when the atmospheric pressure is
760.0 mm Hg, what is the partial pressure of the nitrogen?
Ptot  PN 2  PH 2O
760torr  PN 2  55torr
 705torr
7. 80.0 liters of oxygen is collected over water at 50.0 °C. The atmospheric pressure in the
room is 96.00 kPa. What is the partial pressure of the oxygen?
Ptot  PO2  PH 2O
94torr 101.32kPa
x
 12.53kPa
1
760torr
96.00kPa  PO2  12.53kPa
PH 2O 
 83.47kPa
8. 69. A tank contains 480.0 grams of oxygen and 80.00 grams of helium at a total pressure
of 7.00 atmospheres. Calculate the following.
a. Can’t Do: Not enough information.
WS E: Graham’s Law Questions
9. If equal amounts of helium and argon are placed in a porous container and allowed to
escape, which gas will escape faster and how much faster?
Helium will travel faster because it is a smaller gas
MM Ar
Rate He

Rate Ar
x

1
40
4
MM He

6.32
 3.16TimesFaster
2
What is the molecular weight of a gas which diffuses 1/50 as fast as hydrogen?
RateH 2
Rate X

MM X
MM H 2
50
x
x


:: CrossMulti ply
1
2 1.41
70.7  x : SquareBoth Sides
x  5000 g / mol
10. Two porous containers are filled with hydrogen and neon respectively. Under identical
conditions, 2/3 of the hydrogen escapes in 6 hours. How long will it take for half the neon
to escape?
Extra Credit for the kid who figures this out
11. If the density of hydrogen is 0.090 g/L and its rate of diffusion is 6 times that of chlorine,
what is the density of chlorine?
RateH 2
RateCl2

MM Cl2
MM H 2
6
x
x


:: CrossMulti ply
1
0.090 0.30
1.8  x : SquareBothSides
x  3.24 g / L
12. How much faster does hydrogen escape through a porous container than sulfur dioxide?
RateH 2
RateSO2

MM SO2
MM H 2
x
64
8


 5.65
1
2 1.41
WS E: Gas Laws and Stoichiometry Questions
Solid potassium chlorate (KClO3) decomposes to produce solid potassium chloride and oxygen
gas. What volume of oxygen gas, measured at 40°C and 655 mmHg, will be produced when
13.5 g of potassium chlorate is decomposed?
2KClO3  2KCl  3O2
13.5g
655 mm, 40C, L?
13.5gKClO3 1molKClO3
3molO2
x
x
 0.165molO2
1
122.5gKClO3 2molKClO3
T  40  273  313K
P  655mmHg  0.862atm
n  0.165mol
PV  nRT
V
Latm
nRT (0.165mol)(0.0821 molK
)(313K)

 4.92LO2
P
0.862atm
2.
What volume of chlorine gas, measured at 71.7°C and 1.31 atm, will be produced when
98.4 g of iron(II) chloride is decomposed?
FeCl2  Fe  Cl2
98.4g
1.31atm, 71.7C,L?
98.4gFeCl2 1molFeCl2 1molCl2
x
x
 0.775molCl2
1
127gFeCl2 1molFeCl2
T  71.7  273  344.7K
P  1.3atm
n  0.775molCl2
PV  nRT
Latm
nRT (0.775molCl2 )(0.0821 molK
)(344.7K)

 16.9LCl2
P
1.3atm
3.
How many grams of water are produced when 500 L of hydrogen gas measured at 25°C
and 0.97 atm is ignited with oxygen?
V
 O2  2H2 O
2H2
V = 500L
T  25  273  298K
g?
P = 0.97atm
PV  nRT
PV
(0.97atm)(500L)
n

 19.8molH 2
Latm
RT (0.0821 molK
)((298K)
19.8molH2 2molH2 O 18gH2O
x
x
 357gH2 O
1
2molH2 1molH2 O
4.
If 500 g of carbon disulfide burns in the presence of oxygen to produce carbon dioxide
and sulfur dioxide, how many liters of sulfur dioxide measured at 27°C and 740 mmHg, are
produced?
CS 2  3O2  CO2 
2 SO2
L?
500 g
27C
740mmHg
500gCS 2 1molCS 2 2molSO2
x
x
 13.1molSO2
1
76 gCS 2 1molCS 2
T  27  273  300 K
P  740mmHg  27  0.938atm
n  13.1mol
PV  nRT
V
Latm
nRT (13.1mol )(0.0821 molK )(300 K )

 344 LSO2
P
0.938atm
5. Given the following reaction:
5C(s) +
2SO2(g) -----> CS2(s)
+
4CO(g)
How many liters of CO(g) at 23˚C and 623 mmHg will be formed if 5.0 g of Carbon completely
reacts?
5C(s) +2SO2(g)  CS 2 (s) + 4CO(g)
L?
23C
5g
623mmHg
5gC 1molC 4molCO
x
x
 0.33molCO
1
12gC
5molC
T  23  273  296K
P  623mmHg  0.820atm
n  0.33mol
PV  nRT
V
Latm
nRT (0.33mol)(0.0821 molK
)(296K)

 9.78LCO
P
0.820atm
6.
C6H12O6(s) + 6 O2 (g)
--------->
6CO2(g)
+
6H2O(g)
Given the above reaction, How many grams of C6H12O6(s) will be needed to make 54 mL of CO2
at 550˚C and 8 atm?
C 6 H12 O6 (s) + 6 O 2 (g)  6CO2 (g) + 6H 2 O(g)
g?
V = 54mL = 0.054L
T  550  273  823K
P = 8.0atm
PV  nRT
PV
(8.0atm)(0.054L)
n

 0.0064molCO2
Lat m
RT (0.0821 molK
)(823K)
0.0064molCO2 1molC6 H12O6 180gC 6 H12O6
x
x
 0.192gC6 H 12O6
1
6molCO2
1molC6 H12O 6
7. When the following reaction occurs:
4P(s)
+
5O2(g)
---------->
2P2O5(s)
How many grams of P2O5 is produced when 82.54 mL of oxygen at 6000 K and 45 atm is
completely consumed?
4P(s) + 5O2 (g) 
2P2 O5 (s)
V = 82.54mL = 0.08254L
T  6000K
g?
P = 45atm
PV  nRT
PV
(45atm)(0.08254L)
n

 0.00754molO2
Latm
RT (0.0821 molK
)(6000K)
0.00754molO2 2molP2 O5 142gP2 O5
x
x
 0.428gP2 O5
1
5molO2 1molP2 O5
8.
How many Liters of carbon dioxide is produced at 300 K and 99.2 kPa when 43.65
grams of acetylene, C2H2 is burned?
2C2 H2  5O2  4CO2  2H 2 O
L?
43.65g
300K
99.2kPa
43.65gC2 H2 1molC2 H2 4molCO2
x
x
 3.36molCO2
1
26gC2 H2 2molC2 H2
T  300K
99.2kPa
1atm
x
 0.979atm
1
101.32kPa
n  3.36mol
PV  nRT
P
V
Latm
nRT (3.36mol)(0.0821 molK
)(300K)

 84.5LCO2
P
0.979atm
9. When silicon dioxide reacts with carbon by heating, the following reaction occurs:
SiO2(s) +
3C(s) ----- -----> SiC(s)
+
2CO(g)
What will be the volume of carbon monoxide collected over water will be produced at 22.0˚C
and 657mm when 96.25 grams of SiO2 completely reacts?96.25 grams of SiO2 completely
reacts?
SiO 2 (s) + 3C(s)
 SiC(s)
96.25g
+2CO(g)
L?
22.0 C
657mm
96.25gSiO 2 1molSiO 2 2molCO
x
x
 3.21molCO
1
60gSiO 2 1molSiO 2
T  22 C  273  295K
637.2mm 1atm
P  657mm 19.8 
x
 0.838atm
1
760mm
n  3.21mol
PV  nRT
V
Latm
)(295K)
nRT (3.21mol)(0.0821 molK

 92.7LCO
P
0.838atm
10··. Nitroglycerine explodes violently to form several gasses according to the following
equation:

4 C3H5O9N3 ----------> 12 CO2
+
O2
+
6N2 + 10 H2O
A sealed 1.00 mL container filled with 2.8 g of nitroglycerine is detonated. If the Temperature
inside the container is 300˚C and assuming that the container would not break upon detonation,
what is the pressure inside the container right after detonation? (Put your answer in atm's)
4 C 3H 5O 9N 3  12 CO 2 + O 2 + 6N 2 + 10 H 2O
V = 1.00mL = 0.00100L
2.8g
300 C  573K
P =?
2.8gC 3H 5O 9N 3 1molC 3H 5O 9N 3
29molGases
x
x
1
227gC 3H 5O 9N 3 4molC 3H 5O 9N 3
 0.0894molGases
PV  nRT
Latm
)(573K)
nRT (0.0894mol)(0.0821 molK
P

 4207atm
V
0.00100L

WS F: Calculating Molar Mass Using Stoichiometry and Gas Law Problems
Name: ____________________
Period: _______
1. A 256 mL sample of an unknown gas at 23˚C and 750 mmHg has a mass of 0.80 grams.
What is the molar mass of the gas? (The vapor pressure of water at 23˚C is 21.0 mmHg)
grams
0.80 g

moles molesFromIdealGasLaw
729mmHg
P  750mmHg  21mmHg 
x
M
V
256mL
x
1atm
 0.959atm
760mmHg
1L
 0.256 L
1000mL
n?
Latm
R  0.0821 molK
T  23˚273  296 K
Latm
(0.959atm)(0.256 L)  n(0.0821 molK
)( 296 K )
n  0.0101mol
grams
0.80 g
M

 79.2 g / mol
moles 0.0101mol
2. 0.235 grams of magnesium reacts with excess hydrochloric acid to make 309 mL of hydrogen
gas at 28˚C and 615 mmHg. (The vapor pressure of water at 28˚C is 28.3 mmHg). From the
experimental data what is the molar mass of magnesium? What is the percentage error?
Mg  HCl    MgCl2  H 2
0.235g
gas collected
grams
0.235g
M

moles molesFromIdealGasLaw
586.7mmHg
P  615mmHg  28.3mmHg 
x
V
309mL
x
1atm
 0.771atm
760mmHg
1L
 0.309L
1000mL
n?
Latm
R  0.0821 molK
T  28Þ273  301K
Latm
(0.771atm)(0.309L)  n(0.0821 molK
)(301K)
n  0.00964molH 2
0.00964molH 2
1molMg
x
 0.00964molMg
1
1molH 2
grams
0.235g

 24.4g /mol
moles 00.00964mol
observed  actual
24.4  24.3
%Error 
x100 
x100  0.04%
actual
24.3
M

3. 0.855 grams of Potassium chlorate decomposes into oxygen gas and potassium chloride. A
350 mL sample of oxygen gas was collected at 65˚C and 810 mmHg over water. (The vapor
pressure of water at 65˚C is 187.5 mmHg). According to experimental data, what is the molar
mass of potassium chlorate? What is the percentage of error?
2 KClO3  2 KCl  3O2
0.855 g
gas collected
grams
0.855 g
M 

moles molesFromIdealGasLaw & Stoich
622.5mmHg
1atm
P  810mmHg  187.5mmHg 
x
 0.819atm
760mmHg
350mL
1L
V 
x
 0.350 L
1000mL
n?
Latm
R  0.0821 molK
T  65˚273  338 K
Latm
(0.819atm)(0.350 L)  n(0.0821 molK
)(338 K )
n  0.0103molO2
0.0103molO2
1
M 
x
2molKClO3
 0.00689molKClO3
3molO2
grams
0.855 gKClO3

 124.2 g / mol
moles 0.00689molKClO3
% Error 
observed  actual
124.2  122.5
x100 
x100  1.35%
actual
122.5
4··. A compound contains only nitrogen and hydrogen and is 87.4% nitrogen by mass. A one
liter sample of gas has a mass of 0.977 grams at 710 mm Hg and 100˚C. What is the molecular
formula of the gas?
87.4g 1mol
x
 6.24mol /6.24mol  1
1
14g
12.6g 1mol
H
x
 12.6mol /6.24mol  2
1
1g
EmpiricalFormula  NH2 :: EmpiricalMass  16g /mol
N
grams
0.977g

moles molesFromIdealGasLaw
710mmHg
1atm
P
x
 0.934atm
760mmHg
V  1.0L
n?
M
Latm
R  0.0821 molK
T  100Þ273  373K
Latm
(0.934atm)(1.0L)  n(0.0821 molK
)(373K)
n  0.0305molGas
grams
0.977g
M

 32g /mol
moles 0.0305mol
32g/mol is double of 16 g/mol so the empirical formula needs to
be doubled.
NH 2 x2  N 2 H 4

WS G: Review Mixed Gas Law Problems
1. 0.322-g of an unknown gas was collected. The gas had a volume of 59.8-mL a pressure of
655mm Hg and a temperature of 52˚C. What is the molar mass of the gas?
g
0.322g

mol moles
PV  nRT
655mmHg
1atm
P
x
 0.862atm
1
760mmHg
59.8mL
1L
V
x
 0.0598L
1
1000mL
T  52  273  325K
PV (0.862atm)(0.0598L)
nn

 0.00193mol
Lat m
RT
(0.0821 molK
)(325K)
MM 
MM 
g
0.322g
0.322g


 167g / mol
mol moles 0.00193mol
2. A 6.2-L balloon at 55˚C and 615mm Hg is taken to the top of Mt. Everest (-35˚C and 400mmHg). What is the size of the balloon?
P1 V1 P2 V2

T1
T2
(615atm)(6.2L) (400atm)(V2 )

328K
238K
V2  6.92L
3. 2.5-g of oxygen is at 56˚C and 45.3-atm. What is the volume of the gas?
PV  nRT
P  45.3atm
V ?
n(FindfromMass) 
2.5g 1mol
x
 0.078mol
1
32g
T  56  273  329K
Latm
)(329K)
nRT (0.078mol)(0.0821 molK


P
45.3atm
0.0465L  45.6mL
V

4. 23.5-g of sodium carbonate is reacted with hydrochloric acid to make water, carbon
dioxide and sodium chloride. The gas is collected over water at 24˚C and 615-mmHg.
What volume of carbon dioxide is produced?
Na2 CO3  HCl  NaCl  H2 O  CO2
L?
23.5g
24 C
615mm
96.25gSiO 2 1molNa2 CO 1molCO2
x
x
 0.222molCO2
1
106gNa2 CO 1molNa2 CO
T  24 C  273  297K
P  615mm  22.4mm 
592.6mm 1atm
x
 0.780atm
1
760mm
n  0.222molCO2
PV  nRT
V
nRT (0.222molCO2 )(0.0821 Latm
molK )(297K)

 6.94LCO2
P
0.780atm
5. 0.21-grams of an unknown gas is collected over water. That gas had a volume of 325-mL and
was collected at 744-mm Hg and 21˚C. What is the molar mass of the gas?
g
0.21g
MM 

mol moles
PV  nRT
725.4mmH
1atm
P  744mm  18.6mm 
gx
 0.954atm
1
760mmHg
325mL
1L
V
x
 0.325L
1
1000mL
T  21  273  294K
PV (0.954atm)(0.325L)
nn

 0.0129mol
Latm
RT (0.0821 molK
)(294K)
g
0.322g
0.21g
MM 


 16.3g/ mol
mol moles 0.0129mol
13. A bicycle tire that has a volume of 0.85-L is inflated to 140 pounds per square inch.
What will be the pressure in the tire if the number of moles of gas is doubled?
Since everything else is held constant. The number of moles
double so the pressure does as well. The pressure will be 240
psi
7. 324-mL of oxygen is collected over water at 685-mmHg and 18˚C. It is released when
hydrogen peroxide (H2O2) decomposes. It also forms water. How many grams of hydrogen
peroxide decomposed?
2H2 O2  2H2 O  O2
V = 324mL = 0.324L
g?
T  18  273  291K
P = 685mm -15.5 = 669.5 = 0.881atm
PV  nRT
PV (0.881atm)(0.324L)
n

 0.0119molO2
Lat m
RT (0.0821 molK
)(291K)
0.0119molO2 2molH2 O 34gH2 O2
x
x
 0.812gH2 O2
1
1molO2
1molH2 O2
8. Convert 23.5-mL of N2 gas at 220-kPa and 98.7˚C to STP.
P1 V1 P2 V2

T1
T2
(220kPa)(23.5mL) (101.32kPa)(V2 )

371.7K
273
V2  37.5L
9. What is the density of oxygen gas at 40˚C and 615-mmHg. Hint: Find the grams per
mL. Assume that you have a given amount of grams (You choose) and then convert to
volume. Then divide.
g
L
Assume32g of oxygen
Density 
PV  nRT
615mmH
1atm
P
gx
 0.809atm
1
760mmHg
V?
T  40  273  313K
n
32g 1mol
x
 1mol
1
32g
Latm
nRT (1mol)(0.0821 molK
)(313K)

 31.8L
P
(0.809atm)
g
32g
Density  
 1.01g/ L
L 31.8L
V
10. What is the temperature of a gas that has a volume of 555-mL and 43.5-atm that was initially
at 20˚ , 885-mL, and 2.9-atm?
P1 V1 P2 V2

T1
T2
(43.5atm)(555mL) (2.9atm)(885mL)

T1
293K
T1 = 2756K
11. At 298 K O2 travels at 1200 miles per hour. What is the speed of Helium at the same
temperature?
Rate He

RateO2
MM O2
MM He
Rate He
32 5.66


1200
2
4
Rate He  3394mph
Name ________________
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