Honors Chemistry
Name: ________________________________________ Date: _______________ Mods: _________
10.7 – Kinetic Molecular Theory

Kinetic Molecular Theory: explains physical properties of gases & gas behavior by looking at the
____________________ of molecules (since it deals w/kinetic energy); summarized by 5 statements
(1) Gases consist of many hard, spherical particles (molecules or atoms) in
____________________, random motion
(2) Particles are _____________ - their combined volume is considered insignificant compared to
the total volume in which the gas in contained (most of the volume is _______________ space)
(3) There are essentially NO _______________________ or ______________________ forces
between gas molecules (gas particles don’t interact much due to high speed and vast space
between them)
(4) Collisions are _______________ - when gas particles do hit each other, energy is transferred
without any lost to friction, heat, etc (as long as _______________________ remains constant,
total KE is constant)
(5) Average KE is _______________ proportional to Kelvin temperature at a given temperature,
ALL gas particles have the same avg. KE)
10.1 & 10.2 – Characteristics of Gases & Pressure

What are the four variables needed to define the physical condition, or state, of a gas?

Pressure: the amount of ____________________ applied to an area; gasses exert pressure on
any surface they come in contact with

_________________________ pressure is the weight (a force due to gravity) of air per unit of area.

Units of Pressure & Unit Conversions:
Pascal (Pa) = SI base, kilopascal (kPa), millimeters of mercury (mm Hg or torr), & atmosphere (atm)
0.357 atm = ________________________ torr
Standard Atmospheric Pressure:
1 atm = 760 mm Hg = 760 torr =
6.6 x 10-2 mmHg = ________________________ atm
1.01325 x 105 Pa = 101.325 kPa
177.2 kPa = ________________________ torr
10.3 – The Gas Laws

Standard Temperature and Pressure Conditions (STP) :
Temperature = ____________ or ____________

Pressure = _________________
Boyle’s Law:
Variables Defined in Equation:
Relationship:
Variables Held Constant:
Equation:
Real-life application:
Graphs:
Example Problem: A gas has a pressure of 4.62 atm when its volume is 2.33 L. What will the
pressure be when the volume has changed to 1.03 L? What would this pressure be in torr?

Charles’s Law:
Variables Defined in Equation:
Relationship:
Variables Held Constant:
Equation:
Real-life application:
Graph:
Example Problem: The temperature inside my refrigerator is about 4ºC. If I place a balloon in my
fridge that initially has a temperature of 22ºC and a volume of 0.5 L, what will be the volume of the
balloon when it is fully cooled by my refrigerator?

Gay-Lussac’s Law:
Variables Defined in Equation:
Relationship:
Variables Held Constant:
Equation:
Real-life application:
Graph:
Example Problem: A sample of hydrogen at 47ºC exerts a pressure of 0.329 atm. The gas is
heated to 77ºC. What will be its new pressure? What would this pressure be in kPa?

Combined Gas Law:
Variables Defined in Equation:
Equation:
Variable Held Constant:
Example Problem: A weather balloon has a volume of 4.00 L at 31ºC and 755 mmHg. If the
balloon is released and the volume reaches 4.08 L at 728 mmHg, what is the temperature of the
balloon in degrees Celsius?

Avogadro’s Law:
Variables Defined in Equation:
Relationship:
Variables Held Constant:
Equation:
Real-life application:
Graph:
Example Problem: A sample of N2 gas has 1.70 moles and occupies 3.80 L at 29°C. At the same
temperature, how many moles of N2 would be in a sample that occupies 1.45 L?

Avogadro’s Hypothesis: Equal _____________________ of gases (at the same temperature and
pressure) contain equal numbers of moles

Molar Volume: At STP conditions, exactly _______________ (6.022 x 1023 molecules) of ANY gas
occupies a volume of __________________.
* Note: the molar volume relationship can ONLY be used when the gas is at standard temperature
and pressure conditions!!!
Example Problem: At 1 atm and 273 K, a sample of carbon dioxide gas has a volume of 35.8 L.
How many moles of carbon dioxide are in this sample?
Boyle’s Law WS
1. If I have 5.6 liters of gas in a piston at a pressure of 1.5 atm and compress the gas until its
volume is 4.8 L, what will the new pressure inside the piston be?
2. I have added 15 L of air to a balloon at sea level (1.0 atm). If I take the balloon with me to
Denver, where the air pressure is 0.85 atm, what will the new volume of the balloon be?
3. I’ve got a car with an internal volume of 12,000 L. If I drive my car into the river and it
implodes, what will be the volume of the gas when the pressure goes from 1.0 atm to 1.4 atm?
4. The highest pressure ever produced in a laboratory setting was about 2.0 x 106 atm. If we
have a 1.0 x 10-5 L sample of a gas at that pressure, and then release the pressure until it is
equal to 0.275 atm, what would the new volume of that gas be?
5. Part of the reason that conventional explosives cause so much damage is that their detonation
produces a strong shock wave that can knock things down. While using explosives to knock
down a building, the shock wave can be so strong that 12 L of gas will reach a pressure of
3.8 x 104 mmHg. When the shock wave passes and the gas returns to a pressure of 760
mmHg, what will the volume of that gas be?
Charles’s Law WS
1. If I have 45 liters of helium in a balloon at 250C and increase the temperature of the balloon to
550C, what will the new volume of the balloon be?
2. Calcium carbonate decomposes at 12000C to form carbon dioxide and calcium oxide. If 25
liters of carbon dioxide are collected at 12000C, what will the volume of this gas be after it cools
to 250C?
3. I have 130 liters of gas in a piston at a temperature of 2500C. If I cool the gas until the volume
decreases to 85 liters, what will temperature of the gas be?
4. On hot days, you may have noticed that potato chip bags seem to “inflate”, even though they
have not been opened. If I have a 250 mL bag at a temperature of 190C, and I leave it in my
car which has a temperature of 600C, what will the new volume of the bag be?
5. I have a thermometer which measures temperature by the compressing and expanding of gas
in a piston. I have measured that at 1000C, the volume of the piston is 20 L. What is the
temperature outside if the piston has a volume of 15 L?
Gay Lussac’s Law WS
1. A gas with a pressure of 5.4 atm and at 250C is raised to a new temperature of 780C. What is
the new pressure?
2. A gas with a pressure of 550 torr and at 1100C is raised to atmospheric pressure. What is the
new temperature?
3. A gas with a pressure of 7.5 atm and at 300C is raised to a new temperature of 1500C. What is
the new pressure in mmHg?
4. A gas with a pressure of 780 torr and at 550C is lowered to a new pressure of 640 torr. What is
the new temperature?
5. A gas with a pressure of 5.6 atm and at 1500C is lowered to a new temperature of 200C. What
is the new pressure?
Mixed Gas Laws WS – Charles’s, Boyle’s, & G-L’s
1. A gas has an initial volume of 15 L. If the temperature increases from 330 K to 450 K, find the
new volume.
2. A gas exerts 1.2 atm of pressure. If the temperature is raised from 25oC to 100oC, find the new
pressure.
3. A sample of oxygen takes up 34 dm3 of space when it is under 500 kPa of pressure. When the
pressure is changed to 340 kPa, find the new volume.
4. The pressure of some N2 drops from 315 kPa to 220 kPa. If the initial volume is 1.4 L, find the
new volume.
5. The pressure of neon changes from 786 mm Hg to 1811 mm Hg. If the initial temperature was
87oC, what is the new temperature (in oC)?
6. When the temperature of a gas changes, its volume decreases from 12 cm3 to 7 cm3. If the
final temperature is measured to be 18oC, what was the initial temperature (in oC)?
Combined Gas Law
1. The pressure of a gas changes from 120 kPa to 50 kPa. The volume changes from 45 L to 40
L. If the initial temperature is 81oC, what is the final temperature in oC?
2. A sample of nitrogen goes from 21 m3 to 14 m3 and its pressure increases from 100 kPa to 150
kPa. The final temperature is 300 K. What was the initial temperature in Kelvin?
3. A sample of argon goes from 500 K to 350 K and its pressure changes from 280 kPa to 380
kPa. If the initial volume is 18 dm3, what is the final volume?
4. A sample of neon experiences a pressure drop from 75 kPa to 53 kPa. The temperature
increases from 27oC to 93oC. If the initial volume is 12 L, what is the final volume?
5. The volume of a sample of helium increases from 5 L to 25 L. Its temperature drops from 2000
K to 1750 K. If the initial pressure is 1500 mm Hg, what is the final pressure?
6. The temperature of a gas increases from 212oC to 380oC. The volume goes from 30 dm3 to
18 dm3. If the final pressure is 1.85 atm, what was the initial pressure?
7. A child has a toy balloon with a volume 1.80 L. At the time the balloon was filled, the
temperature was 20oC and the pressure was 1.0 atm. If the child were to let go of the balloon
and it rose 3 km into the sky where the pressure is 0.667 atm and the temperature is 10oC,
what would the new volume of the balloon be?
8. If I initially have a gas at a pressure of 12 atm, a volume of 23 L, and a temperature of 200K,
and then I raise the pressure to 14 atm and increase the temperature to 300K, what is the new
volume of the gas?
9. A gas that has a volume of 28 L, a temperature of 45oC, and an unknown pressure has its
volume increased to 34 L and its temperature decreased to 35oC. If I measure the pressure
after the change to be 2.0 atm, what was the original pressure of the gas?
10. If I have 17 L of gas at a temperature of 67oC and a pressure of 88.89 atm, what will be the
pressure of the gas if I raise the temperature to 94oC and decrease the volume to 12 L?
11. I have an unknown volume of gas at a pressure of 0.5 atm and a temperature of 325K. If I
raise the pressure to 1.2 atm, decrease the temperature to 320K, and measure the final volume
to be 48 L, what was the initial volume of the gas?
12. If I have 2.9 L of gas at a pressure of 5 atm and a temperature of 50oC, what will be the
temperature of the gas if I decrease the volume of the gas to 2.4 L and decrease the pressure
to 3 atm?
Avogadro’s Law WS
1. A 2.50 mole sample of gas originally occupies 500 mL of space. If the volume of the gas is
increased to 750 mL, how many moles of gas must now be present?
2. A sample of nitrogen gas contains 1.70 moles and occupies 3.80 L. What volume will it occupy
with 2.60 moles present?
3. A 6.0 L sample at 25ºC and 1 atm of pressure contains 0.5 moles of a gas. If an additional
0.25 moles of gas at the same pressure and temperature are added, what is the final volume of
the gas?
1. Ammonia is manufactured for fertilizer. The truck hauling the ammonia can hold 450 kiloliters of
the gas, which is 20 moles. If a buyer only needs to purchase 225 kiloliters of the gas, how
many moles is the buyer receiving?’
2. Pedro adds 1.25 moles of helium to a balloon that already contained 4.51 moles of helium creat
ing a balloon with a volume of 8.97 liters. What was the volume of the balloon before the
addition of the extra gas?
4. A cylinder with a movable piston contains 2.00 g of helium at room temperature. More helium
was added to the cylinder and the volume was adjusted so that the gas pressure remained the
same. How many grams of helium were added to the cylinder if the volume was changed from
2.00 L to 2.70 L? (CHALLENGE!)