Name _______________________________
Gas Laws Review
Chemistry
1. Complete this statement with the following words and phrases. Each is used
once.
absolute temperature
increases
constant temperature
kinetic-molecular theory of gases
decreases
pressure
elastic
volume
energy
ideal gas
According to the ____________________________, an __________________ consists of
point-sized particles, with no _________________ whatsoever, that bounce off each
other in perfectly _________________ collisions, without losing any _____________ in
the process. The _______________ of a gas enclosed in a container results from
the collisions of the particles with the walls of the container. If we increase the
temperature of an ideal gas held in a container of constant volume, the pressure
_____________ and always remains directly proportional to the _____________. If we
increase the pressure on a gas held at _________________, the volume of the gas
_____________ proportionately.
2. Describe the 5 properties of gases.
a.
b.
c.
d.
e.
3. Explain how a barometer works.
4. How can we use atmospheric pressure to crush a can or push an egg into a flask?
Explain what happens with the gas molecules.
5. What is STP?
6. Write the laws.
Boyle’s Law
Charles’ Law
Gay-Lussac’s Law
Combined Gas Law
Dalton’s Law
Ideal Gas Law
Ideal Gas Law with
Molar Mass
Ideal Gas Law with
Density
Gas Stoichiometry
Graham’s Law
Explain how you will know when to use this law.
Name _______________________________
Gas Laws Review Problems
Chemistry
page 2
Directions: Determine which law you will need to use. Then solve. Show work.
1. What pressure is needed to compress the air in a 1.105 L cylinder at 760 torr to a
volume of 1.00 mL?
2. A 4.20 L sample of gas is collected over water at a pressure of 97 kPa. The
pressure is adjusted to 101.325 kPa. What is the volume? The temperature of
the gas is 20.0ºC.
3. When 500. mL of helium gas at 25ºC is cooled at constant pressure to 10.0 K,
what does the volume of the gas become?
4. At what temperature does 100. mL of N2 at 305 K and 750 torr occupy a volume
of 525 mL at a pressure of 1.89 atm?
5. What is the volume of 7.5 moles of methane gas under a pressure of 742 mm Hg
and at 25ºC?
6. What is the molar mass of a gas at 32ºC and 0.785 atm and a volume of 2.5 L?
The gas has a mass of 3.68 grams.
7. What will be the pressure of 150 grams of CCl2F2 at a temperature of 15ºC and a
volume of 225 mL?
8. A weather balloon is filled with 1.0 L of helium at 23ºC and 1.0 atm. What
volume does the balloon have when it has risen to a point in the atmosphere
where the pressure is 220 torr and the temperature is –31 ºC?
9. At a temperature of 25 ºC, 125 mL of oxygen is collected over water at standard
pressure. If we raise the temperature to 35ºC and expand the volume to 300 mL,
what will be the pressure of the dry gas?
10. A sample of N2 gas is at a pressure of 475 torr and a temperature of 18ºC.
What is the density of the gas?
11. How many grams of SO2 will be in a 2.5 L container at a pressure of 700 mm
Hg and a temperature of 310 K?
FSK
Gas Laws Review
Chemistry
1. Complete this statement with the following words and phrases. Each is used
once.
According to the kinetic-molecular theory of gases, an ideal gas consists of
point-sized particles, with no volume whatsoever, that bounce off each other in
perfectly elastic collisions, without losing any energy in the process. The
pressure of a gas enclosed in a container results from the collisions of the
particles with the walls of the container. If we increase the temperature of an
ideal gas held in a container of constant volume, the pressure increases and
always remains directly proportional to the absolute temperature. If we increase
the pressure on a gas held at constant temperature, the volume of the gas
decreases proportionately.
2. Describe the 5 properties of gases.
a. Gases Expand to fill their containers
b. Gases will diffuse or effuse from their containers
c. Gases are compressible
d. Gases have a mass and a low density
e. Gases like liquids are considered fluids.
3. Explain how a barometer works.
A column of Hg is placed above a pool of Hg that is supported by the push of
atmospheric pressure any change in that pressure is shown by a change in height of
the column of Hg
4. How can we use atmospheric pressure to crush a can or push an egg into a flask?
Explain what happens with the gas molecules.
By decreasing the pressure inside the can or flask would allow atmospheric
pressure to push in the can or egg.
5. What is STP? Standard temp and Pressure
or 101.3kPa 760 torrs
273K or 0C & 760 mm Hg, 1.00 atm
6. Write the laws.
Boyle’s Law
P1V1 = P2V2
Explain how you will know when to use this law.
Pressure and Volume will be changing
Charles’ Law
V1 = V2
T1
Temperature and Volume will be changing
T2
Gay-Lussac’s Law
P1 = P2
T1
Pressure and Temperature will be changing
T2
Combined Gas Law
Temperature, Pressure and Volume will be changing
Dalton’s Law
PT=P1+P2+P3+…
See the words collected over water, or have two or
more gases being measured.
Ideal Gas Law
PV = nRT
Ideal Gas Law with
Molar Mass
PV = mRT
M
Ideal Gas Law with
Density
Not at STP and all 4 variables are involved.
Know the specific gas and its mass. (got the formula)
D = PM
Need or have Density
RT
Gas Stoichiometry
Using the balanced chemical equation & If at STP 1 mole = 22.4L
Or if not then use PV=nRT
Graham’s Law
𝒗𝒆𝒍𝟏
𝒗𝒆𝒍𝟐
𝑴
= √𝑴𝟐
𝟏
To determine the relative speed of a gas molecule
Name _______________________________
Gas Laws Review Problems
Chemistry
page 2
Directions: Determine which law you will need to use. Then solve. Show work.
1. What pressure is needed to compress the air in a 1.105 L cylinder at 760 torr to a
volume of 1.00 mL?
Boyles solve for P2
P2 = 839,800 Torr
2. A 4.20 L sample of gas is collected over water at a pressure of 97 kPa. The
pressure is adjusted to 101.325 kPa. What is the volume? The temperature of
the gas is 20.0ºC.
Dalton’s law 1st then Boyle’s solve for V2
V2 = 3.92 L
3. When 500. mL of helium gas at 25ºC is cooled at constant pressure to 10.0 K,
what does the volume of the gas become?
Charles Law solve for V2
V2 = 16.78 ml
4. At what temperature does 100. mL of N2 at 305 K and 750 torr occupy a volume
of 525 mL at a pressure of 1.89 atm?
Combined gas law solve for T2
Convert 750 torr to 0.987 atm
T2 = 3066 K
5. What is the volume of 7.5 moles of methane gas under a pressure of 742 mm Hg
and at 25ºC?
V= nRT/P
V = 187.96 L
6. What is the molar mass of a gas at 32ºC and 0.785 atm and a volume of 2.5 L?
The gas has a mass of 3.68 grams.
M = mRT/PV
M = 46.95 g/mol
7. What will be the pressure of 150 grams of CCl2F2 at a temperature of 15ºC and a
volume of 225 mL?
P = mRT/MV
P = 130 atm or 99,009 torr
M of CCl2F2 = 121 g/mol
8. A weather balloon is filled with 1.0 L of helium at 23ºC and 1.0 atm. What
volume does the balloon have when it has risen to a point in the atmosphere
where the pressure is 220 torr and the temperature is –31 ºC?
Combined gas law solve for V2
220 torr = 0.289 atm
V2 = 2.82 L
9. At a temperature of 25 ºC, 125 mL of oxygen is collected over water at standard
pressure. If we raise the temperature to 35ºC and expand the volume to 300 mL,
what will be the pressure of the dry gas?
Combined gas law solve for P2
P1 = 760 mmHg – 23.8 mmHg = 736.2 mmHg
P2 = 317 mmHg or 0.417 atm
10. A sample of N2 gas is at a pressure of 475 torr and a temperature of 18ºC. What is
the density of the gas?
D = PM/RT
D = (475 torr)(28 g/mol)
(62.4 R )( 291 K)
D= 0.732 g/ L
11. How many grams of SO2 will be in a 2.5 L container at a pressure of 700 mm Hg and a
temperature of 310 K?
m = RT/PVM
Molar mass of SO2 =64.1
m = 0.172 g of SO2