BOYLE’s LAW
CHARLES’ LAW
GAY-LUSSAC’S LAW
The VOLUME of a given amount
of gas held at constant
temperature varies INVERSELY
with the PRESSURE
The VOLUME of a given mass of
gas is DIRECTLY proportional to its
Kelvin TEMPERATURE
The PRESSURE of a given mass of
gas varies DIRECTLY with the
Kelvin TEMPERATURE when the
volume remains constant
EXPRESSES THE RELATIONSHIP
BETWEEN PRESSURE, VOLUME,
AND TEMPERATURE OF A FIXED
AMOUNT OF GAS.
Example:
Example:
Example:
Examples:
4.0 liters of helium gas at a
pressure of 1.2 atm is
compressed to 2.5 liters, what is
the new pressure?
A sample of gas at 40.0oC
occupies a volume of 2.32 L. If
the temperature is raised to
75.0oC, what will the volume be?
Pressure is held constant.
The pressure of a gas in a tank is
3.20 atm at 22.0oC. If the
temperature rises to 60.0oC, what
will be the gas pressure in the
tank?
T1 = 40.0oC = 313 K
V1 = 2.32 L
T2 = 75.0oC = 348 K
V2 = ?
P1 = 3.20 atm
T1 = 22.0oC = 295 K
P2 = ?
T2 = 60.0oC = 333 K
A gas at 110 kPa and 30.0oC fills a
flexible container with an initial
volume of 2.00 liters. If the
temperature is raised to 80.0oC
and the pressure increased to 440
kPa, what is the new volume?
V1 = 4.0 liters
P1 = 1.2 atm
V2 = 2.5 liters
P2 = ?
P1V1  P2V2
(1.2 atm)(4.0L) = (X)(2.5 L)
X = 1.9 atm
V1 V2

T1 T2
P1 P2

T1 T2
P2 = 3.61 atm
Practice:
V2 = 2.58 Liters
Practice:
A sample of oxygen gas has a
volume of 250 mL when its
pressure is 0.873 atm. What is
the volume of the gas when the
pressure becomes 0.432 atm?
The temperature is held constant.
Practice:
A gas in an aerosol can is at a
pressure of 4.00 atm at 25.0oC.
What would the gas pressure be
in the can at 56oC?
A sample of neon gas occupies a
volume of 876 mL at 25.0oC.
What volume will the gas occupy
at 70.0oC if the pressure is
constant?
COMBINED GAS LAW
P1 = 110 kPa
T1 = 30.0oC = 303 K
V1= 2.00 liters
P2 = 440 kPa
T2 = 80.0oC = 353 K
V2 = ?
P1V1 P2V2

T1
T2
V2 = 0.58 Liters
Practice:
A helium filled balloon has a
volume of 70.0 mL at 25.0oC and
1.2 atm. What would the volume
be at 0.856 atm and 12.0oC?
DALTON’S LAW
States that the total pressure of
a mixture of gases is equal to the
sum of the partial pressures of
the gases.
PT = P1 + P 2 + P 3 + . . .
Example:
Air contains oxygen, nitrogen,
carbon dioxide, & trace amounts
of other gases. What is the
partial pressure of oxygen at sea
level if the total pressure is 760
mm Hg, PN2 = 593.4 mm Hg, PCO2 =
0.3 mm Hg, and Pothers = 7.1 mm
Hg?
GRAHAM’S LAW of EFFUSION
The lighter the molar mass of
an element or compound the
faster it will spread.
Small molecules effuse faster
than large ones
Example: Which of the following
gases effuses faster, NH3 or CO2?
IDEAL GAS LAW
PV = nRT
P – Pressure (atm)
V – Volume (liters)
n – number of moles
R – Gas Constant 0.0821 L atm/
mol K
T – Temperature (Kelvin)
GAS STOICHIOMETRY
At Standard Pressure and
Temperature
Remember Avogadro’s Law
1mol = 6.02x1023 molecules
1mol = 22.4 liters at STP
This is the molar volume
Example:
If I have 4.0 moles of a gas at a
pressure of 5.6 atm and a volume
of 12 liters, what is the
temperature?
Example:
How many liters of CO2 are
produced when 35.4 grams of
C3H8 are combusted at STP?
n = 4.0 moles
P = 5.6 atm
V = 12 liters
T=?
R = 0.0821 L atm/ mol K
T = PV / nR
T = 205 Kelvin
C3H8 + O2  CO2 + H2O
Balance the equation first
Practice:
If 72 liters of gas is held at a
pressure of 3.4 atm and a
temperature of 225 K, how many
moles of gas are there? What is
the mass of the gas if it is CO2?
Next, Convert grams to moles,
moles to moles, then moles to
liters. Use the molar volume 1
mole = 22.4 at STP.