1. Gas Laws The Combined Gas Law:
states the relationship among pressure, volume,
and temperature of a fixed amount of gas. Pressure is inversely proportional to volume and directly proportional to temperature, and volume is directly proportional to temperature.
P1V1/T1 = P2V2/T2
Cross multiply: P1V1T2 = P2V2T1

2. Gas Laws Avogadro’s principle:
states that equal volume of gases at the same temperature and pressure contain equal numbers of particles
The most convenient unit for counting numbers of atoms or molecules is the mole (Ch. 11)
One mole contains 6.02 x 1023 particles

3. Gas Laws
Molar volume for a gas is the volume that one mole occupies at 0.00°C and 1.00 atm pressure
These conditions of temperature and pressure are known as standard temperature and pressure (STP)
One mole of gas will occupy a volume of 22.4L at STP
Conversion factor: 22.4L/1 mol

4. Avogadro’s Principle
Suppose you want to find the number of particles in a sample of gas that has a volume of 3.72 L at STP. You must first find the number of moles of gas in the sample.
A mole of gas contains 6.02 x 1023 particles:
1 mol
22.4 L
3.72 L x
= mol
6.02 x 1023 particles
1 mol
0.166 mol x
= 9.99 x 1022 particles

5. Ideal Gas Law
Ideal Gas Law describes the physical behavior of an ideal gas in terms of pressure, volume, temperature, and number of moles of gas present.
PV = nRT
p = pressure
v = volume
n = amount of gas present (moles)
R = ideal gas constant ( )
T = temperature
L ∙ atm
mol ∙ K

6. Values of Ideal Gas Constant
Pressure (units): Value of R:
atm L·atm
mol·K
kPa L·kPa
mmHg L·mmHg