1. Gas Laws

2. Kinetic theory Particles in all forms of matter are in constant motion
A gas is composed of particles, usually molecules or atoms.
The particles in a gas move rapidly inconstant random motion.
All collisions are perfectly elastic.

3. Physical behavior of a gas depends on:
volume
temperature
pressure

4. Volume How much space occupied
volume of a gas in a sealed container is the volume of the container
gases not in sealed containers are uncontained
Units can be milliliters, liters, cubic centimeters

5. Temperature Measure of the average kinetic energy of particles in a substance
same temperature = same average kinetic energy
temperature measured using Kelvin scale
Kelvin temperature = 0°C + 273
no upper limit for temperature
lower limit = absolute zero 0 K = -273°C (no motion of particles)

6. To convert from Celsius to Kelvin—add 273
To convert from Kelvin to Celsius– subtract 273

7. Pressure force per area
result of simultaneous collisions of billions of gas particles
units of pressure
atmospheres
mm Hg
Torr
Pascal

8. Standard Temperature and Pressure (STP)
Standard temperature = 0°C = 273 K
Standard pressure = 1 atm
= 760 mm Hg
= 760 Torr
= 101 kPa

11. Avogadro’s Law
equal volumes of gases at the same temperature and pressure contain equal numbers of particles
at STP
1 mole (6.02 X 1023 particles) of any gas occupies 22.4 liters

12. Boyle’s Law
For a given mass of gas at constant temperature, the volume of the gas varies inversely with pressure.
in other words, if pressure goes down, volume goes up and vice versa
P1V1 = P2V2

13. Charles’ Law
The volume of a fixed mass of gas is directly proportional to its Kelvin temperature if the pressure is kept constant
in other words, if temperature increases, volume increases and vice versa
V1 = V2
T1     T2

14. Gay-Lusaac’s Law P1 = P2 T1 T2
The pressure of a gas is directly proportional to the Kelvin temperature if the volume is kept constant.
in other words, if temperature increases, pressure increases and vice versa
P1 = P2
T1     T2

15. Combined Gas Law P1V1 = P2V2 T1 T2
Combines Boyle’s Law, Charles’ Law, and Gay-Lusaac’s Law into one
P1V1 = P2V2
T1         T2

16. Dalton’s Law of Partial Pressures
At constant volume and temperature the total pressure exerted by a mixture of gases is equal to the sum of the partial pressure of each gas.
Ptotal = P1 + P2 + P3 …..
As soon as you see the words ‘over water’ in a problem, begin looking for P1 to subtract vapor pressure out of it and T1 which tells you the temperature to look up in the table so you will know how much to subtract.

17. Ideal Gas Law PV = nRT n = number of moles R = ideal gas constant
T = temperature in Kelvins
P = pressure
V = volume
if pressure is in atmospheres     R = atm L
                                                                       k mol
if pressure is in mm Hg or torr         R = mm Hg
                                                                       k mol
if pressure is in kPa                  R = kPa L
                                                                    k mol