1. Behaviors of Solids, Liquids, and Gases
Source
Behaviors of Solids, Liquids, and Gases
Video 1
Video 2
LO 2.3: The student is able to use particulate models to reason about observed differences between solid and liquid phases and among solid and liquid materials.

2. Properties of Gases Gases expand to fill any container.
random motion, no attraction
Gases are fluids (like liquids).
particles flow easily
Gases have very low densities.
lots of empty space; particles spaced far apart
Gases are easily compressible.
empty space reduced to smaller volume
Courtesy Christy Johannesson

3. Kinetic Molecular Theory (KMT)
Source
Kinetic Molecular Theory (KMT)
Video 1
Video 2
IF the temperature is not changed, no matter what else is listed in the problem, the average kinetic energy of a gas does not change. That is the definition of temperature!
All gases begin to act non-ideally (aka real) when they are at low temperatures and/or high pressures because these conditions increase particle interactions
Under the same conditions, the stronger the intermolecular attractions between gas particles, the LESS ideal the behavior of the gas
LO 2.4: The student is able to use KMT and IMF’s to make predictions about the macroscopic properties of gases, including both ideal and non-ideal behaviors

4. Properties of a Gas - Factors
Source
Properties of a Gas - Factors
Don’t worry about individual gas law names, but do worry about the effect of changing moles, pressure and temperature on a sample of gas
Virtual Lab
LO 2.5: Refine multiple representations of a sample of matter in the gas phase to accurately represent the effect of changes in macroscopic properties on the sample

5. Pressure = Force/Area
KEY UNITS AT SEA LEVEL (also known as standard pressure)
kPa (kilopascal)
1 atm
760 mm Hg
760 torr
14.7 psi
Sea level

6. Standard Temperature & Pressure
STP
STP
Standard Temperature & Pressure
0°C K
1 atm kPa
- OR -

7. Combined Gas Law
P1V1 T1 =
P2V2 T2
P1V1T2 = P2V2T1

8. Molar Volume (Avogadro)
1 mol of all STP have a volume of 22.4 L
Avogadro’s Law V1/n1 = V2/n2
MOLAR VOLUME
One mole of any gas occupies 22.4 liters at standard temperature and pressure (STP).

9. PV = nRT Ideal Gas Law Brings together all gas properties.
P = pressure
V = volume (must be in liters)
n = moles
R = universal gas constant (0.082 or 8.314)
T = temperature (must be in Kelvin)
Can be derived from experiment and theory.

10. Ptotal = P1 + P2 + ... Dalton’s Law
The total pressure of a mixture of gases equals the sum of the partial pressures of the individual gases.
Ptotal = P1 + P
In a gaseous mixture, a gas’s partial pressure is the one the gas would exert if it were by itself in the container.
The mole ratio in a mixture of gases determines each gas’s partial pressure.

11. Gas Mixtures and Dalton’s Law

12. Gas Collected Over Water
When a H2 gas is collected by water displacement, the gas in the collection bottle is actually a mixture of H2 and water vapor.

13. D = (MM)P/RT Gas Density
Larger particles are more dense. Gases are more dense at
higher pressures and lower temperatures
D = density
P = pressure
MM = molar mass
R = universal gas constant
T = temperature (must be in Kelvin)
Can be derived from experiment and theory.

14. Click reveals answer and explanation.
Source
The Ideal Gas Law
Video
LO 2.6: The student can apply mathematical relationships or estimation to determine macroscopic variables for ideal gases
Click reveals answer and explanation.

15. Deviations from Ideal Gas Behavior
Source
Deviations from Ideal Gas Behavior
Video
When watching the video, don’t concern yourself with Van der Walls – AP Exam focuses on LDF’s instead
Click reveals answer and explanation.
LO 2.12: The student can qualitatively analyze data regarding real gases to identify deviations from ideal behavior and relate these to molecular interactions