1. Factors that affect gases

2. Factors that affect gases
Pressure
Force exerted when particles collide with their container
Volume
Amount of space or size of the container
Temperature
Average kinetic energy or “speed” of the particles
Moles
Amount or number of particles

3. Relationships
All of the factors interact and are dependent on each other
When you change one factor, it changes another factor.

4. Pressure Relationships
What happens to the number of collisions if you increase the size of the container?
(speed and number are constant)
What happens to the number of collisions if you increase the speed of the particles?
(size and number are constant)
What happens to the number of collisions if you add more particles?
(size and speed are constant)

5. Volume Relationships Imagine the container is a balloon…
What happens to the size of a container if the particles speed up?
(collisions and number are constant)
What happens to the size of a container if you add more particles?
(collisions and speed are constant)

6. Temperature Relationships
What happens to the speed of the particles if you add more particles?
(collisions and size are constant)

7. Gas Laws show relationships
Boyle’s Law – Pressure and Volume
P1V1 = P2V2
Inverse relationship – one goes up, other goes down
Charles’ Law – Volume and Temperature
V1 / T1 = V2 / T2
Direct relationship – one goes up, other goes up

8. Gas Laws show relationships
Gay-Lussac’s Law – Pressure and Temperature
P1 / T1 = P2 / T2
Direct relationship – one goes up, other goes up
Avagadro’s Law – Volume and moles
V1 / n1 = V2 / n2

9. Gas Laws show relationships
These are in your Reference Tables.
Combined Gas Law – Pressure, Volume, and Temperature
P1V1 = P2 V2
T T2
Ideal Gas Law
P1V1 = P2 V2 or PV = nRT
T1 n1 T2n2
R is the Universal Gas Constant

10. Mixtures of Gases Dalton’s Law of Partial Pressures
Total pressure is equal to the sum of the parts
PT = P1 + P2 + P3 + …
Most often used when gases are collected over water…
Gas’s pressure + Vapor Pressure of Water = Pressure reading

11. Rate of Effusion
Effusion is the escape of a fluid through a small opening
Graham’s Law of Effusion states that the rate of effusion is inversely proportional to the square root of the molar mass.
R1 / R2 = √(MM2) / √(MM1)