1. As always… Lon-Capa assignments Lecture videos Textbook Read
Do text homework

2. Studying Gases Good way to study the process of science.
Distinguish between laws (what) and theories (why).
Make observations.
Use observations to develop theories.
Make more observations.
Continue.

3. Gases – Macroscopic Observations
Gases take up the volume of the container.
1 cup of helium?
Compressible
Gases exert pressure.
Basketballs, bike tires, etc.
Explosions
Density of a gas changes greatly with temperature.
Gases mix well (diffusion).
We can smell ammonia, vinegar, etc.

4. Clicker Question
You are holding two balloons filled with air – a large balloon and a small balloon. What can be said about the relative pressure of air in each balloon?
a) The pressure in the larger balloon is greater because there are more moles of gas.
b) The pressure in the smaller balloon is greater because there is less space inside the balloon.
c) The balloons have essentially the same pressure.

5. Take a Molecular Level View

6. Kinetic Molecular Theory
Gases consist of particles in constant random motion.
Pressure is due to collisions of gas particles with the container.
Temperature is a measure of average kinetic energy.

7. V and n (KMT)

8. V and T (KMT) .

9. V vs. T(°C) (constant P, n)

10. V vs. T(K) (constant P, n)

11. P and T (KMT) .

12. P and V (KMT)

13. P vs. V (constant n, T)

14. PV/nT for Different Gases
(all at 1 atm and 273K)
O2: Latm/molK
N2: Latm/molK
CO2: Latm/molK
NH3: Latm/molK
Ar: Latm/molK