1. Chemistry 101 Dr. Don DeCoste 3014 Chemistry Annex
2-3 pm Mondays and am Thursdays
By appointment
Open door policy

2. To Do… Next three lectures: Chapter 13 Lab tomorrow (gases) OWL
Chapter 8: tonight (1/30)
Chapter 13 (part 1): This Friday, 2/2
Exam 1: Thursday, February 8

3. Name this compound:
You have some a compound labeled “nitrogen oxide” and you want to figure out its actual name.
You know it is 30.4% nitrogen by mass.
What is the name of this compound?

4. Percent Mass Nitrogen in N2O4
Note: we need the molar mass to determine the molecular formula.

5. 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.

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

7. 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.

8. Take a Molecular Level View

9. 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.

10. V and n (KMT)

11. V and T (KMT) .

12. P and V (KMT)