1. Kinetic-Molecular Theory Describes the behavior of an “ideal” gas in terms of particle size, motion, and energy based on 5 assumptions…

2. Gases 1. Do not attract or repel 2. Particles are much smaller than the distances between them 3. Particles are in constant, random motion 4. No kinetic energy is lost during collisions with other particles or walls of container 5. All gases have the same average KE at a given temperature

3. Properties of Gases Low density Compression & Expansion Diffusion & Effusion

4. STP One mole of any gas will occupy a volume of 22.4 L at STP Standard Temperature and Pressure –0° C and 1 atmosphere

5. Pressure Force per unit area How do gases exert pressure? http://phet.colorado.edu/en/simulation/gas- propertieshttp://phet.colorado.edu/en/simulation/gas- properties

6. Air Pressure Torricelli Barometer – used to measure atmospheric pressure

7. Units of Pressure 1 atmosphere 101.3 kPa (Pa = Pascal) 760 mm Hg 760 torr

8. Boyle’s Law

9. Pressure and Volume Inversely proportional If P increases, then V decreases P 1 V 1 = P 2 V 2

10. How to solve Make sure all units are the same for both variables 1 atm = 101.3 kPa = 760 mm Hg = 760 torr Match the units of volume and pressure correctly.

11. Practice A balloon contains 30.0 L of helium at 103 kPa. What is the volume of the balloon where the pressure is 250 kPa? P 1 V 1 = P 2 V 2 (103 kPa) (30.0 L) = (250 kPa) V 2 12.4 L 12 L

12. A gas has a volume of 2.50 L when the pressure is 1.0 atmosphere. If the pressure changes to 175 kPa, what is the new volume?

13. Charles’s Law

14. Temperature and Volume Directly proportional If one increases, so does the other! Celsius to Kelvin  add 273 V 1 = V 2 T 1 T 2 Temperature must be in K

15. Practice A balloon inflated in a 24°C room, has a volume of 4.00 L. The balloon is then placed in a room of 58°C. What is the new volume?

17. Gay-Lussac’s Law

18. Pressure and Temperature Directly proportional P 1 = P 2 T 1 T 2 Remember to match up units correctly!

19. Practice The gas in an aerosol can is at a pressure of 103 kPa at 25 ºC. If the can is thrown into a fire, what will the pressure be if the temperature reaches 923 ºC?