1. Unit 6 Kinetic Theory of Gases

2. Kinetic Theory 3 Parts to Kinetic Theory All particles are in constant random motion

3. Kinetic Theory 3 Parts to Kinetic Theory All particles are in constant random motion The motion of one particle is unaffected by the motion of other particles unless they collide.

4. Kinetic Theory 3 Parts to Kinetic Theory All particles are in constant random motion The motion of one particle is unaffected by the motion of other particles unless they collide. Forces of attraction among particles in a gas can be ignored under ordinary conditions.

5. Kinetic Theory The molecules move in straight lines and at constant velocity They only change directions or speed when they collide with other molecules or the sides of the container

6. Boyle’s Law As the volume of a gas decreases (Squeezing), the pressure increases. The volume of gas is inversely proportional to the pressure applied. Temperature and number of particles are held constant. P1V1= P2V2

11. Charles’ Law As the temperature of a gas increases, the volume increases. The volume of a gas is directly proportional to the Kelvin temperature. Pressure and number of particles are held constant. V1/T1= V2/T2

16. Hot Air Balloons work on Charles Law

17. Hot Air Balloons work on Charles Law

18. Try It At Home! Seal an empty water bottle Throw into the freezer. Wait 20 minutes

19. Try It At Home! Seal an empty water bottle Throw into the freezer. Check it out after it gets cold! Charles Law in effect

20. Why do you always launch balloons early in the morning?

21. Why do you always launch balloons early in the morning? Early morning is cooler, so the temperature difference between the air in the balloon and the outside is greater. Once up high, the air is cooler and you can stay up for a long time.

22. Guy-Lussacs’ Law Guy-Lussacs’ Law. The number of particles of the substance are held constant. P1/T1= P2/T2

23. Why is this a problem?

24. The heat will increase the pressure in the tank until it explodes

25. Try It At Home! Seal an empty water bottle on a high mountain road. Drive down to sea level

26. Try It At Home! Seal an empty water bottle on a mountain road. Check it out at sea level! Guy-Lussac’s Law

27. Combined Gas Law Combination of Boyle’s and Charles’ Law. The number of particles of the substance are held constant. P1V1/T1 = P2V2/T2

28. Why are weather balloons not filled completely at launch?

29. Combined Gas Law Ground: T = 293 K P = 1 Atm V = 100 L 5,000 m: T = 263 K P = 0.5 Atm V = ? 16,000 m T = 213 K P = 0.1 Atm V = ? P1V1/T1 = P2V2/T2

30. Combined Gas Law Ground: T = 293 K P = 1 Atm V = 100 L 5,000 m: T = 263 K P = 0.5 Atm V = ? 16,000 m T = 213 K P = 0.1 Atm V = ? 1.0atm*100L/293K = 0.5atm*V2/263K P1V1/T1 = P2V2/T2

31. Combined Gas Law Ground: T = 293 K P = 1 Atm V = 100 L 5,000 m: T = 263 K P = 0.5 Atm V = 179 L 16,000 m T = 213 K P = 0.1 Atm V = ? 1.0atm*100L/293K = 0.5atm*V2/263K V2 = 179 L P1V1/T1 = P2V2/T2

32. Combined Gas Law Ground: T = 293 K P = 1 Atm V = 100 L 5,000 m: T = 263 K P = 0.5 Atm V = 179 L 16,000 m T = 203 K P = 0.1 Atm V = ? 1.0atm*100L/293K = 0.1atm*V2/203K P1V1/T1 = P2V2/T2

33. Combined Gas Law Ground: T = 293 K P = 1 Atm V = 100 L 5,000 m: T = 263 K P = 0.5 Atm V = 179 L 16,000 m T = 203 K P = 0.1 Atm V = 693 L 1.0atm*100L/293K = 0.1atm*V2/203K V2 = 693 L P1V1/T1 = P2V2/T2

34. Why are weather balloons not filled completely at launch?

35. Why are weather balloons not filled completely at launch? The Atmosphere is much thinner, so the balloon expands

36. Try It At Home! Seal an empty water bottle on a mountain road. Check it out at sea level! Guy-Lussac’s Law