2. Kinetic molecular theory part 2 Chapter 14 continued

3. Avogadro’s Hypothesis and Kinetic Molecular Theory P is also directly proportional to number of particles (n). The gases in this experiment are all measured at the same T and V.

4. Dalton’s Law John Dalton 1766-1844

5. Dalton’s Law of Partial Pressures At constant temperature, the pressure of a mixture of gases that do not react equals the sum of the partial pressures of the gases in the mixture. At constant temperature, the pressure of a mixture of gases that do not react equals the sum of the partial pressures of the gases in the mixture. P total (in gas mixture) = P 1 + P 2 + P 3... P total (in gas mixture) = P 1 + P 2 + P 3...

6. Dalton’s Law of Partial Pressure

7. Dalton’s Law of Partial Pressures What is the total pressure in the flask? P total = P H 2 O + P O 2 = 0.48 atm 2 H 2 O 2 (l) ---> 2 H 2 O (g) + O 2 (g) 0.32 atm 0.16 atm 0.32 atm 0.16 atm

8. Collecting a gas “over water”

9. Collecting Gases over Water Total gas pressure = 769 mm Hg Water vapor Pressure @ 19C= 17 mmHg Total pressure – Water vapor pressure = Pressure of gas 769 – 17 = 752 mm Hg

10. Boyle’s Law Robert Boyle was among the first to note the relationship between pressure and volume of a gas. He measured the volume of air at different pressures, and observed a pattern of behavior which led to his mathematical law During his experiments temperature and amount of gas weren’t allowed to change Robert Boyle (1627-1691). Son of Earl of Porrello, Ireland.

11. Boyle’s Law The volume of a confined gas varies inversely with the pressure, if temperature remains constant. P goes up as V goes down. P 1 V 1 = P 2 V 2

12. As the pressure increases Volume decreases Volume decreases

13. Boyle’s Law and Kinetic Molecular Theory P proportional to 1/V

14. Boyle’s Law: since PV = k (k = constant) P 1 V 1 = P 2 V 2 Ex: A gas has a volume of 3.0 L at 2 atm. What is its volume at 4 atm? What if we had a change in conditions?

15. 1)determine which variables you have: P and V = Boyle’s Law 2)determine which law is being represented:  P 1 = 2 atm  V 1 = 3.0 L  P 2 = 4 atm  V 2 = ?

16. 3) Rearrange the equation for the variable you don’t know 4) Plug in the variables and chug it on a calculator: P 1 V 1 = V 2 P2P2 (2.0 atm)(3.0L) = V 2 (4atm) V 2 = 1.5L

17. How does Pressure and Volume of gases relate graphically? Volume Pressure PV = k (Temperature, # of particles remain constant) ( typical graph for an inverse proportion)

18. Charles’s Law Jacques Charles determined the relationship between temperature and volume of a gas. He measured the volume of air at different temperatures, and observed a pattern of behavior which led to his mathematical law. During his experiments pressure of the system and amount of gas were held constant. Jacques Charles determined the relationship between temperature and volume of a gas. He measured the volume of air at different temperatures, and observed a pattern of behavior which led to his mathematical law. During his experiments pressure of the system and amount of gas were held constant.

19. Charles’s Law The volume of a gas varies directly with the absolute temperature, if pressure remains constant. Pressure & Kelvin Temp. are directly proportional! V 1 V 2 Jacques Charles (1746- 1823). Isolated boron and studied gases. Balloonist. T 1 T 2 =

20. Volume of balloon at room temperature Volume of balloon at 5°C

21. Charles’s Law: since V/T = k Eg: A gas has a volume of 3.0 L at 127°C. What is its volume at 227 °C? V 1 V 2 T 1 T 2 = What if we had a change in conditions?

22. 1)determine which variables you have: (ALWAYS CHANGE CELSIUS TO KELVIN!) T and V = Charles’s Law 2)determine which law is being represented:  T 1 = 127°C + 273 = 400K  V 1 = 3.0 L  T 2 = 227°C + 273 = 5ooK  V 2 = ?

23. 3) Rearrange to solve for unknown: (500K)(3.0L) = V 2 V 2 = 3.75L V 1 T 2 V 2 = 4) Plug in the variables and chug T1T1 (400K) ( 400K

24. Temp How does Temperature and Volume of gases relate graphically? Volume V/T = k Pressure, # of particles remain constant (Typical graph for a direct proportion)

25. Gay-Lussac’s Law The pressure of a gas is directly proportional to the absolute temperature, if volume is constant. If pressure goes up, Kelvin Temp goes up! Joseph Louis Gay- Lussac (1778-1850) P 1 P 2 T 1 T 2 =

26. Gas Pressure, Temperature, and Kinetic Molecular Theory P is directly proportional to Kelvin T

27. Temp Pressure How does Pressure and Temperature of gases relate graphically? P/T = k Volume, # of particles remain constant

28. Gay-Lussac’s Law: What if we had a change in conditions? since P/T = k P 1 P 2 T 1 T 2 = Eg: A gas has a pressure of 3.0 atm at 127º C. What is its pressure at 227º C?

29. T and P = Gay-Lussac’s Law  T 1 = 127°C + 273 = 400K  P 1 = 3.0 atm  T 2 = 227°C + 273 = 500K  P 2 = ? 1)determine which variables you have: (Celsius to Kelvin!!!) 1)determine which law is being represented:

30. 3) Rearrange to solve for unknown: (500K)(3.0atm) = P 2 (400K) P 2 = 3.8atm (P 1 )(T 2 ) P 2 = = 4) Plug in variables and chug T1T1 400K

31. LAWRELATIONSHIPLAWCONSTANTBoyle’s P VP VP VP V P 1 V 1 = P 2 V 2 T, n Charles’ V TV TV TV T V 1 /T 1 = V 2 /T 2 P, n Gay-Lussac’s P TP TP TP T P 1 /T 1 = P 2 /T 2 V, n