1. Gases Pressure (5.1) Gas Laws of Boyle, Charles, Avogadro (5.2) Ideal Gas Law (5.3) Gas Stoichiometry (5.4) Kinetic Molecular Theory (5.6) Effusion & Diffusion (5.7) Real Gases (5.8-5.10) Chemistry- Unit 7

2. Section 1 Pressure (5.1) Gas Laws of Boyle, Charles, Avogadro (5.2) Chemistry- Unit 7

3. Gases …uniformly fill any container. [No defined shape or volume.] …are fluids. …have a low density. …mix completely with any other gas. …exerts pressure on its surroundings. …can be compressed therefore increasing its pressure. [Capable of flowing freely]

4. SI units = Newton/meter 2 = 1 Pascal (Pa) Pressure Force per unit area

5. Barometer Device used to measure atmospheric pressure. Mercury flows out of the tube until the pressure of the column of mercury standing on the surface of the mercury in the dish is equal to the pressure of the air on the rest of the surface of the mercury in the dish.

6. Device used for measuring the pressure of a gas in a container. Manometer

7. Units for atmospheric pressure mm Hg atm torr Pa kPa 1mm Hg = 1 torr 1 atm = 760 mm Hg 1 atm = 760 torr 1 atm = 101,325 Pa = 101.325 kPa

8. The pressure of a gas is measured as 2.5 atm. Represent this pressure in torr, pascals, and kilopascals. Pressure Conversions =2.5x10 2 kPa =250 kPa

9. Denver is at 0.830 atm. What is this in: A) mm Hg B) torr C) kPa Pressure Conversions

10. Standard SI unit is the Kelvin We will use Celsius in lab. Temperature Measure of the average kinetic energy of the particles in a sample of matter K = 273.15 + o C T C = 5/9(T F – 32) T F = 9/5 ● Tc + 32 Absolute Zero= 0 K = -273.15 o C

11. mathematical relationships between volume, temperature, pressure and amounts of a gas Gas Laws  Volume (V)  Temperature (T)  Pressure (P)  Amount (n) [L] [convert mL] [K] [convert o C or o F] [atm] [ ] [mol] [convert grams] convert mm Hg, torr, Pa, kPa

12. volume of a gas with a fixed amount at constant temperature varies inversely with the pressure Pressure & Volume Boyle’s Law 1 V = k P k is a constant for that specific gas

13. Pressure & Volume Boyle’s Law P 1 V 1 = kk = P 2 V 2 P 1 V 1 = P 2 V 2

14. Boyle’s Law

15. Exercise A sample of helium gas occupies 12.4 L at 23°C and 0.956 atm. What volume will it occupy at 1.20 atm assuming that the temperature stays constant? 9.88 L

16. volume of a gas with a fixed amount at constant pressure varies directly with the temperature Volume & Temperature Charles’ Law k is a constant for that specific gas V = kT

17. Volume & Temperature Charles’ Law V = k T V 1 = k T 1 V 2 k = T 2 V 1 V 2 = T 1 T 2

18. Charles’ Law

21. Exercise Suppose a balloon containing 1.30 L of air at 24.7°C is placed into a beaker containing liquid nitrogen at –78.5°C. What will the volume of the sample of air become (at constant pressure)? 0.849 L

22. pressure of a gas with a fixed amount at constant volume varies directly with temperature Pressure & Temperature Gay-Lussac’s Law k is a constant for that specific gas P = kT

23. Pressure & Temperature Gay-Lussac’s Law P = k T P 1 = k T 1 P 2 k = T 2 P 1 P 2 = T 1 T 2

24. mathematical relationship between pressure, volume and temperature with a fixed amount of gas Combined Gas Law PV = k V = k T P = k T PV = k T P 1 V 1 P 2 V 2 = T 1 T 2

25. Exercise At what temperature (in °C) does 121 mL of CO 2 at 27°C and 1.05 atm occupy a volume of 293 mL at a pressure of 1.40 atm? 696 o C

26. Section 1 Homework Set Chemistry- Unit 7 Pg 225 #35, 36, 41, 42, 54, 57, 59, 61