1. Gas Laws Chapter 14

2. Kinetic Molecular Theory of Gases No attraction/repulsion Volume of particles is 0 Constant motion Elastic collisions Temperature equals the average kinetic energy of all particles

3. Factors Affecting Gas Pressure Amount of Gas (n=moles) Volume (Liters) Temperature (Kelvin) Remember: K= o C +273 1atm = 760 mm Hg = 760 Torr = 101.3 kPa = 14.7 psi

4. Boyle’s Law At constant temperature, pressure and volume are inversely related. P 1 V 1 = P 2 V 2

5. Practice: Boyle’s Law A gas system has an initial volume of 2.36L with the pressure unknown. When the volume changes to 2290mL the pressure is found to be 6390torr What was the initial pressure in atm?

6. Charles’s Law At constant pressure, volume and temperature are directly related. V 1 /T 1 = V 2 /T 2

7. Practice: Charles’s Law Calculate the final temperature of a gas in Celsius when 2L of the gas at 128K is compressed to 0.5L?

8. What About Pressure and Temperature? Gay Lussac’s Law At constant volume, pressure and temperature are directly related P 1 /T 1 = P 2 /T 2

9. Practice What is the final pressure of a sample of gas that has an initial pressure of 89.3kPa when its temperature is raised from 25 o C to 100 o C?

10. Combined Gas Law P 1 V 1 /n 1 T 1 = P 2 V 2 /n 2 T 2 http://www.mhhe.com/physsci/chemistry/essentialchemistry/flash/gasesv6.swf A closed gas system initially has pressure and temperature of 1.56atm and 629K with the volume unknown. If the same closed system has values of 195torr, 9940mL and 523K, what was the initial volume in L?

11. ASSIGNMENT Practice Problems (Section 14.2): # 7-14

12. IDEAL GAS LAW PV=nRT R= 0.0821 L*atm/mol*K = 8.31 L*kPa/mol*K Calculate the pressure in a 212 Liter tank containing 23.3 kg of argon gas at 25°C?

13. Ideal v. Real Gases They’re the same except at  EXTREMELY LOW T  EXTREMELY HIGH P

14. Assignment Section 14.3 Assessment # 25-30

15. Ideal Gas Law and Molar Mass M=mRT/PV given n=m/M Where n=moles, m=mass and M=molar mass How many grams of gas are present in a sample that has a molar mass of 70 g/mol and occupies a 2.00 L container at 117kPa and 35.1 o C?

16. Gas Constant (R) 0.0821 L atm mole K 62.4L mm Hg mole K 8.314 L kPa mole K

17. From Friday How many moles of gas were in your bottle each time?

18. Ideal Gas Law and Density D=MP/RT given n=m/M and D=m/V What is the density of a gas at STP that has a molar mass of 44.0 g/mol?

19. Dalton’s Law of Partial Pressure Pressure and moles of gas are directly proportional. P total = P 1 + P 2 + P 3 + … http://www.tlv.com/global/US/steam- theory/steam-partial-pressure-pt1.html http://www.tlv.com/global/US/steam- theory/steam-partial-pressure-pt1.html

20. Gas Stoichiometry If 1.39 g of ethane(C 2 H 6 ) is reacted with oxygen, what volume of carbon dioxide is produced at: STP? 12.3 o C at 107.4KPa?

21. Avogadro’s Principle Equal volumes of gas at the same temperature and pressure have equal numbers of particles. Translation: 1 mole = 22.4 L = 6.02 x 10 23 gas particles

22. Diffusion/Effusion Diffusion- gases move toward areas of lower concentration Effusion- gas escaping through tiny holes in container

23. Graham’s Law of Gaseous Effusion

24. TEST 30 MC Questions 5 problems requiring elegant solutions