Episode I ATTACK OF THE GAS

2. Not so long ago, in a chemistry lab far far away… May the FORCE/area be with you Episode I ATTACK OF THE GAS Gas, being of upmost importance to the entire galaxy and your life, is in constant battle due to the ruthless variations of temperature, pressure, and the amount of particles. It is imperative that you understand properties of gases and how those ruthless variations affect the gases. You will need to make some minor assumptions to conquer this topic. However, there is certainty that you will prevail…

4. Gas Laws: CombinedAt the conclusion of our time together, you should be able to: Combine all three laws into the Combined Gas Law Use the Combined Gas Law to determine either temperature, volume or pressure

5. The Combined Gas Law The combined gas law expresses the relationship between pressure, volume and temperature of a fixed amount of gas. Boyle’s law, Gay-Lussac’s law, and Charles’ law are all derived from this by holding a variable constant.

6. Combined Gas Law If you should only need one of the other gas laws, you can cover up the item that is constant and you will get that gas law! = P1 V1 P2 Boyle’s Law Charles’ Law Gay-Lussac’s Law V2 T1 T2

7. Let’s Review: Mixed Problems: #1, Page 6 Boyle’s Law P1 V1 P2 V2 (34,470 Pa) (473.18 mL) P2 (13.13 mL) 1,242,000 Pa

8. Try This One #8, Page 7 Charles’ Law V1 V2 T1 T2 31.4 L 25.0 L 296.6 K T2 236 K or -37 oC

9. Combined Gas Law Problem A sample of helium gas has a volume of 0.180 L, a pressure of 0.800 atm and a temperature of 29°C. What is the new temperature(°C) of the gas at a volume of 90.0 mL and a pressure of 3.20 atm? Set up Data Table P1 = 0.800 atm V1 = 180 mLT1 = 302 K P2 = 3.20 atmV2 = 90 mLT2 = ??

10. Calculation • P1 = 0.800 atm V1 = 180 mL T1 = 302 K • P2 = 3.20 atm V2 = 90 mL T2 = ?? P1 V1 P2 V2 = P1 V1T2= P2 V2 T1 T1 T2 T2= 3.20 atm x 90.0 mL x 302 K 0.800 atm x 180.0 mL T2 = 604 K - 273 = 331 °C = 604 K

11. Gas Laws: Gay-Lussac’s and CombinedLet’s see if you can: Combine all three laws into the Combined Gas Law Use the Combined Gas Law to determine either temperature, volume or pressure

12. Learning Check A gas has a volume of 675 mL at 35°C and 0.850 atm pressure. What is the temperature in °C when the gas has a volume of 0.315 L and a pressure of 802 mm Hg?

13. Calculation • P1 = 0.850 atm V1 = 675 mL T1 = 308 K • P2 = 1.06 atm V2 = 315 mL T2 = ?? P1 V1 P2 V2 = P1 V1T2= P2 V2 T1 T1 T2 T2= 1.06 atm x 315 mL x 308 K 0.850 atm x 675 mL T2 = 179 K - 273 = -94 °C = 179 K

14. Pass the Clicker!!!

15. What will the new pressure (in atm) be if oxygen gas at room temperature (25.0 oC) and 1.00 atm is heated to 50.0 oC in a fixed container? • 2.00 atm • 0.500 atm • 1.08 atm • 0.923 atm • Not listed

16. A sample of neon gas occupies 266 mL at 25.5oC. At what temperature would the volume of this sample of gas be reduced to half its initial size? (1 atm = 101.325 kPa) • -124oC • 149oC • 119oC • -154oC • Not listed

17. What is the volume of CO2 at STP if the original sample of CO2 had a volume of 65.0 mL at 95.0 mm Hg and 50.0oC? • .00687 mL • 44.4 mL • 6.87 mL • 5220 mL • Not listed

18. Combined Gas Law Problems: #1 • P1 = 12.0 atm V1 = 23.0 L T1 = 200. K • P2 = 14.0 atm V2 = ? L T2 = 300. K P1 V1 P2 V2 = P1 V1T2 = P2V2T1 T1 T2 V2= 12.0 atm x 23.0 L x 300 K 14.0 atm x 200 K = 29.6 L

19. The End!!!