1. CHEMISTRY CATALYSTS Spring 2014 – (Gases)

2. CP Catalyst (5 minutes)  4/3/12 Gases  EQ: How do I use the gas laws?  Solve for P, V, or T as requested.  The gas in a balloon occupies 2.5L at 300K. At what temperature will the balloon expand to 7.5L?  The pressure of a 10cm 3 sample of gas is 1.5 atm. What volume will the gas occupy if the pressure changes to 6.0 atm?

3. THE COMBINED GAS LAW

4. Combining the gas laws Jacques CharlesRobert Boyle P1V1P1V1 =P2V2P2V2 V1V1 T1T1 = V 2 T2T2 These are all subsets of a more encompassing law: The Combined Gas Law P1P1 T1T1 = P2P2 T2T2 P 1 V 1 P 2 V 2 T 1 T 2 = Joseph Louis Gay-Lussac P 1 V 1 T 2 = P 2 V 2 T 1

5. EXAMPLE # 1 2.00 L of a gas is collected at 25.0°C and 745.0 mmHg. What is the volume at STP? P1P1 745.0 mm HgP2P2 760.0 mm Hg V1V1 2.00 LV2V2 ??? T1T1 298 KT2T2 273 K

6. 2.00 L of a gas is collected at 25.0°C and 745.0 mmHg. What is the volume at STP?

7. Example #2  In a large syringe, 48 mL of ammonia gas at STP is compressed to 24 mL and 110 kPa. What must the new temperature of the gas be?  (ANS: 148 K or -125ºC) P1P1 101.3 kPaP2P2 110 kPa V1V1 48 mLV2V2 24 mL T1T1 273 KT2T2 ??? K

8. Poster Project Boyle’s Law:Charles’ Law: Gay-Lussac’s Law:Combined Law:

9. For each section, include…  Title of the gas law  Formula of the gas law  Write it BIG!!!!  A piece of paper folded in half like a hamburger and glued to your poster  Outside: A word problem about gases that can be solved using that gas law  Inside: The solution to your problem, including your step-by-step work

10. Gallery Walk 1. Find a gas laws poster that you like. 2. Answer the 4 questions on the poster. 3. Check your answers to see if you are correct. 4. Find another poster until you have a total of 12 problems worked on your paper.

11. Hon. Catalyst (5 minutes)  4/3/14 Gases  EQ: How do I use the gas laws?  Solve for P, V, or T as requested.  The gas in a balloon occupies 2.5L at 300K. At what temperature will the balloon expand to 7.5L?  The pressure of a 10cm 3 sample of gas is 1.5 atm. What volume will the gas occupy if the pressure changes to 6.0 atm?

12. THE COMBINED GAS LAW

13. Combining the gas laws Jacques CharlesRobert Boyle P1V1P1V1 =P2V2P2V2 V1V1 T1T1 = V 2 T2T2 These are all subsets of a more encompassing law: The Combined Gas Law P1P1 T1T1 = P2P2 T2T2 P 1 V 1 P 2 V 2 T 1 T 2 = Joseph Louis Gay-Lussac

14. EXAMPLE # 1 2.00 L of a gas is collected at 25.0°C and 745.0 mmHg. What is the volume at STP? P1P1 745.0 mm HgP2P2 760.0 mm Hg V1V1 2.00 LV2V2 ??? T1T1 298 KT2T2 273 K

15. 2.00 L of a gas is collected at 25.0°C and 745.0 mmHg. What is the volume at STP?

16. Example #2  In a large syringe, 48 mL of ammonia gas at STP is compressed to 24 mL and 110 kPa. What must the new temperature of the gas be?  (ANS: 148 K or -125ºC) P1P1 101.3 kPaP2P2 110 kPa V1V1 48 mLV2V2 24 mL T1T1 273 KT2T2 ??? K

17. IDEAL GAS LAW

18. Ideal Gas Law UNIVERSAL GAS CONSTANT R=0.0821 L  atm/mol  K R=8.314 L  kPa/mol  K PV=nRT

19. WORK: PV = nRT P(3.25)=(0.412)(0.0821)(289) P = 3.01 atm Ideal Gas Law Problems Calculate the pressure in atmospheres of 0.412 mol of He at 16°C & occupying 3.25 L.

20. Ideal Gas Law Problems Find the volume of 85 g of O 2 at 25°C and 104.5 kPa. = 2.7 mol WORK: 85 g 1 mol = 2.7 mol 32.00 g PV = nRT (104.5)V=(2.7) (8.314) (298) V = 64 L

21. Standard Temperature: 0˚C 273K Standard Pressure: 1 atm 101.3kPa 101,325 Pa 760 torr 760 mmHg P 1 V 1 T 2 = P 2 V 2 T 2