Bell Ringer

# Bell Ringer

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## Bell Ringer

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1. Bell Ringer • The gas with the largest volume at STP is: • 10.0 g He • 10.0 g Ne • 10.0 g Ar • 10.0 g Kr (56.0 L He) 1 mol He 22.4 L He He: 10.0 g He 56.0 L He x x = 4.00 g He 1 mol He Source: 2004 VA Chemistry EOC Exam

2. Bell Ringer • The gas with the largest volume at STP is: • 10.0 g He • 10.0 g Ne • 10.0 g Ar • 10.0 g Kr (56.0 L He) (11.1 L Ne) 1 mol Ne 22.4 L Ne Ne: 10.0 g Ne 11.1 L Ne x x = 20.18 g Ne 1 mol Ne Source: 2004 VA Chemistry EOC Exam

3. Bell Ringer • The gas with the largest volume at STP is: • 10.0 g He • 10.0 g Ne • 10.0 g Ar • 10.0 g Kr (56.0 L He) (11.1 L Ne) (5.61 L Ar) 1 mol Ar 22.4 L Ar Ar: 10.0 g Ar 5.61 L Ar x x = 39.95 g Ar 1 mol Ar Source: 2004 VA Chemistry EOC Exam

4. Bell Ringer • The gas with the largest volume at STP is: • 10.0 g He • 10.0 g Ne • 10.0 g Ar • 10.0 g Kr (56.0 L He) (11.1 L Ne) (5.61 L Ar) (2.67 L Kr) 1 mol Kr 22.4 L Kr Kr: 10.0 g Kr 2.67 L Kr x x = 83.80 g Kr 1 mol Kr Source: 2004 VA Chemistry EOC Exam

5. GAS LAWS Ms. Besal 3/10/2006

6. Lesson Objectives • You will be able to: • Name and describe 5 characteristics of gases • Identify three differences between ideal gases and real gases. • Define the term “STP” • List 4 units for pressure measurement • Explain and describe the relationship between temperature and pressure of gases, according to Charles’ Law. • Explain and describe the relationship between volume and pressure of gases, according to Boyle’s Law. • Explain how temperature, pressure, and volume of gases are all related according to the combined gas law. • Solve mathematic problems about Charles’ Law, Boyle’s Law, and the combined gas law.

7. What are Characteristics of a GAS? E X P A N D A B L E Diffusible... Fluid Compressible Low Density

8. In the REAL WORLD: Gases are fat. (they have mass) Gases hog the sofa. (they have volume) Gases are pushy and have an attitude toward other gases. (they exert forces on each other) In an IDEAL WORLD: Gases are skinny. (they have no mass) Gases make themselves invisible. (they have no volume) Gases are not confrontational. (they do not interact… elastic collisions) : Gas Laws Assumptions Image Source: mtv.com

9. SO FAR… S T P Standard Temperature & Pressure 273 K 1 atmosphere (atm)

10. F P = A What does PRESSURE mean? • In Life: Pressure = a chemistry quiz every day • In Science: • Pressure = force per unit area PSI = Pounds per Square Inch

11. How else can we measure Pressure? 760 mm Hg 1 atmosphere = 760 torr 101.3 kilopascals These numbers reflect STANDARD PRESSURE

12. SO FAR… S T P Standard Temperature & Pressure 273 K 1 atmosphere (atm)

13. How can we change Gases? Action Variable Heat it up/Cool it down Temperature Change container size Volume Compress or Decompress Pressure

14. How are Temperature and Volume Related? Initial Final T1 T2 Temperature V1 V2 Volume

15. How are Temperature and Volume Related? x x x x x x x Volume x x x x x x Temperature “At constant pressure… temperature and volume are directly proportional”

16. Charles’ Law V1 V2 = T1 T2 “At constant pressure… temperature and volume are directly proportional.” Temperature is always measured in Kelvin! 0ºC = 273 K

17. How can we change Gases? Action Variable Heat it up/Cool it down Temperature Change container size Volume Compress or Decompress Pressure

18. How are Volume and Pressure Related? Initial Final V1 V2 Volume P1 P2 Pressure

19. How are Volume and Pressure Related? x x x x x x x Volume x x x x x x Pressure “At constant temperature… volume and pressure are inversely proportional”

20. P1 V1 = P2 V2 x x Boyle’s Law “At constant temperature… volume and pressure are inversely proportional.”

21. V1 V2 = T1 T2 P1 V1 = P2 V2 x x To Recap… • Charles’ Law: Relates Temperature and Volume. • Boyle’s Law: • Relates Pressure and Volume

22. P1 V1 P2 V2 T1 T2 …THEREFORE: • Temperature, Volume, and Pressure are all related! = Combined Gas Law

23. P1 V1 P2 V2 T1 T2 P1 V1 P2 V2 Practice 1. 100.0 cm3 oxygen at 10.50 kPa changes to 9.91 kPa. What is the new volume of the gas? = = Boyle’s Law! (10.50 kPa) x (100.0 cm3 O2) = (9.91 kPa) x (V2) V2 = (10.50 kPa) x (100.0 cm3 O2) = 106 cm3 O2 (9.91 kPa)

24. P1 V1 P2 V2 = T1 T2 P1 V1 = P2 V2 (748 mmHg) x (150.0 mL SO2) (P2) x (140.6 mL SO2) (748 mmHg) (150.0 mL SO2) P2 = = (140.6 mL SO2) Practice 2. 150.0 mL sulfur dioxide at 748 mmHg changes to a new volume of 140.6 mL. What is the new pressure of the gas? = 798 mmHg

25. P1 V1 P2 V2 T1 T2 V1 V2 T1 T2 Practice 3. 75.0 cm3 of hydrogen at 27.0ºC changed to –10.0ºC. What is the new volume of the gas? = = Charles’ Law! Kelvin! 75.0 cm3 H2 V2 = 300 K 263 K V2 = (75.0 cm3 H2) x (263 K) = 65.8 cm3 H2 (300 K)

26. P1 V1 P2 V2 T1 T2 0.560 L 0.400L T1 280.71 K T1 = (0.560 L) x (280.71 K) = 120.ºC (0.400 L) Practice 4. A gas occupies a volume of 0.560 L. The original temperature was cooled to 7.71 ºC and the resulting volume was 0.400 L. What was the original temperature of the gas? = = 393 K

27. P1 V1 P2 V2 T1 T2 Practice 5. 140. L chlorine at 15.0ºC and 110.0 kPa changed to 40.0ºC and 123.5 L. What is the new pressure? = (110.0 kPa) (140 L Cl2) (P2) (123.5 L Cl2) = 288 K 313 K P2 = (110.0 kPa) (140. L Cl2) (313 K) 136 kPa = (288 K) (123.5 L Cl2)

28. P1 V1 P2 V2 T1 T2 (120 kPa) (500.0 mL H2) (101.3 kPa) (V2) 293 K 273 K V2 = (121 kPa) (500.0 mL H2) (273 K) (293 K) (101.3 kPa) Practice 6. 500.0 mL of hydrogen at 20.0ºC and 121 kPa changed to STP. What is the new volume of the gas? = = 556 mL H2 =

29. For Next Class: Homework: Last page of Gas Laws Packet: Problems 1-10, 11-25 ODD QUIZ on Charles, Boyle, and Combined Gas Laws • 24 points. • 3 short answer/FITB problems (2 points each) • 3 math problems (6 points each) • 2 points for correct equation • 2 points for correct math • 2 points for correct labels

30. What Should I Study? • how pressure, temperature, and volume relate to each other in Boyle’s, Charles’, and Combined Gas Laws. • how to determine changing conditions using math (practice problems & homework). • standard conditions of temperature and pressure; how to convert from Celsius to Kelvin, from kPa to atm to mm Hg. • how real gases and ideal gases differ.

31. Lesson Objectives • You should be able to: • Name and describe 5 characteristics of gases • Identify three differences between ideal gases and real gases. • Define the term “STP” • List 4 units for pressure measurement • Explain and describe the relationship between temperature and pressure of gases, according to Charles’ Law. • Explain and describe the relationship between volume and pressure of gases, according to Boyle’s Law. • Explain how temperature, pressure, and volume of gases are all related according to the combined gas law. • Solve mathematic problems about Charles’ Law, Boyle’s Law, and the combined gas law.