1. Weather Unit Investigation IV: Counting Matter Lesson 1: Tower of Air Lesson 2: Lighter Than Air Lesson 3: More Than a Billion Lesson 4: Take a Breath Lesson 5: Up in the Clouds Lesson 6: Rain in the Forecast Lesson 7: Stormy Weather

2. Weather Unit – Investigation IV Lesson 1: Tower of Air

3. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X ChemCatalyst What is the atmosphere? What is it made of? How big is the atmosphere? How do we measure it? (cont.)

4. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X (cont.)

5. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X air pushes down mercury is pushed up (cont.)

6. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X The Big Question How does a column of mercury measure the air pressure on the earth?

7. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X You will be able to: Explain how a mercury barometer works

8. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Activity Purpose: This lesson allows you to explore why mercury is used in barometers to measure air pressure. (cont.)

9. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X 30,000 m 40,000 m sea level 20,000 m 10,000 m 99% of the atmosphere is below ~30,000 m 90% of the atmosphere is below 17,700 m column of air 50% of the atmosphere is below 5,600 m mountaintop (cont.)

10. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X SubstanceAltitudeHeight of the air in m Height of the air in ft Density of the air above Air pressure airsea level30,000 m99,000 m0.00034 g/cm 3 1.0 atm air5,600 m24,400 m80,500 ft0.00022 g/cm 3 0.5 atm air11,000 m19,000 m62,700 ft0.00013 g/cm 3 0.25 atm air17,700 m12,300 m40,600 ft0.00008 g/cm 3 0.1 atm Air Pressure (cont.)

11. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X SubstanceHeight of the water in m Height of the water in ft DensityPressure water10.3 m34.0 ft1.0 g/cm 3 1.0 atm water20.6 m68.0 ft1.0 g/cm 3 2.0 atm water103 m340 ft1.0 g/cm 3 10.0 atm Water Pressure (cont.)

12. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Mercury Pressure SubstanceHeight of the mercury in m Height of the mercury in ft DensityPressure mercury0.76 m2.5 ft13.6 g/cm 3 1.0 atm (cont.)

13. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Making Sense Why does the density of the air decrease as altitude increases? Why isn’t water used in a barometer?

14. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Number density means the number of particles per volume. Notes (cont.)

15. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X The most important gases in the earth’s atmosphere, in terms of their effects on the health of the earth, are nitrogen, oxygen, water vapor, carbon dioxide, methane, nitrous oxide, and ozone. Nitrogen and oxygen make up 99% of the dry atmosphere. Particulate matter refers to tiny particles that are not gases, but are small enough to be airborne. Notes (cont.)

16. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Check-In Why is mercury used in a barometer and not alcohol or water or some other liquid?

17. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Wrap-Up A mercury barometer is used to measure the air pressure of the atmosphere because of its high density. The atmosphere becomes less dense with altitude. There are less gas particles per volume as altitude increases. The atmosphere consists mostly of nitrogen and oxygen gases.

18. Weather Unit – Investigation IV Lesson 2: Lighter Than Air

19. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X ChemCatalyst Why do you suppose meteorologists use helium and hydrogen for weather balloons? Which gas would cause the weather balloon to rise faster? Explain the reasoning behind your answer.

20. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Notes Equal volumes of gases at the same temperature and pressure contain equal numbers of gas particles (atoms or molecules). In two balloons of equal volume # of N 2 molecules = # of He atoms Avogadro’s Hypothesis

21. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X The Big Question What is the relationship between the number of gas particles, the mass, and volume of different gases?

22. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X You will be able to: Apply Avogadro’s Hypothesis.

23. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Activity Purpose: The purpose of today's lesson is to explore the number of gas particles in a specified volume of gas. You will need Avogadro's Hypothesis to help you answer the questions. (cont.)

24. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X 2.0 g 32 1 5 4 22.0 g 4.0 g 28.0 g 8.0 g He N 2 CO 2 (cont.)

25. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X gas# of particles massvolumepressuretemperature He6.02 x 10 23 4.0 g22.4 L1.0 atm273 K He8.0 g44.8 L1.0 atm273 K He11.2 L1.0 atm273 K Ar6.02 x 10 23 40.0 g22.4 L1.0 atm273 K Ar20.0 g1.0 atm273 K N2N2 6.02 x 10 23 28.0 g22.4 L1.0 atm273 K N2N2 3.01 x 10 23 1.0 atm273 K N2N2 6.02 x 10 23 28.0 g11.2 L273 K (cont.)

26. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Making Sense You have: 5.0 L of methane (CH 4 ) at 30°C and 1.0 atm, and 5.0 L of oxygen (O 2 ) at 30°C and 1.0 atm. (cont.)

27. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X List at least three things that are the same. List at least three things that are different. (Consider the volume, temperature, pressure, number of gas particles, identities of the gas particles, mass, and density.) (cont.)

28. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X If you have 22.4 L of a gas at 1 atm and 273 K, then there will be 6.02 x 10 23 gas particles present, regardless of the identity of the gas. This number, 6.02 x 10 23 is also known as Avogadro’s number. Avogadro’s Number Notes (cont.)

29. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Standard temperature and pressure, STP, is 1 atm and 273 K. At STP, 6.02 x 10 23 gas particles occupy 22.4 L. This is true for any gas. Notes (cont.)

30. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Check-In One balloon has 22.4 L of Ar and another balloon has 22.4 L of Ne gas. Both balloons are at STP. Are the balloons the same volume? Do the balloons contain the same number of particles? Why or why not? Will the balloons have the same mass? Why or why not?

31. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Wrap-Up Avogadro’s hypothesis states that equal volumes of gases contain the same number of molecules if they are at the same temperature and pressure, independent of the identity of the gas. Standard temperature and pressure is defined as 1 atmosphere and 273 K.

32. Weather Unit – Investigation IV Lesson 3: More Than a Trillion

33. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X ChemCatalyst Why might it be useful for a chemist to know there are 6.02 X 10 23 gas particles in a certain volume of gas?

34. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X The Big Question How is a mole used for counting particles in gases, liquids, and solids?

35. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X You will be able to: Use the mole as a counting unit for gases, liquids, and solids.

36. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X There are 6.02 x 10 23 particles in a mole. This number of particles is also called Avogadro’s number. Notes

37. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Activity Purpose: In this lesson, you will explore how to count using a new unit called the mole. (cont.)

38. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Part I: 1 mole = 6.02 x 10 23 particles Substance# of moles# of particlestotal # of atoms He (g)16.02 x 10 23 He (g)0.53.01 x 10 23 He (g)2.01.204 x 10 24 H 2 (g)16.02 x 10 23 1.204 x 10 24 H 2 (g)0.53.01 x 10 23 H 2 (g)2.408 x 10 24 Cu (s)1 0.16.02 x 10 22 H 2 O (l)11.806 x 10 24 H 2 O (l)0.53.01 x 10 23

39. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Part II: Counting molecules vs. atoms Materials: (per pair of students) 24 small pieces of paper - index cards or small Post-Its ® work well (cont.)

40. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Formaldehyde clear liquid smells putrid Glucose white solid tastes sweet C 6 H 12 O 6 4 moles CH 2 O 24 moles (cont.)

41. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Making Sense A company has a history of releasing NO 2 gas into the atmosphere, which forms smog. In order to reduce their pollution, they figure out how to release N 2 O 4 instead. For every 1.0 mole of NO 2, they now release 0.75 moles of N 2 O 4 instead. (cont.)

42. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Are there fewer gas particles with the release of 0.75 moles of N 2 O 4 instead of 1.0 moles of NO 2 ? Explain. Are there fewer N atoms being released? Explain. If the amount of smog depends on the number of N atoms, has the company reduced the amount of smog that will be produced? (cont.)

43. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X SubstanceMolecular formula Formaldehyde (embalming liquid)CH 2 O Acetic acid (vinegar)C2H4O2C2H4O2 Glucose (one form of sugar)C 6 H 12 O 6 Sucrose (table sugar)C 12 H 22 O 11 A molecular formula gives the numbers of atoms that remain together as a molecule. (cont.)

44. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Here are some translations for the meaning of 1 mole of C 6 H 12 O 6, glucose: one mole of sugar molecules 6.02 x 10 23 molecules of C 6 H 12 O 6 6 moles of carbon atoms 12 moles of hydrogen atoms 3.612 x 10 24 oxygen atoms 24 moles of atoms (cont.)

45. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Check-In You have 1 mole CH 4 (g) and 1 mole O 2 (g). Which has more atoms? Which has more molecules? Which has more mass?

46. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Wrap-Up A mole is 6.02 x 10 23 units of whatever you are counting. This number is often referred to as Avogadro’s number.

47. Weather Unit – Investigation IV Lesson 4: Take a Breath

48. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X ChemCatalyst Mount Everest lies on the border between Nepal and Tibet. It is approximately 29,000 feet high. Those who climb Mount Everest usually pack along many tanks of oxygen to help them with breathing. Why do you think it is difficult to breathe at high altitudes?

49. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X The Big Question Why is it so difficult to breathe at high altitudes?

50. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X You will be able to: Use the ideal gas law to figure out the number of moles of gas molecules in the air.

51. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X The ideal gas law relates volume (V), temperature (T), pressure (P), and moles (n): PV = nRT where R = 0.082 L-atm/mole-K. Notes

52. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Activity Purpose: This activity will give you practice using the ideal gas law. You will figure out the number of moles of air in an average breath. (cont.)

53. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Materials: (per team of four students) 2 L plastic soda bottle with cap a tub or sink or other large container for water (at least 5 liters) tap water 3 feet of flexible tubing 4 straws (to fit into the tubing) 1 watercolor marker or overhead pen 1 graduated cylinder – 250 mL or 500 mL (cont.)

54. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Part I: Volume of a breath of air The goal of this part of the activity is to determine the volume of a normal breath of air. The outline for a procedure is given below. You will need to decide how many breaths to measure and how you will figure out the air volume. (cont.)

55. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X (cont.)

56. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Part II: Moles in a breath of air Use the volume you determined for one breath to figure out the number of moles of air in one breath at sea level and in one breath on a mountaintop. (cont.)

57. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Making Sense Use your mole calculations to explain why you breathe faster at higher altitudes.

58. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Check-In You fill a 1.0 L plastic bottle with 1.0 mole of air on a mountaintop where the air pressure is 0.5 atm. Why does the plastic bottle become crushed when you bring the bottle to sea level? What is the volume of the bottle at sea level? How many moles per liter are there at sea level?

59. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Wrap-Up The ideal gas law relates volume, pressure, temperature, and the number of moles: PV = nRT, where R = 0.082 L-atm/mole-K.

60. Weather Unit – Investigation IV Lesson 5: Up in the Clouds

61. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X ChemCatalyst What is a cloud? How do you think clouds form?

62. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X The Big Question What causes clouds to form?

63. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X You will be able to: Explain how relative humidity and air pressure influence cloud formation.

64. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Activity Purpose: This activity allows you to create a tiny cloud inside a soda bottle and examine the forces that contribute to cloud formation. (cont.)

65. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Materials: (for groups of 2-4 students) Two 2-liter bottles with caps. (You will need one that is dry.) Long matches Tap water Hot water (cont.)

66. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Making Sense Explain how a cloud was formed in this experiment. What do you think pressure and temperature have to do with cloud formation? (cont.)

67. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Humidity refers to the amount of water vapor in the air. Absolute humidity is simply the number of moles of water vapor per liter of air. Absolute humidity depends on how much water has evaporated. Notes

68. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X When air has the maximum amount of water vapor possible for a given temperature, we say that the air is saturated or that it has reached its saturation point. Notes (cont.) (cont.)

69. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Relative humidity is the amount of water vapor in the air compared to the maximum amount of water vapor possible at the current temperature. Relative humidity describes how close the air is to the saturation point. It is expressed in percent. (cont.)

70. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Check-In What information would you want to know to be able predict if clouds will form?

71. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Wrap-Up Water vapor condenses and forms clouds of water droplets when the temperature drops. Temperature decreases occur in gases when there is a decrease in pressure. Absolute humidity is a measure of the number of moles of water vapor per liter of air. (cont.)

72. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Relative humidity is a measure of the amount of water vapor in the air compared to the maximum possible for a certain temperature. It is expressed in percent. (cont.)

73. Weather Unit – Investigation IV Lesson 6: Rain in the Forecast

74. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X ChemCatalyst Does it always rain when the humidity is high? Why or why not?

75. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X The Big Question How do you know if it will rain?

76. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X You will be able to: Determine the conditions for rain by considering humidity and temperature.

77. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Activity Purpose: This lesson allows you to explore what conditions are necessary for water vapor to condense and form rain. Materials: Rubbing alcohol (about 50 mL total) Water (cont.)

78. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Part I: Maximum absolute humidity The line on the graph below shows the maximum absolute humidity vs. temperature. Use the graph to answer the questions below. (cont.)

79. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X (cont.)

80. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Altitude2000 ft4000 ft6000 ft8000 ft10000 ft Temperature11°C7.2°C3.3°C–1.1°C–5.0°C (cont.)

81. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Part II: How hot you feel How hot you feel depends on both the humidity and the temperature. The following questions will help you understand why. (cont.)

82. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Making Sense What do you need to know to decide if it will rain? Under what weather conditions does sweating work well to cool you off? (cont.)

83. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X It is not possible to have values of the absolute humidity above the curve. Rain or dew No rain or dew (cont.)

84. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Check-In Explain how you can tell if it will rain, if you are given the absolute humidity and the temperature.

85. © 2004 Key Curriculum Press. Unit 3 Investigation IV-X Wrap-Up Condensation of water (rain or dew or cloud formation) occurs when the relative humidity is 100%. The maximum amount of water vapor that can be in a liter of air increases as the temperature increases.