The document discusses the composition and properties of Earth's atmosphere. It provides details on: - The main permanent gases that make up Earth's atmosphere, such as nitrogen and oxygen. - Instruments used to measure gas pressure and atmospheric pressure, such as mercury barometers and manometers. - Gas laws describing the relationships between gas pressure, volume and temperature, including Boyle's law, Charles' law, and Gay-Lussac's law. - The development of the combined gas law integrating these relationships.

1. Gases & The Atmosphere CHEMISTRY 30S UNIT 2

2. Gases & The Atmosphere CHEMISTRY 30S UNIT 2 Our atmosphere is made of several gases. The composition has changed over time and continues to change.

3. Gases & The Atmosphere CHEMISTRY 30S UNIT 2 Present Composition of Our Atmosphere Earth’s air is composed of two types of gases: permanent and variable. The gases are called permanent because their amounts have not significantly changed in recent history. The permanent gases in the atmosphere by percentage are: Nitrogen 78.1% Oxygen 20.9% These two gases comprise 99% of the Earth’s lower atmosphere.

5. Gases & The Atmosphere CHEMISTRY 30S UNIT 2 Historical Development of the Measurement of Pressure Galileo (1564 – 1642) Otto von Guericke (1643-1645) Christiann Huygens (1661) Joseph Louis Gay-Lussac (1808) Evangelist Torricelli (1643) Blasie Pascal (1648) John Dalton (1801) Amadeo Avogadro (1811)

7. Gases & The Atmosphere CHEMISTRY 30S UNIT 2 Evangelista Torricelli (1643) Evangelista Torricelli developed the first barometer. He carried on Galileo’s work by determining the limit to the height with which Galileo’s pump could draw water was due to atmospheric pressure. He invented a closed- end tube filled with mercury into a pan of mercury at sea level. The height of the column of mercury in the tube (in mmHg) is equal to the atmospheric pressure acting on the mercury in the pan.

8. Gases & The Atmosphere CHEMISTRY 30S UNIT 2 Otto von Guericke (1643-1645) Otto von Guericke made a pump that could create a vacuum so strong that a team of sixteen horses could not pull two metal hemispheres apart. Otto von Guericke reasoned that the hemispheres were held together by the mechanical force of the atmospheric pressure rather than the vacuum.

9. Gases & The Atmosphere CHEMISTRY 30S UNIT 2 Blaise Pascall (1648) Blaise Pascal used Torricelli’s “barometer” and traveled up and down a mountain in southern France. He discovered that the pressure of the atmosphere increased as he moved down the mountain. Sometime later the SI unit of pressure, the ‘Pascal’, was named after him.

10. Gases & The Atmosphere CHEMISTRY 30S UNIT 2 Christian Huygens (1661) Christiaan Huygens developed the manometer to study the elastic forces in gases.

11. Gases & The Atmosphere CHEMISTRY 30S UNIT 2 John Dalton (1801) John Dalton stated that in a mixture of gases the total pressure is equal to the sum of the pressure of each gas, as if it were in a container alone. The pressure exerted by each gas is called its partial pressure.

12. Gases & The Atmosphere CHEMISTRY 30S UNIT 2 Joseph Louis Guy-Lussac (1808) Joseph Louis Gay-Lussac observed the law of combining volumes. He noticed that, for example, two volumes of hydrogen combined with one volume of oxygen to form two volumes of water.

13. Gases & The Atmosphere CHEMISTRY 30S UNIT 2 Amadeo Avagadro (1811) Amadeo Avogadro suggested, from Gay- Lussac’s experiments conducted 3 years earlier, that the pressure in a container is directly proportional to the number of particles in that container (known as Avogadro’s Hypothesis). This can be illustrated by blowing up a balloon, ball or tire: the more air is added the larger the container becomes due to increased pressure.

21. Gases & The Atmosphere CHEMISTRY 30S UNIT 2

25. Gases & The Atmosphere CHEMISTRY 30S UNIT 2 Measuring Gas Volume Worksheet

26. Gases & The Atmosphere CHEMISTRY 30S UNIT 2 Boyle’s Law Online Activity

32. Gases & The Atmosphere CHEMISTRY 30S UNIT 2 Boyles Law & The Cartesian Diver

33. Gases & The Atmosphere CHEMISTRY 30S UNIT 2 Charles’ Law Online Activity

38. Gases & The Atmosphere CHEMISTRY 30S UNIT 2 Absolute Zero

40. Gases & The Atmosphere CHEMISTRY 30S UNIT 2 Gay Lussac's Law

45. Gases & The Atmosphere CHEMISTRY 30S UNIT 2 Combined Gas Law It is not always easy to keep the temperature, pressure or volume constant when doing experiments. Therefore, a combined gas law equations was developed using the three laws: Boyle’s, Charles’, & Gay-Lussac’s.

46. Gases & The Atmosphere CHEMISTRY 30S UNIT 2 Combined Gas Law Task: Using the three laws try and develop 1 equations, which uses pressure, temperature and volume.

47. Gases & The Atmosphere CHEMISTRY 30S UNIT 2 Combined Gas Law Step 1: Write Boyles Law Step 2: Multiply by Charles Law Step 3: Multiply by Gay-Lussac’s Law Step 4: Take the Square root

48. Gases & The Atmosphere CHEMISTRY 30S UNIT 2 Combined Gas Law P 1 V 1 = P 2 V 2 T 1 T 2

49. Gases & The Atmosphere CHEMISTRY 30S UNIT 2 Gas Laws

50. Gases & The Atmosphere CHEMISTRY 30S UNIT 2 PowerPoint Research Project Identify various industrial, environmental, and recreational applications of gases. Examples: SCUBA, anaesthetics, air bags, acetylene welding, propane appliances, hyperbaric chambers…

51. Gases & The Atmosphere CHEMISTRY 30S UNIT 2

52. Gases & The Atmosphere CHEMISTRY 30S UNIT 2 http://preparatorychemistry.com/Bishop_Boyles_frames.htm