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Chapter 1: Introduction to Chemistry

This chapter provides an introduction to chemistry by exploring the stories of two chemicals - ozone and CFC. Learn about the importance of the ozone layer, its formation, and the alarming thinning known as the ozone "hole" over Antarctica. Discover the origins and presence of chlorofluorocarbons (CFC) in the atmosphere.

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Chapter 1: Introduction to Chemistry

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  1. Chapter 1:Introduction to Chemistry • Section 1.1 • The Stories of Two Chemicals

  2. The Ozone Layer • The ozone layer allows living things to exist on Earth • It absorbs harmful UV light

  3. Earth’s Atmosphere

  4. Ozone Formation • Ozone = O3 • Located in the stratosphere • Formed when oxygen gas is exposed to ultraviolet radiation • Oxygen gas  Oxygen particles • Oxygen particles + Oxygen gas  Ozone

  5. Ozone Formation • Formed in upper stratosphere • Stored in the lower stratosphere

  6. G.M.B. Dobson • Began measuring ozone in the 1920s • Normal = 300 DU • 1981: ozone recorded at 160 DU over Antarctica

  7. What is the DU? • The most basic measure used in ozone research. • 'Dobson Spectrometer' - measures the intensity of solar UV radiation at four wavelengths, two of which are absorbed by ozone and two of which are not. • 1 Dobson Unit (DU) is defined to be 0.01 mm thickness at STP

  8. The DU

  9. The Ozone is thinning!!

  10. The Ozone “Hole” Over Antarctica

  11. The Ozone Hole Over Time

  12. Chlorofluorocarbons • Thomas Midgley synthesized them in 1928 • CFC = Cl + F+ C • Not naturally occurring • Nontoxic, stable • Ideal coolant for refrigerators • Great propellant for spray cans

  13. CFC in the Atmosphere • CFC was discovered in the atmosphere in the 1970s • Its presences increases every year

  14. The Tale of Two Chemicals Ozone CFC

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