Chapter 17 Section H: Questions
1. What are the layers of the atmosphere? Describe each one - its altitude, thickness, temperature.

2. What makes Earth's atmosphere ideal for life?

3. How are aurora formed?

4. Why might scientists conducting research near the poles have trouble communicating back to their labs?

5. What are CFCs? Where are they found?

6. Give an example of government attempts to curb ozone depletion.

7. What gases are released by volcanoes?

8. What gas is the primary cause of acid rain?

9. How can we curb acid rain?

10. What gas gives photochemical smog its distinctive brown color?

1. Troposphere: 0 - 10 km, 1 - -30 *C
Stratosphere: 10 - 50 km, -30 - 20 *C
Mesosphere: 50 - 80 km, 20 - -60 *C
Thermosphere: 80 - 500 km, -60 - 1000+ *C

2. The atmosphere protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through heat retention (greenhouse effect), and reducing temperature extremes between day and night. Oxygen allows for life to exist.

3. Solar flares (violent eruptions on the surface of the sun) eject electrons and protons into space. These particles collide with molecules in Earth's upper atmosphere. The collisions cause them to become ionized and electronically excited. The excited ions return to the ground state. This process emits light, creating auroras.

4. Auroras disrupt radio transmission.

5. Chlorofluorocarbons are a type of haloalkane used in many industries. CFCs damage and deplete the ozone. Known by the trade name Freon, CFCs are found in coolants for refrigerators and air conditioners and are used in the manufacture of disposable foam products such as cups and plates as well as aerosol in spray cans.

6. In 1985 20 nations, including most of the major CFC producers, signed the Vienna Convention for the Protection of the Ozone Layer which established a framework for negotiating international regulations on ozone-depleting substances. In 1987, representatives from 43 nations signed the Montreal Protocol. At Montreal, the participants agreed to freeze production of CFCs at 1986 levels and to reduce production by 50% by 1999. The Montreal Protocol was strengthened at a 1990 meeting in London.

7. N2, CO2, HCl, HF, H2S, water vapor

8. SO2

9. Two ways to reduce acid rain would be to clean up smokestacks and exhaust pipes and to use alternative energy sources such as wind or solar.

10. NO2

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