Greenhouse gases.The Kyoto Protocol, an international treaty on global warming, is scheduled to go into effect this month. The 132 countries that signed it have pledged to take measures to make preparations; to provide means. See also: measure to reduce their production of six "greenhouse gases." Many scientists believe that these gases contribute to air pollution, which intensifies the greenhouse effect warming the planet. How hard would it be to reduce greenhouse-gas emissions? Read about those six gases, then answer the questions that follow. * Carbon dioxide carbon dioxide, chemical compound, CO2, a colorless, odorless, tasteless gas that is about one and one-half times as dense as air under ordinary conditions of temperature and pressure. (C[O.sub.2]): common uses--refrigerants (storing and transporting ice cream); fire extinguishers; carbonated soft drinks; dry ice; inflating life jackets; foamy foam·y adj. foam·i·er, foam·i·est 1. Of, consisting of, or resembling foam. 2. Covered with foam. foam plastics; in nature--given off when animals (including humans) exhale exhale /ex·hale/ (eks´hal) to breathe out. ex·hale v. 1. To breathe out. 2. To emit a gas, vapor, or odor. * Hydrofluorocarbons hydrofluorocarbons: see under chlorofluorocarbons. (HFCs): common uses--mainly in the manufacture of refrigerators; also as propellants in aerosol cans (such as whipped cream) and air conditioners * Methane (C[H.sub.4]): common uses--production and transport of natural gas, coal, and oil; reinforcing the rubber used in automobile tires; in nature--given off by decomposing vegetable matter (also known as marsh gas marsh gas: see methane. ) * Nitrous oxide nitrous oxide or nitrogen (I) oxide, chemical compound, N2O, a colorless gas with a sweetish taste and odor. Its density is 1.977 grams per liter at STP. It is soluble in water, alcohol, ether, and other solvents. ([N.sub.2]O): common uses--short-term anesthesia (as in dental work), also known as laughing gas; used in aerosol cans * Perfluorocarbons (PFCs): common uses--in aluminum production; manufacture of computer chips and other semiconductors; fire extinguishers; refrigerants Chemical refrigerants are assigned an R number(sometimes the label replaces it with the word Freon) which is determined systematically according to molecular structure. The following is a list of refrigerants with their R numbers, IUPAC chemical name, molecular formula, and CAS number. * Sulfur hexafluoride (S[F.sub.6]): common uses--in electrical-equipment insulation, aluminum production, manufacture of computer chips and other semiconductors; ranked the most-destructive of greenhouse gases QUESTIONS 1. Which greenhouse gas(es) might be keeping your food fresh?-- 2. When you crank up the AC in the car on a hot summer day, which greenhouse gas(es) are you using?-- 3. Some of the compressed chemicals in a home fire extinguisher are which greenhouse gases?-- 4. U.S. manufacturers used PFCs until they found out that they were harmful. They switched to HFCs, considered less harmful. How have HFCs been used?-- 5. Sometimes called marsh grass, one greenhouse gas is also a byproduct of the digestive system of cows. Which gas is it?-- 6. Which gas(es) might be used during a trip to the dentist "A Trip to the Dentist" is episode 21 of season 1 of the television show Veronica Mars. Plot Veronica finally investigates what happened to her the night of Shelly Pomroy's party where she was drugged and date-raped and what she finds out is shocking. ?-- 7. The compressed air used in paintball markers and other air guns is the same gas used to inflate life jackets and lifeboats. Which is it?-- 8. Which greenhouse gas is considered the most destructive?-- 9. Which greenhouse gas do you personally use the most?-- 10. Which greenhouse gas do you think would be easiest to restrict? which would be the hardest?-- 1. carbon dioxide (C[O.sub.2]), hydrofluorocarbons (HFCs), perfluorocarbens (PFCs) 2. hydrofluorecarbons (HFCs) 3. carbon dioxide (C[O.sub.2]), perfluoreearbons (PFCs) 4. making refrigerators; in aerosol cans and air conditioners 5. methane (C[H.sub.4]) 6. nitrous oxide ([N.sub.2]O) 7. carbon dioxide (C[O.sub.2]) 8. sulfur hexafluoride (S[F.sub.6]) 9. Answers will vary. 10. Answers will vary. |
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