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41 Cards in this Set
- Front
- Back
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Where is ozone formed naturally?
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In the stratosphere
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Alternatives to CFC's?
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C3H6, HCLFC3+CF4+C2F6+CF3CH2F
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What is Ozone gas like?
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A pale, bluish gas with an pungent-smelling odor.
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Is Ozone chemically reactive?
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Yes, chemically very reactive (it's a powerful oxidizing agent.)
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What are the sources of Chlorofluorocarbons?
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Spray cans, old refrigerators, air conditioners, in fire extinguishers and they are used as solvents
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Where has the decline of the ozone concentration been in the last 30 years?
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In latitudes 60 degrees south to 60 degrees north
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What features must alternatives to CFC's have?
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Must have a lack of reactivity, low toxicity, low flammability, no C-Cl bonds and preferably show little absorption of infrared radiation
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what colour does ozone gas have?
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bluish
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how far away is the ozone layer from the earths surface?
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15-45 km
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Describe how Nitric acid depletes the ozone layer
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Nitric oxide rises to stratosphere and reacts with ozone reducing its concentration : NO + O3 --> NO2 + O2
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Ozone dissociation
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Less energy required to dissociate O2 molecules - r x n of .O (O3 + .O ->202)
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what are good alternatives for CFCs
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1.hydrocarbons 2.Hydrochlorofluorocarbons 3.Fluorocarbons 4.HFCs hydrofluorocarbons
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What kind of wavelenghts split the double bond between the O2?
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very short UV waves
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What percent of harmful UV light does the ozone layer absorb?
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99%
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What is the formula for Ozone?
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O3
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What is the formation reaction of ozone?
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O2(g) + .O(g) -> O3(g)
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What are the characteristics of ozone gas
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pale blue- pungent odour
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What is the effect of the depletion of ozone on humans?
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1. increase in sunburn 2. increase in melanoma and non melanoma skin cancer 3. increase in eye cataracts and blindness
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What does a decrease in Ozone mean to us?
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More UV Light that reaches earth = more cases of skin cancer, eye cataracts, sunburn damage, suppression of growth and mutations.
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How can bonds in ozone be broken?
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by light of longer wavelength
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as what does the ozone layer act?
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as a shield from harmful UV waves from the sun
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Where has the greatest destruction of the ozone layer taken place?
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South Pole
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How is O2 formed in the stratosphere?
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oxygen free radical reacts with ozone
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What are some alternatives to CFCs?
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Hydrocarbons, hydrochlorofluorocarbons (HClFCs), fluorocarbons, hydrofluorocarbons (HFCs)
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What is the effect of ozone on marne ecosysem?
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marine phytoplanton loss
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what is the ozone in the ozone layer depleted by
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CFCs, chlorofluorocarbons) and nitric oxide
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What do chlorofluorocarbons act like when released into the atmosphere?
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They do not decompose; they float slowly through the atmosphere into the stratosphere.
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What are the effects of ozone depletion?
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UV Light comes through and may cause skin cancer, gentic mutations, cataract etc.
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What is the effect of ozone on weather?
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Stratospheric convection curets altered
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What is a disadvantage of using HFCs as an alternative to CFCs?
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They contribute to global warming.
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By what is ozone depleted?
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CFC's, CO, CO2, NOx
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What are the three alternatives to CFCs?
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chlorodifluoromethane, 1,1,1,2-tetrafluoromethane, and 2-methylpropane
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What are seven consequences of the depletion of ozone?
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1. more harmful uv rays reaching the earth
2. Increased risk of skin cancer 3. Eye cataracts 4. Genetic mutations 5. Sunburn 6. Damage to animals and plants (eg, suppression of plant growth) 7. Climate change |
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What is formed when CCl2F2 reacts with the UV light from the sun?
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CClF2 free radical + Cl free radical
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What is the effect of a decrease in ozone?
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more UV reaches the earth which causes skin cancer & eye catarcts. - supression of plant growth, genetic mutations & changes in climate
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which of the alternative CFC's is the best alternative?
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hydroflurocarbons (HCFs)
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Describe how hydrochlorofluorcarbons are a good alternative for the decrease of ozone depletion??
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They don't decompose as easily BUT are only a temporary solutions to the ozone depletion porblem
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What are some disadvantages of using hydrocarbons as an alternative to CFCs?
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It's flammable and is a greenhouse gas.
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What happens when the bonds in ozone break down?
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reverse process
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What are HClFCs?
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Hydrochlorofluorocarbons
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What arethe effects of ozone on plants?
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1. more suscetible to disease 2. growth inhibited 3. potosynthesis inhibited
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