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31 Cards in this Set
- Front
- Back
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Bond order of Ozone
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one and a half
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Why does the North Pole not have as drastic ozone depletion as in the South Pole?
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The temperatures do not go down to the same extremes + the air with the ozone from lower altitudes is able to diffuse better, which reduces the overall effect on the ozone layer.
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CFCs in ozone depletion
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They catlyze the reaction and therfore are left in equal quantity at the end and reduce the ozone and therfore are fine to deplete more, after as well
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CFCs (chlorofluorocarbons)
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stable compounds with a variety of uses (e.g. refrigerators and propellants)
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Oxygen gas is diatomic, while ozone is
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triatomic
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NO (nitrogen monoxide)
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formed by high temperature reaction between N2 and O2 in supersonic aircraft engines
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Initiation step for catalysis of ozone depletion by CFCs
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The C-Cl bond is broken by uv light. Produces chlorine free radicals CCl2F2 + uv light ---> •CCl2F2 + •Cl
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allotropes
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exists in two or more forms
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Resonance structure
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can be expressed by more than one Lewis structure
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Bond order for ozone
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1.5
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Bond order for oxygen molecule
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2
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NO is formed by
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high temoerature reaction between nitrogen and oxygen gases in supersonic aircraft engines
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Effect of temperature on Ozone Depletion in Polar caps.
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The colder the temperature, the colder air is trapped, which immediately converts more water vapor into ice crystals.
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NO2 + O =
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NO + O2
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CFCs are used in
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refrigiration and propellants in aerosol sprays
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ozone absorbs
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harmful UV rays in the 240-330nm.
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hv meaning
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In presence of light
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Ozone depletion due to CFCs
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CCl2F2+hv->CCLF2+•Cl •Cl+O3->ClO•+O2 ClO•+O•->O2+Cl•
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CCl2F2 + uV light =>
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•CClF2 + •Cl
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•Cl+O3 =>
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ClO• + O2
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Breaking CFCs to produce chlorine free radicals
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CCl2F2 + hv -->⦁CClF2 + ⦁Cl
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Importance of ice crystals
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They behave as surface catalysts and provide the surface area over which pollutants can combine to produce reactive chemicals such as chlorine molecules.
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Energy required for breking O3 vs. O2
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It requires more energy for O2 than O3.
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Ozone deletion in polar regions
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water vapor --> ice crystals; surface catalysts --> create Cl2 --> photodissociates in presence of uv --> becomes •Cl --> catalyzes the destruction of ozone
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Replacement of destroyed ozone
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in spring, ice crystals melt and are therefore no longer available as surface catalysts for the production of Cl2 AND there is a flow of air containing ozone from lower altitude warmer regions
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How is NO formed?
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High temperature reaction between N2 and O2
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Photo-dissociation of NO2 in the presence of uv light
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NO2(g) + hv -> NO(g) +O⦁(g)
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Chlorine free radicals reacting with the ozone to form oxygen molecules
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⦁Cl +O3 -> ClO⦁ +O2
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ClO+O•=
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O2 + Cl•
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wavelength of light is
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inversely proportional to its energy
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Diatomic oxygen and ozone are
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allotropes
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