Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
34 Cards in this Set
- Front
- Back
Bond order of ozone
|
One and a half
|
|
Why does the North Pole not have as drastic ozone depletion as in the South Pole?
|
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.
|
|
CFCs in ozone depletion
|
They catalyze the reaction and therfore are left in equal quantity at the end and reduce the ozone and therefore are fine to deplete more.
|
|
CFCs (chlorofluorocarbons)
|
stable compounds with a variety of uses (e.g. refrigerators and propellants)
|
|
Oxygen gas is diatomic, while ozone is
|
triatomic
|
|
NO (nitrogen monoxide)
|
formed by high temperature reaction between N2 and O2 in supersonic aircraft engines
|
|
Initiation step for catalysis of ozone depletion by CFCs
|
The C-Cl bond is broken by uv light. Produces chlorine free radicals CCl2F2 + uv light ---> •CCl2F2 + •Cl
|
|
allotropes
|
exist in two or more forms
|
|
Resonance structure
|
can be expressed by more than one Lewis structure
|
|
Bond order for ozone
|
1.5
|
|
Bond order for oxygen molecule
|
2
|
|
NO is formed by
|
high temoerature reaction between nitrogen and oxygen gases in supersonic aircraft engines
|
|
Effect of temperature on ozone depletion in polar caps.
|
The colder the temperature, the colder air is trapped, which immediately converts more water vapor into ice crystals.
|
|
NO2 + O -->
|
NO + O2
|
|
CFCs are used in
|
refrigiration and propellants in aerosol sprays
|
|
ozone absorbs
|
harmful UV rays in the 240-330nm.
|
|
hv meaning
|
In presence of light
|
|
Ozone depletion due to CFCs
|
CCl2F2 + hv --> CCLF2+•Cl
•Cl+O3 --> ClO•+O2 ClO•+O• --> O2+Cl• |
|
CCl2F2 + UV light =>
|
•CClF2 + •Cl
|
|
•Cl+O3 =>
|
ClO• + O2
|
|
Breaking CFCs to produce chlorine free radicals
|
CCl2F2 + hv -->⦁CClF2 + ⦁Cl
|
|
Importance of ice crystals
|
They behave as surface catalysts and provide the surface area over which pollutants can combine to produce reactive chemicals such as chlorine molecules.
|
|
Energy required for breking O3 vs. O2
|
It requires more energy for O2 than O3.
|
|
Ozone deletion in polar regions
|
water vapor --> ice crystals; surface catalysts --> create Cl2 --> photodissociates in presence of uv --> becomes •Cl --> catalyzes the destruction of ozone
|
|
Replacement of destroyed ozone
|
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
|
|
How is NO formed?
|
High temperature reaction between N2 and O2
|
|
Photo-dissociation of NO2 in the presence of uv light
|
NO2(g) + hv --> NO(g) +O⦁(g)
|
|
Chlorine free radicals reacting with the ozone to form oxygen molecules
|
⦁Cl +O3 -> ClO⦁ +O2
|
|
ClO+O• -->
|
O2 + Cl•
|
|
Wavelengths that the ozone absorbs
|
Harmful uv rays between 240 and 380 nm
|
|
Wavelength of light is
|
inversely proportional to its energy
|
|
Diatomic oxygen and ozone are
|
allotropes
|
|
Wavelength needed for ozone
|
330nm or less
|
|
Wavelength needed for oxygen
|
242 nm or less
|