Earth's 4 systems revision Flashcards
What is the atmosphere and its composition?
The atmosphere is the gaseous envelop of air that is held close to the Earth’s surface by gravity.
Earth’s atmosphere is composed of about 78 percent nitrogen, 21 percent oxygen, 0.9 percent argon, and 0.1 percent other gases.
What is the structure of the atmosphere?
Troposphere
Stratosphere
Mesosphere
Thermosphere
Exosphere
What are the processes in the troposphere?
~Almost allweatherdevelops in the troposphere because it contains almost all of the atmosphere’s water vapor.
~Clouds, from low-lyingfogto thunderheads to high-altitudecirrus, form in the troposphere.
~Air masses, areas of high-pressure and low-pressure systems, are moved by winds in the troposphere.
~This layer also absorbs heat that is reflected back from the ground in a process called thegreenhouse effect
What are the processes of the stratosphere?
~Strong horizontal winds blow in the stratosphere, but there is little turbulence.
~The stratosphere is very dry and clouds are rare.
~The Stratosphere contains small amounts ofozone, a form of oxygen that prevents harmful UV rays from reaching Earth.
What is the ozone layer and its chemical equation?
~Ozone is a molecule of three atoms of oxygen [O3].
~Ozone forms when ultraviolet light strikes oxygen [O2] molecules, forming individual oxygen atoms.
O3
What is the function of the ozone layer?
~Ozone is good at trapping a type of radiation called ultraviolet radiation, or UV light
~The ozone layer, our Earth’s sunscreen, absorbs about 98% of this devastating UV light.
What is ozone depletion and its chemical process?
~Ozone layer depletion is caused by chemicals such as chlorofluorocarbons (CFCs).
~A CFC molecule contains theelements carbon, chlorine, and fluorine.
~Ozone molecules are continuously being destroyed and reformed naturally.
~But CFCs in the air make it very difficult for ozone to reform once it’s broken apart.
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~Cl combines with ozone [O3] to make ClO and O2.
~UV radiation then causes ClO to react with O to make Cl and O2.
~This Cl can then react with Ozone, and the process repeats.