2.4.1 Chemistry of the Air

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which bonds absorb infrared radiation? where are these bonds found?
C=O/ O-H/ C-H - found in CO2/ H2O/ CH4
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What does the Greenhouse effect of a gas depend on?
atmospheric concentration / ability to absorb IR / residence time
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What is global Warming?
warming of the planet due to increased conc. of greenhouse gases in the troposphere, which enhances the the greenhouse effect
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What is causing global warming?
methane levels increasing as more cows / paddy fields / burning fossil fuels / chopping down trees
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what are the consequences of global warming?
increased sea levels / land lost / flooding / stormier less predictable weather / less rainfall - crop failures - famine / diseases
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what roles are chemists playing in minimising climate change?
provide scientific evidence to governments to verify / monitor atmosphere changes / analyse sea samples // investigate solutions to environmental problems (CCS) // monitor progress against initiatives such as Kyoto
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what is CCS?
carbon capture and storage // removal of CO2 as a liquid and inject into sea beds of deep oceans // react CO2 with metal oxides to form stable solid carbonates
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what is the ozone layer?
naturally occurring region of the atmosphere which has a high conc. of ozone and protects earth from UV radiation
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what is lower atmosphere ozone?
smog - pollutants
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What state is O3 in?
continuously being formed and broken down in the stratosphere by UV radiation - is in eqm
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how is O3 formed?
when UV from the sun's radiation is absorbed by O2 it splits into 2.O // free radicals combine to form O3
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how is O3 destroyed?
UV / O3 + UV --> O2 + O.
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How does ozone protect us?
frequency of UV absorbed is the same as damaging UV / filters out all UVC and 90% UVB / allows life eon earth / skin cancer / premature raging / needed for vitamin D
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What is causing the destruction of the ozone?
CFCs - chlorine free radicals formed when C-Cl bond broken by UV / NOx from air craft engines/ thunder EQUATIONS
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How is the destruction of the ozone being managed?
Legislation to ban CFCs / HCFCs developed / CFCs still entering atmosphere from disused items / still used / long lifetime in atmosphere
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What pollutants do internal combustion engines produce?
nOx - formed when N2 in the air reacts with high temps and sparks // CO // CO2 // unburnt hydrocarbons // soot
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what are the environmental consequences of the pollutants produced by internal combustion engines?
NOx - toxic/depletes O3 // CO - toxic // CO2 - global warming // unburnt H.Carbons - photochemical smog // soot - global dimming and respiratory problems
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what do catalytic converters do?
remove CO, NOx and unburnt H. Carbons from exhaust gases turning them into harmless CO2, N2 and H2O
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how do catalytic converters work?
CO/NO absorbed onto surface of catalyst / weakens bonds in CO and NO lowering Ea / reaction occurs / CO2 and N2 desorbs from surface / catalyst platinum used
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Card 2

Front

What does the Greenhouse effect of a gas depend on?

Back

atmospheric concentration / ability to absorb IR / residence time

Card 3

Front

What is global Warming?

Back

Preview of the front of card 3

Card 4

Front

What is causing global warming?

Back

Preview of the front of card 4

Card 5

Front

what are the consequences of global warming?

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