C9: Chemistry Of The Atmosphere Flashcards
What is the composition of the atmosphere?
78% nitrogen
21% oxygen
0.9% argon
0.04% carbon dioxide
Why are we not certain about the earths early atmosphere?
Not enough evidence from 4.6 bil years ago
How did oxygen levels increase on earth?
1) photosynthesis from algae and plants
How did carbon dioxide levels decrease?
1) it dissolves into oceans and precipitates to form sediment
2) photosynthesis
3)phytoplankton incorporated carbon into their skeleton and it travels down the food chain as it gets eaten
How did volcanoes affect the early atmosphere?
Volcanoes spewed out carbon dioxide and other gases like water vapour(which formed oceans), nitrogen and hydrogen
What is the greenhouse effect?
Short wavelength radiation (UV) is emitted from the sun.
2) when it strikes the surface, some is absorbed and some is re emitted as infrared
3) most of the radiation is trapped in the earth atmosphere by greenhouse gases
Source of methane?
Decomposing plant material, rice fields, cattle, coal mines
Source of water vapour?
Ocean evaporation, hydrocarbons being burned
Sources of carbon dioxide?
Respiration, Forest fires, volcanoes, cement, burning fossil fuels
Effects of global warming and climate change?
Rising sea levels, frequent droughts, storms, heat wave, rainfall
What is carbon footprint?
Total amount of carbon dioxide and other greenhouse gases emitted over the full life cycle of a product
Complete combustion equation (methane)
CH4 + O2 - CO2 + H2O
Incomplete combustion (methane)
CH4 + O2 - C + H2O
How are oxides of nitrogen produces in a car engine?
High temperatures in combustion engines can make the nitrogen react with oxygen
How is sulfur dioxide produced in a car engine?
Fossil fuels are often contaminated with small sulfur impurities, when these fuels are combusted, the sulfur oxidises
How is carbon monoxide produced?
Fossil fuels
Why is carbon monoxide a problem?
Poisonous and odorless
And colourless. Deprived body of oxygen as it combines with haemoglobin
How are carbon particulates produced?
Incomplete combustion
Why are particulates a problem?
They form soot, which can cause respiratory problems and cover statues. It can also cause global dimming, as they reflect sun back out
How is sulfur dioxide produced?
Fossil fuels
What are the effects and properties of sulfur dioxide
Colourless, pungent ,responsible for acid rain. It dissolves in rainwater and causses as acidic solution in rain that causes corrosion and damage to aquatic organisms and polluted crops and water supplies
How are oxides of nitrogen produced?
Combustion of fuel
What are the effects of oxides of nitrogen?
Can contribute to acid rain and cause photochemical smog
