C11 The Earth's Atmosphere Flashcards
How did the earth’s atmosphere develop?
The atmosphere was mostly hydrogen and helium
Volcanoes produced co2, nitrogen and water vapour
Atmosphere similar to that of Venus today
Little or no oxygen
How did the oceans develop
It may have rained for 40,000 years to create the oceans
When did life evolve and how
3.4 billion years ago
Many theories as to how
2.7 billion years ago as simple plants and bacteria evolved oxygen was formed
What is another theory about water arriving ?
Water could have come from space from comets containing lots of ice
As plants increased what happened
More oxygen in the atmosphere
Animal life began to evolve that could not make their own food and relied on plants for food and oxygen to respire
What are the main gases in the atmosphere
Nitrogen Oxygen Carbon dioxide Argon Water and other trace gases
What is the role of nitrogen
78%
Always been in the air
Removed by nitrifying bacteria
No common test
What is the role of oxygen
21%
Added by plants as product of photosynthesis
Removed by animals as product of respiration
Test - re lights a glowing splint
What is the role of carbon dioxide
0.04%
Added as a product of animals respiring and industry
Removed by plants in photosynthesis and ocean uptake
Test by limewater - turns cloudy
What is the role of argon
1%
Always in the air - product of radioactive decay
What is the role of water and other trace gases
Varying small amounts
Added - water by evaporation
Removed by precipitation (rain)
Test - anhydrous copper sulphate turns from white to blue
How does the carbon cycle work
Sunlight and co2 used in photosynthesis Dead organisms and waste products decay Produce fossils and fossil fuels Root and plant respiration take carbon from soil Animal respiration releases co2 Auto and factory emissions release co2
What about ammonia and methane?
Found in earth’s early atmosphere
Not in current atmosphere because
Ammonia- NH3(g)+ H2O(l) -> NH4OH (aq) ammonium hydroxide
Methane- CH4(g)-> CH4(aq) solution
What are the main pollutants
Carbon dioxide Sulphur dioxide Nitrogen oxide Carbon monoxide Carbon particles
Carbon dioxide- how it forms- problems it causes- solution
Formed by complete combustion of fossil fuels
Problem to the environment of global warming but no health problems as we breathe it out
Solutions- use vehicles less, more public transport, use biofuels
