C9 Chemisty of the Atmosphere Flashcards
(37 cards)
How was the early atmoshphere formed?
volcanoes erupted and released lots of gasses
what was the early atmosphere made up of?
carbon dioxide, nitrogen, water vapor, methane, ammonia
when did the earth form?
approximately 4.6 billion years ago
condensed water vapor formed …….?
oceans
how was carbon dioxide removed from the early atmosphere?
it disolved in the oceans
what happened to disolved carbon dioxide?
it went through a series of reactions to form carbonate precipitates, that formed sediments on the sea bed
what did marine animals shells and skeletons contain?
carbonates from the oceans
why did green plants and algae absorb carbon dioxide?
so they could carry out photosynthesis
what happens when plants, plankton and marine animals die?
they fall to the seabed and get buried by layers of sediment
what happens after millions of years to layers of sediment?
they become compressed and form sedimentary rocks oil and gas, the carbon within them trapping
Fossil fuels is when:
coal, crude oil and natural gas are made through a process which involves trapping carbon within compressed sedimentary rocks
what are crude oil and and natural gas formed from
deposits of plankton
what is coal made from?
thick plant deposits
what is limestone made of?
calcium carbonate deposits from the shellls and skeletons made of marine organisms
what is photosynthesis?
when plants use light to convert carbon dioxide and water into sugars.
as well as absorbing carbon dioxide in the atmosphere, green plants and algae produce ……….. by ………….
oxygen by photosynthesis
what happened when oxygen levels built up in the atmosphere over time?
more complex life (like animals) could evolve
what is the composition of our moden atnosphere?
78% nitrogen, 21% oxygen, 1% other gasses
what are some greehouse gasses?
carbondioxide
methane
water vapour
how do greenhouse gasses work?
1) greenhouse gasses like carbon dioxide, methane and watervapour act like an insulating layer in the earths atmosphere - this allows the earth to be warm enough to support life
2) greenhouse gasses dont absorb the incomming short wavelength radiation from the sun - but they do absorb the long wavelength radiation that gets reflected back off the earth.
3) then they re-radiate in all directions - including back towards the earth
4) the long wavelength radiuation is themal radiation, so it warms the surface of the earth.
what are some human activities that affect the amount of greenhouse gasses in the atmosphere?
deforestation - few trees means less photosynthesis removing CO2 from the atmosphere
buring fossil fuels - carbon that was locked up in these fuels is released as CO2
agricullture - more farm animals produce more methane through their digestive processes
creating waste - more landfil sites and wates from agriculture means more CO2 and methane released by decomposition of waste
why is it difficult to fully understand the earths climate?
its complex, there are so mant variables, and its very hard to make a model that isnt oversimplified
what are some consequences of climate change?
an increase in temp:
ice caps melting
flooding
costal erosion
changes in rainfall patterns:
too much/ too little water
affect ability to produce food
frequcency and serverity of storms
what is a carbon foot print?
a measure of the amount of carbon dioxide and other greenhouse gasses relased over the full life cycle of something