Chemistry of the Atmosphere Flashcards
what chemicals is the earths atmosphere made of
nitrogen
oxygen
co2
water vapour
noble gases
how much of the atmosphere is made of nitrogen
80%
how much of the atmosphere is made of oxygen
20%
how much of the atmosphere is made of oxygen
20%
how long have the proportions of gases been like how they are now
for 200 million years
why is evidence of the earths early atmosphere limited
the timescale of 4.6 billion years
the earths early atmosphere theory
intense volcanic activity released gases that formed the early atmosphere
the atmosphere was like mars or venus today with mainly co2 and little or no o2
volcanes produced n2 which gradually built up in the atmosphere and there may have been small proportions of methane and ammonia
water vapour condensed to form the oceans
co2 dissolved in the water and carbonates were precipitated producing sediments, reducing the amount of co2 in the atmosphere
where is the oxygen currently in the atmosphere from
algae and plants produced o2 by photosynthesis
when did algae first produce oxygen
2.7 billion years ago
why did oxygen levels increase after algae produced oxygen
plants evolved
what was the result of an oxygen increase
enabled animals to evolve
how did carbon dioxide in the atmosphere decrease
algae and plants decreased the co2 in the atmosphere by photosynthesis
what other than photosynthesis decrease carbon dioxide
the formation of sedimentary rocks that contain carbon eg limestone and coal
the production of fossil fuels from the remains of dead plants and animals when they decayed
when was methane removed from the early atmosphere
once oxygen was made
when was ammonia removed from the early atmosphere
once oxygen was made
where do scientists think life first evolved from
near underwater volcanoes
what layer did oxygen form in the upper atmosphere
ozone layer