Ch13 The Earth's atmosphere Flashcards
Percentage of gases in today’s atmosphere
nitrogen 78% oxygen 21% argon 0.9% carbon dioxide 0.04% traces of methane and noble gases
How Earth’s early atmosphere was formed
intense volcanic activity released CO2, water vapour and nitrogen
water vapour in atmosphere condensed as the Earth cooled and fell as rain
Water collected in hollows in the crust as rock solidified(the ocean)
Earth’s early atmosphere
mainly carbon dioxide
water vapour
nitrogen
traces of methane(CH4) and ammonia(NH3)
Creation of oxygen in the atmosphere
Algae and bacteria evolved
they used energy from the sun for photosynthesis, producing oxygen and removing carbon dioxide
as levels of oxygen rose, plants colonised the surface, increasing it even more
this allowed animals to evolve
How was methane and ammonia from early atmosphere reduced
oxygen made from evolved plants reacted with gases and removed them
CH4 + 2O2 –> CO2 + 2H2O
4NH3 + 3O2 –> 2N2 + 6H2O
nitrogen builds up
How was the levels of carbon dioxide from the early atmosphere removed
plant photosynthesis
formation of sedimentary rock
formation of fossil fuels
Formation of limestone
carbon dioxide is photosynthesis by plants and stored as carbon in the glucose in plant material
animals eat the plant, and transfers the carbon into their skeletons and shells
The remains build up underground and pressure forms limestone
Formation of coal
carbon dioxide is photosynthesis by ancient trees and ferns and stored as carbon in the glucose in plant material
the plants die in swamps
the remains build up underground
pressure and lack of oxygen compresses the remains to form coal
Formation of natural gases
carbon dioxide is photosynthesis by plants and stored as carbon in the glucose in plant material
animals eat the plant, and transfers the carbon into their tissues
The remains build up underground
are crushed by large-scale movements and heated within the crust over long periods of time
Formation of crude oil
Remains of ancient plankton are deposited in mud on seabed
Remains are covered by sediments that become layers of rock when compressed
Crude oil and natural gas is trapped under rock layers
Incomplete combustion of fuel
creates atmospheric pollutants carbon monoxide carbon soot nitrogen oxides sulfur dioxide water vapour
carbon monoxide
reduces oxygen in the blood by taking up space in the haemoglobin
toxic gas
colourless
odourless
carbon soot particulates
causes global dimming
cause cancer
damages lungs
nitrogen oxides
respiratory problems
sulfur from fossil fuels
sulfur dioxide formed in atmosphere - reacts with water vapour to create acid rain -damages environment respiratory problems can be removed from fuel
