Earth's atmosphere Flashcards
What is the composition of gasses in Earth’s current atmosphere?
78% N
21% O2
0.9% Ar
0.04% CO2
0.06% Other
What was the composition of gasses in Earth’s early atmosphere?
95% CO2
4% water vapour
Trace % N, CH4, NH3
How has the level of water vapour decreased in Earth’s atmosphere?
Earth cooled down so water vapour condensed + formed oceans
How has the level of CO2 decreased in Earth’s atmosphere?
It was dissolved in oceans, trapped in sedimentary rock, absorbed during photosynthesis
How was the level of O2 increased in Earth’s atmosphere?
It was produced during photosynthesis
What is the word equation for photosynthesis?
Carbon dioxide + water -> glucose + oxygen
What is the symbol equation for photosynthesis?
6CO2 + 6H2O -> C6H12O6 + 6O2
What are the three greenhouse gasses?
Water vapour, CO2, CH4
Why are greenhouse gasses important?
They maintain temperatures high enough to support life
What is the greenhouse effect?
Sun emits shortwave radiation which passes through atmosphere to Earth, Earth absorbs shortwave radiation, Earth re-emits longwave radiation, greenhouse gases absorb longwave radiation, greenhouse gasses re-radiate longwave radiation in all directions, Earth heats up
What human activities increase % of CO2 in Earth’s atmosphere + why?
Burning fossil fuels to produce electricity + fuel releases CO2
Deforestation reduces amount of CO2 that gets absorbed by trees
What human activities increase % of CH4 in Earth’s atmosphere + why?
Decomposing waste in landfill produces methane
Cattle farming as cows release methane
Rice farming as bacteria in rice fields release methane
What is the relationship between greenhouse gases + global temperatures?
Global temperatures increase as greenhouse gasses in atmosphere increase
What is complete combustion?
Combustion with enough O2
What is incomplete combustion?
Combustion without enough O2
What is the word equation for complete combustion?
Fuel + oxygen -> carbondioxide + water
What is the symbol equation for complete combustion?
Fuel + 3O2 -> 2CO2 + 3H2O
What is the word equation for incomplete combustion?
Fuel + oxygen -> carbonmonoxide + carbon + water vapour
What is the symbol equation for incomplete combustion?
Fuel + 3O2 -> 2CO + C +4H2O
What is carbon footprint?
Total amount of greenhouse gases emitted over the full life cycle of a product, service or event
What are some potential affects of climate change?
Rising sea levels as ice caps melt, more frequent extreme weather events, changes in distribution of species, loss of species/habitat, crop instability as rainfall patterns change
How can we reduce C emissions?
Increase renewable energy sources, make electrical devices more energy efficient, use C neutral fuels, use C capture + storage technology
How is SO2 formed?
S reacts with O2 during combustion
How is CO + soot formed?
Incomplete combustion
How is NOx formed?
N reacts with O2 from the air at high temperatures
What problems does SO2 cause?
Acid rain
What problems does NOx cause?
Acid rain, smog
What problems does C cause?
Lung irritation, global dimming
What problems does CO cause?
Health problems as it binds to hemoglobin
