C9 Chemisty of the Atmosphere Flashcards
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
what can have a carbon footprint?
service eg buses
event eg olympics
product eg toastie maker
why is it hard to measure the total carbon footprint
there are so many difrent factors to consider eg for a product: manufacturing, use and disposal
what are someways of reducing our carbon footprint?
1) renewable energy sources
2) more efficient processes that concerve and cut waste
3) goverment taxing on the amount of greenhouse gasses emitted
4) goverments putting a cap on emmisions of all greenhouse gasses
5) using technology that captures the CO2 produced by fossil fuels before its releases into the atmosphere
why is it hard to reduce our carbon footprint?
goverments are worried that chamges will impact economic growth.
not everyone is on board so its hard to make international agreements to reduce emmisions
how can people reduce their carbon footprint?
cyle or walk instead of using a car
reducing air travel
doing anything at home that saves energy eg turing heating down
what happens when theres not enough oxygen in combustion?
INCOMPLETE COMBUSTION -some of the fuel doesnt burn and particulates made of soot and unburned hydrocarbons are released and carbon monoxide can be produced as well as carbon dioxide
what problems can particulates in the air cause?
if they are inhaled they can get stck in the lungs and cause damage, this can lead to respiratory problems
particulates reflect sunlight back into space, so less light reaches the earth causing globall dimming
what happens when corbon monoxide stops your blood from carrying oxygen around the body?
it binds to the haemoglobin in your blood that normally carries oxygen, so less oxygen is able to be transported around your body. this can cause fainting, comas and even death.
why is carbon monoxide so dangerous?
its colourless and ourdorless so its very hard to detect.
when is sulfur dioxide released?
during the combustion of fossil fuels such as coal, that contain sulfur impurities - the sulfur becomes oxidised
when are nitrogen oxidies created?
a reaction between nitrogen and oxygen in the air caused by heat eg internal combusion engines of cars
what happens when sulfur dioxide and nitrogen oxides mix with water in clouds?
they form dilute sulfuric acid or dilute nitric acid. this then falls as acid rain
what are the dangers of acid rain?
acid rain kills plants and damages buildings and limestone statues. it also makes metal corrode
sulfur dioxide and nitrogen oxides also causes risparotary problems if breathed in
