C13 - History of Earth's atmoshpere

Question 1

when did the earth form

Answer 1

4.6 billion yrs ago

Question 2

how did the early atmosphere form

Answer 2

volanic activity

Question 3

theory of early atmosphere formation

Answer 3

-volcanoes released co2, water vapour, nitrogen

Question 4

how did oceans form

Answer 4

watre vapour condensed as Earths temp cools
-fell as rain
-collecting in hollows of the crust
-icy comets rained down on Earth = melted

Question 5

gases in early atmosphere

Answer 5

mainly co2
-h2o
n2
methane and ammonia
no o2

Question 6

when did life begin

Answer 6

3.4 billion yrs ago

Question 7

how did first organisms live

Answer 7

used breakdown of chemicals as energy

Question 8

what happened 2.7 bn yrs ago

Answer 8

-algae used enegry from sun to photosynthesis
-producing o2 as a waste product

Question 9

how did o2 levels rise

Answer 9

growth of algae/bacteria in oceans thrived
-released o2 as a waste product
-plants populated Earth

Question 10

why did early microorganisms die out

Answer 10

as o2 levels rose
-couldn’t tolerate rich o2 atmosphere as they weren’t used to it

Question 11

carbon ‘locked in’ rock

Answer 11

co2 in photosynthesis is converted to glucosed = plant structure
-as animals consume plants converted into body/bones
-skeletons of marine life built up at bottom ocean
-covered w layers of sediment
-extreme pressure = sedimentary rock

Question 12

limestone

Answer 12

contains mainly calcium carbonate
-sedimentary rocks

Question 13

formation of fossil fuels,

Answer 13

-remains of ancient organisms
-crushed by large scale movements of earth
-heated within earth’s crust over long time

Question 14

coal formation

Answer 14

-sedimentary rock
-formed by plants dying in swamps
-in absence of o2 and being compressed

Question 15

crude oil/ natural gas formation

Answer 15

-formation from plankton in muds/ seadbeds
-covered by sediment/ compressed
-trapped beneath layers of rocks

Question 16

how was co2 removed from early atmosphere

Answer 16

-by dissolving in oceans
-reacted w metal oxide + precipitate fell to seabeds

Question 17

ammonia + methane removed early atmosphere

Answer 17

-reacted w o2 from photosynthesis

Question 18

nitrogen build up in atmosphere

Answer 18

-unreactive gas so it stayed

Question 19

today gas composition

Answer 19

78% = nitrogen
21% = o2
argon = 0.9%
co2 = 0.04%

Question 20

greenhouse gases

Answer 20

absorb energy radiated from earth’s surface

Question 21

greenhouse effect

Answer 21

-earth is heated by the sun
-30% is reflected back to space
-earths emits longer wavelength infrared to cool
-ghg absorb infrared
-trapped radiation = heats molecules + raises temp

Question 22

ghg allow what

Answer 22

short - wavenlength (UV) to pass through

Question 23

higher ghg proportion=

Answer 23

more infrared absorbed

Question 24

increase of co2 due to

Answer 24

combustion of fossil fuels
- electricity

Question 25

increase of methane is due to

Answer 25

-grazing cattle
-rice farms
-decomposing waste
-more landfills

Question 26

co2 sinks

Answer 26

tropical rainforests
oceans

Question 27

oceans as a co2 sink decreasing

Answer 27

-temps rise
-co2 is less soluble so less effective

Question 28

rainforests as co2 sinks decreasing

Answer 28

deforestation
-less co2 removed as photosynthesis is reduced

Question 29

increased ghg from humans

Answer 29

increase global temps

Question 30

ice caps drilled from greenlands ice sheets shows

Answer 30

-gas trapped inside
-analysis of air shows change
-most co2 than past 440 000 yrs

Question 31

rising sealevels due to

Answer 31

-melting ice caps
-expansion of warmer oceans

Question 32

rising sea levels means

Answer 32

-flooding
-islands disappear
-coastal erosion

Question 33

impacts of climate change

Answer 33

rising sealevels
-more frequent/severe weather storms

Question 34

changes in temp + rainfall

Answer 34

affect food production
dry lands will get drier
-monsoons = heavier
-extinction of species

Question 35

carbon footprint of an event/ product

Answer 35

-total amount ghg emitted over its full life cycle

Question 36

carbon capture and storage

Answer 36

-pump co2 produced deep underground
-absorbed by porous rocks

Question 37

carbon capture con

Answer 37

increases cost of electricity by 10%

Question 38

how to reduce methane from cattle

Answer 38

less demand for beef
-plant based diets instead helps agricultural land be used more effectively

Question 39

reduction of fossil fuel use

Answer 39

taxing consumption

Question 40

biofuels

Answer 40

-made from plant material that absorbs co2 during photosynthesis
-returns co2 when burned
-carbon neutral

Question 41

sulfur from fossil fuels

Answer 41

-sulfur reacts w o2 - sulfur dioxide

Question 42

sulfur dioxide

Answer 42

-acidic toxic gas
-causes acid rain
-damages trees/marine life
-attacks buildings made from limestone

Question 43

remove sulfur

Answer 43

-remove before burnt
-either in petrol or gas fired power stations

Question 44

removing sulfur dioxide in gas power station

Answer 44

-removed from waste/ flue gases be reacting with calcium oxide/hydroxide

Question 45

not enough o2 in engine

Answer 45

-incomplete combustion occurs

Question 46

incomplete combustion

Answer 46

-co formed
-toxic gas
-odourless and colourless

Question 47

why is co toxic

Answer 47

binds to haemoglobin instead of o2
starves body of o2
symptoms of drowsiness

Question 48

nitrogen oxide

Answer 48

-high temps in engines cause unreactive nitrogen to react with o2
-toxic and triggers asthma
-acid rain

Question 49

diesel engines

Answer 49

-burn larger molecule hydrocarbons
-don’t burn fully
-releases particulates

Question 50

particulates

Answer 50

tiny solid particles of carbon + unburnt hydrocarbons in air
-travel to upper atmosphere
-refelect sunlight into space = global dimming effect
-causes cancer