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Chemistry GCSE > the earth > Flashcards

Flashcards in the earth Deck (38):
1

what is the earths core made from

Nicole and iron

2

where does the minerals and other resources that we depend on come from

the crust- it's oceans

and the atmosphere

3

what are tectonic plates

a number of huge pieces the earths crust and upper mantle is cracked into

they are comradely moving slowly

4

what causes the motion of tectonic plates

radioactive atoms decay releasing heat

makes molten minerals expand, they become less dense and rise

cooler material take their place

forces created by the convection currents makes the tectonic plates move

5

what happens at the plate boundaries of tectonic plates

huge stresses build up causing mountains and volcanos

6

what causes earthquakes

if two tectonic plates suddenly slip past eachother

7

is it easy to predict earthquakes and volcanos

no, cannot measure all the tremmers under the earths crust

8

how did volcanic activity form the oceans

volcanoes produce water vapour

the water vapour condensed to form oceans

9

how did volcanoes form the early atmosphere

volcanos release carbon dioxide, water vapour and nitrogen gas - these gases formed the early atmosphere

the early atmosphere would also contian traces of methane and ammonia

10

why has the amount of carbon dioxide decreased so much since the start and the amount of oxygen increased

plants and algae spread over the earths and seaand replaced some carbon dioxide with oxygen during photosynthesis

oceans formed and absorbed carbon dioxide and it got locked up in sedimentary rocks or fossil fuels

11

what does the earth consists of

a series of layers

dense solid core
liquid core
mantle
thin crust
layer of gas called atmosphere surrounding the earth

12

what is the Miller Urey experiment

a theory of how the atmosphere developed include the arrival of living things on earth

13

what does the Miller Urey experiment say

used a mixture of water ammonia methene and hydrogen to model early atmosphere, then the energy required for the gases to react were provided by stimulating lightening

the mixture formed 11 types of amino acids

amino acids make up molecules that make up living things and contain carbon hydrogen nitrogen and oxygen

conclusion: it provided evidence that is was possible to makes the molecules of life from our early atmosphere

14

what are the problems with other theories about how life started on earth

they are unproven. we can't be sure about the events that resulted in the first life forms on earth

15

what are the main gases in the earths atmosphere

78% nitrogen
21% oxygen
0.9% Argon
0.04% Carbon Dioxide
trace amounts of others

16

how can you separate the main gases in the air

fractional distillation

there gases are used in industry as useful raw materials

17

where has most of the carbon dioxide in the earths atmosphere gone

carbon is taken by plants and animals

they die and build up in oceans

form sedimentary carbonate rocks

form fossils and therefore most of the carbon from the early atmosphere has been locked within the earths crust

18

what happened to the ammonia and methene from the early atmosphere

amonia and methene reacted with oxygen and the nitrogen levels built up

19

how do u fractionally distillate air

the air is cooled to -200c

it is then warmed up at the different elements are separated because of their boiling tempreture

nitrogen= -196
argon= -186
oxygen= -183

20

what has kept carbon levels stable over the past 200+ million years

the natural cycle of carbon

the fact oceans absorb carbon and release it when it's in short supply

the fact plants remove carbon dioxide from the atmosphere

animas add to carbon dioxide via respiration

and when fossil fuels (rocks) are butt it produces carbon dioxide

21

why has the amount of carbon dioxide in the earths atmosphere rises recently

due to the amount of fossil fuels we now burn

22

has the atmosphere changed since the earth was formed

yes and still changing

been the same for the last 200million years and provides conditions needed for life

human activities have resulted in further changes in atmosphere

23

what is the earths diameter

12800km

23

why is the earths core denser than the crust

millions of years ago the heavy materials sank towards the center of the earth while the lighter materials floated on the top

24

how do we know the structure of the earth if no one has ever seen it


by observing how seismic waves following an earthquake travel scientists have built up out picture of the inside of the earth

also calculated the mass of earth and density, it's a lot denser than the rocks found in the crust. so inside of the earth must be a lot denser than crust

25

why can't scientist accurate predict when ear quakes and volcanic eruptions will occur

Because they are very complex and difficult to know when the tectonic plates will slip past eachother - so don't know when or where earthquakes will happen

26

what was wegners evidence of continental drift

1. continents fit like jigsaw
2. Africa and South America have the same patterns of rock layers and same types of plants and animal fossils
3. there couldn't have been a piece of land connecting South America and Africa meaning hey have been joined

27

why didn't scientists accept wegners ideas

1. no explains toon for how the continents moved

2. he was known as a meteorologist not a geologist therefor less credit for his ideas

28

when were wegners ideas accepted

1960 when Atlantic ridge was discovered

scientist found out ocean floo was younger than rocks on the continent

youngest rocks formed near magma pushing older rocks away and fitted with the theory of continental drift. it was explained that continental drift is caused by convection currents

29

how do scientist try to predict volcanos and raw isles

measure angles of volcano (bulges before eruption)

rocks heat us before earthquakes as a result of extreme compression so I rated satiates can monitor earths surface

30

how was it possible for animals to evolve

plants evolved and successfully colonised the surface of the earth do more oxygen

eventually enough oxygen for animals to use to respire

31

why don't we know about how life was first formed

all theories are unproven

32

name another theory of how life on Earth was created based on analysis of meteorites that crash to earth from space

1969 meteor fell and had a range of organic materials found in it called murchison meteorite

70 different amino acids, shows molecules capable of starting life on Earth might have arrived from outer space

33

how do seas and oceans absorb and release carbon dioxide when nessacawy

as co2 levels I the atmosphere go up so does the co2 levels in sea water.

make insolvable carbonates and are deposited as sediment on ocean floor. insolvable carbonates Produce soluable hydrocarbons tes thT remain dissolved in sea water

34

what's carbon capture and storage

pumping carbon dioxide in power stations deep underground to be absorbed into porous rocks

35

give an advantage and disadvantage of carbon capture and storage

adv- reduce co2 emissions

disadv- increase cost of producing electricity by 10%

36

how did continents form

the earth cooled forming a super continent called Pangaea which formed the separate continents

37

why did volcanos reduce

because the earth cooled forming a crust