The Earth’s atmosphere p2

Question 1

composition of earth’s atmosphere 4.6 billion years ago

Answer 1

-high CO2
lots of volcanoes, biggest component of atmosphere

-low O2
very little oxygen

-nitrogen, N2
released by volcanoes

-water vapour, H2O
released by volcanoes, vapour as earth was too hot for it to condense

-other gases
ammonia, methane may have also been present

Question 2

composition of earth’s atmosphere 2.7 billion-200 million years ago

Answer 2

—>CO2
began to decrease as:
-water condenses to form oceans where CO2 dissolved
-algae started to photosynthesis
-CO2 precipitates in oceans as solid carbonates (sediments) that form rocks (locked up in sedimentary rocks)
-CO2 taken in by plants and animals, when they die, carbon locked up as fossil fuels

—>oxygen
-starts to increase as a product of photosynthesis

—>nitrogen
continues to increase (stable molecule so any process that produces it causes overlal amount to build up overtime

—>water vapour
starts to decrease
as earth cools, vapour condenses and forms oceans

Question 3

200 million years ago to the present

Answer 3

Carbon dioxide
-about 0.04%

Oxygen
about 20%

Nitrogen
about 80%

water vapour
very little overall, collcts in large clouds as part of the water cycle

other gases
small proportions of other gases e.g noble gases

Question 4

evidence of atmosphere from 4.6 billions years to about 2.7 billion years ago

Answer 4

very little evidence

Question 5

evidence of atmosphere from 2.7 billion years ago to 200 million years ago

Answer 5

still limited
can look at processes that happen today like photosynthesis
and make theories about the past

Question 6

evidence of atmosphere from 200 million yearsa ago to present

Answer 6

ice core
evidence for millions of years ago and lots of global measurements taken recently

Question 7

list 3 greenhouse gases

Answer 7

carbon dioxide, methane, water vapour

Question 8

how has carbon dioxide increased in past 150 years

Answer 8

combustion of fossil fuels, deforestation

Question 9

how has methane increased in past 150 years

Answer 9

planting rice fields, cattle farming

Question 10

list effects of climate change

Answer 10

-global warming
-sea levels rising
-extreme weather events
-changes in amount and time of rainfall
-polar ice caos melting

Question 11

define carbon footprint

Answer 11

the amount of carbon dioxide and methane that is released into the atmosphere by a product, person, or process

Question 12

name 4 other pollutants released in combustion of fossil fuels

Answer 12

1.carbon monoxide
2. particulates (soot and unburnt hydrocarbons)
3.sulfur dioxide
4.oxides of nitrogen

Question 13

how are carbon monoxides released

Answer 13

incomplete combustion of fossil fuels

Question 14

what is the effect of carbon monoxides being released

Answer 14

colourless & odorless toxic gas

Question 15

how are particulates released

Answer 15

incomplete combustion of fuels (especially in diesel engines)

Question 16

what is the effect of particulates being released

Answer 16

global dimming

also respiratory problems - potential to cause cancer

Question 17

how is sulfur dioxide released

Answer 17

surlfur impurities in fuel reacting with oxygen in air

Question 18

effect of releasing sulfur dioxide

Answer 18

acid rain
also respiratory problems

Question 19

what are oxides of nitrogen released

Answer 19

nitrogen from air being heated near an enfine and reacting with oxygen

Question 20

what is the effect of releasing NOx

Answer 20

acid rain and respiratory problems