Chemistry of the Atmosphere

Question 1

what chemicals is the earths atmosphere made of

Answer 1

nitrogen
oxygen
co2
water vapour
noble gases

Question 2

how much of the atmosphere is made of nitrogen

Answer 2

80%

Question 3

how much of the atmosphere is made of oxygen

Answer 3

20%

Question 4

how much of the atmosphere is made of oxygen

Answer 4

20%

Question 5

how long have the proportions of gases been like how they are now

Answer 5

for 200 million years

Question 6

why is evidence of the earths early atmosphere limited

Answer 6

the timescale of 4.6 billion years

Question 7

the earths early atmosphere theory

Answer 7

intense volcanic activity released gases that formed the early atmosphere
the atmosphere was like mars or venus today with mainly co2 and little or no o2
volcanes produced n2 which gradually built up in the atmosphere and there may have been small proportions of methane and ammonia
water vapour condensed to form the oceans
co2 dissolved in the water and carbonates were precipitated producing sediments, reducing the amount of co2 in the atmosphere

Question 8

where is the oxygen currently in the atmosphere from

Answer 8

algae and plants produced o2 by photosynthesis

Question 9

when did algae first produce oxygen

Answer 9

2.7 billion years ago

Question 10

why did oxygen levels increase after algae produced oxygen

Answer 10

plants evolved

Question 11

what was the result of an oxygen increase

Answer 11

enabled animals to evolve

Question 12

how did carbon dioxide in the atmosphere decrease

Answer 12

algae and plants decreased the co2 in the atmosphere by photosynthesis

Question 13

what other than photosynthesis decrease carbon dioxide

Answer 13

the formation of sedimentary rocks that contain carbon eg limestone and coal
the production of fossil fuels from the remains of dead plants and animals when they decayed

Question 14

when was methane removed from the early atmosphere

Answer 14

once oxygen was made

Question 15

when was ammonia removed from the early atmosphere

Answer 15

once oxygen was made

Question 16

where do scientists think life first evolved from

Answer 16

near underwater volcanoes

Question 17

what layer did oxygen form in the upper atmosphere

Answer 17

ozone layer

Question 18

why was the ozone layer important for life on land

Answer 18

shield the earth from harmful uv light so organisms could leave the water

Question 19

how was co2 removed in the ocean

Answer 19

some dissolved in ocean and was taken up by small sea creatures to form their shells

Question 20

what do greenhouse gases do

Answer 20

maintain temperatures on earth high enough to support life

Question 21

examples of greenhouse gases

Answer 21

water vapour
carbon dioxide
methane

Question 22

describe the greenhouse effect

Answer 22

radiation at short wavelengths from the sun passes through the atmosphere
the earth absorbs some radiation and warms up but some heat is radiated from the earth as long wave infrared radiation
some of this infrared radiation is absorbed by greenhouse gases in the atmosphere
atmosphere warms up leading to the greenhouse effect and global warming

Question 23

which human activities increase methane

Answer 23

raising livestock eg cows - more waste produced
decay of organic waste in landfill sites

Question 24

which human activities increase carbon dioxide

Answer 24

driving
consuming electricity

Question 25

why is it difficult to predict climate change

Answer 25

it is hard to understand the earths climate as it is complex and there are many variables

Question 26

what is done because it is hard to understand climate change

Answer 26

simplified models speculation opinions presented in the media that are based on only parts of the evidence

Question 27

what is a major cause of climate change

Answer 27

an increase in global temperature

Question 28

what are the potential effects of global climate change

Answer 28

extinction of species rising sea levels due to melting polar ice caps migration as people move from areas suffering drought/flooding decrease in crop yield for all major world crops

Question 29

when does global warming happen

Answer 29

when the greenhouse effect is enhanced as more thermal radiation is absorbed and radiated back to earth

Question 30

what is carbon footprint

Answer 30

the total amount of co2 and other greenhouse gases emitted over the full life cycle of a product, service or event

Question 31

which chemicals need to be reduced to reduce carbon footprint

Answer 31

reducing emissions of carbon dioxide and methane

Question 32

which activities can reduce carbon footprint

Answer 32

using less electricity so using less fossil fuels using an alternative source of electricity reducing amount of travel or transportation of goods or people planting more trees

Question 33

why might carbon footprint reduction action be limited

Answer 33

its more difficult can be more expensive planting trees takes away land that could be used to grow crops

Question 34

what is the combustion of fuels a source of

Answer 34

atmospheric pollutants

Question 35

what do most fuels contain

Answer 35

carbon and or hydrogen maybe sulfur

Question 36

which gases can be released into the atmosphere when a fuel burns

Answer 36

carbon dioxide water vapour carbon monoxide oxides of nitrogen

Question 37

what products other than these gases may be released when a fuel burns

Answer 37

solid particles unburned hydrocarbons which form particulates

Question 38

which gases are released in incomplete combustion

Answer 38

soot (carbon) carbon monoxide unburnt fuel

Question 39

what does the combustion of hydrocarbons release

Answer 39

energy

Question 40

what happens to carbon and hydrogen in fuels during combustion

Answer 40

oxidised to form carbon dioxide and water

Question 41

features of carbon monoxide

Answer 41

toxic colourless gas odourless not easy to detect

Question 42

features of sulfur dioxide and oxides of nitrogen

Answer 42

cause acid rain cause respiratory problems in humans

Question 43

features if particulates

Answer 43

cause global dimming human health problems