CHEMISTRY OF THE ATMOSPHERE CGP

Question 1

why is evidence for the early atmosphere limited

Answer 1

because of time scale of 4.6 billion years

Question 2

phase 1 for how atmosphere formed/developed

Answer 2

1) first billion years- intense volcanic activity-
released gases that formed early atmosphere
Volcanoes released nitrogen- built up in atmosphere as well as small % methane and Ammonia

Question 3

what was the early atmosphere like

Answer 3

like atmospheres of mars and venus today.
Mainly CO2 with very little to no O2
small but increasing amount of nitrogen

Question 4

phase 2 for how atmosphere developed

Answer 4

-water vapour in atmosphere condense to oceans.
-CO 2 removed from atmosohere- dissolved into oceans
-dissolved CO2 goes through reactions to form carbonate precipitates that form sediment
-marine animals evolve- shells + skeletons contain carbonates from ocean
-green plants + algae take in CO2 for photosynthesis

Question 5

how did CO2 decrease x2

Answer 5

algae and plants photosynthesised
formation of sedimentary rocks + fossil fuels that contain carbon

Question 6

how is carbon locked up in rocks + fossil fuels

What are fossil fuels

Answer 6

-organisms take in carbon when alive
-die + fall to seabed, buried in layers of sediment
-compressed over millions of years- form sedimentary rock, oil + gas. (carbon trapped in them)
-things like coal, crude oi, natural gas formed by this process.

Question 7

how are the fossil fuels crude oil and natural gas formed

how is coal made

Answer 7

from deposits of plankton
the fossil fuels form reservoirs under sea bed when trapped in rocks.
from thick plant deposits that form sedimentary rock

Question 8

how is limestone made

Answer 8

from calcium carbonate deposits from the shells, skeletons which form sedimentary rock.

Question 9

phase 3
EQUATION
algae first produced O2 …….. years ago
over next billion years

Answer 9

plants + algae photosynthesise-
6CO2 + 6H2O → C6H12O6 + 6O2
2.7 billion
green plants evolved and O2% increased so animals could evolve

Question 10

proportion of gases in atmosphere now

how ling have proportions stayed same for

Answer 10

80%nitrogen
20% Oxygen
>1% other gases -carbon dioxide, water vapour, noble gases
200 million years

Question 11

name 3 greenhouse gases
what do they do (good)

Answer 11

carbon dioxide, methane, water vapour
maintain temperatures on earth high enough to support life.

Question 12

describe green house effect in terms of wavelength- 4 points

Answer 12

-(All particles absorb certain frequencies of radiation. )
-short wavelength radiation emitted from sun by sunlight, green house gases don’t absorb them.
-Earth reflects long wave radiation back, greenhouse gases absorb these.
-green house gases re-radiate longwave radiation in all directions inc. back to earth
-This long wave radiation is thermal radiation- causes warming of the earth- this is the greenhouse effect

Question 13

-human activities which affect amount of which gases-
-which human activities x4 and how they add

Answer 13

-CO2 -METHANE
deforestation-
-fewer tress= less CO2 removed by photosynthesis
burning fossil fuels
-carbon locked up in fuels released as CO2
agriculture
-more farm animals produce more methane (digestive processes)
creating waste
-more landfill sites- more waste from agriculture.
=more CO2 + methane released by decomposition of waste

Question 14

what do scientists believe about human activities

-how have they come to this conclusion

Answer 14

-human activities will cause temperature of earth atmosphere to increase at the surface
-this will result in global climate change

-used peer reviewed evidence- info is reliable

Question 15

why is it hard to understand earths climate and systems like climate change x4

Answer 15

difficult to model complex systems like climate change- many variables
This leads to simplified models,
speculation on link btwn co2 and climate change
opinions in media that are based on parts of evidence- biased.

Question 16

describe briefly four effects of climate change

Answer 16

1) polar ice caps melting- causing rise in sea level - increased flooding in coastal areas + coastal erosion
2) changes in rainfall patterns-(amount, timing,distribution)- cause regions to get too much/little water. This + temp change affects food production
3) frequency and severity of storms increase
4) changes in temp + amount of water available in habitat affects wild species, changing the distribution

Question 17

-what is a major cause of climate change
-why is it important to make predictions about consequences of climate change

Answer 17

-increase in average global temperature
-so policy makers can make decisions now

Question 18

how can scientists work out what atmosphere was like

Answer 18

look at chemical composition of rocks-
look for the appearance of organisms in fossil record- work out what caused changes
-antarctic ice cores- each layer of ice has tiny air bubbles trapped. deeper in the ice, the older the air. analysing bubbles from different layers shows how atmosphere changed

Question 19

what is the carbon footprint

how does it help us

Answer 19

total amount of carbon dioxide and other greenhouse gases emitted over full life cycle of product, service, or event
-we can avoid the the worst emitters,work on reducing their emissions
-know how damaging it is, weigh out whether its worth it

Question 20

carbon footprint can be reduced by

why is it hard to measure total carbon footprint of something, sometimes impossible

Answer 20

reducing emissions of carbon dioxide and methane (greenhouse gases)
-many different factors to consider- eg
-how raw materials were sourced
-emissions released in manufacturing all parts of product
-then in the making of the product
-emissions in transporting product
-emissions produced when used
-emissions produced when disposed off

Question 21

how can we reduce co2 and methane emissions
x4
renewable
waste
government
carbon capture
cap

Answer 21

-use renewable energy sources like nuclear energy instead of fossil fuels
-Waste decomposes to release methane. use more effective manufacturing processes- conserve energy, reduce waste– less decomposers to release methane
-government tax companies/ ppl on amount of greenhouse gas emissions. eg ppl choose more fuel efficient cars so less pollution so pay less tax
-Carbon capture technology- captures CO2 produced by burning fossils bfore released into atmosphere.- then stored underground in cracks in rocks eg old oil wells.
-put cap on greenhouse emissions that companies make. sell licences for emissions up to the cap.

Question 22

why is it hard to cut greenhouse emissions
x5 and explain

Answer 22

-Alternative technologies(that lower CO2) like carbon capture + storage- fairly new idea- technology still developing
-renewable energy tech eg solar panels more expensive than fossil fuels- more development needed to make it cheaper + widely available.
-governments worried making changes to reduce co2 emission- affect economic growth -affect wellbeing, esp in developing counties
-All countries X on board. Hard to make international agreements- most countries X sacrifice economic growth unless all countries will.
—-individuals in developed countries need to change—–
-Hard to make ppl change if they don’t want to. X enough education on why changes necessary + how to change

Question 23

how can an individual reduce personal carbon footprint x4

Answer 23

cycle/ walk/ use public transport X car
reduce how much air travel used
save energy day to day eg turn down heating
use renewable energy

Question 24

major cause of atmospheric pollutants
what do most fuels contain
name a toxic gas-

Answer 24

combustion of fossil fuel
hydrogen, carbon (hydrocarbons) , maybe some sulfur
carbon monoxide

Question 25

what happens to fossil fuels during complete combustion x2

what happens to fossil fuels during incomplete combustion - what is released x4

Answer 25

hydrogen and carbon in the fuel is oxidised,
carbon dioxide + water vapour released into atmosphere

some fuel X burn-
Solid particles(particulates) made up of soot + unburned hydrocarbons released.
carbon monoxide + carbon dioxide released.

Question 25

what happens to fossil fuels during complete combustion x2

what happens to fossil fuels during incomplete combustion - what is released x4

Answer 25

hydrogen and carbon in the fuel is oxidised,
carbon dioxide + water vapour released into atmosphere

some fuel X burn-
Solid particles(particulates) made up of soot(carbon) and unburned hydrocarbons are released.
carbon monoxide + carbon dioxide released.

Question 26

what problems can particulates cause

Answer 26

-if inhaled, get stuck in lungs + cause damage.— lead to respiratory issues
-bad for environment. Particulates and clouds they produce , reflect sunlight back into space- less light reaches earth- global dimming

Question 27

why is carbon monoxide dangerous
2 reasons- explain eahc- total 4 bp’s

Answer 27

-can stop blood from carrying Oxygen around body.
-binds to haemaglobin (carries O2) in blood- causes less O2 to be delivered around body.
-Lack of O2 in blood can lead to fainting, coma , death
-carbon monoxide colourless-odourlesss-vry hard to detect

Question 28

how is sulfur dioxide released

how are nitrogen oxides created

Answer 28

combustion of fossil fuels that have sulfur impurities.- the sulfur gets oxidised
-reaction btwn nitrogen and oxygen in AIR , caused by heat from burning- can happen in internal combustion engines of cars

Question 29

what effects do nitrogen oxides and sulfur dioxides cause x2- how

Answer 29

-acid rain
when the gases mix with water in clouds they form dilute sulfuric/nitric acid. this falls as acid rain.
respiratory problems- bad for health when breathed in.

Question 30

effects of acid rain
where is methane found

Answer 30

acid rain-kills plants- damage buildings + statues- corrodes metal
-in natural gas

Question 31

how can you test for sulfur impurities 3 points

Answer 31

bubbling gases from combustion through universal indicator solution.
If fuel contains sulfur, gas will contain SO2
which will form sulfuric acid and turn universal indicator red

Question 32

examples of fuels- what are they used for
what do fuels do

Answer 32

coals- to generate electricity in power stations
hydrocarbons-used to power vehicles
-release energy when combusted

Question 33

3 potential products of combustion

Answer 33

carbon dioxide
water vapour
carbon monoxide