chem of atmosphere

Question 1

phase 1

Answer 1

• 1st billion years surface covered with volcanoes that erupted and released lots of gases
• this is how we think early atmosphere was formed

Question 2

what was early atmosphere probably mostly made up of

Answer 2

carbon dioxide
virtually no oxygen
(similar to atmopsheres of mars and venus today)
volcanic activity also released nitrogen which built up in atmosphere over time as well as water vapour and small amounts of methane and ammonia

Question 3

Phase 2

Answer 3

• water vapour in atmosphere condensed and formed oceans
• lots of carbon dioxide removed from early atmosphere as it dissolved in oceans
• marine animals evolved their shells and skeletons contained some carbonates from the oceans
• green plants and algae evolved and absorbed some carbon dioxide in order to carry out photosynthesis

Question 4

what happened to dissolved carbon dioxide in oceans

Answer 4

went through series of reactions to form carbonate precipitates that formed sediments on the seabed

Question 5

what happened to some carbon that organisms took up from atmosphere when they died

Answer 5

it became locked up in rocks and fossil fuels

Question 6

how do fossil fuels and rocks containing carbon form

Answer 6

• marine animals die and fall to seabed and get buried by layers of sediment
• over 1 mill years they become compressed and form sedimentary rocks, oil and gas, trapping carbon within them

Question 7

examples of fossil fuels

Answer 7

coal, crude oil, natural gas

Question 8

crude oil and natural gas

Answer 8

formed from deposits of plankton and form reservoirs under seabed when thet get trapped in rocks

Question 9

coal

Answer 9

it is sedimentary rock made from thick plant deposits

Question 10

limestone

Answer 10

sedimentary rock made mostly of calcium carbonate deposits from shells and skeletons of marine organisms

Question 11

phase 3

Answer 11

• green plants and algae produce oxygen by photosynthesis
• algae evolved first (2.7 bill years)
• then over next bill years green plants evolved
• as oxygen levels built up in atmosphere over time more complex life like animals could evolve

Question 12

composition of atmopshere today and when did the atmosphere reach this point

Answer 12

approx. 200 million years ago
* 80% nitrogen
* 20% oxygen
* small amount of other gases each making up less than 1% ( carbon dioxide, noble gases, water vapour)

Question 13

what do greenhouse gases do + examples

Answer 13

(carbon dioxide, methane, water vapour)
* act like an insulating layer in the earths atmosphere which contributes to allowing the earth to be warm enough to support life

Question 14

greenhouse effect

Answer 14

• don’t absorb incoming short wavelength radiation from sun
• do absorb long wavelength radiation that gets relfected back off earth
• they then re-radiate in all directions including back towards earth
• longwave radiation is thermal radiation so results in warming the surface of the earth

Question 15

examples of human activity that affect amount of greenhouses gases in atmosphere

Answer 15

• deforestation (fewer trees= less Co2 removed via photosyntheis)
• burning fossil fuels (carbon ‘locked up’ in these fuels is released in form of CO2)
• agriculture (more farm animals produce more methane through their digestive processes)
• creating waste (more landfill sites, more agricultural waste means more CO2 and methane released by decomposition of waste

Question 16

what has to happen to climate change evidence to ensure it is reliable

Answer 16

it has to be peer reviewed

Question 18

why is it hard to fully understand the earth’s climate

Answer 18

it is very complex and their are many variables so it is very hard to make a good model that isn’t oversimplified

Question 19

dangerous consequences of climate change

Answer 19

• increase in global temp - ice caps melt - rise in sea levels - increased flooding in coastal areas and also coastal erosion
• changes in rainfall pattern (amount, timing and distribution), too much or too little water along with temp changes could affect ability of certain regions to produce food
• frequency and severity of storms may increase
• changes in temp and amount of water available in a habitat may affect wild species leading to differences in distribution

Question 20

carbon footprint

Answer 20

measure of amount of carbon dioxide and other greenhouse gases released in a full cycle of something e.g school bus, olympics, toastie maker

HWVR a rough calculation can give a good idea of what the worst emitters are so people can avoid them in the future

Question 21

how to reduce carbon footprint

Answer 21

essentially anything that reduces amount of greenhouse gases given out
* renewable or nuclear energy sources instead of fossil fuels
* more efficient processes can conserve energy and cut waste - reduce methane that lots of waste gives out
* gov taxes on companies based on amount of greenhouse gases they emit e.g taxing polluting cars
* gov put a cap on emissions of all greenhouse gases that companies make
* tech that captures co2 produced by burning fossil fuels before it is released back into the atmosphere then it can be stored deep underground in cracks in rocks such as old oil wells

Question 22

carbon capture and storage

Answer 22

• relatively new and still in developmental stage

Question 23

problems with making reductions in greenhouse gases

Answer 23

• tech is new
• renewable enrgy tech is expensive
• gov worried that making changes to reduce co2 emissions could be bad for economic growth which could be bad for peoples well being - more so important for developing countries
• not everyone is on board so hard to make international agreements - don’t want to sacrifice economic development if others won’t also do so
• individuals need to make changes to lifestyle which is hard if they don’t want to

Question 24

what happens to fossil fuels during combustion

Answer 24

they contain hydrocarbons and during combustion carbon and hydrogen in these are oxidised so co2 and water vapour is released

Question 25

impacts of incomplete combustion

Answer 25

particulates (solid particles made up of soot - carbon- and unburned hydrocarbons) are released and carbon monoxide can also be produced alongside carbon dioxide

Question 26

problems with particulates

Answer 26

• if inhaled can get stuck in lungs and cause damage and lead to respitory problems
• bad for environment - reflect sunlight back into space meaning less light reaches earth causing global dimming

Question 27

problems with carbon monoxide

Answer 27

stops blood carrying oxygen around body by binding to haemoglobin that normally carries O2 so less O2 transported around body

this can lead to fainting coma or death

no colour or smell so very hard to detect

Question 28

what to sulfur dioxide and nitrogen oxide do (problems)

Answer 28

mix with water in clouds and form dilute sulfuric and nitric acid which falls as acid rain which can kill plants and damage statues amd buildings and make metal corrode

also sulfur dioxide and nitrogen oxide can cause respiratory problems if inhaled