9 Chemistry of the atmosphere

Question 1

proportion of gasses in our atmosphere

Answer 1

around 79% nitrogen
around 20% oxygen
around 1% or very small percentage of other gasses eg.CO

Question 2

evolution of the atmosphere phase 1

Answer 2

• surface covered in volcanoes
• constantly erupted releasing gasses
• atmosphere mostly Carbon dioxide with virtually no oxygen
• also released nitrogen which built up the atmosphere over time
• also released small amounts of water vapour, methane and ammonia

Question 3

evolution of the atmosphere phase 2

Answer 3

• planet cooled down, water vapour condensed forming oceans
• lots of CO2 removed - dissolved in the ocean
• dissolved CO2 formed carbon precipatates - formed sediment on the seabed
• green plants and algae evolved and absorbed some CO2 so they could carry out photosynthesis
• later marine animals evolved - their shells and skelletons contained carbonates from the oceans
• when these organism died formed coal, crude oil and gas after compression

Question 4

evolution of the atmosphere phase 3

Answer 4

• green plants and algae produced oxygen through pohtosynthesis
• 6CO2 + 6H2O —> C6H12O6 + 6O2
• algae evolved first 2.7 billion years ago then over the next billion years plants evolved
• As oxygen levels built up more complex life could evolve
• about 200 million years ago atmohpere reached a composition similiar to what it is now

Question 5

explain the greenhouse affect

Answer 5

• Electromagnetic radiation at most wavelengths passes through the Earth’s atmosphere.
• The Earth absorbs most of the radiation and warms up.
• The Earth radiates energy as infrared radiation.
• Some of the infrared radiation goes into space.
• Some of the infrared radiation is absorbed by greenhouse gases in the atmosphere.
• The lower atmosphere warms up.

Question 6

what are the main green house gasses

Answer 6

• water vapour
• carbon dioixde
• methane

Question 7

examples of human activity which affect amount of greenhouse gasses in atmosphere

Answer 7

• deforestation - fewer trees means less CO2 removed from atmosphere via photsynthesis
• burnign fossil fiuels - carbon that was locked up in fuels rleased as CO2
• Agriculture - more farm animals produce more methane through tjeir digestive processes
• creatign waste - more landfill sites and mor ewadte from agriculture menas more CO2 and methane released by decomposotion of wate

Question 8

consequences of climate change

Answer 8

• increase in glabal temp leads to polar ice caps melting -> rise in sea levels -> increasing flooding in coastal areas -> coastal eroison
• changes in rainfall patterns -> causes regions to get too much/too little water -> may affect ability of certain regions to porduce food
• frequencey and severity of storms may also increase
• changes in temp and amount of water available in a habitate may affect wild species leading to differences in distribution

Question 9

what is a carbon footprint

Answer 9

a measure of the amount of carbon dioxide and other greenhouse gasses released over the full lifecycle of something

Question 10

ways to reduce carbon footprints

Answer 10

• renewable energy sources or nuclear energy could be used instead of fossil fuels
• using more efficient processes to conserve energy and cut waste - lots of waste decomposes releasing methane
• governments could tax companies/individuals based on amount of greenhouse gasses they emit
• governments couls also put a cap on emmisions of all greenhouse gasses that comapnies make
• use technology that captures CO2 produces by burning fossil fuels before released into atmosphere, can be stored deep underground in cracks in rocks

Question 11

why is making reductions of carbon footprints difficult

Answer 11

• alternative technology not fully devrloped
• many governments worry making changes will impact on economic growth of communities - bad for poeples wellbeing, especially important in devloping countries
• hard to make international agreements to reduce emmisions - countries don’t want to risk economic development
• individuals in developed countries need to make changes in their lifestyles - may be hard to get people to make changes if don’t want to and if not enough education provided on why necessary and how

Question 12

what compounds play a role in air pollution

Answer 12

• particulates
• carbon monoxide
• sulfur dioxide
• Nitrogen Oxides

Question 13

how to particluates cause a probem

Answer 13

• if inhaled can get stuck in lungs and cause damage - leads to respiratory problems
• reflect sunlight back into space meaning less light reaches earth causing global dimming

Question 14

how does sulfur dioxide pose problems

Answer 14

• sulfur impurtities somrtimes exist in fossil fuels
• when fossil fuels burn sulfur also burns oxidising forming sulfur dioxide
• when this mixes with clouds to form dilute sulfuric acid making acidic rain
• kills plants and damages buildings, statues and corrodes metal
• bad for human health - can cause respiratory problems

Question 14

how does CO pose a problem

Answer 14

• can stop blood carrying oxygen around the body
• very strongly binds to heamoglobin so less oxygen can be transported sround the body
• lack of oxygen can lead to fainting, coma or death
• hard to detect - doesn’t have any colour or smell

Question 15

how do nitrogen oxides prose problems

Answer 15

• during combustion in the engine nitrogen can be mixed in oxidising with oxygen form nitrogen oxides
• mix with clouds forming dilute nitric acid and falling as acid rain
• kills plants and damages buildings, statues and corrodes metal
• bad for human health - can cause respiratory problems