chemistry in the atmostphere

• Now

  80% Nitrogen

  20% oxygen

  <1% - carbon dioxide, water vapour, noble gases
• this is only a theory


  there is lots of evidence but it has taken place over 4.6 billion years - we still don't know a lot
• 1st billion years 


  Earth = dry

  Intense volcanic activity - produced lots of $CO_2$, water vapour and noble gases - mainly $CO_2$ - like Venus and mars today - their were smaller amounts of methane and ammonia

  as water vapour condensed into liquid water, if formed oceans - allowed $CO_2$ from the atmosphere to dissolve in the oceans to make carbo precipitates and sediments
• 2.7 billion years ago


  algae slowly appeared but then green plants evolved - can photosynthesise

  as algae and plants photosynthesise the volume of ​CO2​​ decreased and the volume of $H_2O$ increased - this allowed more complex life to evolve

  algae - only had small amounts of carbon - when they die they fall to sea bed and become sediment - sediment is compressed to form sedimentary rock, oil and gases (depends on what was trapped and conditions)
• photosynthesis 


  Carbon dioxide + water -> Glucose + Oxygen

  $6CO_2\ +$$6H_2O\ \rightarrow\ C_6H_{12}O_6\ +$$6O_2$
• earth's atmosphere has a protective layer of gases = acts like an insulating blanket or greenhouse - keeps sun's energy so the Earths temperature stays at the optimum level
• As sun's short waves come does to Earth, it goes through the atmosphere and hits the surface if the Earth -> energy is absorbed and heats up the ground - most is re-emitted or reflected back in longer wavelength radiation - some energy goes back into space - most ends up hitting particles of gas which absorb the energy after a short delay - they re-emit the energy in random directions - this happened over and over again - heat energy is stores in Earth for longer
• Greenhouse effect


  gases that absorb and re-emit the sun's energy = greenhouse gases ;

  • Carbon dioxide
  • water vapour
  • methane

  Problem - humans produce too much greenhouse gases - makes concentration of the gases increase - therefore, the greenhouse effect is stronger - global warming
• Carbon dioxide 


  produced

  • burning too much fossil fuels which releases the carbon that was locked up inside the fuel as carbon dioxide
  • chopping too many trees - deforestation - less photosynthesis
• Methane 


  produce

  • farm animals - digestion
  • huge amounts of waste - decomposed
• Earth is getting warmer - consequences


  hard to know because there are so many variables to take into account
• Earth is getting warmer - global warming 


  significant impact on plants - climate change
• climate change 


  the effects of global warming on the planet

  consequences - rare weather events (droughts, hurricanes) become more common and severe
• climate 


  long - term weather patterns
• climate change - sea levels rising 


  1. high temperatures - ice melts - flows into oceans
  2. as ocean water is warmed up it expands, so its volume increases

  can lead to seasonal flooding, submerging of islands and coastal towns
• climate change - general impact 


  temperature and rainfall pattern change - adapted species might not be able to survive anymore - some may be able to adapt to new conditions or migrate - however a lot of species can't adapt or migrate fast enough - biodiversity is likely to fall
• carbon footprint 


  total amount of carbon dioxide and other greenhouse gases that are emitted over somethings ( product, service or event) entire lifecycle

  benefit of working it out -

  • we have a better idea about how these thing are damaging our environment (are they worth it)
  • we can see the most polluting activities and reduce their emissions
• carbon footprint - problem 


  measuring is very hard - have to take into account ;

  • how raw materials were sourced
  • the manufacture process
  • total amounts of power that it uses over its lifetime
  • disposal
  • transportation

  we can only make rough estimates
• carbon footprints - rough calculations


  we can roughly calculate the worse emitters and compare

  once we understand where emissions are coming from - make sensible plans to reduce emissions;

  • renewable energy - solar, wind, nuclear
  • more efficient manufacturing processes - less energy and waste - waste = broken down by decomposers (releases methane)
  • governments - laws and tax for companies
  • carbon capture technology - capture the $CO_2$ burned/released from fossil fuels before it is released into the atmosphere - store deep underground in cracks in rocks
• reducing carbon emissions - easier said then done


  problem;

  • expensive - hard to change
  • every individual needs to be responsible for their consumption and willing to make changes
  • prioritise the environment, whole economy might suffer
  • international agreements = difficult
• air pollution


  burning fossil fuels like coal, oil and natural gases - produces $CO_2$ and water and energy

  only happens when hydrocarbons are burned with plenty of oxygen - allows hydrocarbons to burn completely - complete combustion ( $hydrocarbon\ +$$\ O_2\ \rightarrow\ H_2O\ +$$\ CO_2$ ) - doesn't always happen - pollutants
• complete combustion - not enough oxygen 


  incomplete combustion - releases carbon monoxide particulates - solid particles of carbon (soot);

  • inhaled = stuck in lungs = lung damage = reparatory problems
  • forms smog - reflects sunlight back into space - global dimming
• carbon monoxide


  colourless and odourless - difficult to detect

  dangerous if we breathe it in - it diffuses into our blood steam and binds to our haemoglobin - the haemoglobin can't carry oxygen - less oxygen in our dobies - leads to;

  • fainting
  • coma
  • death

  as the brain in doesn't have enough oxygen
• sulphur dioxide 


  $SO_2$ - hydrocarbons have impurities such as sulphur - so when it burns it gets oxidised as sulphur dioxide

  • breathe in - lung damage
  • as they mix with clouds - dissolve - dilute sulphuric acid forms - acid rain - corrosion of buildings, plants get damaged and soil becomes acidic
• nitrogen oxide 


  nitrogen and oxygen from the air react - rare (high temperature is needed)

  these temperatures are reached in inside internal combustion engines - cars

  same effects as sulphur dioxide