c6.2

• without greenhouse gases the atmosphere would be cold
• the early atmosphere had volcanic eruptions and it released different gases.

  • carbon dioxide- dominated the early atmosphere
  • water vapour- condensed to form the ocean atmospheric concentration of co2 decreased as it began dissolving in the oceans.
  • nitrogen- slowly built up in the atmosphere
• factors that reduced atmospheric carbon dioxide


  • oceans
  • photosynthesis
  • marine animals
• proportion of gases in the earths atmosphere


  • 78% nitrogen
  • 21% oxygen
  • other gases 1% eg carbondioxide, watervapour
• plants and algae make their own food through photosynthesis, they absorb carbondioxide from the atmosphere and release oxygen.

  co2+h2o -> glucose + oxygen
• What do burning fossil fuels produce?

  Carbon dioxide and water
• What is required for complete combustion of hydrocarbons?

  Plenty of oxygen
• What happens during incomplete combustion?

  Generates carbon monoxide and particulates
• What are particulates produced from burning hydrocarbons called?

  Soot
• How do particulates contribute to global dimming?

  They reflect sunlight back into space
• Why is carbon monoxide particularly dangerous?

  It binds to hemoglobin, reducing oxygen transport
• Why is carbon monoxide hard to detect?

  It is colorless and odorless
• How is sulfur dioxide produced when burning hydrocarbons?

  Sulfur impurities are oxidized
• How are nitrogen oxides formed during combustion?

  Nitrogen and oxygen react at high temperatures
• What common situation reaches the high temperatures needed for nitrogen oxides to form?

  Internal combustion engines
• What are the two main problems associated with sulfur dioxide and nitrogen oxides?

  Damage lungs and cause acid rain
• What happens when sulfur dioxide and nitrogen oxides mix with clouds?

  They form dilute sulfuric and nitric acid
• What is acid rain and how does it affect the environment?

  Damages buildings, statues, and plants
• How does acid rain affect soil and plants?

  Makes soil more acidic, hindering growth
• What is complete combustion and its products?

  • Complete combustion occurs with plenty of oxygen
  • Products: water and carbon dioxide
• What is incomplete combustion and its products?

  • Incomplete combustion occurs with limited oxygen
  • Products: carbon monoxide and particulates (soot)
• What are the health effects of inhaling pollutants?

  • Damage lungs and cause respiratory problems
  • Contribute to acid rain and environmental damage
• What are the sources of sulfur dioxide and nitrogen oxides?


  • Sulfur dioxide: from burning hydrocarbons with sulfur impurities
  • Nitrogen oxides: from high-temperature reactions of nitrogen and oxygen
• What are the effects of acid rain?

  • Damages buildings and statues
  • Harms plants and alters soil chemistry
• • complete combustion occurs when hydrocarbons burn with plenty of oxygen, producing only co2 +water
  • incomplete combustion happens when theres insufficient oxygen during burning, leads to formation of pollutants
• formation of pollutants: carbon monoxide


  CO is formed during incomplete combustion when there isnt enough oxygen for complete burning of hydrocarbons

  formation process:

  • limited oxygen prevents full conversion to co2
  • carbon atoms partially oxidize
  • molecular formula: 2C+O2--> 2CO
• EFFECTS OF CARBON MONOXIDE:

  • carbon monoxide is dangerous because of how it interacts with hemoglobin in human blood.
  • CO binds to haemoglobin in the same spot as oxygen
  • prevents oxygen from being transported in the bloodstream and throughout the body
  • reduces overall oxygen delivery to body tissues
• critical danger


  CO is colourless and odorless, making it extremely difficult to detect
• formation of particulates ( soot)


  • tiny, solid carbon particles formed during incomplete combustion
  • occurs when hydrocarbon burn with insufficient oxygen.
  • carbon atoms cannot fully convert to CO2
  • tiny solid carbon particles are released instead
• common sources of soot

  • diesel engine
  • coal burning
  • wood fires
• soot ( PARTICULATES) characteristics:


  • tiny black carbon particles
  • visible as dark clouds or smoke
  • can remain suspended in air
• health effects of particulates


  • can be inhaled deep into lungs
  • cause respiratory problems
  • potentional damage lung tissues
  • increase risk of respiratory diseases
• environmental effects on particulates:


  • forms dark clouds or smog
  • reflects sunlight back into space
  • causes global dimming
  • reduces amount of sunlight reaching earths surface
• global dimming - reduction in solar radiation reaching the Earth's surface due to increased amounts of particulate matter in atmosphere.
• formation of sulfur dioxide


  • forms when fossil fuels containing sulfur impurities are burned
  • formation process:
  • some fossilfuels are naturally containing sulfur atoms
  • during combustion, these sulfur atoms get oxidized
  • chemical reaction s+02-> so2
• common sources of sulfur dioxide


  • coal burning
  • oil combustion
  • industrial processes
• if a fuel contains more sulfur impurities, more sulfur dioxide will be produced during combustion
• formation of nitrogen oxides

  • forms under a specific high temp
  • process-

  requires extremely high temp

  nitrogen and oxygen from air combine

  chemical reaction= N2+O2-> 2NO
• conditions for nitrogen oxides


  • internal combustion engine
  • industrial furnace
  • temp typically above 1600 degrees
• uses for nitrogen oxides

  • car engine
  • power plant combustion
  • industrial manufacturing