C11 - chem

• How did the earths atmosphere form?

  1. Scientists believed the earth was around 4.6 billion yrs ago.
  2. The 1st 1 bill yrs volcanoes released: water vapour, co2 and a little nitrogen ammonia and methane.
• How did the 1st water come to be on earth?

  • Earth cooled then causes water vapour to condense forming rain which fell creating oceans.
• Where did the co2 go?

  • it dissolved into oceans which formed carbonates which precipitated to form sediments which eventually form rocks.
• Where did the oxygen come from?

  • scientists believe algae started producing O around 2.7 billion yrs ago.
  • photosynthesis
• What’s the greenhouse effect?

  It’s a natural process that warms the earths surface
• What are the 4 stages of how greenhouse effect works?

  1. Short wavelength radiation from sun
  2. which passes through atmosphere to earths surface.
  3. earths surface radiates diff wavelengths.
  4. which r absorbed by greenhouse gases to produce temperature increase
• Main greenhouse gases

  • Water vapour
  • -CO
  • Methane
• The earth's atmosphere is composed of 78% nitrogen, 21% oxygen, 1% argon, and small amounts of other gases
• What types of human activity increased the level of CO2?

  1. burning fossil fuels: for electricity/ running cars
  2. deforestation : cutting down trees reduces the amount of CO2 absorbed from atmosphere by photosynthesis
• What types of human activity increased the level of methane?

  1. Cattle production of methane : they are reared for humans for consumption which produce methane.
  2. landsites: the decay of waste in landfills by microorganisms produce methane.
• what are the effects of global climate change?

  1. flooding : as average global temp increases:

  • polar ice caps melt
  • sea levels nice
  • Flooding causes coastal erosion / habitat loss
• what are the effects of global climate change?

  2. extreme weather: there r more common + serve which cause lots

  of damage
• What are the effects of global climate change?

  3) change in rainfall

  • heavy rain can damage crops
  • lack of rain causes drought
  • affect production
• What are the effects of global climate change?

  4) extinction

  • as climate changes rapidly, animals + plants can’t adapt to the environment then die out
• What’s a carbon footprint?

  total amount of co2 nd other greenhouse gases emitted over the full life cycle of a product , service or event
• How do scientists model climate change ?

  1. they must have hypotheses
  2. they collect data and write computer programmes
  3. model ‘predict’ future
• how can we reduce the emission of carbon footprin?

  • develop efficient process that use less energy
  • use renewable energy sources
  • government could tax companies or individuals based on the amount of greenhouse gasses they emit
• How are atmospheric pollutants from fuels produced ?

  Combustion of fuels ( both incomplete and complete )
• What are the problems caused by products combustion?

  Carbon particulates

  • its formed by incomplete combustion ( reacts w O of C in fuel)
  • PROBLEMS: blackens buildings
  • reduce by ensuring there’s good supply of air / O when burned .
• What are the problems caused by products combustion?

  sodium dioxide

  • formed by combustion of S + O in fuel
  • PROBLEMS: acid rain
  • reduce it by removing S from fuel b4 burning or remove SO4 after burning
• What are the problems caused by products combustion?


  nitrogen oxide

  • formed by reaction of N2 in air + O2 in air at high temperatures
  • PROBLEMS: acid rain
  • reduces it by engines use catalytic converters: filters out harmful by products in the exhaust gases are burnt up