C3 - Chemicals in Our Lives

Tectonic Plates
1. Earth Layers
  1. Crust
    1. Earths crust broken
  2. Mantle
    1. Slow moving solid
  3. Core
    1. Iron and Nickel
2. Move around
  1. Continental drift
  2. Few cm per year
3. Proof of continental drift
  1. Magnetic clues
    1. Constructive plate boundaries new crust forms
      1. Magnatised
    2. 500,000 years Earth's polarity changes
      1. Rock solidifies either normal or reversed polarity
        Pattern
        Used to estimate rock ages
        Tracks movement
4. Sedimentary rocks
  1. Rocks formed in different positions
    1. Different climates
    2. Different conditions
  2. Geologists study the features to work out the environment in which they were formed
    1. Fossils
      1. Age
      2. Conditions based on species
    2. Ripples
      1. Formed underwater
        Sea
        River
    3. Shape of grains
      1. Water-borne
      2. Air-blown
Minerals in Earth's crust
1. Different rock types = different minerals
2. Formation Processes
  1. Mountain building
  2. Sedimentation
  3. Dissolving
  4. Erosion
  5. Evaporation
3. Limestone
  1. Sedimentary
    1. Layers of sediment form seas or lakes
      1. From shells, animal bones or erosion of pre-existing rocks
  2. Calcium Carbonate
  3. Formed from sea shells
  4. Grey white
4. Coal
  1. Fossilisation of plant matter
  2. Carbon
    1. Black
  3. Hard
    1. Formed under extreme pressures
      1. ie. Mountain building
5. Salt
  1. Evapouration
  2. Britain
    1. Underground deposits
      1. Formed when ancient seas containing dissolved salt evaporated
      2. eg. Cheshire and Teeside
Salt
1. Salt mining
  1. Involves physical extraction of the salt
    1. Rock salt is:
      1. Drilled
      2. Blasted
      3. Dug out
      4. Transported to suface
    2. Involves machinery
  2. Usually impure
    1. Used as grit on roads
    2. Can be separated
      1. Pure salt used for food flavourings
      2. Used for making chemicals
2. Solution mining
  1. Water injected into the salt deposit
    1. Salt dissolves to form brine
      1. Pressure forces brine up to the surface
        Brine stored in surface wells
        Pumped to refinearies when needed
  2. Impurities are removed at refinearies before water is evaporated leaving salt
    1. More pure
      1. Chemical and food industry
3. Sea
  1. Salt can also be obtained from sea water
    1. Most pure
  2. Hot counties
    1. Natural evaporation in shallow pools
4. Environmental issues
  1. Land collapsation
    1. Subsidence
      1. Effects buildings and homes
      2. Risk can be reduced by leaving well-supported caverns in mines
        Caverns can be filled with land-fill after use
  2. Needs a lot of energy
    1. Burns fossil fuels
      1. Uses up finite resources
Salt in the Food Industry
1. Use
  1. Enhances flavour
  2. Preservative
    1. Longer shelf life
    2. Dries the meat and thereofre kills bacteria
2. Health Issues
  1. High blood pressure
    1. Strokes
    2. Heart attacks
  2. Increased chance of:
    1. Stomach cancer, renal failure and osteoporosis
3. Government guidelines
  1. FSA
    1. Provides advice
  2. GDAs
    1. Given as %
      1. Clear and easy to understand
  3. DoH
    1. Carry out risk assesments
    2. Advises Public
4. Economics
  1. Reformulating costs too high
  2. Taste bad
  3. Not last long
    1. Decreased sales
Life Cycle Assessments
1. Show total environmental costs
2. Looks at each stage of the 'life' of a product
  1. Works out potential impact of each
3. Stages
  1. Choice of Material
  2. Manufacture
  3. Transportation
  4. Use
  5. Disposal of end product
4. When products are recycled...
  1. Look is closed
  2. Disposal impacts are reduced
  3. Choice of material is the disposed product
5. For more info:
  1. See page 34

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C3 - Chemicals in Our Lives

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	Created by nicole_j_baldwin almost 11 years ago