C3 - Chemicals in Our Lives

C3 - Chemicals in Our Lives

1. Tectonic Plates

   • Earth Layers
     • Crust
       • Earths crust broken
     • Mantle
       • Slow moving solid
     • Core
       • Iron and Nickel
   • Move around
     • Continental drift
     • Few cm per year
   • Proof of continental drift
     • Magnetic clues
       • Constructive plate boundaries new crust forms
         • Magnatised
       • 500,000 years Earth's polarity changes
         • Rock solidifies either normal or reversed polarity
           • Pattern
             • Used to estimate rock ages
             • Tracks movement
   • Sedimentary rocks
     • Rocks formed in different positions
       • Different climates
       • Different conditions
     • Geologists study the features to work out the environment in which they were formed
       • Fossils
         • Age
         • Conditions based on species
       • Ripples
         • Formed underwater
           • Sea
           • River
       • Shape of grains
         • Water-borne
         • Air-blown

2. Minerals in Earth's crust

   • Different rock types = different minerals
   • Formation Processes
     • Mountain building
     • Sedimentation
     • Dissolving
     • Erosion
     • Evaporation
   • Limestone
     • Sedimentary
       • Layers of sediment form seas or lakes
         • From shells, animal bones or erosion of pre-existing rocks
     • Calcium Carbonate
     • Formed from sea shells
     • Grey white
   • Coal
     • Fossilisation of plant matter
     • Carbon
       • Black
     • Hard
       • Formed under extreme pressures
         • ie. Mountain building
   • Salt
     • Evapouration
     • Britain
       • Underground deposits
         • Formed when ancient seas containing dissolved salt evaporated
         • eg. Cheshire and Teeside

3. Salt

   • Salt mining
     • Involves physical extraction of the salt
       • Rock salt is:
         • Drilled
         • Blasted
         • Dug out
         • Transported to suface
       • Involves machinery
     • Usually impure
       • Used as grit on roads
       • Can be separated
         • Pure salt used for food flavourings
         • Used for making chemicals
   • Solution mining
     • Water injected into the salt deposit
       • Salt dissolves to form brine
         • Pressure forces brine up to the surface
           • Brine stored in surface wells
             • Pumped to refinearies when needed
     • Impurities are removed at refinearies before water is evaporated leaving salt
       • More pure
         • Chemical and food industry
   • Sea
     • Salt can also be obtained from sea water
       • Most pure
     • Hot counties
       • Natural evaporation in shallow pools
   • Environmental issues
     • Land collapsation
       • Subsidence
         • Effects buildings and homes
         • Risk can be reduced by leaving well-supported caverns in mines
           • Caverns can be filled with land-fill after use
     • Needs a lot of energy
       • Burns fossil fuels
         • Uses up finite resources

4. Salt in the Food Industry

   • Use
     • Enhances flavour
     • Preservative
       • Longer shelf life
       • Dries the meat and thereofre kills bacteria
   • Health Issues
     • High blood pressure
       • Strokes
       • Heart attacks
     • Increased chance of:
       • Stomach cancer, renal failure and osteoporosis
   • Government guidelines
     • FSA
       • Provides advice
     • GDAs
       • Given as %
         • Clear and easy to understand
     • DoH
       • Carry out risk assesments
       • Advises Public
   • Economics
     • Reformulating costs too high
     • Taste bad
     • Not last long
       • Decreased sales

5. Life Cycle Assessments

   • Show total environmental costs
   • Looks at each stage of the 'life' of a product
     • Works out potential impact of each
   • Stages
     • Choice of Material
     • Manufacture
     • Transportation
     • Use
     • Disposal of end product
   • When products are recycled...
     • Look is closed
     • Disposal impacts are reduced
     • Choice of material is the disposed product
   • For more info:
     • See page 34