CHEMISTRY UNIT 1

HideShow resource information
  • Created by: slr674
  • Created on: 18-09-14 17:01
View mindmap
  • Chemistry
    • Earth's atmosphere
      • Nitrogen 78%
      • Oxygen 21%
    • Continental drift
      • Alfred Wegener
        • Theory of crustal movement
          • Earth's land once joined together = "supercontinent"
            • Broke up over millions of years ago = land masses moved apart
        • Before, scientists thought features on worlds surface were caused by shrinking
          • 1.Earth cooled after it was formed
          • 2.Its crust shrank and wrinkled to form mountains
        • based on observations involving SOUTH AMERICA and AFRICA
        • NO evidence to show how continents could move
    • Earth's structure
      • Crust
        • Thinnest layer
      • Mantle
        • Thick layer between crust and core
      • Core
        • Radius is just over half of Earth's radius
      • Moving plates
        • tectonic plates move a few centimetres a year
        • Move because of CONVECTION CURRENTS in mantle
          • CURRENTS driven by HEAT from natural RADIOACTIVE processes in Earth
        • Earth movements can be sudden making it difficult to predict WHEN earthquakes will happen
          • Plates collide or push against each other, sudden movements happen causing earthquakes
    • Hardening plant oils
      • Unsaturated vegetable oils have double bonds
        • Polyunsaturated oils have lots of double bonds
        • Unsaturated oils better for health
      • Bromine Water is orange
        • Turns colourless when mixed with UNSATURATED substance.
          • Double bonds change to singular bonds
            • More double bonds = more bromine water can be added before becomes colourless
      • Hardened veg. oils described as HYDROGENATED
        • Less unsaturated  than oils used to make them
          • higher melting point than original oils
            • Solid at room temp.
            • Used to make margerine
            • Useful in cakes and pasteries
        • How are vegetable oils hardened?
          • Hydrogen added to oil at 60°C with nickel catalyst, adds hydrogen to the C=C double bond
        • Why are vegetable oils hardened?
          • Hardened vegetable oils have high melting points, so stay solid at room temperature. This means they can be used in cakes/pasteries/margarine
    • Emulsions
      • If oil and water shaken together, they form EMULSION
        • Emulsions are:
          • thicker (more viscous)
          • have better texture and appearance
            • This makes them useful for paints, salad dressings, ice cream and cosmetics
              • thicker (more viscous)
              • have better coating ability (stick to food/other objects better)
          • have better coating ability (stick to food/other objects better)
      • Hydrophilic = water loving
        • Head = dissolves in water
      • Hydrophobic = water hating
        • tail = dissolves in oil
      • Why are emulsions useful in household paints?
        • emulsions have good coating ability, so stick to walls well
        • QUESTIONS
          • Why does a layer of olive oil form on top of vinegar after a while?
            • Oil does not dissolve in vinegar (which is mostly water) and oil is less dense than water
          • Why is egg yolk an ingredient in many salad dressing?
            • Egg yolk contains an emulsifier which stabilises the emulsion (stops the oil and vinegar seperating)
      • QUESTIONS
        • Why does a layer of olive oil form on top of vinegar after a while?
          • Oil does not dissolve in vinegar (which is mostly water) and oil is less dense than water
        • Why is egg yolk an ingredient in many salad dressing?
          • Egg yolk contains an emulsifier which stabilises the emulsion (stops the oil and vinegar seperating)
    • Vegetable oils
      • 1. Steam distillation
        • Water is boiled =STEAM
          • STEAM passes through the PLANT MATERIAL
            • STEAM carries OIL away
              • The mixture or STEAM and OIL is COOLED
                • OIL floats on condensed steam
        • 2 ways that oils can be extracted from SEEDS, NUTS and FRUITS
          • 2. Pressing and filtering
            • Plant material must be CRUSHED to release oil and water from the plant cells
              • The oil floats on top of the water and crushed plants
                • Crushed plant material may need to be PRESSED to remove oil
                  • Crushed plant material can be removed by FILTRATION
                    • Oil and water are separated to make a useful product
      • 2. Pressing and filtering
        • Plant material must be CRUSHED to release oil and water from the plant cells
          • The oil floats on top of the water and crushed plants
            • Crushed plant material may need to be PRESSED to remove oil
              • Crushed plant material can be removed by FILTRATION
                • Oil and water are separated to make a useful product
      • Vegetable oils have higher boiling points than water...
        • ... This means oil:
          • cooks at higher temps
          • cooks faster than water
          • has different FlaVouRS
          • DOESN'T release more energy when it is eaten
    • Ethanol
      • this is the alcohol in alcoholic drinks
        • it is also a fuel and it has industrial and chemical uses
      • How to produce your own ethanol:
        • 1. HYDRATION OF ETHENE, most ethanol for industrial use is made by this way
          • Ethene and steam react together in the presence of a catalyst to make...
            • ...ETHANOL!!!
        • 2.Fermentation is a natural process
          • Use yeast ( a type of microorganism) to convert sugar from plants into ethanol
            • sugar - ethanol + carbon dioxide
      • What does one see during fermentation?
        • bubbles!
  • 2.Fermentation is a natural process
    • Use yeast ( a type of microorganism) to convert sugar from plants into ethanol
      • sugar - ethanol + carbon dioxide

Comments

No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all ALL resources »