C3 | Mindmap

Water
1. Hard Water
  1. Needs more soap to form a lather
    1. Because it contains dissolved compounds that react with the soap
      1. Forms Scum
    2. Soapless detergents dont react witht he hard water to form scum
  2. Contain Mg 2+ ions or Ca 2+ ions
  3. Temporary Hard water - when heated - reacts and forms scale
    1. Deposited in kettles etc.
  4. Calcium ions are good for teeth & bones and reduce the risk of Heart Disease
2. Removing Hardness
  1. Made soft when Mg 2+ ions & Ca 2+ ions are removed
  2. Tempory hard water made soft when heated as the Mg 2+ ions & Ca 2+ ions react
  3. Can also be removed using sodium carbonate that reacts with the calcium ions to form calcium carbonate
  4. Or removed using an Ion exchange column, that swaps sodium ions for Mg 2+ ions & Ca 2+ ions
3. Water treatment
  1. The stages of treatment - Not shown in the pictrure; Aluminium sulfate is added to clump small bits of sediment together in the sedementation tank
Periodic Table
1. Early Periodic Table
  1. They arranged the elements in atomic weight rather than in proton numbers
  2. 1863 - Newlands proposed his Law of Octaves
    1. It stated there would be similar properties every eigth element
    2. Didnt work after the 20 element - Calcium
  3. Mendeleev - 1869
    1. He left gaps for undiscovered elements
      1. This left elements with similar elements
      2. When missing elements werer discovered, Mendeleev's predictions were confirmed
2. Modern periodic Table
  1. Now aranged in proton number
  2. Groups have similar properties as they have the same number of electreons on the outer shell
3. Alkali Metals
  1. Group 1
    1. 1 electron in outer shell
  2. Soft Solids at room temp.
  3. Low Density
  4. React with Halogens to form salts that are white/colourless
4. Transition Metals
  1. Middle of table
  2. Malleable & Ductile
  3. Strong and dense
  4. Often used as alloys for building
5. Halogens
  1. Non - Metals & in group 7
  2. 7 electrons in outer shell
Energy & Fuel
1. Energy Released when oxidation occurs e.g. when food reacts with water
  1. Use a calorimeter to Measure this
    1. Work out the amount of energy transferred using the equation
      1. Q = m c *T
        Energy Transferred = mass of substance X Specific heat capacity X Temp. change
        E.G ~ Q=m c *T
        Q = 200g X 4.2 X 30
        Q = 25200 J
        = 25.2 KJ
      2. * represents delta
2. When we work out the energy transfer in solutions we:
  1. Assume it has the same properties of water: 1cm3 = 1g & it has a specific heat capacity of 4.2
    1. This stays the same even if a solid is added
3. Energy Level Diagrams
  1. An energy level diagram of an exothermic reaction
  2. It is exothermic as the energy of the products is less than the reactants
4. Bond Energies
  1. It is the energy required to make or break a bond
    1. Energy Change is 'Bonds Made' - 'Bonds Broken'
5. Fuel Issues
  1. Fossil fuels are running out - new fuels need to be developed
  2. Hydrogen - Can be used in fuels cells or burnt in a combustion engine
    1. Ads - burns easily, release a large amount of energy per gram, produces no C02 when burnt only water
    2. Dis - the supply, storage of the gas, safety problems
    3. Fuel cell vehicles need to match normal vehicles in; performance, convienience & costs
Analysis and synthesis
1. Positve Ions
  1. Flame Test
    1. Dip a clean flame test loop in the sample solution. Hold the flame test loop at the edge of a Bunsen burner flame. Observe the changed colour of the flame, and decide which metal it indicates. Clean the loop in acid and rinse with water, then repeat steps 1 to 3 with a new sample
  2. Most of the Metal hydoxides are insolouble - Some have colurs and so we can identify them from that
    1. The reaction is the ion + sodium hydroxide
    2. When excess NaOH is added to AlOH the AlOH precipitate dissolves
2. Negative Ions
  1. Carbonate Ions
    1. Add HCl to substances if there is a gas produced and it turns limewater milky it contains carbonate ions
  2. Halide Ions
    1. Add Nitric acid, then silver nitrate
      1. Chloride ion - white precipitate
      2. Bromide ions = Cream Precipitate
      3. Iodide ions = Yellow precipitate
  3. Sulphate ions
    1. Add dilute HCl, the barium chloride. If white precipitate forms, sulphate ion present.
3. Titrations
  1. When an Acid and alkali react, a neutralisation reaction occurs
    1. The volumes of acid & alkali that react exactly can be found using titration
  2. 1. Use a pipette to add the correct volume of Alkaline to a conical flask
    1. Add a few drops of indicator to the alkali
      1. Fill a burette with acid. Remove any bubbles by opening the stopcock
        Record the start measuremnt on the burette & slowly add acid to the solution and swirl the conical flask.
        When the solution changes colour, close the stopcock and record the reading on the burette. Work out the difference.
        Repeat for improved reliability

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Medienanhänge

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