Chemistry Facts

Chemistry Facts

1 Principles of Chemistry
1. mass of particles
  1. proton= 1
  2. neutron= 1
  3. electron= 1/1836
  4. charge of particles
    1. neutron= 0
    2. proton= +1
    3. electron= -1
2. isotopes
  1. same number of protons, different number of electrons
3. Electrolysis
  1. molten lead bromide
    1. cathode -
      1. Pb²⁺ + 2e⁻ → Pb
    2. anode +
      1. 2Br⁻ → Br₂ + 2e⁻
  2. of aqueous solutions
    1. Sulphuric acid
      1. cathode -
        2H⁺ + 2e⁻ → H₂
      2. anode +
        4OH⁻ → O₂ + 2H₂O + 4e⁻
    2. Sodium Chloride
      1. cathode -
        2H⁺ + 2e⁻ → H₂
      2. anode +
        2Cl⁻ → Cl₂ + 2e⁻
    3. Copper (ii) sulphate
      1. cathode -
        Cu²⁺ + 2e⁻ → Cu
      2. anode +
        4OH⁻ → O₂ + 2H₂O + 4e⁻
    4. cathode- hydrogen unless metal ion is less reactive
    5. anode- hydroxide unless halide ions present
4. Electrolysis- calculating masses
  1. charge= current x time
  2. 96,000 Coulombs= 1 faraday = one mole of electrons
2 Chemistry of the Elements
1. Group 1
  1. more reactive down the group
  2. metal + water → metalhydroxide hydrogen
2. Group 7
  1. The Halogens
  2. Chlorine
    1. green gas
      1. colourless in water
  3. Bromine
    1. red-brown liquid
      1. orange in water
  4. Iodine
    1. dark grey solid
      1. brown in water
  5. more reactive up the group
  6. Hydrogen chloride gas dissociates in water but not in methylbenzene
  7. halogens displace eachother
3. reactions of metals
  1. metal + acid → salt + hydrogen
    1. MASH
4. reactivity series
  1. Potassium
    1. Sodium
      1. Lithium
        Calcium
        Magnesium
        Aluminium
        (Carbon)
        Zinc
        Iron
        (Hydrogen)
        Copper
        Silver
        Gold
        Goats
        Some
        Coz of
        Hiding
        Into
        Zebras
        Counting
        About
        Made
        Calculation
        Little
      2. Simple
    2. Perfectly
5. Iron
  1. iron + oxygen + water → hydrate iron (iii) oxide (rust)
6. TESTS- see tests sheet
7. Oxygen in reactions
  1. making O₂ in the labs
    1. decomposition of Hydrogen peroxide (H₂O₂)
      1. manganese (iv) oxide catalyst
      2. 2H₂O₂ → 2H₂O + O₂
  2. Burning with oxygen
    1. Magnesium
      1. white flame
      2. magnesium oxide forms
        alkaline when dissolved in water
    2. Carbon
      1. orange yellow flame
      2. carbon dioxide forms
        slightly acidic when dissolved in water
    3. Sulphur
      1. pale blue flame
      2. sulphur dioxide forms
        acidic when dissolved in water
8. making CO₂ in the lab
  1. HCl + CaCO₃ → CaCl₂ + H₂O +CO₂
    1. (hydrochloric acid and limestone)
  2. thermal decomposition of metal carbonates
    1. e.g. copper (ii) carbonate
      1. green copper (ii) carbonate →black copper (ii) oxide
  3. used in fizzy drinks and fire extinguishers
3 Organic Chemistry
1. alkanes
  1. order...
    1. methane
      1. CH₄
      2. ethane
        propane
        butane
        pentane
        C₅H₁₂
        C₄H₁₀
        C₃H₈
        C₂H₆
  2. CₓH₂ₓ₊₂
  3. complete combustion
    1. alkane + oxygen → carbon dioxide + water (+energy)
  4. incomplete combustion
    1. alkane + oxygen → carbon + carbon monoixde + water (+energy)
  5. react with halogens to make haloalkanes
    1. UV needed
    2. alkane + 'bromine' → 'bromo'methane +hydrogen'bromide'
2. alkenes
  1. order...
    1. ethene
      1. propene
        butene
        C₄H₈
        C₃H₆
      2. C₂H₄
  2. CₓH₂ₓ
  3. react with halogens to make haloalkanes
    1. shake with bromine water, orange → colourless (test for alkenes)
    2. ethene + 'bromine' → di'bromo'ethane
      1. 'di' because there are two bromine atoms
3. Ethanol production
  1. Fermentation
    1. impure
    2. slow
    3. batch
    4. sugar= a renewable resource
  2. steam + ethene
    1. conditions
      1. phosphoric acid
      2. 300°C
      3. 60-70atmospheres
    2. pure
    3. fast
    4. continuous
    5. C₂H₄ + H₂O → C₂H₅OH
      1. (reversible)
    6. ethene= a nonrenewable resource
  3. dehydrating ethanol
    1. remove water
    2. hot catalyst of Al₂O₃ (aluminium oxide)
4 Physical Chemistry
1. Indicators
  1. phenolphthalein
    1. acids- colourless
    2. alkalis- bright pink
  2. methyl orange
    1. acids- yellow
    2. alkalis- red
  3. litmus
    1. acids- red
    2. neutral- purple
    3. alkalis- blue
2. reactions of acids
  1. acid + metal oxide → salt + water
  2. acid + metal carbonate → salt + water + carbon dioxide
3. energy transfer
  1. EXOTHERMIC
    1. heat given out
      1. temp increase
    2. bonds broken
    3. energy loss
  2. ENDOTHERMIC
    1. bonds formed
    2. heat taken in
      1. temp decrease
    3. energy gain
5 Chemistry in Industry
1. Extracting Aluminium
  1. Cryolite
    1. 900 °C
  2. aluminium uses
    1. aircraft bodies
      1. property: low density
  3. electrolysis
2. Extracting Iron
  1. C + O₂ → CO₂
    1. CO₂ + C → 2CO
      1. 3CO + Fe₂O₃ → 3CO₂ + 2Fe
    2. temp raised to 1500°C
  2. iron is molten and dense when formed
  3. removing impuritites
    1. main impurity is sand (silicon dioxide)
      1. limestone removes it
    2. CaCO₃ → CaO + CO₂
      1. CaO + SiO₂ → CaSiO₃
        molten slag forms
        cooled solid slag used for road-building and fertilisers
      2. limestone decomposed by heat
  4. iron uses
    1. ornamental gates
      1. property: malleable
  5. blast furnace
3. fractional distillation
  1. fractions
    1. bitumen
      1. Fuel Oil
        Diesel
        Kerosene
        Naptha
        'Chemical feedstock'
        Gasoline
        refinery gases
  2. uses
    1. road surfacing, asphalt for roofs
      1. domestic central heating, fuel for big ships
        diesel engined cars, lorries, trains
        jet engines, pain solvents
        making plastics, dyes, drugs, explosives, paints
        fuel for cars
        bottled gas, making glass, pottery
4. pollutants
  1. acid rain is caused by sulfur dioxide and nitrogen oxides
5. Cracking
  1. conditions
    1. catalyst: silica or alumina
    2. temp: 600-700°C
6. polymerisation
  1. uses of polymers
    1. poly(ethene)
      1. plastic bags
    2. poly(propene)
      1. kettles, food containers, carpets
    3. poly(chloroethene)
      1. insulating electrical cables, clothes, pipes
7. The Haber Process
  1. making Ammonia
    1. Uses
      1. making nitric acid
      2. making ammonium nitrate fertilisers
  2. source of reactants
    1. nitrogen from air
    2. hydrogen from natural gases
  3. conditions
    1. 450°C
    2. 200atmospheres
    3. iron catalyst
8. The Contact Process
  1. making sulphuric acid
    1. S + O₂ → SO₂
      1. 2SO₂ + O₂<->2SO₃
        SO₃+ H₂SO₄ → H₂S₂O₇
        H₂S₂O₇ + H₂O → 2H₂SO₄
        OLEUM is diluted forming concentrated sulphuric acid
        sulphur trioxide is dissolved in concentrated sulphuric acid to form liquid OLEUM
        reversable reaction
  2. conditions
    1. 2atmospheres
    2. 450°C
    3. vanadium (V) oxide
  3. 99% yield
  4. happens quickly
  5. uses
    1. (phosphate) fertilisers
    2. detergents (cleaning)
    3. makes a white pigment used in paint
9. electrolysis of brine
  1. products and their uses
    1. Chlorine
      1. making bleach and HCl
      2. sterilising water supplies
    2. Hydrogen
      1. Haber Process
      2. oil → fats making margarine
    3. Sodium hydroxide
      1. used to make soap, bleach and paper pulp
  2. concentrated brine= sodium chloride solution

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