Chem Paper 2

• Rate of reaction

  • Reaction rate is higher at the start of a reaction as there are more frequent successful collisions
  • Successful collisions need sufficient energy - activation energy
  • Catalysts provide an alternative pathway, reducing activation energy required
• Le Chatelier's Principle

  • Changing the conditions of a reaction with a dynamic equilibrium will cause the the equilibrium to shift to counteract the change, re-establishing an equilibrium
  • Temperature increase: favours endothermic
  • Pressure increase: favours least gas moles
  • Concentration increase: favours lowest concentration
• Amino acid


  • naturally occurring monomer with functional group:
  • NH₂ & COOH

  Polymerises to form:

  • polypeptides
  • A long chain polypeptide is a protein
• Sugar can polymerise as starch or cellulose
• Impure substance

  • range of melting/boiling points
  • different melting/boiling points to data book
• Chromatography

  • mobile phase - where the molecules can move
  • stationary phase - where the molecules cannot move
  • Rf = distance traveled by substance/distance traveled by solvent
• Flame emission spectroscopy

  • ions are heated up
  • when they return to original energy levels, light is emitted and recorded by a spectroscope
  • The wavelengths present are graphed
• Dangers of Carbon Monoxide


  Bonds to haemoglobin preventing oxygen from bonding
• Soda-lime glass

  limestone + glass + sodium carbonate (+ heat)
• Borosilicate glass


  • higher melting point than soda-lime glass
  • sand + boron trioxide
• Composites

  Reinforcement (fibres/fragment)

  +

  Matrix (binder)
• Bronze =


  copper + tin
• Brass=


  copper + zinc
• Corrosion

  • iron + oxygen + water -> hydrated Iron(III) oxide (rust)
  • electroplating - covering iron with a layer of another metal
  • sacrificial - more reactive metal place on top
  • Aluminium corrodes with a protective aluminium oxide layer forming
• Bioleaching

  • uses bacteria
  • Leachate solution formed.
  • copper obtained via electrolysis or displacement (usually with scrap iron)

  Phytomining

  • the ash produced has a higher concentration of copper than the soil
• Potable water - from fresh water

  Fresh water -> mesh (removes large solids eg. twigs) -> sand/gravel filtration (all other solids) -> sterilisation (using either UV or O3 or Cl2)
• Potable water - from sea water


  Desalination either by:

  reverse osmosis

  • partially permeable membrane allowing only water through
  • stops salt

  or distilation
• Potable water - from waste water

  Screening -> settlement tank (solids either settle to the bottom or float to they top

  If they settle:

  • anaerobic respiration
  • producing methane gas
  • and sludge - used as fertiliser

  If they float:

  • aerobic respiration
  • producing water which is released to the environment
• The Haber Process


  N2 (g) + 3H2 (g) <->2NH3 (g)

  N₂ + 3H₂ ⇌ 2NH₃

  Industrially:

  temperature - 450°C:

  • compromise
  • higher temp inhibits forward reaction
  • higher temp increases reaction rate

  pressure - 200 atm:

  • favours forward reaction
  • compromise between cost and yield

  Iron catalyst:

  • lowers activation energy
• NPK fertilisers - Nitrogen

  • Ammonia + nitric acid -> ammonium nitrate
  • NH3 + HNO3 -> NH4NO3
  • this ammonium nitrate is used in many fertilisers as it has a high amount of nitrogen per unit mass
  • Nitrogen also collected from the air
• NPK fertilisers - Phosphorous

  Phosphate rock - mined but cannot be used directly

  Either:

  1. Reaction with NO3 (nitrate) producing phosphoric acid + calcium nitrate
  2. Reaction with H3SO4 (sulphuric acid) producing CaSO4 ( calcium sulphate) + calcium phosphate
  3. Reaction with H3PO4 (phosphoric acid) producing calcium phosphate
• NPK fertilisers - Potasium

  KCl and KSO4 are mined and can be used directly
• Electroplating


  covering iron with a layer of another metal