Paper 2 Chemistry

• Rate of a reaction


  How quickly a reaction happens
• Rate


  A measurement of an amount of something divided by time
• Measuring rate of reaction


  • Volume of gas made
  • Color change
  • Turbidity (cloudiness)
• Factors affecting rate of reaction


  • Surface area
  • Concentration/pressure
  • Temperature
  • Catalyst
• Measuring rate using gas syringe

  Collect gas in gas syringe
• Measuring rate using sodium thiosulfate and hydrochloric acid

  1. Make different concentrations of hydrochloric acid

  2. Add to sodium thiosulfate in conical flask

  3. Time how long it takes for solution to become cloudy
• Reversible reactions


  Reactions that go both ways
• Equilibrium


  In a closed system, the rate of the forward reaction is the same as the rate of the reverse reaction
• Le Chatelier's principle


  If an equilibrium is disturbed, the reaction will move to counteract the change and reach equilibrium again
• Haber process


  1. Nitrogen + Hydrogen -> Ammonia

  2. High pressure increases yield

  3. Low temperature increases yield

  4. Iron catalyst decreases activation energy
• Hydrocarbons


  Molecules containing only carbon and hydrogen
• Fractional distillation of crude oil

  1. Heat crude oil

  2. Vapors condense at different heights based on boiling points

  3. Obtain fractions like LPG, petrol, diesel, etc.
• Alkanes


  Hydrocarbons with single carbon-carbon bonds
• Alkenes


  Hydrocarbons with at least one carbon-carbon double bond
• Testing for alkenes


  1. React with bromine water

  2. Bromine water turns colorless if alkene is present
• Cracking


  1. Break long alkane molecules using catalyst and high temperature

  2. Produces shorter alkane and alkene
• Alcohols


  Molecules with an -OH (hydroxide) group
• Carboxylic acids


  Molecules with a -COOH (carboxyl) group
• Alkene


  Unsaturated compound
• Reaction of alkene with hydrogen

  Makes an alkane (saturated compound)
• Reaction of alkene with halogen (e.g. bromine)

  Makes a haloalkane (e.g. bromoalkane, chloroalkane)
• Reaction of alkene with water

  Makes an alcohol
• Alcohol


  Molecule with an -OH (hydroxide) group
• Reaction of alcohol with sodium

  Makes sodium alkoxide and hydrogen
• Oxidation of alcohol


  Makes a carboxylic acid
• Carboxylic acid


  Compound with a -COOH (carboxyl) group
• Reaction of carboxylic acid with alcohol

  Makes an ester
• Ester


  Compound with a pleasant smell, like pear drops
• Reaction of carboxylic acid with metal

  Makes a salt and hydrogen
• Reaction of carboxylic acid with hydroxide

  Makes a salt and water
• Polymer


  Large molecule made from smaller molecules (monomers)
• Addition polymerisation


  Polymerisation of alkenes (e.g. ethene to polyethylene)
• Condensation polymerisation


  Polymerisation of monomers with different functional groups (e.g. alcohol and carboxylic acid to make polyester)
• Amino acid


  Compound with both a carboxylic acid and an amine (-NH2) group
• Polymerisation of amino acids

  Makes peptides, polypeptides, and proteins
• Nucleotide


  Monomer that can polymerise to form polynucleotides (e.g. DNA)
• Carbohydrate


  Polymer of glucose (e.g. starch)
• Finite/non-renewable resource


  Resource that cannot be replaced once used (e.g. fossil fuels)
• Renewable resource


  Resource that can be replaced (e.g. wind, sunlight, trees)
• Potable water


  Water that is safe to drink