Paper 2

• Rate of reaction


  How quickly a reaction happens
• Mean rate


  The rate could be changing over the time you measure, but this is true for any measurement over time
• Experiment to measure rate of reaction

  1. Reacting hydrochloric acid and sodium thiosulfate in a conical flask

  2. Measuring the time until the solution becomes cloudy

  3. Repeating at different temperatures
• As temperature increases


  The time taken for the reaction decreases
• Experiment to measure rate of reaction

  1. Using a gas syringe to measure the volume of gas produced

  2. Plotting a graph with quantity on y-axis and time on x-axis
• Tangent on rate graph


  Used to find the rate at any time
• Ways to increase the rate of a reaction

  • Increasing the concentration of reactants
  • Increasing the pressure of gas reactants
  • Increasing the surface area of solid reactants
  • Increasing temperature
  • Adding a catalyst
• Reversible reaction


  Reactions where the products can return to the original reactants
• Equilibrium


  The point where the rates of the forward and reverse reactions are equal, so there is no overall change
• Increasing pressure


  Favours the forward reaction in a reversible reaction
• Increasing temperature


  Favours the endothermic (reverse) reaction in a reversible reaction
• In a reversible reaction, if the forward reaction is exothermic, the reverse reaction must be endothermic, and vice versa
• Crude oil


  Mixture of hydrocarbons formed from buried plankton
• Alkanes


  Hydrocarbons with single carbon-carbon bonds
• Alkane names


  • Methane
  • Ethane
  • Propane
  • Butane
  • Pentane
  • Hexane
• Fractional distillation of crude oil

  1. Heating to evaporate

  2. Condensing at different heights in the fractionating column based on boiling points
• Fractions from fractional distillation

  • LPG (gases)
  • Petrol
  • Kerosene
  • Diesel oil
  • Heavy fuel oil
• Viscosity


  Measure of a liquid's thickness or resistance to flow
• Longer hydrocarbon fractions have higher viscosity
• Alkenes


  Hydrocarbons with carbon-carbon double bonds
• Unsaturated


  Having a carbon-carbon double bond
• Testing for alkenes


  Adding bromine water, which turns colourless if an alkene is present
• Cracking


  Breaking down longer alkanes into shorter alkanes and alkenes
• Catalytic cracking


  1. Using a zeolite catalyst at around 550°C

  2. Steam cracking at over 800°C with no catalyst
• Alcohol


  Organic compound with an -OH functional group
• Reactions of alcohols


  1. Combustion to CO2 and H2O

  2. Reaction with sodium to form sodium alkoxide and hydrogen
• Carboxylic acid


  Organic compound with a -COOH functional group
• Addition polymerisation


  Joining together monomers with double bonds
• Condensation polymerisation


  Joining together monomers with two functional groups, releasing water
• Amino acid


  Organic compound with both an amino (-NH2) and a carboxyl (-COOH) group
• DNA


  Double-stranded polymer made from nucleotide monomers
• Starch


  Natural polymer made from glucose monomers
• Cellulose


  Natural polymer made from beta-glucose monomers
• Melting point and boiling point


  Used to test the purity of a substance
• Formulation


  Mixture with specific quantities of different substances for a particular purpose
• Chromatography


  Technique for separating the components of a mixture
• DNA


  It's made from two polymers that spiral around each other in a double helix and it's made from four different monomers called nucleotides
• Starch


  A natural polymer where the monomer is glucose
• Cellulose


  A polymer that's made from beta glucose
• Proteins


  Have amino acids as their monomers