Chem

• 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 (increased turbidity)

  3. Repeating at different temperatures
• Increasing temperature

  Decreases the time taken for the reaction
• Experiment to measure rate of reaction

  1. Measuring the volume of gas produced using a gas syringe

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

  3. Drawing a tangent to find the rate at any time
• Ways to increase the rate of a reaction

  • Increasing the concentration of reactants in solution
  • 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 reaction that produces the least amount of moles 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


  A mixture of hydrocarbons formed from the burial of plankton under water
• Alkanes


  Hydrocarbons with single carbon-carbon bonds
• Alkane names

  • Methane (1 carbon)
  • Ethane (2 carbons)
  • Propane (3 carbons)
  • Butane (4 carbons)
  • Pentane (5 carbons)
  • Hexane (6 carbons)
• Fractional distillation of crude oil

  1. Heating to evaporate and separate the different length alkanes based on their boiling points

  2. Collecting the fractions at different heights in the fractionating column
• Fractions from fractional distillation

  • LPG (up to 4 carbons)
  • Petrol
  • Kerosene
  • Diesel oil
  • Heavy fuel oil
  • Bitumen
• Viscosity


  The thickness or fluidity of a liquid
• Longer alkane fractions

  Have higher viscosity
• Shorter alkane fractions


  Are more flammable
• 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 degrees

  2. Steam cracking at over 800 degrees with no catalyst
• Alcohols


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

  1. Combustion to produce carbon dioxide and water

  2. Reaction with sodium to produce sodium alkoxide and hydrogen
• Carboxylic acids


  Organic compounds with a -COOH functional group
• Addition polymerisation


  Joining together monomers with double bonds
• Condensation polymerisation


  Joining together monomers with 2 functional groups, producing water
• Amino acids


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


  A large molecule that stores genetic code, made from two polymers of nucleotides
• Starch and cellulose


  Natural polymers made from glucose monomers
• Melting point and boiling point


  Tests to determine if a substance is pure
• Formulation


  A mixture designed for a specific purpose, with carefully controlled quantities of different substances
• Chromatography


  A technique for separating the components of a mixture
• Polymer


  Molecules made from a large number of monomers joined together in a chain
• Nucleotides


  4 different monomers that make up DNA
• Starch

  Natural polymer where the monomer is glucose
• Cellulose


  Polymer made from beta glucose
• Amino acids


  Monomers that make up proteins
• Melting point


  A way to tell if a substance is pure
• Boiling point

  A way to tell if a substance is pure