Hydrocarbons

9.10C Recall the formulae of molecules of the alkanes, methane, ethane, propane and butane, and draw the structures of these molecules, showing all covalent bonds
  • Alkane molecules can be represented in the following forms:

  • The first 4 alkanes are methane, ethane, propane and butane (MEPB: Monkeys Eat Peanut Butter)
9.11C Explain why the alkanes are saturated hydrocarbons
  • Contains no C=C double bonds
9.12C Recall the formulae of molecules of the alkenes, ethene, propene, butene, and draw the structures of these molecules, showing all covalent bonds (but-1-ene and but-2-ene only)
  • The first 2 alkenes are ethene and propene.
  • Unsaturated carbons can be represented in the following forms:

9.13C Explain why the alkenes are unsaturated hydrocarbons, describing that their molecules contain the functional group C=C
  • Contain one or more C=C double bonds
9.14C Recall the addition reaction of ethene with bromine, showing the structures of reactants and products, and extend this to other alkenes
  • Ethene + bromine -> 1,2-dibromoethane
9.15C Explain how bromine water is used to distinguish between alkanes and alkenes
  • Alkenes react with bromine water, turning it from orange to colourless – alkanes DO NOT react with bromine water
9.16C Describe how the complete combustion of alkanes and alkenes involves the oxidation of the hydrocarbons to produce carbon dioxide and water
  • The combustion of hydrocarbons releases energy. During combustion, the carbon and hydrogen in the fuels are oxidised.