Alkenes

• What is the chemical test and result for a C=C?

  Bromine water

  orange to colourless
• what does unsaturated mean?

  contains double bonds
• Explain what happens in addition polymerisation reactions

  Double bonds are broken

  Single bonds are formed

  to form polymers
• Explain why polymers do not react with bromine water

  they don't have a double bond
• Give 3 uses of poly(chloroethene) and why

  Electric wires as insulator

  Flooring tiles as rigid due to lots of IMF

  Plastic windows as don't react with acids
• Explain why PVC can be made into rigid window frames and also more flexible sheeting?

  By adding plasticises

  it keeps the polymer chains further apart

  weakening the IMF

  making it more flexible
• Explain why addition polymers are so unreactive

  No C=C bond

  strong C-C and C-H bonds

  non-polar
• Describe the IMF between polymer chains of polyethene

  VdW

  movement of electrons in one atom causes temporary induced dipole in another

  weak IMF between chains
• What type of reactions do alkenes undergo, and why?

  Electrophilic additions

  as C=C form electron rich area which can easily be attacked by electrophiles
• What is an electrophile


  an electron pair acceptor
• Markovnikovs rule- the Br adds onto the C with the fewest H atoms
• Alkyl induction- alkyl groups push electron density towards adjacent C atom. Alkyl groups stabilise the carbocation.