Polymers and giant covalent structures

Cards (14)

  • What type of bonds do polymers and giant covalent substances have?

    Covalent bonds
  • What defines a polymer?

    • Long chains of repeating units
    • Formed by linking small units together
    • Contains strong covalent bonds
  • What is the repeating section in a polymer called?
    Repeating unit
  • How do you find the molecular formula of a polymer?

    Write the molecular formula of the repeating unit in brackets and put an 'n' outside.
  • What is the molecular formula of polyethene?

    (CH₂)<sub>n</sub>
  • Why are most polymers solid at room temperature?

    Because the intermolecular forces between polymer molecules are larger, requiring more energy to break them.
  • How do the boiling points of polymers compare to ionic or giant molecular compounds?

    Polymers generally have lower boiling points than ionic or giant molecular compounds.
  • What are the characteristics of giant covalent structures?

    • All atoms are bonded by strong covalent bonds
    • Very high melting and boiling points
    • Do not conduct electricity (except for some like graphite)
  • What are the main examples of giant covalent structures?
    Diamond, graphite, and silicon dioxide (silica)
  • How many covalent bonds does each carbon atom form in diamond?

    Four covalent bonds
  • How does the bonding in graphite differ from that in diamond?

    In graphite, each carbon atom forms three covalent bonds and has one delocalised electron.
  • What is silicon dioxide commonly known as?

    Silica
  • What is required to melt or boil a giant covalent substance?

    You have to break very strong covalent bonds.
  • What is needed to melt or boil a simple molecular substance or a polymer?

    Only the weak intermolecular forces need to be broken.