Polymers and Properties of Materials

• What are plastics made of?

  Plastics are made of long-chain molecules called polymers.
• How are polymers formed?

  Polymers are formed when many small molecules called monomers join together.
• What is the process called when monomers join to form polymers?

  This process is called polymerisation.
• What conditions are usually needed for polymerisation?

  Polymerisation usually needs high pressure and a catalyst.
• What are the typical monomers of plastics?

  The typical monomers of plastics are often alkenes.
• What determines the properties of polymers?

  The properties of polymers are determined by the forces between the different chains.
• What type of bonds hold the atoms together in polymer chains?

  Strong covalent bonds hold the atoms together in polymer chains.
• What happens if a plastic is made up of chains held together by weak intermolecular forces?

  If the chains are held together by weak intermolecular forces, the plastic can be stretched easily and has a low melting point.
• What characterizes plastics with strong bonds between polymer chains?

  Plastics with strong bonds have higher melting points, are rigid, and cannot be stretched.
• What is the relationship between the structure and bonding of materials and their properties?

  • Different types of materials have unique properties.
  • Properties are determined by the structures and bonding in the material.
  • Individual atoms do not possess these properties; it's the bonds that do.
• What type of bonds does chlorine form in ionic compounds like sodium chloride?

  Chlorine forms strong ionic bonds in compounds like sodium chloride.
• Why does sodium chloride have a high melting and boiling point?

  Sodium chloride has a high melting and boiling point due to the strong electrostatic attraction between the ions in its lattice structure.
• What type of substances does chlorine form, and what are their properties?

  Chlorine forms simple molecular substances like chloromethane, which have strong covalent bonds but weak intermolecular forces, resulting in low melting and boiling points.
• How does the structure of polyvinyl chloride (PVC) contribute to its properties?

  PVC is strong and rigid because the intermolecular forces between the polymer chains are relatively strong.
• Why do sodium chloride, chloromethane, and PVC have different properties despite containing chlorine?

  They have different properties because of the structure and bonding of each substance, not because they contain chlorine atoms.
• What are the bulk properties of materials?

  • Bulk properties refer to the properties of a whole material.
  • They arise from the type and strength of the bonds in the material.
  • Individual atoms do not exhibit these properties.