07 - Rusting

• What is rusting?

  Rusting is the corrosion of iron(and steel). It forms on the surface of iron(or most steels).
• Rust is a soft and crumbly substance. It will soon flake off exposing more iron that will rust.
• Which metals rust?

  Only iron
• What process is rusting?

  Oxidation(addition of oxygen, loss of electrons).
• What is needed for rusting to occur?

  Oxygen and water(moisture).
• What is a catalyst for rusting?

  Salt
• What is the chemical name for rust?

  Hydrated iron(III) oxide.
• Explain why rusting is known as an oxidation reaction.

  The iron is gaining oxygen, therefore its oxidation.
• What are the two ways that we can prevent rusting?

  1. Preventing iron from coming into contact with water and oxygen in the air.
  2. Coating the iron with a more reactive metal to lose its electrons instead of iron.
• What is a physical barrier?

  Having something physically block the water and oxygen from getting to the iron. E.g. paint, oil
• What is sacrificial protection?

  A more reactive metal which coats the object so it loses its electrons instead.
• What two metals are often used to 'sacrificially protect' iron?

  Magnesium and zinc.
• What is the process called when iron is coated in zinc?

  Galvanisation