corrosion

• What is the general term that refers to the process by which metals are slowly broken down by reacting with substances in their environment?

  Corrosion
• What is rusting specifically an example of?

  Rusting is an example of corrosion.
• What substances are involved in the rusting of iron?

  Iron reacts with oxygen and water.
• What is the chemical name for rust?

  Hydrated iron oxide
• At the atomic level, what happens to iron atoms during rusting?

  Iron atoms lose three electrons to become iron three plus ions.
• What happens to oxygen atoms during the rusting process?

  Oxygen atoms gain electrons to become oxygen two minus ions.
• Why is the rusting process considered a redox reaction?

  Because both oxidation and reduction are taking place in the same reaction.
• What are the two conditions required for rusting to occur?

  Both oxygen and water must be present.
• Describe the setup of the three test tubes used to demonstrate rusting.

  1. First test tube: Contains water but no oxygen (boiled water with oil layer).
  2. Second test tube: Contains air (oxygen) but no water (calcium chloride at the bottom).
  3. Third test tube: Contains both air (oxygen) and water.
• Which nail in the test tubes would rust and why?

  Only the nail in the last tube would rust because it contains both oxygen and water.
• Why does only the surface of a metal corrode?

  Because only the surface is exposed to substances in the environment like water and oxygen.
• What happens to rust that forms on the surface of iron?

  The rust flakes off, revealing new metal underneath, which can also rust.
• How does corrosion differ in aluminum compared to iron?

  In aluminum, a protective layer of aluminum oxide forms, preventing further corrosion.
• What are the two main categories of methods to prevent rusting?

  1. Barrier methods

  • Painting
  • Oiling or greasing
  • Electroplating

  1. Sacrificial methods

  • Adding a more reactive metal (e.g., aluminum or zinc)
• What is the purpose of barrier methods in preventing rusting?

  They prevent oxygen and water from touching the iron.
• What is one example of a barrier method to prevent rusting?

  Painting the iron.
• What is an example of a sacrificial method to prevent rusting?

  Adding a more reactive metal like aluminum or zinc to the iron.
• What is galvanizing in the context of rust prevention?


  Coating the iron object in a layer of zinc.
• How does galvanizing serve as both a barrier and sacrificial method?

  It forms a protective coating and reacts with oxygen if scratched, protecting the iron underneath.
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