corrosion

• What is the definition of corrosion?

  Destruction of materials by chemical reactions
• To which materials does rusting apply?

  Iron and alloys of iron
• What term should be used for metals other than iron?

  Corroding
• What is the setup of the first test tube in the rusting experiment?

  Iron nail in distilled water, open to air
• What does boiling the water in the second test tube do?

  Removes dissolved air from the water
• What is the condition of the iron nail in test tubes 2 and 3 after several days?

  No rust is found
• What do the results of the rusting experiment indicate?

  Rusting requires both air and water
• How can corrosion be prevented?

  By using a barrier between materials and environment
• What are some methods to create a barrier against corrosion?

  Grease, paint, or electroplating
• What happens to aluminum when it reacts with oxygen?

  Forms a protective layer of aluminum oxide
• What is galvanizing?

  Coating metal with zinc
• What is the role of zinc in preventing iron corrosion?

  Zinc acts as a barrier and sacrificial metal
• Why does zinc corrode instead of iron?

  Zinc is more reactive than iron
• What is sacrificial protection?

  Using a more reactive metal to prevent corrosion
• How often are zinc bars on a ship replaced?

  Every couple of years
• What are the conditions required for rusting?

  • Presence of air
  • Presence of water
• What are the methods to prevent corrosion?

  1. Use of grease or paint
  2. Electroplating
  3. Galvanizing
  4. Sacrificial protection