Redox and Rusting

Question 1

Ways to prevent rusting:

Answer 1

• Oiling
• Greasing
• Painting
• Coating in thin layer of plastic
• Galvanising
• Sacrificial Protection

Question 2

Galvanising

Answer 2

• Coating the metal in a thin layer of zinc. The zinc is more reactive, therefore will react first, preventing the metal underneath from rusting.

Question 3

Preventing rusting

Answer 3

• Both water and air need to be present for rusting to occur.
• Boiling the water removes oxygen.
• Layer of oil prevents oxygen from re-entering.
• Anhydrous calcium chloride removes any water vapour in the water.

Question 4

Materials in the blast furnace:

Answer 4

Reducing agent: Carbon monoxide
Ore: Haematite
Coke: (Carbon), forms carbon monoxide in the air by reacting with carbon dioxide
Limestone: (Calcium carbonate) Helps remove acidic impurities by reacting with them to form molten slag. Thermally decomposes into calcium oxide, reacts with silica, produces slag. Neutralisation.
Air: Allows coke to burn