Corrosion
The process by which metals are slowly broken down by chemical reactions with substances in their environments
oxygen + iron + water → hydrated iron (III) oxide (rust)
redox reaction
Corrosion only takes place at the surface level of the metal as it is the only part exposed to the environment
Iron goes through corrosion and forms a layer of rust along its surface
This layer eventually flakes away thus breaking down the surface layer of metal and revealing a new layer of metal
This process continues until their is no iron left for oxygen and water to react with
Only the outer layer of aluminium goes through corrosion to form aluminium oxide
This is because as the outer layer corrodes, a protective layer is formed around the rest of the aluminium thus protecting is from corroding.
Place a nail into three separate test tubes
Fill the first beaker with water (ensuring to boil it first to remove oxygen) and adding a layer of oil (to stop new oxygen from the air dissolving into the water
Fill the second beaker with solid calcium chloride to one beaker (to remove water vapor in the air)
Fill the third beaker with water but exclude a layer of oil
The third beaker will be the only one in which the nail will rust as it is the only one with suitable conditions for rusting to take place.
Effective on big pieces o metals (side of a ship)
Necessary for objects with moving parts (bike chain)
Uses electrolysis to cover the iron in a thin layer of another metal to protect the iron underneath
When a more reactive metal (aluminium/zinc) is added the iron
The extra metal is more reactive then iron so it will be oxidised as opposed to the iron
Iron will not rust as it is not exposed to oxygen
The zinc is more reactive then the oxygen
During the reaction the zinc will be oxidised as opposed to the iron therefore preventing the iron from rusting
When the zinc is coated around the iron, it acts as a protective layer stopping oxygen from coming into contact with the iron
The process by which metals are slowly broken down by chemical reactions with substances in their environments
oxygen + iron + water → hydrated iron (III) oxide (rust)
redox reaction
Corrosion only takes place at the surface level of the metal as it is the only part exposed to the environment
Iron goes through corrosion and forms a layer of rust along its surface
This layer eventually flakes away thus breaking down the surface layer of metal and revealing a new layer of metal
This process continues until their is no iron left for oxygen and water to react with
Only the outer layer of aluminium goes through corrosion to form aluminium oxide
This is because as the outer layer corrodes, a protective layer is formed around the rest of the aluminium thus protecting is from corroding.
Place a nail into three separate test tubes
Fill the first beaker with water (ensuring to boil it first to remove oxygen) and adding a layer of oil (to stop new oxygen from the air dissolving into the water
Fill the second beaker with solid calcium chloride to one beaker (to remove water vapor in the air)
Fill the third beaker with water but exclude a layer of oil
The third beaker will be the only one in which the nail will rust as it is the only one with suitable conditions for rusting to take place.
Effective on big pieces o metals (side of a ship)
Necessary for objects with moving parts (bike chain)
Uses electrolysis to cover the iron in a thin layer of another metal to protect the iron underneath
When a more reactive metal (aluminium/zinc) is added the iron
The extra metal is more reactive then iron so it will be oxidised as opposed to the iron
Iron will not rust as it is not exposed to oxygen
The zinc is more reactive then the oxygen
During the reaction the zinc will be oxidised as opposed to the iron therefore preventing the iron from rusting
When the zinc is coated around the iron, it acts as a protective layer stopping oxygen from coming into contact with the iron
