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52 SCIPAD - BIG IDEAS - BOOK 2
BASIS OF CHEMICAL REACTIONS
Corrosion II
Iron is a relatively cheap metal so it is widely used in industry. Scientists have had to develop ways
of protecting iron from rusting.
Preventing Rusting
Aim: To investigate a number of techniques that may prevent rusting.
Equipment: Four test tubes, test tube rack, a bung, four iron nails, tap water, petroleum jelly, nail
polish or paint, zinc pellets or magnesium ribbon.
Method: 1. Label four test tubes A - D and place in a test tube rack.
2. Fill all test tubes with equal volumes of water - enough to cover the nails.
3. Test tube contents: A: Iron nail.
B: Iron nail covered in petroleum jelly.
C: Iron nail painted with nail polish or paint.
D: Iron nail with a small piece of magnesium ribbon wrapped
around it, or with zinc pellets added to the test tube.
4. Leave the test tubes undisturbed for at least three days.
Observations:
1. What is the purpose of including a plain nail in water (test tube ‘A’) in the investigation?
2. Complete the following paragraph using the word list provided.
grease galvanised salt prevented plastic oxygen environment paint water zinc
An iron nail will corrode if it comes into contact with the .
Corrosion also occurs quicker if or are present.
Corrosion of iron can be by creating a barrier between
the iron and the . This can be achieved by coating the iron
in , or .
Iron can also be coated in more reactive metals such as . Iron or
steel nails coated with zinc are called nails.
A
Plain nail observations
B
Nail + Vaseline observations
C
Painted nail observations
D
Nail and Zn/Mg observations
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