ZIMSEC O Level Combined Science Notes: Experiment: Investigating the rusting of iron
Aim: Investigating the rusting (oxidation) of iron
Materials: 4 iron nails, 1 steel nail, a piece of copper/brass, 5 test tubes, cotton wool, solid calcium chloride, magnesium ribbon
Method
- Half fill two test tubes with water
- Put an iron nail in one test tube and label it A and a steel nail in another tube label it B
- Put an iron nail in a dry test tube and label it C and plug with a small piece of cotton wool on which a few pieces of calcium chloride are placed.
- Calcium chloride is a drying agent
- Wrap a piece of magnesium ribbon around and an iron nail and put it into the fourth test tube and label it D fill it with water
- Half fill the remaining test tube with boiled water. Put an iron nail with a layer of oil to exclude air and label the tube E
- Leave the test tubes for a few days and observe the results
Results and Observations
- The iron nail in test tube A will be covered with a layer of rust after a few days
- There is very little if any rust on the steel nail in test tube B
- There is no rust observed on the iron nail in test tube C
- There is no rust/little rust on the iron nail in test tube D
- There is no rusting on the iron nail in test tube E
Conclusion
- Iron is susceptible to rusting
- Rusting can only occur in the presence of moisture (water) and air
- Controlling humidity ( test tube C) prevents rusting
- Galvanising using a more reactive metal such as zinc prevents the rusting of iron
- Oiling reduces/prevents rusting
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