Experiment 1
The first experiment that we did consisted of us using four different types of metal, and submerging them in five different concentrations of salt water. Our aim was to see which metals rusted, how fast these metals rusted, and what would happen to them over a period of time.
Method:
1. First we took sheets of Steel, Brass, Copper and Aluminium and cut each sheet into 15 strips of metal which measured at 7x1 cm.
2. Next, we made up 5 different concentrations of salt water, with the masses of salt that were added being a control, 10g,15g, 20g and 25g in 600 millilitres of water.
3. We then added 50 millilitres of each solution to each strip of metal in separate boiling tubes, repeating this three times for each metal.
4. We then left each boiling tube for a week.
Results:
At the beginning of the experiment:
Here you can see our 60 boiling tubes of aluminium, copper, brass, and steel in the four different concentrations of salt water and the control (no salt in the water)
Method:
1. First we took sheets of Steel, Brass, Copper and Aluminium and cut each sheet into 15 strips of metal which measured at 7x1 cm.
2. Next, we made up 5 different concentrations of salt water, with the masses of salt that were added being a control, 10g,15g, 20g and 25g in 600 millilitres of water.
3. We then added 50 millilitres of each solution to each strip of metal in separate boiling tubes, repeating this three times for each metal.
4. We then left each boiling tube for a week.
Results:
At the beginning of the experiment:
Here you can see our 60 boiling tubes of aluminium, copper, brass, and steel in the four different concentrations of salt water and the control (no salt in the water)
Results of experiment one: after 24 hours
This is our control experiment, with (from left to right) copper, aluminium, steel and brass. The steel appears to have rusted the most, even in water containing no salt.
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This is our most saline experiment, with (from left to right) copper, aluminium, steel and brass in a solution poured from 600ml water and 25g salt. The steel, as predicted, has rusted the most, while the copper and brass have formed bue compounds in their water and the aluminium a white compound.
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Results of experiment one: after six days
This is our control experiment after 6 days, with 0g of salt in the water, and (from left to right) copper, alumnium, steel and brass. The steel has rusted significantly.
This is the second set of test tubes after 6 days. The water contains 10g of salt. Going left to right, the copper remains largely unchanged, with a white compound forming on the aluminium. The steel has rusted more than in the control, and a blue compound has formed in the brass test tubes.
This is the third set of test tubes after 6 days. The water contains 15g of salt. Going left to right, the copper has formed a blue compound, with a white compound forming on the aluminium, significant rust on the steel and a blue compound on the brass test tubes. These changes are more noticeable than the previous set.
This is the fourth set of test tubes after 6 days. The water contains 20g of salt. Going left to right, the copper has formed a blue compound, with a white compound forming on the aluminium, significant rust on the steel and a blue compound on the brass. These changes are more noticeable than the previous set.
This is the fifth and final set of test tubes after 6 days. The water is the most saline, containing 25g of salt. Going left to right, the copper has formed a blue compound, with white compound forming on the aluminium, significant rust on the steel and a blue compound on the brass. These changes are the most noticeable out of all of the sets.
Experiment 2
Rusting of iron occurs in the presence of water and air and it occurs more rapidly in the presence of salt solution.
Iron is initially oxidised to Fe2+ ions (in the presence of O2) and then subsequently to Fe3+. Water then reacts with these ions to produce rust:
2Fe2O3•1.5H2O(s)
The aims of this experiment were to investigate what causes iron to rust, and demonstrate how rusting might be prevented.
1. First we took a test tube rack and 9 test tubes.
2. We then collected 9 nails – 8 iron nails and 1 galvanised nail.
3. We weighed each nail and record its mass.
4. The first iron nail was put into a test tube and sealed with a bung and then labelled this test tube 'moist air'.
5. The second nail was put into a test tube and two spatulas of anhydrous calcium chloride was then added.
6. The third nail was put into a test tube with 4cm3 of TAP WATER and sealed with a bung.
7. The fourth test was done with 4 different nails (4a, 4b, 4c and 4d) and was put into a test tube and 4cm3 of SALT SOLUTION (1g, 2g, 3g, and 4g) added and then sealed with bung.
8. The fifth nail was put into a test tube and 4cm3 of BOILING WATER added and then we sealed this with VASELINE and then seal the test tube with a bung as well.
9. The sixth nail (galvanised) was put into 4cm3 of tap water and the sealed with a bung.
We left this for 24 hours before recording down the results that we found.
This picture shows the nine test tubes at the start of the experiment, where they are labelled 1 - 6. They are each in their according states, within different conditions.
Iron is initially oxidised to Fe2+ ions (in the presence of O2) and then subsequently to Fe3+. Water then reacts with these ions to produce rust:
2Fe2O3•1.5H2O(s)
The aims of this experiment were to investigate what causes iron to rust, and demonstrate how rusting might be prevented.
1. First we took a test tube rack and 9 test tubes.
2. We then collected 9 nails – 8 iron nails and 1 galvanised nail.
3. We weighed each nail and record its mass.
4. The first iron nail was put into a test tube and sealed with a bung and then labelled this test tube 'moist air'.
5. The second nail was put into a test tube and two spatulas of anhydrous calcium chloride was then added.
6. The third nail was put into a test tube with 4cm3 of TAP WATER and sealed with a bung.
7. The fourth test was done with 4 different nails (4a, 4b, 4c and 4d) and was put into a test tube and 4cm3 of SALT SOLUTION (1g, 2g, 3g, and 4g) added and then sealed with bung.
8. The fifth nail was put into a test tube and 4cm3 of BOILING WATER added and then we sealed this with VASELINE and then seal the test tube with a bung as well.
9. The sixth nail (galvanised) was put into 4cm3 of tap water and the sealed with a bung.
We left this for 24 hours before recording down the results that we found.
This picture shows the nine test tubes at the start of the experiment, where they are labelled 1 - 6. They are each in their according states, within different conditions.
Here we can see the results that can be seen after 24 hours.
1. This is our control experiment, where the nail hasn't been put in anything but air. It is clear that no changes have taken place.
2. This nail has had anhydrous calcium chloride added to it, yet there has also been no change.
3. This nail has had tap water added to it, and here a bit of rusting has occurred.
4a) This has had 4cm3 of the 1g salt solution added to it, and a small amount of rusting has occurred.
4b) This has had 4cm3 of the 2g salt solution added to it, and a small amount of rusting has occurred.
4c) This has had 4cm3 of the 3g salt solution added to it, and a small amount of rusting has occurred.
4d) This has had 4cm3 of the 4g salt solution added to it, and a small amount of rusting has occurred.
(The experiment will be left for another 48 hours. Only minor differences can be seen at this point.)
5. This nail was smothered and sealed with petroleum jelly. No change can be seen.
6. This nail has been galvanised and put in tap water. No change can be seen here.
1. This is our control experiment, where the nail hasn't been put in anything but air. It is clear that no changes have taken place.
2. This nail has had anhydrous calcium chloride added to it, yet there has also been no change.
3. This nail has had tap water added to it, and here a bit of rusting has occurred.
4a) This has had 4cm3 of the 1g salt solution added to it, and a small amount of rusting has occurred.
4b) This has had 4cm3 of the 2g salt solution added to it, and a small amount of rusting has occurred.
4c) This has had 4cm3 of the 3g salt solution added to it, and a small amount of rusting has occurred.
4d) This has had 4cm3 of the 4g salt solution added to it, and a small amount of rusting has occurred.
(The experiment will be left for another 48 hours. Only minor differences can be seen at this point.)
5. This nail was smothered and sealed with petroleum jelly. No change can be seen.
6. This nail has been galvanised and put in tap water. No change can be seen here.