Thursday (07/02/13)
Today is the day I begin my Chemistry experiment. The aim of this experiment is to investigate how different concentrations of salt (NaCl-Sodium Chloride) in an aqueous solution affect the corrosion process of iron nails and galvanised iron nails. The general outline of this experiment is going to be testing 8 iron nails and 8 galvanised iron nails in 4 different salt concentration solutions. These nails will be submerged in these solutions which will be contained in plastic cups, exposed to oxygen in the air and left to corrode for 16 days. Today I labelled my cups (name, number and concentration) and got 8 iron nails and 8 galvanised iron nails of the same length.
Monday (11/02/13)
Today I made my solutions and put them into their respective cups. The solutions I made were 15000ppm, 30000ppm, and 45000ppm salt concentrations. I will also be using distilled water as a control for my experiment. To make the solutions, i measured 15g, 30g, and 45g of salt and each amount of salt in 1L of distilled water.
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| Putting 15g of NaCl into 1L of distilled water to create the 15000ppm solution |
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| Dissolving the solution |
Once all the solutions were made, I poured 200mL of each solution into it's respective cup. Eventually, I ended up with 4 cups with 200mL of distilled water, 4 cups with 20 mL of 15000ppm solution, 4 cups with 200mL of 30000ppm solution and 4 cups with 200mL of 45000ppm solution. For each solution, 2 of the 4 cups would contain an iron nail and the other 2 would contain a galvanised iron nail. In the end, the set-up looked like this:
The nails were weighed before they were submerged into the solutions.
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| Weighing the nail using an electronic scale |
The weight of the nails before they were submerged into the solutions is given in the following table:
Number
|
Weight (grams)
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1
|
12.56
|
2
|
12.62
|
3
|
12.57
|
4
|
12.56
|
5
|
12.59
|
6
|
12.57
|
7
|
12.45
|
8
|
12.39
|
9
|
8.63
|
10
|
8.74
|
11
|
8.82
|
12
|
8.66
|
13
|
8.79
|
14
|
8.93
|
15
|
8.73
|
16
|
8.80
|
Nails number 1 to 8 are the iron nails and nails 9 to 16 are the galvanised nails. Once the weight of the nails were recorded, the nails could be submerged into the solutions and the corrosion process would be initiated.
Day 1 (Tuesday 12/02/13)
It is clear that the corrosion process in the ungalvanised nails is well under way The colour of the solutions 1 to 8 have already turned an orange-ish colour. The galvanised nails on the other hand appear to have not began corroding yet. The weight of the cups was recorded today as well.
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| Ungalvanised Iron Nails in solutions Day 1 |
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| Galvanised Iron Nails in solutions Day 1 |
Day 3 (Thursday 14/02/13)
Today it can be seen that the ungalvanised iron nails are well under way in the corrosion process. The solutions for the cups 1 to 8 have a slightly cloudy orange colour, whereas the ungalvanised nails do not show any sign of corrosion yet. I also noticed for cups 1 to 8 small amounts of precipitate on the bottom of the cups and a bit on the surface of the nails.
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| Day 3 of Corrosion Experiment |
Day 7 (Monday 11/02/13)
Today I noticed that the blunt ends of the nails that are just out of the solution, tend to lift the surface of the water. The following picture shows how the water 'grips' onto the nail.
I also noticed that there is much more precipitate on the bottom of the cups that hold ungalvanised nails. However the galvanised nails still seem to have no reaction to the solutions at the moment.
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| Ungalvanised Iron Nails in Distilled Water Day 7 |
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| Ungalvanised Iron Nails in 15000 ppm solution Day 7 |
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| Ungalvanised Iron Nails in 30000 ppm solution Day 7 |
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| Ungalvanised Iron Nails in 45000 ppm solution Day 7 |
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| Galvanised Iron Nails in Distilled Water Day 7 |
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| Galvanised Iron Nails in 15000 ppm Day 7 |
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| Galvanised Iron Nails in 30000 ppm Day 7 |
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| Galvanised Iron Nails in 45000 ppm Day 7 |
Day 8 (Tuesday 19/02/13)
Nothing much has changed since yesterday. The ungalvanised nails might have a slight increase of precipitate on the surface of the nails but apart from that, everything seems almost identical to yesterday.
Day 10 (Thursday 21/02/13)
Today I noticed a larger amount of precipitate has formed on the bottom of the cups 1 to 8 and also on the surface of the nails in these cups. Cups 9 to 16 show no signs of corrosion.
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| Ungalvanised Iron Nails in Distilled Water Day 10 |
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| Ungalvanised Iron Nails in 15000 ppm solution Day 10 |
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| Ungalvanised Iron Nails in 30000 ppm solution Day 10 |
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| Ungalvanised Iron Nails in 45000 ppm solution Day 10 |
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| Galvanised Iron Nails in Distilled Water Day 10 |
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| Galvanised Iron Nails in 15000 ppm solution Day 10 |
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| Galvanised Iron Nails in 30000 ppm solution Day 10 |
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| Galvanised Iron Nails in 45000 ppm solution Day 10 |
Day 14 (Monday 25/02/13)
Today I saw that the ungalvanised nails have a cloudier and more orange solution. But what surprised me today was that I saw a tiny amount of white precipitate on the galvanised nails.
My guess is that the white precipitate is the product of the corroding zinc layer that galvanises the iron nail.
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| Day 14 of Corrosion Experiment |
Day 16 ( Wednesday 27/02/13)
Today is the final day of the experiment and all the solutions will have to be filtered so that the products of corrosion can be collected and measured as well as the weight of the nails after the corrosion process. To do this I used a filtering flask and filter paper. Firstly I weighed the filter paper so that I could deduct the weight of the paper later on when I collect the precipitate onto the paper and weigh it. The weight of the filter paper was 0.5 grams. Then I placed the filter paper onto the filter flask and secured it by pressing the pump a few times. Then I grabbed a cup and scraped off as much corrosion product off the nail as possible with a scalpel or something like it. Then I poured the solution into the filter flask and pumped the solution through. If there was any corrosion product left in the cup, I put a little bit of distilled water into the cup and rinsed it into the filter flask. Once all of the corrosion product had been removed from the cup, the filter paper was taken off the filter flask and placed onto an evaporating basin and left to dry. The nail that was in the cup would also be placed on the same basin so that I could identify the nails and the amount of product it produced after 16 days of corrosion. Also the basin was labelled with the same number as the cup so I wouldn't get confused or mix up the nails. I repeated this for each of the cups.
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| Filtering the solution through the filter flask |
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| Products of corrosion collected with their corresponding nails |
Once the collected products on the filter papers were dry, I could weigh them and the nails by using the electronic scales and record the results.
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| Weighing the amount of product formed through corrosion |
