Rusting out: how acids affect the rate of corrosion
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Rusting out: how acids affect the rate of corrosion
Hello, I am doing this project! I am stuck because I do not know why lemon juice is not rusting the steel wool as much as the vinegar. Even though the vinegar has a pH level of 3 and lemon juice a pH level of 2.2. I recorded the temperature of the steel wool in vinegar and it increased more than the lemon juice. I did some research and it said that citric acid actually helped remove rust. I am very confused. I do not know how this is possible because if lemon juice (citric acid) is more acidic why does it not rust faster than vinegar.Or how does the lemon juice even remove the rust when it supposes to cause rusting to occur or is it another type of corrosion. Someone, please help before Jan. 15 as I have an important due date. Thank You, I would really appreciate your help!
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norman40
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Re: Rusting out: how acids affect the rate of corrosion
Hi aannyylin,
In your experiment you measure the temperature of the steel wool to gauge the amount of oxidation. More acidity (indicated by lower pH) increases the rate of the steel wool oxidation. You should see a faster temperature increase (change in temperature with time) for lemon juice than for vinegar. The “normal rainwater” should give the slowest temperature rise.
The change in temperature with time will be easy to see if you make a graph with time on the x-axis and temperature on the y-axis (see step 3 under “Analyzing Your Results” in the project procedure). Does the “normal rainwater” show the slowest temperature change with time? If the time/temperature graphs are very similar for the lemon juice and vinegar it may be that the pH values for your samples are too close together to see a difference in temperature rise. You might want to repeat the experiment with different samples of lemon juice and vinegar. Or you might want to try another acid with pH between lemon juice and “normal rainwater” (tomato juice for example).
A quick online search turned up several recipes for homemade rust removers that include either lemon juice or vinegar. I think these work by partially dissolving some of the corrosion but they also require some scrubbing to remove the rust. I don't think this will influence the results of your experiments.
I hope this helps. Please ask again if you have more questions.
A. Norman
In your experiment you measure the temperature of the steel wool to gauge the amount of oxidation. More acidity (indicated by lower pH) increases the rate of the steel wool oxidation. You should see a faster temperature increase (change in temperature with time) for lemon juice than for vinegar. The “normal rainwater” should give the slowest temperature rise.
The change in temperature with time will be easy to see if you make a graph with time on the x-axis and temperature on the y-axis (see step 3 under “Analyzing Your Results” in the project procedure). Does the “normal rainwater” show the slowest temperature change with time? If the time/temperature graphs are very similar for the lemon juice and vinegar it may be that the pH values for your samples are too close together to see a difference in temperature rise. You might want to repeat the experiment with different samples of lemon juice and vinegar. Or you might want to try another acid with pH between lemon juice and “normal rainwater” (tomato juice for example).
A quick online search turned up several recipes for homemade rust removers that include either lemon juice or vinegar. I think these work by partially dissolving some of the corrosion but they also require some scrubbing to remove the rust. I don't think this will influence the results of your experiments.
I hope this helps. Please ask again if you have more questions.
A. Norman