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Corrosion of a Nail

Hey I got a science assignment I have to do and it's asking me to test how much rust is on a nail after we put it in dishwashing detergent Our teacher hasn't told us how to do it and he won't answer any questions about it so if you could help me it would be appreciated. Can you answer A.S.A.P. thanks

Matt Vagg
- Perth, W.A., Australia
2000

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Not sure, about testing how much rust is on the nail, does that mean surface area or actual weight/no of molecules. If you've wired up the nail to a galvanometer in the detergent, then you can measure the amps passing through it. multiply the amps by the time in the detergent, seconds, this gives you a number of coulombs (again check the spelling). For an iron atom (Fe) to oxidise to an iron ion (rust) will take a certain number of electrons for Fe2+ takes two electrons, for Fe3+ three electrons.

Most iron will turn to Fe2+ so divide the number of electrons that have passed (there are so many electrons per coulomb)by 2, this gives you the number of iron atoms that have turned into ions, if you want an actual weight then divide this number (should be quite large) by Avogadro's Number and multiply by the atomic weight (not number) of iron.

If you want to be clever say that the nail will rust more at the head and the point. If asked why, it's because these are areas of higher energy. And that is because there is energy locked up in the lattice distortions caused in forming the nail (i.e., beating it into shape).

Hope this helps, oh a friend just suggested weighing the nail before it rusts - take the rust off afterward and then weighing again, if you've got a microbalance this could work. Ian

Ian Brooke
University - Glasgow, Scotland
2000

Use a diocaliper to measure how far the rust has grown off the nail after you have done the experiment. That's what I did with mine. I got a good grade also.

Steven Michael Dyer
- Fairfield California United States
2001