I am doing an experiment about rust. I need a way to measure the rust that grows on various nails submerged in glasses of water (and other stuff). My plan is to use an analytical balance, measure nails with no rust and the nails after rusting and the second weight should be more. Then I will compare the difference of the two weights for all the nails, and the one with the greatest difference rusted most. Will this work? And I have a problem: I tested this and a lot of the rust fell to the bottom of the glass. It was very loose and fell when I lifted the nail. So how can I accurately weigh the rust that has fallen off the nail? I can't just weigh the whole glass because the rust is partly made up of oxygen from the water, so the whole glass wouldn't weigh much more since the rust's ingredients (iron from the nail and oxygen from the water) are in the glass to start with.
Instead of trying to weigh the rusted object, you could remove the rust in a non-abrasive way, and weigh how much of the iron or steel is left.
One way that should work is the electrolytic method described at:
http://www.stovebolt.com/techtips/rust/electrolytic_derusting.htm
The method you mentioned, using an analytical balance to measure the weight of the nails before and after rusting, can give you an idea of the amount of rust that has accumulated. However, it may not provide an accurate measurement if a significant amount of rust falls off the nail and is left at the bottom of the glass, as you observed.
To accurately measure the weight of the rust that has fallen off the nail, you can try the following steps:
1. After the nails have rusted, carefully pour the contents of the glass through a fine mesh sieve or filter paper. This will help separate the loose rust particles from the water.
2. Rinse the separated rust particles from the sieve or filter paper with distilled water to remove any remaining water or impurities.
3. Spread out the collected rust particles on a clean, dry surface and allow them to air dry completely. This will ensure that you are only weighing the rust and not any residual water.
4. Once the rust particles are dry, use an analytical balance to measure their weight. Place a clean and dry weighing boat or container on the balance, tare it to zero to account for the weight of the container, and then carefully transfer the dry rust particles into the container.
By following these steps, you should be able to accurately measure the weight of the rust that has fallen off the nail. However, keep in mind that rust may still contain oxygen from the water, so there might still be some discrepancy between the weight of the rust and the weight of the iron originally present in the nail.
Alternatively, if you want to remove the rust from the nails and measure the remaining iron or steel, you can consider using the electrolytic method as described in the resource you mentioned (http://www.stovebolt.com/techtips/rust/electrolytic_derusting.htm). This method involves immersing the rusty nails in a solution and applying an electric current to remove the rust. You can then measure the weight of the cleaned nails to determine how much iron or steel has remained.
Remember to always handle rust and chemicals with caution, following proper safety procedures and disposal methods.