# How to accurately determine mass transfer using balances?

I had troubles the other day using a balance that goes to the tenth of a milligram place (i.e. .0005 vs .001 g), when trying to determine how much solid I transferred. I would take some amount of mg, record it, and then set it aside. I'd take the receiving flask, tare it, and add the solid to said flask. The # I would get would either be wildly lower or slightly lower. I am very sure I am not mispouring anything.

So I am wondering, is it possible these sensitive balances cannot handle things with larger masses, or if the receiving flask is not perfectly flat, would that mess up the mass? Similarly, would the location where I put the flask or weigh paper on the balance matter (e.g. dead center, to the left, right, etc.)? Is there another thing I could do? technically I could take the difference in weigh paper with solid vs without, but that doesn't tell me what got into the receiving flask.

• Like many manipulations in chemistry, there is technique involved in weighing. Did you touch anything with your bare hands? Was the balance pan swinging? Is the substance being weighed hygroscopic? If you're weighing to the milligram using weighing paper just seems wrong. – MaxW Jan 12 at 9:04

As for the other things you could do, I'd like to recommend you to check out some weighing practice manuals. You can start with the balances manufacturers - Mettler has brief Good Weighing Practice whitepapers, maybe others like Sartorius have something similar. Analytical chemistry handbooks should have something to offer. Then, check out the manual for your balances. Aren't you trying to weigh something more accurately than the accuracy of the balances (remember, accuracy $$\ne$$ resolution)? Then, if you don't, just ensure that you are following the recommended weighing practices as closely as humanly possible.