John Cuthber

When I did this (many years ago) as a high school experiment we got coke bottles fitted with bungs, and short lengths of rubber tubing. We weighed the bottles (etc) full of air then drew the air out with a vacuum pump (a vacuum cleaner doesn't produce a nearly good enough vacuum), tied the rubber tubing to seal out the air then re-weighed the bottles. I remember being quite suprised at how much the air weighed -it's about 1.2 g / litre. For most classrooms the air in the room probably weighs more than you do. (BTW, Evon1020v I may or may not think mathematically, but I can't for the life of me see what measuring "g" has to do with the question.)

There are only 2 common metals that disolve in NaOH solution ; Zn and Al. Zn doesn't work nearly as well. The solution of aluminate or zincate will give a ppt of the hydroxide if you neutralise it with acetic acid. Zinc hydroxide will dissolve in ammonia solution.

There is another way of separating racemic mixtures. It doesn't always work but it has historical importance because it's the first method that got reported (By Pasteur iirc). With some racemic mixtures the molecules prefer to associate with others of the same type so, if you crystalise the stuf slowly, you get 2 sorts of crystals- one set are right handed and the others left handed. You can then sort them out with a pair of tweezers (Of course this only works because you can tell left from right and that, in turn, means that you are chiral).

Probably the most important bit of information in trying to find out what it's made of is "where did you get it?". If you found it in the street it probably isn't anything rare or expensive. If it came from a bottle labeled "zinc" then it's not unreasonable to test for zinc.