Sciencemadness Discussion Board

Unlabelled jar with metal.

Maja - 18-7-2006 at 07:57

I have one unlabelled jar with granulated, dense metal... And I would like to figure out what is that metal... That metal chloride is soluble in water - so it's isn't Lead. I think that is Zn or Sn. I found that Zn and Sn has pretty same properties ,but melting point of Sn is lower, but I can't measure it right now. Can someone give me idea to figure out what is that metal and how... ?

On the right zinc :

http://img410.imageshack.us/my.php?image=comparemy7.jpg

Here is the bottle :

http://img410.imageshack.us/my.php?image=metaliq8.jpg

Grrrr.... Why ".jpg" forum shows like separate thing from that link ?! Just copy/paste in new window link. Thanks.


[Edited on 18-7-2006 by Maja]

chromium - 18-7-2006 at 08:33

Tin has so low melting point compared to Zn that you do not need thermometer to notice difference. For example pure tin will melt when touched with soldering iron, droped to kitchen hotplate or held for a while in candle flame. It is still wise to make some additional tests as it may be some other metal or alloy with low mp.


[Edited on 18-7-2006 by chromium]

The_Davster - 18-7-2006 at 13:56

Zinc reacts with Dil HCl much faster than Sn. Ni2+, Co2+, Fe2+ will react with zinc but not tin.

Maja - 18-7-2006 at 14:22

Quote:
Originally posted by chromium
Tin has so low melting point compared to Zn that you do not need thermometer to notice difference. For example pure tin will melt when touched with soldering iron, droped to kitchen hotplate or held for a while in candle flame. It is still wise to make some additional tests as it may be some other metal or alloy with low mp.


[Edited on 18-7-2006 by chromium]


Yes, I will test it for melting... And I think that it's pure metal because it's from analytical lab, I do not think that they use alloys.
rogue chemist, thank you very much for that kind of information I will test it for Ni2+ ions tomorrow. Will report.

chemoleo - 18-7-2006 at 15:04

You could easily determine the density by the way. Just take a number of pellets, and put them in a measuring cylinder where water is in it to a certain mark. Then weigh the dry pellets, and voila, the density.

If it is tin then you can do a quick test - take one pellet with two strong pliers, and bend it. If it is tin, it makes a screeching noise, which results from the tin crystals being broken.

However, it is possible that some other metals do this too, but simply aren't so famous for it.

YT2095 - 19-7-2006 at 01:27

the first thing I`de try would be a magnet, that eliminates 4 metals, then a color test of the salts, a flame test for color or a borax bead test is also good.
and as mentioned the all critical mass/volume test.

sometimes it`s worth getting a periodic table and making many photocopies of it, and using that as a Tick-Off list, to narrow the options down :)

AllanD - 19-7-2006 at 15:40

I once found an unlabeled jar of granulated metal in the lab
when cleaning, my boss said "chuck it", So I did, into the "save for personal purposes" box....

I'm real glad I did, because as it turned out it was a bit over
100gms of Pt...

You say "dense" but don't say how dense.

Is it soft? Malleable?
are the granules shiny or dull?
Can they be pressed or formed into shiny bits?

Don't discount the possibility of it being Sb or
or metallic As (bad news)

AllanD

Brie - 27-7-2006 at 14:07

Quote:
Originally posted by AllanD
I'm real glad I did, because as it turned out it was a bit over
100gms of Pt...



*whistles* :o
yay for "acquiring" things like this...

Jdurg - 29-7-2006 at 17:27

You can probably rule out arsenic because "metallic" Arsenic will tarnish VERY rapidly in open air into a dull grey, non-metal like mass.

unionised - 31-7-2006 at 11:46

If you think its Sn or Zn, cast it into a bar, bend it and listen. Tin cries, zinc doesn't. (Sn isn't the only metal that does this but IIRC the others have very low meilting points).

12AX7 - 2-8-2006 at 15:06

Eh, zinc cries for me. I must be a depressing person... even annealed iron sometimes does (somewhat differently).

For that matter, last year when explaining "tin cry" in class... they used zinc rods...cheapasses!

Tim

IrC - 2-8-2006 at 23:41

I thought tin cried because it does not have a magnetic personality and cannot get women.

OK, crystal structure, blah blah blah.