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Topic: PLEASE HELP IDENTIFY THIS UNKNOWN  (Read 6166 times)

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Offline avpunresponsive

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PLEASE HELP IDENTIFY THIS UNKNOWN
« on: December 13, 2007, 03:48:06 PM »
i'm in ap chemistry. we did a lab on solubility and molecular structure. we used iodine and KMnO4 crystals and put them in test tubes of water, ethanol, cyclohexane, and ethylene glycol. like dissolves like. we also used an unknown. if anybody can identify what the unknown is based on these pictures, PLEASE DO!
links go to tinypic.com - image uploader
much appreciated =]

http://tinypic.com/view.php?pic=6sq3t47&s=1
http://tinypic.com/view.php?pic=7yfrha0&s=1
http://tinypic.com/view.php?pic=6ugix6t&s=1

sorry about the fuzzy pictures. but that's the right color.
crystals are about 1mm-2mm large. orangy color ish. kind of see through

Offline agrobert

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Re: PLEASE HELP IDENTIFY THIS UNKNOWN
« Reply #1 on: December 13, 2007, 11:34:36 PM »
Maybe potassium dichromate.  If it is, its a pretty carcinogenic unknown.

http://en.wikipedia.org/wiki/Potassium_dichromate
In the realm of scientific observation, luck is only granted to those who are prepared. -Louis Pasteur

Offline Rabn

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Re: PLEASE HELP IDENTIFY THIS UNKNOWN
« Reply #2 on: December 17, 2007, 06:07:20 AM »
Potassium Dichromate is straight out..there was no chromium listed as a reacted. Secondly Erin Brockavich wouldn't be happy about it. Now onto your problem. Look at how KMnO4 and Iodine may or may not react with your particular organic reactants. Also find out about any special uses either have in the identification of organics. I can assure you that once that information sought out, the answers will be readily apparent.

Offline agrobert

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Re: PLEASE HELP IDENTIFY THIS UNKNOWN
« Reply #3 on: December 17, 2007, 04:10:33 PM »
Potassium Dichromate is straight out..there was no chromium listed as a reacted. Secondly Erin Brockavich wouldn't be happy about it. Now onto your problem. Look at how KMnO4 and Iodine may or may not react with your particular organic reactants. Also find out about any special uses either have in the identification of organics. I can assure you that once that information sought out, the answers will be readily apparent.

I think they used this orange unknown, not made it.  OP wants to knw what it is, do you have any ideas?
In the realm of scientific observation, luck is only granted to those who are prepared. -Louis Pasteur

Offline Rabn

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Re: PLEASE HELP IDENTIFY THIS UNKNOWN
« Reply #4 on: December 17, 2007, 06:06:17 PM »
Ah, well then my apologies for srtiking down your suggestion.  From the looks of the reactants and solutions I would bet is a hydrated oxidizer of some sort.  I still find it unlikely to potassium dichromate, you generally don't run into that until university, it's pretty dangerous for high schools to use it, although I've seen crazier things done. At any rate, in order to identify it I would really need more data than just a picture. I'm nearly certain that it isn't organic, those are usually small and white to light yellow crystals. I would guess it is a hydrated transition metal salt of some kind, since it's orange I would guess fome kind of Iron possibly...maybe hydrated lead nitrate. The real key to I dentifying it is what if any reactions occurred when the crystals were added to the solutions. For instance, if it was a bromine salt of some kind, which is another possibility, it would have reacted very similarly to the iodine although it would have been much more vigorous.  KMnO4 may have oxidized ethanol to to ethanoic acid, at the same time the iodine my have halogenated the double bond of the ethylene glycol. I just need more data.

Offline IITian

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Re: PLEASE HELP IDENTIFY THIS UNKNOWN
« Reply #5 on: December 18, 2007, 07:03:10 AM »
did you use a lead salt? Lead Iodide might have a similar colour as your pic!!

Offline avpunresponsive

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Re: PLEASE HELP IDENTIFY THIS UNKNOWN
« Reply #6 on: December 25, 2007, 02:48:35 PM »
alright. got it.
it's cobalt nitrate

thanks though to everybody for their suggestions

Offline IITian

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Re: PLEASE HELP IDENTIFY THIS UNKNOWN
« Reply #7 on: January 05, 2008, 10:10:09 AM »
how did you find out?

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