vampirexevipex
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Copper ammonia complex
Hello i recently reacted Copper hydroxide and Ammonia, everything went well; the reaction was deep blue color but... i saw some weird white
precipitate (WDF?). The copper hydroxide i used was pure without contaminants, but i also saw that the ammonia had the same white precipitate. Could
this be a contaminant? I bought the ammonia and it already had that, could it be the ammonia or a contaminant? I've been searching and the ammonia
doesnt suppose to have that. Also, why when i reacted ammonia and copper hydroxide, why most of the copper hydroxide didn't dissolve? even with excess
ammonia. Can someone answer my questions?
[Edited on 22-02-12 by vampirexevipex]
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Hexavalent
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Are you certain that the hydroxide was pure? It begins reacting to form copper oxide almost immediately and could have been mixed with a small amount
of, say, copper carbonate to begin with.
Where did you get your ammonia?
"Success is going from failure to failure without loss of enthusiasm." Winston Churchill
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vampirexevipex
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I got the hydroxide when i did electrolysis in aqueous sodium carbonate with copper anodes (i used a copper anode and a copper cup  ) then i filtered it and washed it a couple of times with water and poured ammonia
through the the filter so only the disolved copper goes through, but some of the copper didn't dissolve. And the ammonia, i got it from a local
supermarket. It says its pure 10% ammonia and the rest is water.
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sargent1015
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what brand ammonia?? Did you check the MSDS?
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Hexavalent
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That was what I was thinking of, sargent; a dissolved impurity in the ammonia.
OP - when you shake the ammonia, do you see bubbles form? Does the solution soap/foam up when agitated??
As you used sodium carbonate for the electrolysis, there is a chance that you also have produced some copper carbonate that doesn't complex with
ammonia easily because of its physical properties. Some copper oxide may also have formed by the decomposition of the copper hydroxide, which would
present the same problem as before.
If I were you, I'd just filter the mixture off and see what colour the filtrand is....report back with your findings.
[Edited on 9-6-2012 by Hexavalent]
"Success is going from failure to failure without loss of enthusiasm." Winston Churchill
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vampirexevipex
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Ok, i filtered it and the solution, is deep blue (copper ammonia complex), and the solution still has the annoying precipitate.
Oh and no bubbles neither foam form when its agitated, just the annoying precipitate i cant filter out of the solution (fine white particles).
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sargent1015
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Was the filter paper just a coffee filter? Do you have any finer paper?
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vampirexevipex
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Right now im using coffee filters, and no i dont have any finer paper...
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sargent1015
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There's really no way to tell what the mystery substance is unless you can separate it out from the solution 
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triplepoint
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It is possible that you had impurities in your copper that led to the mystery pcipitate. I dealt with the same thing recently while seeking to
produce CuAc.
Also, you say that only the dissolved copper goes through your filter. You are assuming that and it may not be accurate. It sounds to me like other
dissolved substances or fine suspended solids may be making it through your filtering process.
Even though this can be frustrating, to me it is also satisfying to see the ways in which real life is more complicated than things seem when simply
theorized.
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SulfurApothecary
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Hmm... Separate it from solution and take the melting point of it. Also, get a different brand of ammonia and repeat the reaction, see if your NaOH to
form the Cu(OH)2 had any impurities. That might be it...
You can't arrest me, it was for science!
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