Chemgineer
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Copper Nitrate
So I produced some copper nitrate by reacting copper pipe with nitric acid, I then used an oven to dry the product to a solid. After grinding it into
a powder I tried to ignite some powdered sugar with it. I got a slight fizzing and some worm formations but nothing spectacular.
Is this normal for copper nitrate or does my sample still contain allot of water and this is damping down the reaction?
[Edited on 25-8-2021 by Chemgineer]
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violet sin
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If I recall correctly, aqueous made copper nitrate, cannot be dehydrated to anhydrous salt by heating without extensive decomposition to oxide or
still having hydration. Wet nitrate performs poorly, dry oxide performs poorly, at oxidizing sugar. There should be a LOT of conversations on here
about getting anhydrous copper nitrate.
If I'm wrong, I'm sure I'll be swiftly reminded by the smarter amongst us. And if that's the case my apologies for sowing disinformation.
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woelen
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Violet sin is right, heating hydrated copper nitrate leads to decomposition, with loss of HNO3 and formation of a mixed oxide/nitrate. Stronger
heating leads to complete decomposition with loss of NO2 and O2 and then only CuO remains.
Making anhydrous Cu(NO3)2 has eluded chemists until fairly recently. Not before the 1960's a method was found for making the anhydrous salt. This
requires dissolving copper metal in a solution of NO2/N2O4 in a suitable solvent (I don't remember which non-reactive solvent was used). This then
leads to solvated copper nitrate. This solvated copper nitrate then can be heated carefully to drive off the solvent and leaving copper(II) nitrate
behind. The anhydrous compound is a covalent somewhat volatile compound, which is very reactive and not commercially available. It is an expensive lab
curiousity.
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DraconicAcid
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The solvent woelen is thinking of was ethyl acetate.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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unionised
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...which is "brave".
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DraconicAcid
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Safer than ether......
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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Chemgineer
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I just spotted there is a video by NurdRage where he specifically heats copper nitrate to produce nitric acid! I sure did choose the wrong salt to
try and dry out!
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Chemgineer
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I've taken my partially decomposed sample of copper nitrate, I dissolved it in ethanol as that is what I had to hand. I've then filtered off the
oxide which wasn't soluble in ethanol and I have a clear blue solution again. I note that any kind of heating produces more green oxide but if I
leave it in an open beaker the ethanol is gradually evaporating. I plan to leave it for an extended period out of curiosity and see if anything
crystallises out of solution that is not green.
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Sulaiman
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If you seal the beaker with a sheet of filter
paper
the ethanol will evaporate away a little more slowly
but I think that moisture would be fairly well excluded due to the slightly raised internal pressure.
CAUTION : Hobby Chemist, not Professional or even Amateur
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macckone
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put two beakers in a plastic bag, one with anhydrous calcium chloride and one with your ethanol mix.
The calcium chloride will absorb any water and ethanol.
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Tsjerk
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Quote: Originally posted by Sulaiman  | If you seal the beaker with a sheet of filter
paper
the ethanol will evaporate away a little more slowly
but I think that moisture would be fairly well excluded due to the slightly raised internal pressure. |
This will unfortunately not work, water inside and outside will be in equilibrium because there is enough time to reach it. There will be a pressure
of ethanol inside the beaker concentration wise, but this won't exclude water from the outside. If there is absolute ethanol vapour inside it will
even attract water as it is hygroscopic.
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Fantasma4500
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copper sulfate and calcium nitrate works but its at about 60*C you will get nitric acid from it, it will decompose in solution giving you copper
oxynitrate i believe, turqouise colored insoluble compound sometimes used in pyrotechnics as a weak oxidizer / colorant
i really wonder what properties of anhydrous copper nitrate tetraammine would be like, the hydrated form showed quite high brisance, blowing a clean
hole in 3mm steel with just 16 grammes in a glass bottle
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