jgourlay
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Tell me more about what you told me before!
In a prior thread, one of you told me that adding ethanol to copper sulfate solution would cause the copper sulfate solution to precipitate out.
I tried that this evening, and it was a smashing success all the way around, complete with the much coveted, "LOOK DADDY, IT'S WORKING IT'S
WORKING!!!"
I'd like to know more about it. What makes this work?
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12AX7
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Copper sulfate, and many other salts, are less soluble in a water-EtOH mixture, which has the same effect as changing the temperature (cooling,
usually) or removing solvent: the relative saturation becomes supersaturated and it precipitates.
The fighting force is the salt remaining dissolved, tending to dehydrate the ethanol instead. So this only works for salts that precipitate easier
than the added solvent.
Tim
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Formatik
National Hazard
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Ethanol is less polar than water, this creates a poor solubility (insoluble). The non-polarity comes from C-C and C-H bonds in the molecules. Thus,
isopropanol may even work better. Another member also explained it some time ago.
| Quote: | Originally posted by Pomzazed
Ethanol has lower polarity comparing to water. thus adding it lowering the ability of ionic species to be soluble in it. thus they precipitate out.
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[Edited on 20-10-2008 by Formatik]
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Nicodem
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Also, learn about why ionic compounds dissolve at all: http://en.wikipedia.org/wiki/Solvation (search for more info in a library)
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jgourlay
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Thanks gents!
Thanks!
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