I was making sodium potassium tartrate from pottasium bitartrate and sodium carbonate. I dissolved both in water and they reacted to form CO2. I spent
about an hour evaporating away the water with an alcohol burner. Then, not having time to continue the reaction, i stopped. I expected crstallization
to perhaps occur over the few days i left it. It didnt. Today, when i picked the beaker there was a clear liquid. I didn't check if it was congealed
or not. Then, using a hotplate i continued to boil it down, expecting a crystal precipitant.
The solution boiled and after a while i turned down the heat. Then it bubbled like it was much more viscous. Slow, large bubbles. The vapors began to
smell sweet. Is this characteristic of sodium potassium tartrate? It didn't exactly crystallize, just kind of congealed.
Perhaps i boiled away all the solvent and it hasn't crystallized yet. Perhaps it was super saturated. Perhaps my reagents were impure? I don't know.
Information would be appreciated though.
Chemkid
[Edited on 22-12-2007 by chemkid]
[Edited on 22-12-2007 by chemkid]YT2095 - 22-12-2007 at 10:13
Rochelle salt is soln is Very viscous, if you heat further, the tiniest nucleation site will turn the whole lot into compact "Snow" within minutes
when it`s cold
ideally to need to take a small amount of this and dry it in a Warm place (not Hot just warm) and then keep a few of these crystals as Seeds.chemkid - 22-12-2007 at 10:20
A few minutes later it has cooled and is now firmly stuck in my beaker. It is water soluble so at least my beakers safe . Could i perhaps dissolve the whole lot back into water the crystallize it in the
freezer? Would that keep it from sticking to my beaker again. There is no hope of scraping it out of the beaker w/o shattering it.
[Edited on 22-12-2007 by chemkid]chemkid - 22-12-2007 at 10:40
Mystery solved. It seems to have worked just fine. I got a little excited when it didn't go just exactly as i thought it would. This thread is stupid
and can probably be deleted. Anyone who tries this out, do it in an evaporating dish or a likewise sturdy vessel to scrap the crystals out. Or you can
do it as YT suggested and precipitate them.
And yes it should smell like sugar when your heating it.
ChemkidYT2095 - 22-12-2007 at 10:51
LOL, so you know what I mean by Compact "Snow"
you Can add a little more water to this and heat it gently again stirring well as it starts to liquify, but keep a few scrapes of this crystaline mass
back before you do this as Seed crystals
you can grow Fantastically large a beautiful crystals with this material!MagicJigPipe - 22-12-2007 at 13:23
How can you obtain potassium sodium tartrate from 2 substances that contain no potassium?chemkid - 22-12-2007 at 13:45
Damn good question. That would be potassium bitartrate
Chemkidnot_important - 22-12-2007 at 17:22
Two words - water bath, or steam bath might be a bit better. Evaporating to dryness, when the goal is just to crystallise from solution,
and overheating the product once the water is gone both seem to be not-uncommon errors of amateur research.YT2095 - 23-12-2007 at 01:41
Quote:
Originally posted by MagicJigPipe
How can you obtain potassium sodium tartrate from 2 substances that contain no potassium?
you can`t, but as mentioned in the OP the One substance already had one of the replaceable hydrogens taken up with a Potassium ion, tartaric acid is
Dibasic (like sulphuric) so it has a -2 charge, cream of Tartar has one free Hydrogen left, so the the Sodium takes that place.
think of KHSO4, it`s still acidic and works a little like a Monobasic acid.
I`m sure someone will be able to explain it little better than myself a bit later
. Could i perhaps dissolve the whole lot back into water the crystallize it in the
freezer? Would that keep it from sticking to my beaker again. There is no hope of scraping it out of the beaker w/o shattering it.