heating to solute

TERRY KING (KINGNAPOLEONPHOTO@compuserve.com)
Thu, 16 Apr 1998 17:29:00 -0400

Message text written by Phaedrus
>
I have always had to use heat to get potassium and ammonium dichromates to
go into solution. Is this wrong? And when the solutions cool, usually a
large amount re-crystalizes.

<

At normal room temperatures, about 20 C , you should be able to dissolve
about 11g of potassium dichromate when water has been added to make 100ml.
The figure for ammonium dichromate is about 33 ml. These are both
saturated solution in that the solution will not dissove any more unless it
is heated but as the solution cools the additional salt will recrystalise.
More of the solid salt will appear as the solution cools further.

If. at 20 C you have solid salt at the bottom of the bottle you know that
you have a saturated soluton.
Terry King