FotoDave@aol.com
Wed, 13 Jan 1999 14:53:02 -0500 (EST)
In a message dated 1/13/99 1:36:19 AM Pacific Standard Time,
henk.thijs@eurocontrol.be writes:
> What about the Am.Dichromate in that sense, any chance that solutions in
> brown
> bottles will change if not kept in the dark?
Henk,
Dichromate will lose strength with age. I believe Judy mentioned this in the
first or second issue of the journal.
I don't know whether the loss of strength is caused by some chemical reaction
or simply precipitation. For my case, the bottom and side of the bottle is
covered by a layer of precipitate. Warming the bottle didn't re-dissolve it.
About 2 weeks ago I ran into special problem with this losing of strength. All
my tests didn't seem to work.
As you all know that I am crazy, I did the following check: I carefully
measured and weighed my dichromate solution and with calculation, I found that
it was about 4% when it was about 11-13% when prepared in the summer. And
after another calculation, I added an amount of dichromate (I use potassium)
to make the solution 10%.
And the solution did become "up to speed" again. :-)
Dave
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