Re: Questions on Chemistry

John L. Bordley, Jr. (jbordley@seraph1.sewanee.edu)
Fri, 26 Aug 94 08:39:36 CDT

>I am aquiring the chemicals to begin making Kallitypes and have
>a few questions. The most important one concerns sodium acetate.
>I have called Bryant Lab in Berk. and was told that it comes in
>two different formulas. One with 3 molecules of water, the other
>without any water at all.. though they are both in crystal form.
>I have been unable to locate information which makes it clear
>which acetate I should be using. I have no idea. Does anyone
>out there have one?
>

Common solubility rules, as mentioned in all general chemistry texts, say
that virtually all acetates and all sodium compounds are soluble. So
solubility is not a problem. The formula weight of sodium acetate is 82
and that of the trihydrate is 136. In other words, 82 grams of sodium
acetate contains the same amount of sodium acetate as does 136 of the
trihydrate; 41 g is like 68 g, 20.5 g is like 34 g. You could use either
one, adjusting the exact amount (if that is even important!) depending on
what your recipe calls for and which form you use. In case you are
concerned about the 3 molelcues of water per formula unit of sodium
acetate, that amount of water is inconsequential when compared to the
amount of water that you will be dissolving the compound in.

>I'd also be interested in hearing the various ways ferric oxalate
>is diluted in water.

I don't understand what you are asking in this second question. Do you
mean what dilution factors do people use or what are the forms of the iron
and oxalate ions as the solid dissolves?

John Bordley
Professor of Chemistry
The University of the South
Sewanee, TN 37383