RE: bichromate gum

[Loris Medici <mail@loris.medici.name>]

Indeed. There are two forms of NaDi: anhydrous and dihydrate. My
calculation was made according to dihydrate -> since that's what you
"usually" get from the chemical suppliers. Maybe Judy's NaDi was the
anhydrous form, therefore in her experience NaDi was faster than KDi at
the same w/v strength.

Lets re-make the calculation for anhydrous NaDi:

[KDi Strength] * ( [NaDi m.w.] / [KDi m.w] ) = [equiv. NaDi Strength]

10% * ( 262.01 / 294.19 ) = 8.9% (~ 9%)

So, 8.9-9% NaDi is virtually the same as 10% KDi (or 8.5% NH4Di)...

Thank you for the remark Alberto.

Regards,
Loris.


12 Temmuz 2008, Cumartesi, 8:15 am tarihinde, Alberto Novo yazmış:
> The "reply-to" of Loris' message was set to his personal address instead
> of
> The List, so I post my reply again
>
>
>>    sodium dichromate's (NaDi) molar mass is 298.02g
>
> this is for Na2Cr2O7.2H2O.
> For the anhydrous form, the M.W. is 262.01. In this case the math changes
> accordingly.
>
> Alberto