On Sun, 25 Apr 2004 10:09:23 +1000, Adam Seychell
<
adam_seychell@...> wrote:
> Yes, the exact amount of initial water for titration is not important.
> The
> water is generally required so you have more solution volume to look at.
> 10
> drops of solution would be difficult to see and properly mix, since if a
> small bit splashed on the side of the glass it may not get mixed and give
> false reading.
>
Yea i love it. I tried several times and found the reading is really the
same,
even with the eyedroppers...
> 3 molar HCl is not too high. The only problem with high acid is fumes. If
> HCl fumes are not a problem then you could of left it at 3 molar.
> Concentrated HCl is about 12 molar.
> http://www.howe.k12.ok.us/~jimaskew/cabconc.htm
Too high HCl attacks the steadtler RED, i want to keep it low enough.
> I found more copper is needed get get faster etching, I think the SG of
> my
> solution was around 1.25 to 1.30 . Remember HCl is consumed during
> etching
> so adding more copper means even less acid in your solution.
yes i know that and i have left a bit of room to the "ideal" fill height
for additional acid.
Today it looks much more colored already, but the hydrometer is still way
off range..
(is my assumption correct that i need to dissolve 200gram copper to raise
the density by 0,2?
in a 1l container...)
I'll try to get more copper in, and i also decided i need some of these
eyedropper bottles.
then i can keep one filled with 1mol NaOH and use the other (equal-sized)
eyedropper for the etchant.
ST