[alt-photo] Re: Stoichiometry for the nonscientist

[EJ Photo]

Loris, It may be irrelevant to your take on the conversation, but for many
that don't mix it and have been told to make it acidic, they may want to
know.  I base my on the measurements that I made years ago. I did not
research it, nor did I run equations. I put a pH meter in and measured it. I
have those notes down at my studio, but if I recall correctly; 5.4 is the
number that comes to mind.  

Eric Neilsen
Eric Neilsen Photography
4101 Commerce Street, Suite 9
Dallas, TX 75226
 
www.ericneilsenphotography.com
skype me with ejprinter
www.ericneilsenphotography.com/forum1
Let's Talk Photography
 
-----Original Message-----
From: alt-photo-process-list-bounces at lists.altphotolist.org
[mailto:alt-photo-process-list-bounces at lists.altphotolist.org] On Behalf Of
Loris Medici
Sent: Thursday, August 05, 2010 4:00 PM
To: The alternative photographic processes mailing list
Subject: [alt-photo] Re: Stoichiometry for the nonscientist

  Hi Eric,

Since - in the currenct context - we are synthesizing K2C2O4, the source 
irrelevant.

http://www.chem.purdue.edu/gchelp/howtosolveit/Equilibrium/Salt_Solutions.ht
m

According to this:
"...Soluble salts that contain anions derived from weak acids form 
solutions that are basic..."
and
"...Soluble salts that contain cations derived from weak bases form 
solutions that are acidic..."

The anion in our context is C2O4(-2), comes from a relatively weak acid 
(not so weak, but definitely a lot weaker than say HCl...), and the 
cation is K(+1), and it comes from a pretty strong base. Therefore, to 
me, it seems that (pure) potassium oxalate solution (that results from a 
carefully balanced reaction) has higher chance of being basic. (Assuming 
the water content of the potassium carbonate was low...)

Also,

http://en.wikipedia.org/wiki/Basic_salt

"...Basic salts are salts which are the product of the neutralization of 
a strong base and a weak acid..."

Anyway, that's nice I'm (trying) to learn something here - it's 
definitely not simple stuff...

I 100% agree that a the result of a simple test made with a simple pH 
test paper will be definitive.

Best regards,
Loris.


05.08.2010 23:28, EJ Photo yazmış:
> Well, the best way I know is to measure it. The figures on the web, may
not
> be the ones in your possession. For this solution pH paper test indicators
> will be fine. broad range will work.
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