[alt-photo] Re: Math mystery

[Philippe Berger]

Il suffit d'appliquer la règlette proportionnelle de la chimie analytique.
On étudie cette formule analtytique en première candidature de chimie.
C'est sans problème réel

Philippe Berger

mineurdecharbon at skynet.be
http://www.philippeberger.net/

----- Original Message ----- 
From: "Jacques Kevers" <jacqueskv at gmail.com>
To: "The alternative photographic processes mailing list" 
<alt-photo-process-list at lists.altphotolist.org>
Sent: Thursday, February 28, 2013 8:30 PM
Subject: [alt-photo] Math mystery


> Hi,
> I have a problem to understand the math behind this (related to making a
> hardening solution with formalin):
> "Add 25ml of formalin to 1,000ml of distilled water which makes a 3%
> formalin hardening solution."
> I mean, even if the formalin is 100% pure, 25 ml on 1000 is only 2.5% ,
> right?
> So, when using a 37% solution of formalin, I would think that you have to
> use around 80ml of the formalin solution...
> What am I missing?
> Thanks,
> Jacques
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