[alt-photo] Re: Decreasing volumes of H2O2

[Alberto Novo]

Joao, 

> I'd like to start again mordançage.
> The formula I had (and lost)  asked for some 200 vol. H2O2.
> The formulas I found today ask for 40 volumes H2O2.
> How do I conver the volumes? From 200 and 135 to 40?

Volume strength is the volumes of oxygen liberated by one volume of hydrogen 
peroxide solution. One mole (34.02 g) of H2O2 gives 1/2 moles of O2, that is 
(@ 0°C and 1 atm) 22.414/2 = 11.2 volumes of oxygen.
So, converting from volumes to volumes is equal to converting from moles/L 
to moles/L.
So, to convert from volumes to volumes it is enough to apply the simple 
"cross rule". For example, from 200 to 40 vols: 

200    40
  \ /
   40
  / \
0    160
     ---
     200 

Take 40 parts (volumes) of 200 vols. and 160 parts of pure water (0 vols) to 
make 200 parts of 40 vols. solution. 

Alberto
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