Re: Hydrogen Peroxide Warning

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alnovo@inwind.it
Date: 03/01/01-02:01:24 AM Z


> I find this discussion on peroxide both alarming and confusing. 35% seems a
> little extreme and potentially dangerous. We buy peroxide from pharmacies
> here at either 20 or 30 vols which I assume means 2 or 3%.
> Randall Webb
>

the concentration of H2O2 in vols means: "volumes of O2 (oxygen) that 1 vol of solution of H2O2 can liberate from its decomposition".
So, a 10% H2O2 is about 100/34 (mol. weight of H2O2) = about 1.47 moles of H2O2 in 1 dm3 of solution. Every mole of H2O2, decomposing, yelds 1 mole of H2O and 1/2 mole of O2. As 1 mole of perfect gas, at 273 Kelvin degrees (0 centigrades) and at sea level pressure, has a volume of 22.4 dm3, 1.5 moles of O2 will have a volume of 1.47*22.4 = 32.9 dm3.

The ratio between % and vols is then 3.3. A 20 and 30 vols solutions are respectively equivalent to 6.6 and 9.9%

Alberto


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