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gas % to ppm conversion

Posted: Mon Dec 21, 2015 10:33 am
by peerm.abdul
Greeting guys,



I need help to convert gas % to ppm, here are the gases:

H2: 40%
CO2: 35%
N2: 20%
O2: 5%

Thanks. I

Re: gas % to ppm conversion

Posted: Mon Dec 21, 2015 2:33 pm
by rb6banjo
I always think about gas-phase ppm as "µmoles analyte/mole of ideal gas". So, for 5% O2:

0.05 mole O2/mole of ideal gas x 10^6 µmole O2/mole O2 = 50,000 ppm O2

etc. It turns out that the volume ratio is the same as the molar ratio (transformation using the ideal gas law, at a fixed pressure and temperature of course). I just like to think about concentrations in terms of some type of mass relationship.

Re: gas % to ppm conversion

Posted: Tue Dec 22, 2015 3:23 pm
by AICMM
Are you asking about converting to weight ppm? As in trying to do a mass balance?

Best regards,

AICMM

Re: gas % to ppm conversion

Posted: Tue Dec 22, 2015 10:41 pm
by la_donz27
Simple. There are one million "parts per million" in any mixture. When using percentage, 100.0000% is useful to consider. Thus, 0.0005% is 5 ppm. It follows that 1% is 10,000 ppm, and 6.5% is 65,000 ppm. And so forth. See the pattern?

Merry Christmas!