Did someone know how to transform data from gas contents (for He as example) in geothermal waters from μmol/mol to ppm. data are frequently given in both unities in different papers?
Thank you so much for your feedbacks.
Sincerly
the molecular weight of He=4 gr/mol (the conversion factor)
1 umol =10^-6 mol
10^-6mol x 4 gr/mol=4x10^-6 gr gas He =4 ppm on a mass basis
Hello El Mehdi Jeddi ,
Let me paraphrase your request. You are given the amount of helium present in water in units of μmol/mol (μmoles of He/moles of H2O), and you would like to convert the units to ppm on a mass basis (grams of He/106 grams of H2O = μgrams of He/grams of H2O). Note, the demoninator is actually the solution or mixture of H2O and He, but since the amount of He is so small compared to H2O, it (the He) can be ignored. It would seem that the original units, μmol/mol, is equivalent to ppm on a mole basis, i.e., μmoles of He/moles of H2O = moles of He/106 moles of H2O, and you simply want to convert it to ppm in a different basis, such as mass. Have I restated your question correctly? If the answer is, yes, then, I believe, the conversion should be done to both the numerator and denominator as follows to yield the desired multiplicative conversion factor (CF): [μmoles of He /moles of H2O] x [4 μgrams of He/μmole of He] x [1/(18 grams of H2O/mole of H2O)] = [μmoles of He /moles of H2O] x CF, where CF = 0.222 μgrams of He - moles of H2O/μmole He - grams of H2O.
Regards,
Tom Cuff