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Re: phreeqc-2 v2.7 molarity/molality conversion oddity




Sorry about the typo, yes my first sentence should be "molarity".

> molality is moles/kg total solution and not moles/kg solvent (in this
case water)

However, "molality" is moles per kilogram water; "formality" is moles per
kilogram of solution. Whatever, I am sure that PHREEQC makes the
conversions correctly.

David


David Parkhurst (dlpark@xxxxxxxx)
U.S. Geological Survey
Box 25046, MS 413
Denver Federal Center
Denver, CO 80225

Project web page: https://wwwbrr.cr.usgs.gov/projects/GWC_coupled



                                                                                                                  
                      Eric Breynaert                                                                              
                      <Eric.Breynaert@xxxxxxxx        To:       David L Parkhurst <dlpark@xxxxxxxx>               
                      uven.ac.be>                     cc:                                                         
                                                      Subject:  Re: phreeqc-2 v2.7 molarity/molality conversion   
                      11/06/2003 01:34 AM              oddity                                                     
                                                                                                                  
                                                                                                                  




Dear Mr. Parkhurst,

Thank you very much for your fast reply. I assume you meant MolaRity is
moles/L in your
first sentence. Then it's completely clear to me. I forgot to take into
account that
molality is moles/kg total solution and not moles/kg solvent (in this case
water).

kind regards,

eric breynaert

> Molality is moles/L and the assumed density is 1.0. That implies that the
> input concentrations are equal to moles/kgsolution. To convert this to
> moles./kgw, the sum of the mass of the solutes is subtracted from 1 kg of
> solution to obtain the number of kilograms of water. The moles divided by
> the number of kilograms of water gives molality. If you increase your
> concentrations, you will see more of an affect.
>
> David
>
>
>
> David Parkhurst (dlpark@xxxxxxxx)
> U.S. Geological Survey
> Box 25046, MS 413
> Denver Federal Center
> Denver, CO 80225
>
> Project web page: https://wwwbrr.cr.usgs.gov/projects/GWC_coupled
>
>
>
>







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