# Re: SOlution Fractions

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I'm modeling the dilution/concentration of
stream solutions at 1 -> 2. Can I use the
flow volume ratios at pt.1:pt. 2 to estimate
solution fractions to compare against the
sol'n 1:sol'n 2 fractions given in Phreeqc ?
I can adjust this ratio by changing the
uncertainty limit.

I'm not sure about your setup. If streams A and B mix to form stream C,
then yes, the mixing fractions of A and B should be approximately the
relative flows of A and B.

Let me know if this is a reasonable interpretation
of solution fractions in your model.
I've also noticed that the H2O(g) mole transfer
is in the 10 to 100 range (does this limit
use of the model since it is > 1 ?).

You need to interpret the numbers carefully. All of the mole transfers,
including water, are in moles. There are 55.5 moles H2O per kilogram, so
addition of 55.5 moles of H2O would represent a dilution by a factor of 2.
Mixing fractions can be interpreted as number of kilograms of water water.
If H2O is removed (negative mole transfer), then it is probably the result
of a mixing fraction greater than 1 for one or more of the initial
solutions. There is a mole balance on H, which is essentially a mole
balance on water. If you convert everything to either moles or kilograms,
you will find conservation of water.

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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