rawls423 Posted January 13, 2014 Share Posted January 13, 2014 Hi, I have the following information and am wondering if it is possible to calculate the pH. I do not know anything more specific about the alkalinity. All concentrations are mg/L. The sample is open to the atmosphere Ba ++ 383Ca ++ 2438Fe ++ 5.904K+ 109.1Li+ 24.9Mg++ 238Mn++ 1.672Na+ 11786.4SiO2 (aq) 42.55Sr++ 431.2Cl- 23100.0SO4-- 35.5Br- 263NO3- 17.9Carbonate Alkalinity 292 mg/L as CaCO3 Thank you! Quote Link to comment Share on other sites More sharing options...
Brian Farrell Posted January 15, 2014 Share Posted January 15, 2014 Hi, The GWB programs require you to set pH explicitly when using the alkalinity to constrain the total carbonate component concentration. Typically when you measure alkalinity you should measure the initial pH as well. Autotitrators that record pH as acid is added are really nice for this. If you had this information, you would use SpecE8 to add each of the above species to the Basis pane and set their values with mg/l units. For HCO3-, you would set the concentration to 292 with units mg/l_as_CaCO3. For H+, you would choose pH units. Since you know the fluid is open to the atmosphere, you might guess the pH and run the equilibrium model to determine the CO2 fugacity. Use trial and error to find a pH that yields a log CO2 fugacity of -3.5. Hope this helps, Brian Farrell Geochemist Aqueous Solutions LLC Quote Link to comment Share on other sites More sharing options...
rawls423 Posted January 17, 2014 Author Share Posted January 17, 2014 Yes it does, thank you! Quote Link to comment Share on other sites More sharing options...
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