hredzak

Absolutely, thank you Tom! 9-9-09Run.rea

Hi Tom, Okay, I think I got it - but for the mineral view I want to make sure I'm interpreting these predictions right. So basically for the barium minerals, witherite and barite will both form in the solution in small amounts (up to 10-4M), then where these curves level off it is precipitaing out of solution at that point? Thank you!

One more question, how can I tell what will be precipitated? (Can I tell what will be precipitated?) Essentially I want to know if it will be BaSO4 and see how much.

Also - I guess I need Ba++ concentration in my starting solution?

Under simple reactant - aqueous I only have BaCl+. Under minerals I have BaCl2*H2O and BaCl2*2H20. Do I have to do something to get just BaCl2 as an option? Thanks Tom!

Hi Tom, Thanks again for all you help! Now can you walk me through the steps of a BaCl2 titration into this system? Best,

If I have a partial pressure of 8mbar CO2, how do I translate that to the "log of a fugacity"? Is that an equation? How did you get -3.5?

Hi again Tom, Thanks for your patience with my many question! So I just talked with my supervisor - as for cations both Ca++ and Mg++ can be varied, as they are supersaturated in our solution. We don't know the HCO3-, can it calculate it?

Great point - I think part of the problem is that these are all the set concentrations of things we could measure. There's probably something else in the system, but we don't know what...

Hi Tom, Thanks for getting back to me. So the problem is that all those concentrations must be pretty much set. I can't allow say Na+ to change. What do you suggest I use that's not already in the picture?

Thanks Tom! So I've set HCO3- to charge balance, now I have this error: Residuals too large, 663-th interation Largest residual(s): Resid Resid/Totmol Cbasis -------------------------------------------------------- HCO3- 0.0002174 1.723e+200 4.703e-203 -------------------------------------------------------- 8-31-09 Run.rea

For some reason I'm getting this error message anyways: Caution: molality of Cl- component forced negative by charge balance: -0.0002024 *N-R didn't converge after 999 its., maximum residual = 1, Xi = 0.0000 Largest residual(s): Resid Resid/Totmol Cbasis -------------------------------------------------------- ClO4- 2.072e+006 1 3.293e-009 --------------------------------------------------------

Okay, I understand the difference btw an open and closed system. But I have somewhat of an interesting case - where the solution is exposed to and interacting with external atmosphere which has circulated into the headspace of the beaker. But it's not an open system in a traditional sense... Would this still be considered an open system or closed?

Hi, So Cl- usually comes up as the thing to be used to charge balance. But my Cl- concentration is more or less fixed, so I don't want to use that. But what else can I use that won't change my other fixed concentrations? Thanks!

Thanks! So finally I want to try the model using the pH we measured. The pCO2 is still the same (8.3mbars). How can I input this, so that it stops yelling at me that I need HCO3-? (I was guessing at HCO3- previously so I want to take this value out).