[robertss]

Barium Nitrate is added to 1.00L aqueous solutionc with .1 mols Potassium Carbonate and .002 mols Potassium Floride at twenty five degrees celcius. Which will precipitate first, BaC03 or BaF2? Assume no change in volume.

My answer:
Potassium Carbonate produces .1 mols CO₃^2-. Divide that by total volume (1 L) and you get a solubility of .1 M.

The Potassium Fluoride would produce .002 mols F^-. You need half the Ba⁺ to react with that though, since the formula for Barium nitrate is BaF₂. So you would need .001 mols Ba²⁺ for the barium fluoride.

Because you would need less Barium Ions for the BaF2, that would precipitate first.

Thanks!

[robertss]

Wait. They gave me the Ksp for BaCO3 and BaF2? Does that need to be part of my calculations?

[Borek]

Yes, your calculations should be based on Ksp. i don't know what you tried to do earlier - and I don't wanna know.