Solubility of Barium sulfate and calcium sulfate

[Kathryn]

Hi
What molarity do you use for barium sulfate and calcium sulfate for precipitation pracs? I made 0.1M solutions but they are very cloudy. I have even diluted the barium sulfate down to 0.01M and it is still cloudy. Should I be doing something to increase the solubility?

Kathryn

[Jazz]

barium sulfate is insoluble in water, calcium sulfate has limited solubility 0.2gr per 100 mL
https://en.wikipedia.org/wiki/Solubility_table

[Rock]

Hi Kathryn,
Usually barium sulphate is one of the precipitates in precipitation pracs. Are you looking at the products from the prac rather than the solutions needed? Maybe check with the teacher exactly what they are doing.

[Kathryn]

They are for precipitation pracs - so she has a laminated chart with cations on one side and anions on the other including both calcium sulfate and barium sulfate. The students have to determine which reactions produce a precipitate. Bit hard if you are starting with a cloudy solution.

[Kathryn]

Actually I have just noticed in "The Laboratory" it says to filter CaSO4