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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: NYM on April 05, 2008, 10:25:30 AM

Title: CaSO4 - soluble in water or not?
Post by: NYM on April 05, 2008, 10:25:30 AM

Is CaSO4 soluble in water? Wikipedia contradicts itself:

From http://en.wikipedia.org/wiki/Solubility#Solubility_of_ionic_compounds_in_water:
Soluble: sulfates (except Ag+, Pb2+, Ba2+, Sr2+ and Ca2+)

From http://en.wikipedia.org/wiki/Solubility_chart: Slightly soluble.

The same question with CuX2, where X is Cl-, Br- and I.

Thank you.

Title: Re: CaSO4 - soluble in water or not?
Post by: Borek on April 05, 2008, 10:35:47 AM

That's because there are no totally insoluble salts. They all dissolve to some extent. Saturated solution of NaCl is close to 6M, saturated solution of AgI is arounf 10^-9M if memory serves me well. CaSO₄ is generally considered insoluble, but of many insoluble salts it is one of the best soluble ;)

Title: Re: CaSO4 - soluble in water or not?
Post by: NYM on April 05, 2008, 01:05:37 PM

Great, thanks!