what is the solubility of anhydrite CaSO4 at 25 celsius (ksp - 10-5) in pure?

Question

water

Answer 1

Let's assume that the molar solubility is s mole/L then

.. .. .. .. .. .. CaSO4 <=> Ca(+2) + SO4(-2)
Dissolve .. .. .. s
Produce .. .. .. .. .. .. .. .. .. .. s .. .. .. .. s
At Equil . .. .. .. .. .. .. .. .. .. .. s .. .. .. .. s

Ksp =[Ca(+2)][SO4(-2)] = s*s= s^2 =>
s= squareroot (Ksp) =SQRT(10^-5) = 3.16*10^-3 mole/L