Question

The free energy change for dissolution of CaSO4 at 25C is 28.774kJ/mole. What is the solubility of this compound.

i got ksp
lnK = deltaG/RT
lnK= 28774/(-8.31*298)
Ksp = 2.39e-12

i don't know waht to do after this..

Answer 1

CaSO4 ==> Ca^+2 + SO4^-2

Ksp = (Ca^+2)(SO4^-2)
S = solubility CaSO4; then
S = (Ca^+2)
S = (SO4^-2)
Substitute and solve for S.

Answer 2

thanks for the help but im still not getting the right answer

Answer 3

im getting 1.54e-6