Question

Ionic solids dissolve in water and break up into their ions. However, some ionic solids only partially dissolve, leaving a significant amount of solid undissolved. In some cases, the amount that dissolves is very small and is almost zero. A mathematical formula that indicates the extent to which an ionic solid dissolves in water is called the solubility product constant. The solubility product constant, commonly referred to as Ksp, indicates the extent to which an ionic solid dissolves. What is the Ksp for the following reaction if the concentration of Ca2+ and SO42- were both measured to be 4.89 × 10-3 M?

CaSO4(s) ⇌ Ca2+(aq) + SO42−(aq)
a. Ksp = 5.72 × 10-10
b. Ksp = 2.39 × 10-5
c. Ksp = 9.78 × 10-3
d. Ksp = 5.88 × 10-4

Answer 1

b. Ksp = 2,39×10⁻⁵

Step-by-step explanation:

For the equilibrium:

CaSO₄(s) ⇌ Ca²⁺(aq) + SO₄²⁻(aq)

The solubility product constant is defined as:

`ksp = [Ca^(2+)] [SO_(4)^(2-)]`

-The concentration of CaSO₄ is not taken into account because is a solid that has an activity of 1.-

As the concentration of both Ca²⁺(aq) and SO₄²⁻(aq) were 4,89×10⁻³ M

The ksp is:

4,89×10⁻³ M × 4,89×10⁻³ M =

b. Ksp = 2,39×10⁻⁵

I hope it helps!