Question

Would a precipitate form if a solution contained 8.0 x 10-4 m silver nitrate and 1.8 x 10-4 m potassium chromate? you will have to find ksp values from your text or from another source.

Answer 1

Chemical reaction: 2Ag⁺(aq) + CrO₄²⁻(aq) → Ag₂CrO₄(s).
Ksp(Ag₂CrO₄) = 1,1·10⁻¹².
[Ag⁺] = c(AgNO₃) = 8.0·10⁻⁴ M.
[CrO₄²⁻] = c(K₂CrO₄) = 1.8·10⁻⁴ M.
Q(Ag₂CrO₄) = [Ag⁺]²·[CrO₄²⁻]. 
Q = (8.0·10⁻⁴ M)² · 1.8·10⁻⁴ M.
Q = 1.152·10⁻¹⁰.
Q > Ksp, a precipitate of silver chromate will form.
Ksp is the solubility product constant for a solid substance dissolving in an aqueous solution.

[Ag⁺] is equilibrium concentration of silver cations.
[CrO₄²⁻] is equilibrium concentration of chromate anions.