Precipitation and Dissolution

solubility expression

Since the ________ has no denominator, it is a product, not a quotient.

Equilibrium

________ can be approached from either direction.

Ksp

When the ion product= the ________, the solution is saturated.

ordinary equilibria

In ________, we have a reaction quotient, Q, the products over the reactants (to the correct exponents)

point of precipitation

If Q= Ksp: the solution is saturated, just at the ________.

Ksp values

________ can be used to predict whether a precipitate will form when ions (from solutions) are added to water.

equilibrium constants

Like all ________, Ksp has a fixed value at a given temperature.

equilibrium

A(n) ________ exists between the precipitate and its ions.

Example

AgCl(s) ⇌ Ag+(aq) + Cl-(aq)     K < 1

Ksp

solubility product constant

Molar solubility

when solubility has units of moles per liter (M)

Common ion effect

the presence of an ion common to the salt REDUCES solubility

If Q > Ksp

a precipitate will form, decreasing the ion concentrations until equilibrium is established

If Q < Ksp

the solution is unsaturated, no precipitate will form, and if desired more compound can be dissolved

If Q = Ksp

the solution is saturated, just at the point of precipitation

Both complexes must have the same cation

anion ratio

When the ion product = the Ksp,

the solution is saturated

Molar solubility:

when solubility has units of moles per liter (M)