13 Solubility Ksp Help Sheet - Solubility Product Constant(Ksp Insoluble Salts(Ionic Compound dissociate to a very small extent so it becomes a

# 13 Solubility Ksp Help Sheet - Solubility Product...

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AP Chemistry Solubility Product Help Sheet Solubility Product Constant (K sp ) Insoluble Salts (Ionic Compound) dissociate to a very small extent so it becomes a reversible dissociation process. For equilibrium to be established, there must be small amount of dissociation of the salt and there must be some solid salt in the solution. Only insoluble salts can establish this equilibrium. Insoluble salt solution at equilibrium is a saturated solution. Soluble salts dissociate completely and therefore is not reversible and so no equilibrium. Dissociation of Salts Equation: (Writing Equations) AgCl (s)  Ag + + Cl - Ag 2 SO 4(s)  2Ag + + SO 4 -2 Solubility Product Expression(K sp ): K sp = [Cation] coeff [Anion] coeff K sp = [Ag + ][Cl - ] = x 2 K sp = [Ag + ] 2 [SO 4 -2 ] = 4x 3 Solving K sp Problems: 1. Solubility (x) = the amount of insoluble salt that dissolved and dissociate into ions, so solve for [ions] or x , use mole ratio of salt to ion to solve for grams/liter if needed. 2. Solubility product constant (K sp ) = solve for K sp . Precipitation Problems: Insoluble Salt In a precipitation reaction, the precipitate will form only if the concentration of ions of the insoluble salt is greater than the solubility concentration. When Q>K