Ksp Quiz

K_sp

solubility product constant; molar concentration of ions raised to their stoichiometric powers

What is solubility affected by?

pH and concentrations of other ions in solution; decreases wehn a common ion is added

Molar Solubility

number of moles of solute dissolving to form a liter of saturated solution; expressed in mol/L; can use stoichiometry to find it if you know molarity of products

Expressing K_sp

same as a rate law; usually no reactants since they are in the solid state

How do you write an equation for the dissolving of a precipitate?

write the equation like the precipitate is in water; ex: CaF₂ (s)

Le Chatelier’s Principle

reaction will shift away from an increase or toward a decrease

Adding a strong acid to a precipitate

will form a weak acid with an ion and with increase the solubility

Determining ion concentrations

use what is in question; find equilibrium if necessary

Calculating K_sp

convert solubility into molar solubility with molar mass; then convert into molar concentration of ions at equilibrium (ICE chart if necessary); plug the concentrations into K_sp expression

Determining the mass of solute that can dissolve in a solvent

find the molar solubility using K_sp then convert to grams

Q > K_sp

precipitate will form until equilibrium

Q = K_sp

equilibrium exists

Q < K_sp

solid dissolves until equilibrium

Selective Precipitation

removal of one metal ion from a solution

Qualitative Analysis

designed to detect the presence of metal ions

Quantitative analysis

designed to determine how much metal ion is present