• For solids dissolving to form aqueous solutions

○ Ksp = solubility product constant =

■ Ksp value depends on ion concentration → more cations & anions = higher value

■ Solids not included in equilibrium expression because their concentration do not change

■ Only affected by temp

• Solubility = s = concentration of solid that dissolves

○ Solubility has the same units as molarity (moles/liters)

○ Solubility can vary with different factors → can speed or slow down the attainment of equilibrium but not its value

■ Ex: Speed up by increasing surface area (grinding up the solid or stirring the solution); decrease as with common ion effect

Solubility Product Practice

• Type 1: Given solubility → calculate Ksp value

1. Write out balanced equation & ICE table

○ S instead of x → solubility is our s that will plug in

• Type 2: Given Ksp → calculate solubility:

2. Write out balanced equation and ICE table

○ Solve for s

Relative Solubilities

• In questions, will be given salts and must be able to decide which one is more soluble/greater molar solubility
• Ksp will only allow us to compare the solubility of salts that fall apart into the same number of ions

○ Bigger Ksp value = more soluble

Ex: same number of ions so can compare

Ex:  diff number ions so can’t use Ksp to compare

■ Will have to solve for solubility (s) and compare those → bigger s value = more soluble

Calculations Involving Precipitation/Will a Precipitate Form?

• Must calculate Q and compare it to Ksp

• Focus on the compound whose Ksp value has been given and write balanced equation for how it breaks up
• Steps:
1. Set up Q using FINAL Molarity (if not given use M1V1 = M2V2)

■ Do M1V1 = M2V2 for both solutions → plug in the 2 M2 into Q

Note: V2 = volume of the 2 solutions combined; M2 = concentration of the ion

• Q > Ksp → Precipitation
• Q < Ksp → No precipitate
• Q = Ksp → Equilibrium