Saturated Solution

A solution that cannot dissolve more solute.
Extra solute settles at the bottom as crystals.

Unsaturated Solution

A solution that can still dissolve more solute.
No solid settles at the bottom.

Making a Saturated Solution Unsaturated

• Add more solvent
  This allows more solute to dissolve. The solution becomes dilute.

• Heat the solution
  Higher temperature increases solubility of the solute.

Making an Unsaturated Solution Saturated

• Add more solute
  Keep adding solute until no more can dissolve.

• Evaporate the solvent
  Less solvent means the solution becomes more concentrated.

• Cool the solution
  Lower temperature reduces solubility, causing saturation.

FACTORS AFFECTING SOLUBILITY

1. Temperature

High temperature increases solubility of most solids.
Solvent particles move faster and dissolve solute quickly.

2. Size of Particles

Smaller particles dissolve faster than large ones.
Powders have more surface area than lumps.

3. Polarity

Polar solutes dissolve in polar solvents (e.g. salt in water).
Non-polar solutes dissolve in non-polar solvents (e.g. oil in petrol).

Ways to Increase Solubility

• Stir the solution
  Stirring spreads solute evenly and speeds up dissolving.

• Crush the solute
  Smaller particles dissolve faster due to larger surface area.

• Heat the solution
  Heat increases particle movement, helping solute dissolve quicker.