1.10 Solubility

Solubility

mass of solid that will saturate 100g of water (or solvent) at particular temperature

14g/100g water at 40°C

14g of solid is required to saturate 100g of water at 40°C

1cm³

= 1ml

1g

= 1000mg

1 litre

= 1000ml/ 1000cm³

Saturated solution

no more solute will dissolve at that temperature

Solubility curve

graph showing solubility of substance plotted against temperature

Temperature and solubility of solids

as temperature increases, solubility increases

Why crystallisation happens

solubility of salt/ solid decreases as solution cools

Hot, concentrated solution is cooled

some of the solute is deposited

Mass of solid deposited if solution containing 15g/100g of water at 30°C is cooled to 10°C

• Use solubility curve to find at 10°C (10g)

• Water can only dissolve 10g, not entire 15g

• Mass of solid deposited = 15g - 10g = 5g

Temperature and solubility of gases

as temperature increases, solubility decreases

Different substances

have different solubilities