Solubility of Compounds in Water and Saturated Solutions

CSEC CHEMISTRY
NOTES ON SOLUBILITY OF COMPOUNDS IN WATER and SATURATED SOLUTION

Reference: Chemistry, a Concise Revision Course for CXC by Anne Tindale
From Chemistry for CSEC by Tania Chung-Harris and Mike Taylor

Factors that influence solubility
Temperature
* The solubility of solids in liquids generally increases as temperature increases. * The solubility of gases in liquids generally decreases as temperature increases. (gases are less soluble in warm water than in cold water).

Pressure * The solubility of gases in liquids increases as pressure increases (gases dissolve more in liquids at higher pressure).

Type of solvent * ionic materials dissolve in water (to form aqueous solutions) * covalent materials dissolve in covalent liquids (to form non-aqueous solutions)

Solubility
The maximum amount of solute that can be dissolved in a given quantity of solvent at a specific temperature.

Saturated solution
At a given temperature, the solution that results when the maximum amount of a substance has dissolved in a solvent.

Supersaturated solution
A solution that contains more of the solute than is present in a saturated solution.

Solubility of some compounds (salts, hydroxides and oxides) on water
We’ll return to this information next term for the topic – Acids, Bases and Salts

Salts, oxides, and hydroxides are IONIC compounds. Some salts, oxides and hydroxides are soluble in water and some are insoluble. The reason some ionic compounds are insoluble in water is given here.

All NITRATE compounds are soluble in water e.g. * sodium nitrate * ammonium nitrate * copper (II) nitrate * lead (II) nitrate * zinc nitrate * potassium nitrate

All POTASSIUM, SODIUM and AMMONIUM compounds are soluble in water e.g. * ammonium chloride * sodium sulphate * potassium carbonate * sodium hydroxide * potassium oxide

Table I showing rules for solubility in water SALTS | SOLUBLE