Solubility
Definition and meaning of Solubility in chemistry.
Solubility is the maximum amount of a solute that can dissolve in a given amount of solvent at a specific temperature and pressure, forming a saturated solution.
In more detail
Solubility is heavily temperature-dependent. For most ionic compounds, solubility increases at higher temperatures because increased molecular motion and thermal energy help overcome the ionic attractions in the crystal lattice. Gas solubility, conversely, decreases with temperature but increases with pressure. The empirical principle "like dissolves like" successfully explains solubility trends: polar solvents readily dissolve polar solutes, while nonpolar solvents dissolve nonpolar solutes. Chemists express solubility in various units such as grams per 100 mL solvent, molarity (mol/L), or mass percentage to predict whether precipitation will occur when solutions are mixed and to design solutions with specific concentrations.
Key facts
| Field | Physical Chemistry |
|---|---|
| Common units | grams per 100 mL solvent, mol/L (molarity), percentage |
| Key principle | Like dissolves like: polar solvents dissolve polar solutes |
| Temperature effect | Most ionic solids increase with temperature; gases decrease with temperature |
Sodium chloride (NaCl) has a solubility of approximately 36.0 grams per 100 mL water at 20°C, increasing to about 37.3 g/100 mL at 60°C.
Frequently asked questions
How is solubility different from dissolution?
Solubility is a measure of how much can dissolve (a physical property); dissolution is the process of dissolving.
Why does salt dissolve better in hot water?
Higher temperature increases molecular motion, providing energy to overcome ionic bonds in the salt crystal structure, allowing more ions to enter solution.