When dissolved ions form a solid.
A saturated solution is at its equilibrium solubility for given conditions; an unsaturated one can dissolve more solute. A supersaturated solution contains more dissolved solute than the stable equilibrium amount and can crystallise. Solubility varies with temperature and substance; warming often reduces gas solubility.
Mixing soluble salts can produce an insoluble combination of ions. A net ionic equation omits spectators and conserves both atoms and charge. For example, silver ions and chloride ions form AgCl(s), while sodium and nitrate may remain spectators.
How much crystallises?
Explore the relationship
An illustrative salt has solubility (20 + 0.5T) g per 100 g water. Saturated solution, no evaporation.
Tap or focus a plotted point to read its values.
View plotted data as a table
| Series | Final temperature / °C | Mass remaining dissolved / g |
|---|---|---|
| Mass remaining dissolved / g | 0 | 20 |
| Mass remaining dissolved / g | 1 | 20.5 |
| Mass remaining dissolved / g | 2 | 21 |
| Mass remaining dissolved / g | 3 | 21.5 |
| Mass remaining dissolved / g | 4 | 22 |
| Mass remaining dissolved / g | 5 | 22.5 |
| Mass remaining dissolved / g | 6 | 23 |
| Mass remaining dissolved / g | 7 | 23.5 |
| Mass remaining dissolved / g | 8 | 24 |
| Mass remaining dissolved / g | 9 | 24.5 |
| Mass remaining dissolved / g | 10 | 25 |
| Mass remaining dissolved / g | 11 | 25.5 |
| Mass remaining dissolved / g | 12 | 26 |
| Mass remaining dissolved / g | 13 | 26.5 |
| Mass remaining dissolved / g | 14 | 27 |
| Mass remaining dissolved / g | 15 | 27.5 |
| Mass remaining dissolved / g | 16 | 28 |
| Mass remaining dissolved / g | 17 | 28.5 |
| Mass remaining dissolved / g | 18 | 29 |
| Mass remaining dissolved / g | 19 | 29.5 |
| Mass remaining dissolved / g | 20 | 30 |
| Mass remaining dissolved / g | 21 | 30.5 |
| Mass remaining dissolved / g | 22 | 31 |
| Mass remaining dissolved / g | 23 | 31.5 |
| Mass remaining dissolved / g | 24 | 32 |
| Mass remaining dissolved / g | 25 | 32.5 |
| Mass remaining dissolved / g | 26 | 33 |
| Mass remaining dissolved / g | 27 | 33.5 |
| Mass remaining dissolved / g | 28 | 34 |
| Mass remaining dissolved / g | 29 | 34.5 |
| Mass remaining dissolved / g | 30 | 35 |
| Mass remaining dissolved / g | 31 | 35.5 |
| Mass remaining dissolved / g | 32 | 36 |
| Mass remaining dissolved / g | 33 | 36.5 |
| Mass remaining dissolved / g | 34 | 37 |
| Mass remaining dissolved / g | 35 | 37.5 |
| Mass remaining dissolved / g | 36 | 38 |
| Mass remaining dissolved / g | 37 | 38.5 |
| Mass remaining dissolved / g | 38 | 39 |
| Mass remaining dissolved / g | 39 | 39.5 |
| Mass remaining dissolved / g | 40 | 40 |
| Mass remaining dissolved / g | 41 | 40.5 |
| Mass remaining dissolved / g | 42 | 41 |
| Mass remaining dissolved / g | 43 | 41.5 |
| Mass remaining dissolved / g | 44 | 42 |
| Mass remaining dissolved / g | 45 | 42.5 |
| Mass remaining dissolved / g | 46 | 43 |
| Mass remaining dissolved / g | 47 | 43.5 |
| Mass remaining dissolved / g | 48 | 44 |
| Mass remaining dissolved / g | 49 | 44.5 |
| Mass remaining dissolved / g | 50 | 45 |
| Mass remaining dissolved / g | 51 | 45.5 |
| Mass remaining dissolved / g | 52 | 46 |
| Mass remaining dissolved / g | 53 | 46.5 |
| Mass remaining dissolved / g | 54 | 47 |
| Mass remaining dissolved / g | 55 | 47.5 |
| Mass remaining dissolved / g | 56 | 48 |
| Mass remaining dissolved / g | 57 | 48.5 |
| Mass remaining dissolved / g | 58 | 49 |
| Mass remaining dissolved / g | 59 | 49.5 |
| Mass remaining dissolved / g | 60 | 50 |
Explore: Cool the illustrative saturated solution. How much solute can remain dissolved?
A salt dissolves 40 g per 100 g water at 60 °C and 25 g at 20 °C.
- Cooling a saturated solution made with 100 g water reduces the dissolved capacity by 15 g.
- If equilibrium is reached with no water loss, 15 g crystallises.
Assumed knowledge
Ionic formulas and balancing.
Learning checkpoints & source
YOUR LEARNING CHECKPOINT- Distinguish saturated and unsaturated solutions.
- Apply solubility rules and write net ionic equations.