Physical Science / Unit 6: Solutions, Acids and Bases
6.2 Solubility
Notes
Solubility is the maximum amount of solute that dissolves in a given amount of solvent at a given temperature.
- Unsaturated: can dissolve more. Saturated: holds the maximum. Supersaturated: holds more than normal (unstable).
- Solids usually dissolve better in warmer water. Gases dissolve better in colder liquids and at higher pressure (a warm soda goes flat faster).
- Stirring and crushing speed up dissolving but do not change how much can dissolve.
- Example: At 20 degrees C, 36 g of NaCl dissolves in 100 g of water. If 50 g is added, 36 g dissolves and 14 g stays undissolved.
Practice
A solution contains the maximum amount of dissolved solute at its temperature. It is:
A saturated solution cannot dissolve more.
At 20 degrees C, 36 g of salt dissolves in 100 g of water. If 40 g is added to 100 g of water, how much stays undissolved?
$40 - 36 = 4$ g.
Why does a warm soda lose its fizz faster than a cold soda?
Gas solubility decreases as temperature rises.
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