1. Factors Affecting Solubility
SCH 3U1
Factors Affecting Solubility

2. Solubility
Measures mass of a solute that can dissolve in a specific solvent at a certain temperature.

3. 1. Polarity Soluble Insoluble Insoluble Soluble Soluble Insoluble
NON POLAR
POLAR
Water
Cyclohexene
C6H6
CoCl2 I2
Sucrose (C12H22O11)
POLAR
Soluble
Insoluble
NON POLAR
Insoluble
Soluble
POLAR
Soluble
Insoluble
“Like Dissolves Like”

4. Sucrose has 8 polar OH groups able to form hydrogen bonds with water
1. Polarity
Solutes dissolve in a solvent with similar forces of attraction
Sucrose has 8 polar OH groups able to form hydrogen bonds with water

5. 2. Molecule Size
Molecules with small non-polar sections can be soluble in polar solvents
miscible
miscible
miscible
Decreasing solubility
Effect of polar OH predominates
Effect of non-polar portion predominates

6. 3. Temperature
Solubility of a solid solute in a liquid solvent usually increases with temperature

7. 3. Temperature
Solubility of most gases in most liquid solvents decreases with an increase in temperature

8. 4. Pressure
Increased pressure of a gas above a liquid solvent increases the solubility of that particular gas

9. Solubility Curves solubility of a solute changes with temperature
solubility of each compound is different at different temperatures
solubility of each compound changes in a different way as temperature changes

10. UNSATURATED, SATURATED AND SUPERSATURATED SOLUTIONS
UNSATURATED SOLUTION
more solute can be dissolved while the temperature remains constant
*any point in the region under the solute’s solubility curve
2. SATURATED SOLUTION
no more solute can be dissolved into the solution at a fixed
temperature
* any point ON the solubility curve
3. SUPERSATURATED SOLUTION
solution containing more dissolved solute than normal at particular temperature
unstable
may suddenly form solid crystals leaving only a saturated solution behind
* any point ABOVE the solubility curve

11. 1. Is the solution saturated, unsaturated or supersaturated if there are 20g of KNO3 at 30°C

12. 3. Is the solution saturated, unsaturated or supersaturated if there are 20g of KNO3 at 50°C
g H2O is saturated with KNO3 at 100°C. How much KNO3 will come out of solution if the temperature is decreased to 48°C?
Saturated
57 g-18 g = 39 g

13. Practice
Solubility Worksheet (SS02W)