1. Unit 4: Solutions and Kinetics
Solubility

2. Solubility
Solubility: the amount of a substance that dissolves in a given quantity of solvent at a given temp to form a saturated solution
Units: grams/100 grams water

3. Supersaturated Solution
More solute is dissolved than normally possible. Any point above the curve 10 20 30 40 50 60 70 80 90
100 5 15 25 35 45
Temperature (oC)
g KNO3 / 100 g H2O
Solubility Curve for KNO3

4. Saturated Solution Saturated solution:10 20 30 40 50 60 70 80 90
100 5 15 25 35 45
Temperature (oC)
g KNO3 / 100 g H2O
Solubility Curve for KNO3
Saturated solution:
Contains maximum amount of solute, will NOT dissolve any more
Any point ON the curve

5. Unsaturated Solution Unsaturated solution:10 20 30 40 50 60 70 80 90
100 5 15 25 35 45
Temperature (oC)
g KNO3 / 100 g H2O
Solubility Curve for KNO3
Unsaturated solution:
will dissolve more solute if added
Any point below the curve

6. g/100 g H2O
Solubility curves use concentrations in:
g solute/100 g H2O
To calculate:
mass solute (in grams) x 100g H2O
mass H2O (in grams)

7. Example #1:
What is the solubility of potassium nitrate at 40oC?

8. Example #2:
What is the temperature at which sodium nitrate’s solubility is 120 g/100 mL?

9. Example #3:
If you add 100 g of sodium chloride to 100 mL of water at 20oC, what mass of solid will have settled on the bottom of the dish?