1. Solubility
The maximum quantity of the substance, expressed in grams, that will dissolve in a certain solvent at a specific temperature.

2. Solute + Solvent = Solution
Solution – a homogeneous mixture of two or more substances of ions or molecules
Solute – the part of a solution that is being dissolved (usually the lesser amount)
Solvent – the part of a solution that dissolves the solute (usually the greater amount)
Salt Water
(Solution)
Salt
(Solute)
Water
(Solvent)

3. Types of Solutions
Saturated – a solution that contains the maximum quantity of solute that dissolves at that temperature.
Unsaturated – a solution that contains less than the maximum amount of solute that can dissolve at a particular temperature.
Supersaturated – a solution that contains more dissolved solute than a saturated solution.
Supersaturated solutions can be attained by heating the solution up to dissolve more solute at that higher temperature and then letting the solution cool.
Once cooled, the solution is disturbed which causes crystals to precipitate (separate from solution) out of the supersaturated solution.

4. SUPERSATURATED SOLUTION
UNSATURATED SOLUTION
more solute can dissolve
SUPERSATURATED SOLUTION
becomes unstable, crystals form
SATURATED SOLUTION
no more solute can dissolve at given temperature
increasing concentration

5. Solubility and Temperature Increasing the temperature of a solvent speeds up the particle movement. This causes more solvent particles to bump into the solute, resulting in solute particles breaking loose and dissolving faster. Solubility Curve A graph of the solubility of a compound (grams/100 grams water on the Y-axis) at various temperatures (Celsius on X- axis). Each compound has a different curve.

6. Solubility Curve Graph *Solubility is dependent on temperature
Solubility vs. Temperature for Solids
Solubility (grams of solute/100 g H2O) KI
KCl 20 10 30 40 50 60 70 80 90
110
120
130
140
100
NaNO3
KNO3
HCl
NH4Cl
NH3
NaCl
KClO3
SO2
gases
solids
Temperature °C
Solubility Curve Graph
*Solubility is dependent
on temperature
What trends do you see on the graph?
How is the solubility of gases and solids different?
What is the solubility of NaNO3 at 50°C?
What is the solubility of NH4Cl at 90°C?

7. If you stir faster, will that make you dissolve more solute?
Solubility vs. Temperature for Solids
Solubility (grams of solute/100 g H2O) KI
KCl 20 10 30 40 50 60 70 80 90
110
120
130
140
100
NaNO3
KNO3
HCl
NH4Cl
NH3
NaCl
KClO3
SO2
gases
solids
Temperature
No, stirring allows you to dissolve substances at a faster rate, but not more of the substance.
Increasing the temperature usually does allow you to dissolve more solid solute.

8. Solubility vs. Temperature
What term describes 48g KCl at 70C?
Saturated!
What about 30g KCl at the same temperature?
Unsaturated
What about 60g KCl at the same temperature?
Supersaturated

9. Solids are more soluble at...higher temperatures.
Solids dissolved in liquid Gases dissolved in liquids To
Sol. To
Sol.
As To solubility
As To solubility
Solids are more soluble at...higher temperatures.
Gases are more soluble at...lower temperatures &
higher pressures.

10. Solubility of Sodium Acetate
Temperature (oC) 25 50 75
100
Solubility(g/100 g H2O)
150
Supersaturated
solution
Unsaturated
Saturated
on this line
Add 100 g sodium acetate into 100 g of water at 55oC.
Allow to cool to 20oC. Only 82 g of sodium acetate should remain in solution at this temperature.
Place a seed crystal in the supersaturated solution and ~18 g of sodium acetate will precipitate out of solution.
The resulting solution will be saturated.
Include a table of data for students to graph.

11. Pause for Solubility Practice of NaCl How much NaCl (in grams) can dissolve in 25 mL of distilled water at room temperature??

12. Solubility vs. Temperature
What term describes 48g KCl at 70C?
Saturated! (it’s on the line)
What about 30g KCl at the same temperature?
Unsaturated (below the line)
What about 60g KCl at the same temperature?
Supersaturated
(above the line)