1. Solubility
Solubility: The maximum amount of a solute that can be dissolved in a given solvent at a certain temperature and pressure.
Try thinking of it like “solute capacity”, like the seating capacity of a restaurant
solubility = seating capacity
solute = people
solvent = seats
Every restaurant is different!

2. Solubility of Solids in Water
Solids with ionic bonds are called salts.
Ionic solids are soluble in water because the cation (+) and anion (-) can be pulled apart by the polar ends water.
Some ionic bonds are so strong that when water pulls on the ions, they don’t come apart. These are INSOLUBLE ionic salts, like marble.
Solids with covalent bonds are soluble in water if the bond is a polar covalent bond.
Sugar is polar. It has 8 –OH groups that water can make hydrogen bonds with, so sugar is very soluble.

3. Solubility of Solids
In general, the solubility of solids increases with temperature.
There are a few exceptions to this rule.
Pressure does not affect the solubility of solids.
In order to be sure about a particular substance, we can refer to a solubility graph.

4. y-axis: solubility mass of solute in a given volume
x-axis: temperature
Solubility graphs show how many grams of solute will dissolve in a set amount of solvent at different temperatures.

5. Self Test:
About how much KNO3 will dissolve in 300 grams of water at 80°C to make a saturated solution?

6. Solubility of Gases hot sodas go flat SCUBA
The solubility of a gas is affected by temperature and pressure.
Solubility is inversely proportional to temperature for gases.
The lower the temperature of the solvent,
the higher the solubility
Solubility is directly proportional to pressure for gases.
The higher the pressure,
SCUBA

7. Gas Solubility Graphs
The slope of the solubility graph for a gas is negative.
Gases become less soluble at higher temperatures.

8. Solution Concentration
Unsaturated: Less than the maximum amount of solute dissolved by solvent
Dilute: low ratio of solute to solvent
Concentrated: high ratio of solute to solvent
Saturated: Exactly the maximum amount of solute dissolved by solvent
Supersaturated: MORE than the maximum amount of solute dissolved by solvent

9. Solubility Curves Will 50 grams dissolve in 100g of water at 75°C?
For any point
below the solubility curve
the solution is UNSATURATED
Yes, it can. Will the solution be saturated, unsaturated, or supersaturated with 50 grams at 75°C?

10. Solubility Curves
Is a solution with 70g of solute dissolved at 40°C saturated, unsaturated, or supersaturated?
For any point above the
solubility curve the
solution is
SUPERSATURATED

11. Solubility Curves