1. Solutions

2. Solutions Goals a. Describe solutions in terms of • solute/solvent
• conductivity
• concentration
b. Explain factors affecting the rate a solute dissolves in a specific solvent.
c. Explain that solubility is related to temperature by constructing and reading a solubility curve.

3. A solution is made up of two parts—a solute and a solvent.
A solute is the substance being dissolved, while a solvent is the substance doing the dissolving.
For example, in a saltwater solution, salt is the solute and water is the solvent.
The ability of a substance to dissolve in another substance is called solubility.

4. Can you think of an example of each???
Types of Solutions
Liquid-liquid
Liquid-solid
Liquid-gas
Solid-gas
Solid-solid
Gas-gas
Can you think of an example of each???
Solutions Video Clip

5. Ex: Antifreeze (ethylene glycol).
Effects of Adding a Solute to a Solvent
Freezing point depression
Raising of the boiling point
Adding a solute interferes with the formation of the solid making it harder for the solvent to freeze.
Ex: Antifreeze (ethylene glycol).
Solute particles interfere with the evaporation process and more energy is needed for the molecules to escape into the gas phase.

7. Solutions and Conductivity
Solutions can only conduct electricity if the atoms ionize (break apart into ions)
Ionically bonded
Solutions that conduct electricity are called electrolytes.
Solutions that do not conduct electricity are called nonelectrolytes.
They do not produce ions in solution.
Strong vs. Weak Electrolytes
Strong: Ionize completely. NaCl
Weak: Produce few ions in solution.

8. For Gases: Pressure above the solvent
Factors affecting the rate a solute dissolves in a specific solvent.
What Affects the rate at which a solute will dissolve in a solvent?
Increased surface area increases the rate of dissolving. Remember: dissolving occurs at the surface.
Crystal Size
Temperature
For Gases: Pressure above the solvent
Increases the speed of the molecules in the solvent.
More atmospheric pressure pushing down on the solvent makes it harder for the gas molecules to escape the solvent.

9. Factors affecting the rate a solute dissolves in a specific solvent.
Polar
Molecular Structure
Nonpolar
Polar solutes ( & ionic) dissolve in Polar solvents
Nonpolar solutes dissolve in Nonpolar solvents
“Like dissolves like”
EX: Gas and Oil
EX: Water and HCl

11. Concentration Concentrated Dilute NOT VERY Precise!
A lot of solute in a little solvent
A little solute in a lot of solvent
NOT VERY Precise!
To be more precise we need to express the concentration by volume. Usually as a percentage by volume.
In order to compare concentrations, we express the amount dissolved in 100g of water.

12. Can dissolve more solute at a given temperature
Unsaturated
Saturated
Supersaturated
Can dissolve more solute at a given temperature
Contains all of the solute it can hold (MAXIUM)/ dissolve at a certain temperature
Contains more solute than a saturated solution at a given temperature. Can be created by cooling a saturated solution without disturbing it- no solute come out of solution.
MORE THAN THE MAXIUM
Clip

16. Solubility Curves As the temperature increases...
The amount of oxygen that is able to dissolve in water…
decreases.

21. Solubility Curves 50g of NaCl @ 20˚C? 56g of NaCl @ 20˚C?
30g of 120˚C?
50g of 20˚C?
56g of 20˚C?
120g of 20˚C?
How would you make a saturated sol. of KNO3 at 80˚C?
110 80 70 60 50 40 30 20 10 20 40 60 80
120
180

22. CuSO4
KBr