1. Chapter 24
Molecular Mixing

2. What is a molecule? Groups of atoms tightly bonded by covalent bonds
Examples water, oxygen, carbon dioxide

3. Rule of Charges Opposites always attract Like always repel
Atoms arrange themselves based on these two rules
e.g. Na+ will tend to attract to Cl-, but Na+ tends to push away other Na+ ions

4. Ionic Bonds
Charges are easily determined in ionic bonds…you’ve already done it….
-atoms with 3 or more valence electrons want to lose, therefore they are +
-atoms with 5 or more valence electrons want to gain, therefore they are –
Na+ Cl-

5. Covalent Bonds More difficult to determine charge
Many do not have a charge
These are called NONPOLAR molecules
They share valence electrons equally
e.g. all the diatomic elements

6. Polar Molecules Comes from the word “pole” like on a magnet
-opposite ends of a molecule have opposite charges.
*Some atoms pull shared electrons harder than other…this property is called electronegativity
*Fluorine pulls the hardest, then chlorine and oxygen.

7. Polar Molecules
Atoms that pull the hardest on the electrons have more of a negative charge
Atoms that pull the least on the shared electrons have more of a positive charge

8. The ability of Polar Molecules
Polar molecules have the ability to dissolve ionic bonds because of the charges of the ends of the covalent molecules.
Water = red & white, Chlorine = green, Sodium = orange

9. Solubility
A measure of how well a substance dissolves in another substance
Solvent- substance in the larger amount; does the dissolving
Solute- substance in smaller amount; is dissolved
In salt water—Salt is the solute, water is the solvent.

10. What makes something soluble?
Salt mixes with water, oil does not.
What is the difference?
Remember our rule of charges:
Opposites will _________________
Like will _______________

11. Solute/Solvent Relationships
The rule of whether or not something will dissolve is simple:
Like Dissolves Like
A Polar molecule will dissolve another polar molecule (salt and water)
A nonpolar molecule will dissolve another nonpolar molecule (Nail polish and nail polish remover)

12. Insoluble
Substances that do not dissolve (like oil and water) are considered insoluble
Oil is nonpolar—(has no charge at all)
Water is polar—(has a positive and negative end)
The water is attracted to itself more than to the oil so they will not mix.

13. What thing affect solubility?
Polarity/Nonpolarity is the main one
Temperature Increase
As things warm molecule movement increases
Makes things more likely to mix
Pressure Increase
As things get pushed together

14. Saturated vs. Unsaturated
All substances can only mix so much.
Once you put so much salt in water, that solution will not accept any more salt.
-It is said to be SATURATED
Before it reaches that point, those water particles can still accept more salt, so it is said to be UNSATURATED

15. Soaps and Detergents
How do soaps and detergents work on everything or do they?
There seems to be a cleaning agent for everything.
Soaps and detergents have both polar and nonpolar parts, so they are able to dissolve either kind of dirt and grime.