1. Reactions in Solution
Electrolytes

2. Solutions: Homogeneous mixtures of two or more pure substances.
The solvent is present in greatest abundance.
All other substances are solutes.

3. Dissociation
When an ionic substance dissolves in water, the solvent pulls the individual ions from the crystal and solvates them.
This process is called dissociation.

4. Electrolytes
Substances that dissociate into ions when dissolved in water.
A nonelectrolyte may dissolve in water, but it does not dissociate into ions when it does so.

5. Electrolytes and Nonelectrolytes
Soluble ionic compounds tend to be electrolytes.

6. Electrolytes and Nonelectrolytes
Molecular compounds tend to be nonelectrolytes, except for acids and bases.

7. Electrolytes
A strong electrolyte dissociates completely when dissolved in water.
A weak electrolyte only dissociates partially when dissolved in water.

8. Strong Electrolytes Are…
Strong acids

9. Strong Electrolytes Are…
Strong acids
Strong bases

10. Strong Electrolytes Are…
Strong acids
Strong bases
Soluble ionic salts

11. Solubility

12. Factors Affecting Solubility
Chemists use the axiom “like dissolves like”:
Polar substances tend to dissolve in polar solvents.
Nonpolar substances tend to dissolve in nonpolar solvents.

13. Factors Affecting Solubility
The more similar the intermolecular attractions, the more likely one substance is to be soluble in another.

14. Factors Affecting Solubility
Glucose (which has hydrogen bonding) is very soluble in water, while cyclohexane (which only has dispersion forces) is not.

15. Factors Affecting Solubility
Vitamin A is soluble in nonpolar compounds (like fats).
Vitamin C is soluble in water.

16. Polarity

17. Polarity Unequal electronegativities create polar bonds.
But just because a molecule possesses polar bonds does not mean the molecule as a whole will be polar.

18. Polarity
By looking at the dipoles and the shape of the molecule, one can determine if there exists two types of dipoles on the exterior of the molecule = polarity.

19. Polarity

20. Ion-Dipole Interactions
A fourth type of force, ion-dipole interactions are an important force in solutions of ions.
The strength of these forces are what make it possible for ionic substances to dissolve in polar solvents.

21. Dipole-Dipole Interactions
Molecules that have permanent dipoles are attracted to each other.
The positive end of one is attracted to the negative end of the other and vice-versa.
These forces are only important when the molecules are close to each other.

22. Dipole-Dipole Interactions
The more polar the molecule, the higher is its boiling point.

23. Hydrogen Bonding
The dipole-dipole interactions experienced when H is bonded to N, O, or F are unusually strong.
We call these interactions hydrogen bonds.

24. Hydrogen Bonding
Hydrogen bonding arises in part from the high electronegativity of nitrogen, oxygen, and fluorine.
Also, when hydrogen is bonded to one of those very electronegative elements, the hydrogen nucleus is exposed.

25. Unit 3: Reactions
In this unit we will memorize what forms a precipitate (activity)
We will classify types of reactions and practice predicting products (activity)
We will review acid-base reactions
We will review redox reactions
We will perform a redox titration lab…cool stuff!