1. Today you will learn the difference between acids and bases.
pH in Chemistry
Today you will learn the difference between acids and bases.

2. Introduction
-Svante Arrhenius, a Swedish chemist, found a distinction between different chemicals when they were dissolved in water. -With this discovery came the definition of acids and bases.

3. I. Acids A. Acids are hydronium ion (H3O+) generators.
1. When a substance dissolves in water it produces hydronium ions.

4. Acids (cont) Strong acids ionize completely in aqueous solutions.
Weak acids only form a small amount of ions.

5. Acids (cont) B. Properties of Acids 1. Tastes sour
2. Able to conduct electricity
3. Mostly liquids and gases

6. Acids (cont) Organic acids are called carboxylic acids.
When they ionize in an aqueous solution, hydronium ions form.
Forms: COOH- + H3O+

7. Bases
A. When bases are placed in an aqueous solution, hydroxide ions (OH-) form.

8. Bases (cont) Properties of bases: Bitter taste Mostly solids
In solutions, they are slippery to touch.
Dissolve easily in water—called alkaline solutions.

9. Bases (cont)
Organic bases derive from ammonia NH3

10. III. Bronsted-Lowry Acids & Bases
A. Johannes Bronsted & Thomas Lowry scientists who define acids and bases as either a hydrogen proton donor or acceptor.

11. Bronsted-Lowry Acids are H+ donors. H2SO4 + H2O  H3O + + HSO4-
Bases receive the donated H +.
NH3 + H2O  NH4 + + OH -

12. IV. Strength of Acids & Bases
It’s strength is determined by how many of the ions (H3O+ or OH-) form in solution.
Strong = HIGHLY corrosive

13. Neutralization
Something that isn’t acidic or basic is considered to be neutral.
Acids and bases can be mixed together to become a neutral substance.
Ex: H3O + OH  H2O

14. Strength
C. The strength of an acid or base can be determined by using the pH scale.

15. Strength
D. A buffer is used in a solution to resist the change in pH.