1. Acids
&
Bases

2. Acids and Bases Goals A. Explain the structure of the pH scale.
B. Compare and contrast the components and properties of acids and bases.
C. Determine whether common household substances are acidic, basic, or neutral.

3. The pH Scale
pH comes from the Greek word potenz meaning power (and H for hydrogen).
Measurement system that indicates the number of H+ ions in solution.

4. NaOH  Na+ + OH- HCl  H+ + Cl-
Acids are molecules that release hydrogen ions in solution.
HCl  H+ + Cl-
Bases are molecules that either take up hydrogen ions or give off hydroxide ions in solution.
A strong acid, such as hydrochloric acid, dissociates completely.
NaOH  Na+ + OH-

5. Characteristics of Acids
pH less than 7
Produces hydrogen ions (H+) in solution.
When added to water H+ interacts with the H2O to produce H30 + (Hydronium ion)
Taste sour
Corrosive
Look at page 697.
What do all of the acids have in common?

6. Characteristics of Bases
pH higher than 7
Produces hydroxide ions (OH-) in solution
Bitter taste
Strong bases can be corrosive.
Look at page 699.
What do all of the bases have in common?

7. Strength of Acids & Bases7
Strength of Acids & Bases
Bases
Strong: Ionize Completely in Solutions.
Acids
Strong: Ionize Completely in Solutions.

8. Neutralization ACID + Base ==> SALT + WATER
HCl(aq) + NaOH(aq)==> NaCl(aq) + H2O(l)
H+ ions react with the OH- to produce water.
A salts forms from the negative ion in the acid and the positive ion in the base.
ACID + ALKALI ==> SALT + WATER
HCl(aq) + Ca(OH)2(aq)==> CaCl2(aq) + H2O(l)

9. Litmus Paper / pH paper

10. Litmus paper contains a substance that changes color in either an acid or a base.

11. Red Litmus Paper
If red turns blue, it is a BASE!

12. Blue Litmus Paper
If blue turns red, it is an ACID!

13. Litmus Paper

14. Acids & Bases Video