2. Acids and Bases The pH scale

3. What do vinegar, lemons, and orange juice have in common?

4. Characteristics of Acids Taste Sour React with metals Often produce hydrogen gas Can burn your skin

5. What do milk, Comet, and Tums have in common?

6. Characteristics of Bases Taste Bitter Feel Slippery Neutralize Acids –Antacids Dissolve grease

7. But, what exactly are acids and bases?

8. Substance that ionizes in water to give hydrogen ions (H + ) Acid

9. Examples of Acids HCl H 2 SO 4 HNO 3 HF Juices

10. Substance that ionizes in water to give hydroxide ions (OH - ) Base

11. Examples of Bases NaOH Ca(OH) 2 KOH Soap, Ammonia, Baking Soda

12. The pH Scale Measurement system that indicates the concentration of H + ions in solution. –The pH scale ranges from 0 to 14.

13. The pH Scale pH = “power of hydrogen” –Each step increases by a power of ten

14. pH Scale

16. Acidic Solutions Solutions with a pH below 7 are called acidic because they have more H + ions than OH - ions. The lower the pH, the greater the acidity.

18. Basic Solutions Solutions with a pH above 7 are called basic because they have more OH - ions than H + ions. The higher the pH, the more basic the solution.

20. pH Scale

21. pH and Water Why does water have a pH of 7? –H–Hydronium ions = hydroxide ions –(–(H + ) = (OH - ) H 2 0H + + OH -

22. pH paper

23. Litmus paper

25. Interesting fact… Water can act as an acid or a base!!!

26. Video Clip