1. The pH Scale Is a substance an acid or a base?

2. ACIDS AAAAn acid is a compound that increases the number of hydrogen ions when dissolved in water (H+) AAAAn acid solution tastes sour AAAAn acid can change the color of certain compounds

3. What is an ion? **An ion is an atom that has lost or gained an electron giving it a positive (+) or negative (-) charge. ** Charged Atom

4. USES OF ACIDS  Citric acid and ascorbic acid (Vitamin C) are found in orange juice  Carbonic acid and phosphoric acid give a “bite” to soft drinks  Acids in your stomach aid in digestion  Sulfuric acid is the most widely used industrial acid in the world. It is used in making metals, paper, paints, and fertilizers.

5. BASES  A base is any compound that increases the number of hydroxide ions (OH-) when mixed with water  A base solution tastes bitter  A base solution feels slippery  A base can change the color of certain compounds

6. Uses of Bases  Bases are used in soaps (remember, bases are slippery)  Bases are used to make paper, in oven cleaners, and to unclog drains  Ammonia is a base and is used in many household cleaners

7. Detecting Acids and Bases  You can detect an acid using an indicator.  INDICATOR - A substance that changes color in the presence of an acid or a base.

8. INDICATORS  Litmus paper is an indicator  An acid turns blue litmus paper red  A base turns red litmus paper blue

9. pH Scale Acid Base 0 7 14 Zumdahl, Zumdahl, DeCoste, World of Chemistry  2002, page 515 [H + ] pH 10 -14 14 10 -13 13 10 -12 12 10 -11 11 10 -10 10 10 -9 9 10 -8 8 10 -7 7 10 -6 6 10 -5 5 10 -4 4 10 -3 3 10 -2 2 10 -1 1 10 0 0 1 M NaOH Ammonia (household cleaner) Blood Pure wate Milk Vinegar Lemon juice Stomach acid 1 M HCl Acidic Neutral Basic

10. pH of Common Substances Timberlake, Chemistry 7 th Edition, page 335

11. Did we Miss something??  What happens when the pH of a substance is 7?  Ans: A pH level of 7 indicates a Neutral Substance i.e: Water!

12. Why Learn about pH?  What do you think is the pH level of NYC tap water?  The pH of a swimming pool must be checked periodically. Why?  Is it important for Lakes & Rivers to maintain a certain pH?

13. How do Antacids Work?  Normal pH in your stomach is 3  If your stomach pH drops below 3 you don’t feel so well  An antacid neutralizes the acid in your stomach and brings the pH up to a 3 or 4

14. Antacids  A base can't neutralize your acid all by itself.  A base needs some chemical "helpers”  All antacids contain at least one of these four primary ingredients:  * Sodium  * Calcium  * Magnesium  * Aluminum.

15. HOW DO WE MEASURE pH?

16. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 A CID B ASE NEUTRALNEUTRAL The pH Scale

17. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 A CID B ASE NEUTRALNEUTRAL The pH Scale

18. Let’s see what you’ve learned!  Professor Know-It- All wants to know what you’ve learned. Answer the following questions carefully.

19. Question #1  Lemon juice has a pH of 2.2. Is it an acid or a base?

20. Question #2  Detergents such as Tide have a pH of about 10. Is Tide an acid or a base?

21. Question #3  Seawater has a pH of 8.2. Is seawater an acid or a base?

22. Question #4  The inside of your mouth has a pH of 7. Is it an acid or a base?

23. Question #5  How do you think we came up with the term “acid rain”?

24. Question #6  409 cleaner contains ammonia that has a pH of 12. What will 409 do to red litmus paper?

25. Question #7 Question #7  A soft drink has a pH of 3.2. What will it do to a piece of red litmus paper?