1. Acids & Bases

2. Goals for today To determine the difference between Acids & Bases
Discuss the importance of studying Acids & Bases

3. What is the pH scale?
The pH scale measures how acidic or basic a solution is.

4. The pH scale
Range of
Pure water has a pH of 7 and is considered a “neutral solution”
(it is not an acid or a base)

5. Identifying Acids and Bases
Acids have a ph from 0-7
Lower pH value indicates a stronger acid.
Bases have a pH from 7-14
Higher pH value indicates a stronger base.

6. 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!

7. Test Your Knowledge What is the range of an ACID on the pH scale?
Ans: 0-7
What is the range of a BASE and what is another name for a BASE?
Ans: 7-14, Alkaline

8. Characteristics Of Acids
A sour taste.
It turns blue litmus paper red
It tastes sour. Try drinking lemon juice (citric acid)
React with certain metals
React with bases
How do you know if a chemical is an acid?
It usually starts with Hydrogen.
HCl, H2SO4, HNO3, etc. (but not water!)

9. Acids React with Carbonates and Bicarbonates
HCl + NaHCO3
Hydrochloric acid + sodium bicarbonate
NaCl + H2O + CO2
salt + water + carbon dioxide
An old-time home remedy for relieving an upset stomach

10. Effects of Acid Rain on Marble (marble is calcium carbonate)
George Washington:
BEFORE acid rain
George Washington:
AFTER acid rain

11. How acids are used in the real world!!!!

12. Sulfuric Acid = H2SO4
Highest volume production of any chemical in the U.S. (approximately 60 billion pounds/year)
Used in the production of paper
Used in production of fertilizers
Used in petroleum refining; auto batteries

13. Nitric Acid = HNO3 Used in the production of fertilizers
Used in the production of explosives
Nitric acid is a volatile acid – its reactive components evaporate easily
Stains proteins yellow (including skin!)

14. Hydrochloric Acid = HCl
Used in the “pickling” of steel
Used to purify magnesium from sea water
Part of gastric juice, it aids in the digestion of proteins
Sold commercially as Muriatic acid

15. Phosphoric Acid = H3PO4 A flavoring agent in sodas (adds “tart”)
Used in the manufacture of detergents
Used in the manufacture of fertilizers
Not a common laboratory reagent

16. Acetic Acid = HC2H3O2 (also called Ethanoic Acid, CH3COOH)
Used in the manufacture of plastics
Used in making pharmaceuticals
Acetic acid is the acid that is present in household vinegar

17. Characteristics of Bases
A Base is characterized by:
A bitter taste. (Milk of Magnesia)
It feels slippery. (Soapy Water)
It turns Red Litmus Blue.
React with acids

18. How bases used in the real world!!!

19. Examples of Bases (metallic hydroxides)
Sodium hydroxide, NaOH (lye for drain cleaner; soap)
Potassium hydroxide, KOH (alkaline batteries)
Magnesium hydroxide, Mg(OH)2 (Milk of Magnesia)
Calcium hydroxide, Ca(OH)2 (lime; masonry)

20. Measuring acid or base?
1. Litmus paper – turns red in an acid, blue in base.
2. Phenolphthalein – Used to test for the presence of a base. It is clear and turns bright pink in a base and stays clear in acids.
3. pH paper – Uses a range of colors that indicates the pH.

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