1. Acids and Bases

2. Our Goals for today
To determine the difference between Acids & Bases and their properties.
Explain how an acid can be neutralized by a base.
Discuss pH and what it is.

3. General properties ACIDS Taste sour Turn litmus
React with active metals – Fe, Zn
React with bases
BASES
Taste bitter
Turn litmus
Feel soapy or slippery (react with fats to make soap)
React with acids
blue to red
red to blue

4. Svante August Arrhenius
(February 19, 1859 – October 2, 1927)
Swedish chemist; Nobel Prize in Chemistry, 1903
* Arrhenius equation (activation energy)
* Greenhouse effect
Johannes Nicolaus Brønsted
(February 22, 1879-December 17, 1947)
Danish physical chemist
Thomas Martin Lowry
(October 26, 1874–November 2, 1936)
English organic chemist
Gilbert Newton Lewis
(October 23, 1875-March 23, 1946)
American physical chemist

5. Definitions Acids – produce H+ Bases - produce OH- Acids – donate H+
Bases – accept H+
Acids – accept e- pair
Bases – donate e- pair
Arrehenius
only in water
Bronsted-Lowry
any solvent
Lewis
used in organic chemistry,
wider range of substances

6. Acid Nomenclature Review
No Oxygen
w/Oxygen
An easy way to remember which goes with which…
“In the cafeteria, you ATE something ICky”

7. Some Properties of Acids
Produce H+ (as H3O+) ions in water (the hydronium ion is a hydrogen ion attached to a water molecule)
Taste sour
Corrode metals
Electrolytes
React with bases to form a salt and water
pH is less than 7
Turns blue litmus paper to red “Blue to Red A-CID”

8. Some Properties of Bases
Produce OH- ions in water
Taste bitter, chalky
Are electrolytes
Feel soapy, slippery
React with acids to form salts and water
pH greater than 7
Turns red litmus paper to blue “Basic Blue”

9. How do you neutralize an acid? How do you neutralize a base?

10. Neutralization HCl + NaOH  NaCl + HOH HCl + Mg(OH)2 
In general: Acid Base  Salt + Water
All neutralization reactions are double displacement reactions.
HCl NaOH  NaCl HOH
HCl Mg(OH)2 

11. How do we measure how acidic or basic something is?

12. The pH scale is a way of expressing the strength of acids and bases
The pH scale is a way of expressing the strength of acids and bases. Instead of using very small numbers, we just use the NEGATIVE power of 10 on the Molarity of the H+ (or OH-) ion. Under 7 = acid 7 = neutral Over 7 = base

13. 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.

14. across United States in 2001
pH of Rainwater
across United States in 2001
You are here!
air masses
Increasing acidity
Why is the eastern US more acidic?

15. Indicators? How can we tell whether or not a substance is an acid or a base? Turn to page 238. What is an indicator?

16. Indicators
Litmus Paper – litmus is a mixture of a different dyes that come from lichens. They are then absorbed into paper to be used as indicators.
Phenolphthalein – colorless in acid and pink in a base.

17. Red Cabbage
A natural indicator that changes a variety of different colors based on pH.

18. Red Cabbage Experiment Time