1. Do Now Sit SILENTLY and answer the following questions in your notes…
List 5 things you eat that are sour. Do you think these are made of acids or bases?
List 5 things that you eat that taste bitter. Do you think these are made of acids or bases?
Do you think water is an acid or a base?

2. ACIDS & BASES BY
Mr. Miller

3. BACKGROUND
Acid and base are terms used by chemists to categorize chemicals according to their pH.
An acid is generally considered to be any material that gives up a hydrogen ion in solution,
While a base is any material that creates a hydroxide ion in solution.
Many of these acids and bases are familiar in everyday life.

4. ACIDS -
A class of compounds whose water solutions taste sour, turn blue litmus to red, and react with bases to form salts.
Scientists theorized that acids were made of sharply pointed particles that literally pricked the tongue or scratched the metal.

5. Acids produce solutions that:
Taste sour
Turn blue litmus paper red
Conduct electricity
react with metals to liberate a hydrogen gas
are corrosive (acid rain)
lose the above properties when reacted with a base.

6. ACIDS Examples of acids: Vinegar Lemon Juice Soft Drink Battery Acid
Stomach Acid
Apple Juice
Black Tea

7. STRONG AND WEAK ACIDS Strong Acids Weak Acids
Strong Acids – any acid that dissociates completely in aqueous solution.
Weak Acids – any acid that dissociates only partially in aqueous solution.
Strong Acids
Weak Acids
chloric acid, HClO3
hydorbromic acid, HBr
hydorchloric acid, HCl
sulfuric acid, H2SO4
nitric acid, HNO3
acetic acid, Ch3COOH
boric acid, H3BO3
hydorfluoric acid, HF
phosphoric acid, H3PO4
sufurous acid, H2So3
Note: aqueous solution is any solution where water is the solvent.

8. BASES -
A class of compounds that taste bitter, feel slippery in water solution, turn red litmus to blue, and react with acids to form salt and water.

9. Bases produce solutions that:
taste bitter
turn red litmus blue
conduct electricity
feel slippery
are corrosive (basic solution in glass container)
lose the above properties when reacted with an acid.

10. BASES Examples of bases: Detergent Baking Soda Drain Cleaner Ammonia
Soaps (hand, dish)
Antacid

11. STRONG AND WEAK BASES Strong Bases Weak Bases
Strong Bases – any base that dissociates completely.
Weak Bases – any base that dissociates only partially in aqueous solution.
Strong Bases
Weak Bases
barium hydroxide, Ba(OH)2
calcium hydroxide, Ca(OH)2
potassium hydroxide, KOH
sodium hydroxide, NaOH
trisodium phosphate, Na3PO4
ammonia, NH3
aniline, C6H5NH2
potassium carbonate,K2CO3
sodium carbonate, Na2CO3
trimethylamine, (CH3)3N

12. NEUTRAL These are items that are neither acids or bases.
Neutral items will turn blue and red litmus paper green.
The main example of a neutral item is: Pure Water

13. DETERMINING ACIDS & BASES
Red litmus paper
Blue litmus paper pH
Red Cabbage Juice

14. RED BLUE LITMUS PAPER & Robert Boyle discovered litmus paper
certain plant extracts, such as litmus, can be used to distinguish acids from bases.
blue and red litmus paper turn red when dipped in an acid
red and blue litmus paper turn blue when exposed to a base

15. pH -
the negative logarithm of the hydronium ion concentration of an aqueous solution; used to express acidity.
pH is the measure of the acidity or basicity of a solution.
The pH scale ranges from 1 to 14
1 through 6 being acidic
7 is considered neutral
8 through 14 being basic

16. RED CABBAGE JUICE
red cabbage can be used as an acid/base indicator
after boiling the red cabbage, pour a small amount of the juice into a small sample of a substance your checking
the juice will turn blue if the substance is a base
the juice will turn red if the substance is an acid

17. ACID-BASE THEORIES There are three common acid-base theories:
the Arrhenius theory
the Bronsted-Lowry theory
the Lewis theory

18. Arrhenius Theory Svante Arrhenius was a Swedish chemist.
In 1887, he published a paper concerning acids and bases.
He concluded that solutions with acids and bases in them released particles when dissolved.
He concluded that acids were substance which separated (ionized) in water solution to produce hydrogen ions (H+, or free protons).
He also believed that bases were substance which ionized to produce hydroxide ions (OH-) in water solution.
HCl H+ + Cl-
NaOH Na+ + OH-
He knew that solutions containing acids or bases conducted an electric current, and tried to explain why.

19. BRONSTED-LOWRY THEORY
T. M. Lowry was an English scientist, while J. N. Bronsted was a Danish scientist.
In 1923, they independently proposed a new definition of the terms acid and base.
They stated that in a chemical reaction, any substance which donates a proton is an acid and any substance which accepts a proton is a base.
When hydrogen chloride gas is dissolved in water, ions are formed:
HCl + H2O H3O+ + Cl-
acid
base
Lowry
Bronsted

20. LEWIS THEORY Gilbert Newton Lewis was and American chemist.
In 1923, proposed an even broader definition of acids and bases.
Lewis focused on electron transfer instead of proton transfer.
He defined and acid as an electron-pair acceptor, and a base as an electron-pair donor.
This definition applies to solutions and reactions which do not even involve hydrogen or hydrogen ions.

21. SUMMARY OF ACID-BASE THEORIES
THEORY
ACID DEFINITION
BASE DEFINITION
Any substance which releases H+ ion in water solution.
Any substance which releases OH- ions in water solution.
Arrhenius Theory
Bronsted-Lowry Theory
Any substance which donates a proton.
Any substance which accepts a proton.
Lewis Theory
Any substance which can accept an electron pair.
Any substance which can donate an electron pair.

22. IN YOUR BODY
Proteins in your hair, nails, cell membranes, and other parts of you body consist of amino acids.
Enzymes that catalyze reactions in your body are composed of amino acids.
Hydrochloric acid is in your stomach to aid in the digestion of food.
Organic bases are major components of DNA and products of the digestion of proteins.

23. Catalysts
A substance that increases the rate of reactivity of a chemical reaction without itself undergoing a chemical change.
Elephant Toothpaste

24. DNA
DNA contains thousands of sites where H+ ion transfer can take place
Therefore DNA fits the definition of a Bronsted acid.
DNA is a weak acid, but it is stronger than phosphoric acid.

25. SUMMARY
ACID - A class of compounds whose water solutions taste sour, turn blue litmus to red, and react with bases to form salts.
BASE - A class of compounds that taste bitter, feel slippery in water solution, turn red litmus to blue, and react with acids to form salts.
NEUTRAL - These are items that are neither acids or bases.
There are 4 main ways to determine if a substance is and acid or a base. They are: Red litmus paper, Blue litmus paper, pH, and Red Cabbage Juice.

26. SUMMARY The body is a sea of acids and bases.
There are 3 common acid-base theories: the Arrhenius theory, the Bronsted-Lowry theory, and the Lewis theory.
The body is a sea of acids and bases.
DNA is an acid based on Bronsted’s definition of an acid.

27. Exit Ticket!!!
______ _____ in the 1660s, discovered that certain plant extract could be used to distinguish between acids and bases.
Name an example of an acid that was mentioned on one of the slides.
Name an example of a base that was mentioned on one of the slides.
The three common acid-base theories are the Lewis theory, ________ theory, and the Bronsted-Lowery theory.
True or False. DNA is a weak acid, and it is weaker than phosphoric acid.