Do Now Sit SILENTLY and answer the following

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?

• Acid and base are terms used by chemists to categorize chemicals according to their p. H. • 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.

A class of compounds whose water solutions taste sour, turn blue litmus to red, and react with bases to form salts.

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.

Examples of acids: • Vinegar • Lemon Juice • Soft Drink • Battery Acid • Stomach Acid • Apple Juice • Black Tea

• 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 1. chloric acid, HCl. O 3 1. acetic acid, Ch 3 COOH 2. hydorbromic acid, HBr 2. boric acid, H 3 BO 3 3. hydorchloric acid, HCl 3. hydorfluoric acid, HF 4. sulfuric acid, H 2 SO 4 4. phosphoric acid, H 3 PO 4 5. nitric acid, HNO 3 5. sufurous acid, H 2 So 3 Note: aqueous solution is any solution where water is the solvent.

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.

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.

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

• Strong Bases – any base that dissociates completely. • Weak Bases – any base that dissociates only partially in aqueous solution. Strong Bases Weak Bases 1. barium hydroxide, Ba(OH)2 1. ammonia, NH 3 2. calcium hydroxide, Ca(OH)2 2. aniline, C 6 H 5 NH 2 3. potassium hydroxide, KOH 3. potassium carbonate, K 2 CO 3 4. sodium hydroxide, Na. OH 4. sodium carbonate, Na 2 CO 3 5. trisodium phosphate, Na 3 PO 4 5. trimethylamine, (CH 3)3 N

• 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: Water Pure

• Red litmus paper • Blue litmus paper • p. H • Red Cabbage Juice

• 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

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

• 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

There are three common acid-base theories: • the Arrhenius theory • the Bronsted-Lowry theory • the Lewis 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 • Na. OH H+ + Cl. Na+ + OH-

• 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 any substance which accepts a proton is a base. • When hydrogen chloride gas is dissolved in water, ions are formed: • HCl + H 2 O acid H 3 O+ + Cl- base Lowry Bronsted

• 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.

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

• 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.

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

• 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.

• 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, p. H, and Red Cabbage Juice.

• 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.

1. ______ in the 1660 s, discovered that certain plant extract could be used to distinguish between acids and bases. 2. Name an example of an acid that was mentioned on one of the slides. 3. Name an example of a base that was mentioned on one of the slides. 4. The three common acid-base theories are the Lewis theory, ____ theory, and the Bronsted-Lowery theory. 5. True or False. DNA is a weak acid, and it is weaker than phosphoric acid.