A c i d s B a s e s & S a l t s

Acid and Bases

When we think of acids and bases we tend to think of chemistry lab acids and bases like But we are surrounded by acids and bases in the world. Most of them are weak. Acids cause: Lemons to be sour Acid rain to eat away at sculptures Eat cavities in your teeth Digest food in your stomach Fight off other invading ants

Properties of an Acid  Tastes sour  Turns blue litmus paper red  Has a pH of less than 7  Lemon juice and vinegar are good examples. ACID

Properties of a Base  Turns litmus paper blue  Has a pH greater than 7  Tastes bitter and have a slippery feel  Bases that are soluble (dissolve in water) are called alkalis Most hand soaps and drain cleaners are bases

Tea contains tannic acid Strenuous exercise causes a buildup of lactic acid in muscle tissue Carbonated soft drinks contain carbonic acid and phosphoric acid

Acid rain (nitric /sulfuric acid) corroding a limestone sculpture. Fruit contains citric acid

p H A measure of how acidic something is

T h e p H S c a l e A N e u t r a l s o l u t i o n h a s a p H o f 7. A n A c i d i c s o l u t i o n h a s a p H b e l o w 7. A B a s i c s o l u t i o n h a s a p H a b o v e 7. A N e u t r a l s o l u t i o n h a s a p H o f 7. A n A c i d i c s o l u t i o n h a s a p H b e l o w 7. A B a s i c s o l u t i o n h a s a p H a b o v e 7.

Indicators These are chemicals that change colour in the presence of an acid or a base. We get them from Plants.

This lake looks ok, but it is dead No fish life in this lake. Acid rain kills trees and aquatic life.

All Acid rain is either caused by impurities or not burning fuel well.

Summary

H/W P 221 Q 1,2,3,4,6,7,8.