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

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 Hp H

A measure of how acidic something is

A measure of how acidic something is

T h e p H S c a l eT 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 .

IndicatorsThese 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.