Acids, Bases and pH

Our Goals for today

• To determine the difference between Acids & Bases

• Discuss the importance of studying Acids & Bases

• Perform an experiment dealing with Acids & Bases

Characteristics Of Acids

Acids can be characterized by:

1. A sour taste

2. Acids turn litmus paper red

3. Are corrosive

Characteristics of Bases

A Base is characterized by:

1. A bitter taste

2. It feels slippery

3. It turns litmus paper blue

Note: You should know the old school name for “basic” - alkaline

What is the pH scale?

• The pH scale measures how acidic or basic a solution is

1 2 3 4 5 6 7 8 9 10 11 12 13 14

← Acidic Neutral Basic →

Identifying Acids and Bases

• Acids have a pH from 0-7

• Bases have a pH from 7-14

Did we Miss something??

• What happens when the pH of a substance is exactly 7?

• Ans: A pH level of 7 indicates a Neutral Substance– Example: Distilled water

Identifying Acids and Bases

• Acids– Lower pH value indicates a

stronger acid.

• Bases– Higher pH value indicates a

stronger base.

Test Your Knowledge

• What is the range of an ACID on the pH scale?

Ans: 0-7

• What is the range of a BASE and what is another name for a BASE?

Ans: 7-14, Alkaline

Why Learn about Acids & Bases?

• What do you think is the pH level of De Soto tap water?

• Is it important for Lakes & Rivers to maintain a certain pH?

pH and your body

• Blood pH must be between 7.35 and 7.45

• A change of 0.1 lands you in intensive care

• A change of 0.2 is lethal

Your body has buffers!

• Blood has chemicals which act like playpen walls keeping your blood pH where it should be

• It adds chemicals to get the pH back to neutral– Combine acids and

bases – get WATER

Owwww!

• When your blood can’t get the acids built up in the muscles when you exercise moved away fast enough…

• YOU CRAMP!!!

• So what should you drink to fix the excess of acid???

Today’s Experiment

• Test the pH of several solutions

• Report your results to the class list

• Suggest which solution would be best to fix the cramp

• GOOD LUCK!!!