Acids and bases

1. Acids and Bases
Holt: Chapter 15, Sections 2 and 3
Fusion: Lesson 6 (starts on p 190)

2. Acids
• An acid is any compound that increases the number of hydronium
ions (H+) when dissolved in water
• Acids typically begin with hydrogen, H.
• Examples: H2SO4, HCl

3. Acids and their properties
• Sour taste ex: citric acid (we NEVER taste in a lab)
• Corrosive- they destroy body tissue, clothing, and many other things
• Can be poisonous
• Reacts with some metals to produce hydrogen gas
• Can conduct electric current ex: battery acid
• Acid turns blue litmus paper red
• What is litmus paper?
• An indicator. An indicator is a substance that changes
color in the presence of an acid or base. Litmus paper
is NOT the only indicator.

4. Uses of acids
• H2SO4 is sulfuric acid. Is the most widely made industrial chemical in
the world. Used to make paper, paint, detergent and fertilizers.
• Used in swimming pools to kill algae
• HCl used in your stomach to digest food
• Citric acid and ascorbic acid are in orange juice
• Carbonic acid and phosphoric acid are in soda

5. Bases
• A base is any compound that increases the number of hydroxide ions,
(OH- ) when dissolved in water.
• Most bases end with OH-
• Examples: NaOH, Ca(OH)2

6. Bases and their properties
• Bitter taste
• Slippery feel
• Many bases are corrosive
• Bases turns red litmus paper blue
• Conduct electric current

7. Uses of bases
• NaOH (sodium hydroxide) is used to make soap and paper, oven
cleaners and products to unclog drains
• Ca(OH)2 (calcium hydroxide) is used to make cement and plaster
• Ammonia is found in household cleaners and to make fertilizer
• Magnesium hydroxide and aluminum hydroxide are used in antacids
to treat heartburn.

8. Strengths of acids and bases
Acids
• Strong acids have additional H+
• All of the acid’s molecules break
apart
• Examples of strong acids: H2SO4
(sulfuric acid), H2CO3 (carbonic
acid), H3PO4 (phosphoric acid)
Bases
• Strong bases have additional OH-
• All of the base’s molecules break
apart
• Examples of strong bases:
Ca(OH)2 (calcium hydroxide),
Ba(OH)2 (barium hydroxide)

9. Neutralization
• The reaction between acids and bases is a neutralization reaction.
• React to form water (which is neutral) and a salt.
• A salt is an ionic compound formed from the positive ion of a base
and the negative ion of an acid.
• Salts are a large group of compounds; not just table salt!

10. pH scale
• Indicators are used to identify whether a solution contains an acid or
a base.
• A pH scale is used to describe how acidic or how basic a solution is.
• pH is a measure of the hydronium ion concentration.
• pH of 7 is neutral; pure water
• pH of less than 7 is acidic
• pH of greater than 7 is basic

11. pH values of common materials