1. Acids and Bases
Chapter 32

2. Acids An acid is a substance that turns blue litmus paper red.
Acids have a sour sharp taste.
Everyday Acids
Lab Acids
Lemon juice (citric acid)
Hydrochloric acid
Rain Water (Carbonic acid)
Sulfuric acid
Vinegar

3. Bases A base is a substance that turns red litmus paper blue.
Bases are the opposite of acids.
Everyday Bases
Lab Bases
Toothpaste
Sodium hydroxide
Bleach
Calcium carbonate
Indigestion Tablets
Limewater

4. Bases
Bases that are soluble in water are called alkalis.

5. Neutral
Some substances are neither acid or base they are said to be neutral.
Water is an example of a neutral substance.

6. Indicators
An indicator is a substance that shows, by means of colour change, whether a substance is acid or base.
Examples Litmus
Universal Indicator

7. Universal Indicator
A universal indicator is used to measure the pH of a substance.
Neutral solutions are pH 7
Acids have a pH less than 7
Bases have a pH more than 7

8. pH Scale
The pH scale is a scale from 1 to 14 that tells us how strong an acid of base is.
The stronger the acid the lower the pH.
The stronger the base the higher the pH

9. pH Scale

10. Making a salt from an Acid an a Alkali
Acid + Base = Salt + Water
A salt is formed when the metal ion replaces the hydrogen in an acid.
HCl + NaOH = NaCl + H20

11. Reactions of Acids Acid + Base = Salt + Water
Hydrochloric acid + Sodium Hydroxide = Sodium Chloride + Water
HCl + NaOH = NaCl + H20

12. Reactions of Acids Acid + Carbonate = Salt + Water + Carbon dioxide
Hydrochloric acid + Calcium carbonate =
Calcuim chloride + Water + carbon Dioxide
2HCl + CaCO3 = CaCl2 +H2O +CO2