1. 7.3 Describing acids and bases
Key concepts: what are the properties of acids and bases? What are acids and bases commonly used?
Key terms: acid, corrosive, indicator, base

2. Properties of acids
An acid is a substance that tastes sour, reacts with metals and carbonates, and turns blue litmus paper red (hydrochloric acid, sulfuric acid, etc)

3. Properties Sour taste – e.g. lemons
Reactions with metals – react with certain metals to produce hydrogen gas. Not all metals, but magnesium, zinc, and iron. Metals disappear into the solution. Acids are corrosive – “eat away” at other materials

4. Reaction with carbonates – acids also react with carbonate ions in a characteristic way.
Carbonate ions contain carbon and oxygen atoms bonded together. They carry an overall negative charge. One product of an acid’s reaction with carbonates is the gas carbon dioxide.

5. Reactions with indicators
Litmus – example of an indicator – a compound that changes color when in contact with an acid or base. Acids turn the blue litmus paper red.

6. Properties of bases Bases are another group of compounds.
Bases are substances that taste bitter, feel slippery, and turn red litmus paper blue.
Bitter taste
Slippery feel – (e.g. soap is a base)
Reactions with indicators – turn red litmus paper blue
Don’t react with carbonates

7. Uses of acids and bases
Acids and bases are used pretty much, like uhm, everywhere and stuff
Cleaning agents – bleach (base); vinegar (acid)
They also make stuff – food, industry stuff