1. Classifying
Compounds

2. Acids, Bases & Salts
Compounds are classified into 3 categories:
Acids
Bases
Salts

3. Formulas usually start with “H”
Acids
Any compound that:
Turns blue litmus paper red
Tastes sour
Reacts with some metals to produce H2 gas
Conducts electricity when dissolved in water
Produces H+ ions when dissolved in water
e.g.
HCl
hydrochloric acid (stomach acid)
H2SO4
sulphuric acid (battery acid)
H3C6H5O7
citric acid (lemons, oranges, etc.)
HCH3COO
acetic acid (vinegar)
Also can be written as CH3COOH or HC2H3O2
Formulas usually start with “H”

4. Formulas usually end with “OH”
Bases
Any compound that:
Turns red litmus paper blue
Tastes bitter
Feels slippery
Conducts electricity when dissolved in water
Produces OH- ions when dissolved in water
e.g.
NaOH
sodium hydroxide (drain cleaner)
KOH
Potassium hydroxide (used in batteries)
NH4OH
Ammonium hydroxide (household cleaner)
Al(OH)3
Aluminum hydroxide (antacid)
Formulas usually end with “OH”

5. Indicators
Some dyes can help classify acids and bases; they change different colours in the presence of either acids or bases.
These dyes are called INDICATORS
ACID
BASE
e.g.
Litmus
Red
Blue
Phenolphthalein
Colourless
Pink (fuchsia)
Bromothymol blue
Yellow
Blue
(See your data booklet for a more detailed listing)

6. Neutralization reactions
When acids react with bases they form salts and water
Acid Base  Water Salt
e.g.
HCl(aq) + NaOH(aq)  HOH(l) + NaCl(aq)
HCl(aq) + NaOH(aq)  HOH(l) + NaCl(aq)
This is called a NEUTRALIZATION reaction
In an neutralization reaction, the properties of the acid and base are lost as water and a salt are formed.

7. Assignment
In Class:
Acid / Base Worksheet
Homework:
Workbook Page 91