1. Acids and Bases

2. Introduction
Acids and Bases are compounds that have special properties and characteristics.
They are not always liquids you see on TV that eat through anything.
Acids and bases are molecular compounds dissolved in water.

3. Comparisons Acid Base Common Properties Soluble in water Tastes sour
Turns blue litmus
paper red
Tastes bitter
Feels slippery
Turns red litmus
paper blue
Common Reactions
Reacts with metals
in single displacement
reactions to produce
hydrogen gas
Reacts with carbonate
ions to release carbon
dioxide gas
Reacts with organic
compounds and
breaks them up

4. Comparisons Acid Base Chemical Make-Up Releases Hydrogen
ions in water (H+)
Always contains
Hydrogen
Releases Hydroxide
ions in water (OH)
Usually contains
either hydroxide or
bicarbonate
Examples
Hydrochloric acid
(HCl)
Vinegar – Acetic
acid
Carbonic acid – in
soft drinks
Baking Soda –
Sodium Bicarbonate
Sodium Hydroxide
– Drain cleaner

5. Naming Common Acids 2 most important classes of acids:
Binary Acids: Hydrogen bonded with a single non-metal element.
Named according to the element bonded with Hydrogen
Ex: HF(aq) = Hydrofluoric Acid, H2S(aq) = Hydrosulphuric Acid
Oxyacids: Hydrogen bonded with polyatomic compounds.
Named according to the polyatomic ion bonded with Hydrogen, however it is not as systematic as binary acids.
Ex: H2SO4(aq) = Sulphuric Acid, HNO3(aq) = Nitric Acid

6. The pH Scale
Solutions are classified on the pH (power of Hydrogen) scale which describes how acidic or basic it is.
Pure water has a pH of 7 (neutral).
Substances with a pH below 7 are Acidic.
Substances with a pH above 7 are Basic.
pH = -log10 [H+]

7. The pH Scale The pH scale is a logarithmic scale.
Every change of 1 on the pH scale represents a 10-fold effect in the concentration.
Ex: pH of 2 is 10X more acidic than a pH of 3.
pH of 2 is 100X more acidic than a pH of 4.
pH paper can be used to determine the pH of liquids.
Changes colours depending on the pH of the substance it’s in.

8. Homework
Read pages
Answer Check Your Learning questions 2, 3, 5 and 8 on Page 271