1. Acids and Bases

2. When we think of acids and bases we tend to think of chemistry lab acids and bases like
But we are surrounded by acids and bases in the world. Most of them are weak.
Acids cause:
Lemons to be sour
Acid rain to eat away at sculptures
Cavities in your teeth
Digestion of food in your stomach
Ants to give you a nasty bite

3. What are Acids and Bases?
Properties of an Acid
Tastes sour
Turns litmus paper red
Has a pH of less than 7
Lemon juice and vinegar are acids
Properties of a Base
Taste bitter and have a slippery feel
Turns litmus paper blue
Has a pH greater than 7
Bases that are soluble (dissolve in water)
are called alkalis
Most hand soaps and drain cleaners are bases

4. What are Acids and Bases?
Hydrochloric acid, HCl and sulfuric acid H2SO4 are very corrosive
Carbonic acid is used in fizzy drinks
Ethanoic acid is in vinegar
Citric acid is in oranges and lemons
Sodium hydroxide, NaOH is very corrosive
and is known as caustic soda
Calcium hydroxide Ca(OH)2 forms
limewater when dissolved in water

5. Carbonated soft drinks contain carbonic acid
Tea contains tannic acid
Carbonated soft drinks contain carbonic acid
Fruit contains citric acid

6. Acid rain (nitric /sulfuric acid) corroding a limestone sculpture.
Strenuous exercise causes a buildup of lactic acid in muscle tissue

7. Acid Rain
Acid rain kills trees and aquatic life

8. Universal indicator H2SO4 pH = 1 turns red Lemon juice pH = 3
turns orange
Rainwater
pH = 6
turns yellow
Window cleaner
pH = 10
turns blue
NaOH
pH = 14
turns navy

9. pH Scale
The pH scale is a way of expressing the strength of acids and bases The pH scale goes from 0 to 14 Under 7 = acid 7 = neutral Over 7 = base

10. pH Scale

11. Indicators
These are chemicals that change colour in the presence of an acid or a base.
There are a number of different indicators that change color at different pH’s.

12. Making salt Cl + OH H Na HCl + NaOH  NaCl + H2O
Acids and alkalis react together to form a neutral salt and water
A salt is formed when a metal ion replaces the hydrogen in an acid
Cl OH H Na
HCl + NaOH  NaCl + H2O

13. Sodium hydroxide and litmus indicator solution
OC38
Burette
Retort stand
Hydrochloric acid
Conical flask
Sodium hydroxide and litmus indicator solution

14. Acids with Carbonates 2HCl + CaCO3  CaCl2 + H2O + CO2
Acid + Carbonate  Salt + Water + Carbon Dioxide
2HCl + CaCO3  CaCl2 + H2O + CO2