1. Module III - Ionic Phenomena
PHYSICAL SCIENCE 416
MODULE III

2. ACIDS, BASES AND SALTS Objectives
2.1 To identify the properties normally used to classify substances in aqueous solutions as either acids, bases, or salts.
2.2 To determine the conditions under which substances will show the
properties of acids, bases, or salts.

3. Substances
BASES
ACIDS
SALTS

4. ACIDS = “acidus” (latin word) meaning sour.
The word acids comes from one of its characteristic properties, its taste.
ACIDS = “acidus” (latin word) meaning sour.

5. Bases BASES Bases are substances that are
very slippery to touch and have
a strong bitter taste.

6. Salts
SALTS
Salts are a source of ions that are easily absorbed by living organisms.
They are often used to change the physical properties of various solutions by lowering the freezing points or raising the boiling points

7. Properties of Acids, Bases and Salts
Electrical
Conductivity
Magnesium
Taste/
Touch
Litmus
Paper
ACID
YES
Reaction
Sour
Turns
red
BASE
No Reaction
Bitter/
Slippery
Blue
SALT
Salty
Depends on the solution
Electrolytes – solutions that conduct electricity

8. (USED TO DETECT ACIDS OR BASES)
INDICATORS
(USED TO DETECT ACIDS OR BASES)
Litmus paper is a type of indicator
(thin strip of paper that is dipped into a solution)
2 Types: Blue Litmus Paper
Red Litmus Paper
ACIDS – Turn blue litmus paper red
BASES – Turn red litmus paper blue BB

9. Indicators SALTS – not all salts are neutral
- can be either acidic or basic
(test with litmus paper)

10. Indicators INDICATORS Phenolphthalein is another type of indicator
Bases turn clear phenolphthalein pink
INDICATORS

11. NEUTRALIZATION ACID - BASE -
“Making a solution chemically neutral”
Chemically neutral – means does not contain an acid or base
ACID -
Neutralize it with a base
BASE -
Neutralize it with an acid
Acids and bases neutralize each other forming a salt and water
Ex. Acid + Base = Salt + water

12. REMEMBER... Acids, bases and salts conduct electricity Tap water
will conduct
(free ions around)
Distilled water
does not
conduct
(no free ions!)

13. Depends on the solution
KEY POINTS
Review chart: (very important!)
Electrical
Conductivity
Magnesium
Taste/
Touch
Litmus
Paper
ACID
YES
Reaction
Sour
Turns
red
BASE
No Reaction
Bitter/
Slippery
Blue
SALT
Salty
Depends on the solution

14. PRACTICE PROBLEMS
Worksheet # 1
Study guide, Module 3, page 2

15. References Science Quest, Grenier,Daigle & Rheaume, 1998
Physical Science Student Study Guide
Animation Factory
Google Images