Class notes Chemistry

Grade 9 Chemistry Notes

1. Introduction to Chemistry
Chemistry is the study of matter, its composition, properties, and the changes it undergoes.

1 Organic Chemistry: Study of carbon compounds
2 Inorganic Chemistry: Study of other elements
3 Physical Chemistry: Energy and laws
4 Analytical Chemistry: Analysis of substances
5 Biochemistry: Chemistry of living organisms


2. Matter and Its Properties
Matter is anything that has mass and occupies space.

State Shape Volume Movement
Solid Fixed Fixed Vibrates
Liquid No fixed shape Fixed Flows
Gas No fixed shape No fixed volume Moves freely



3. Atomic Structure

1 Proton: Positive charge, located in nucleus
2 Neutron: No charge, located in nucleus
3 Electron: Negative charge, orbits nucleus
Atomic Number = Number of protons
Mass Number = Protons + Neutrons


4. Chemical Bonding

1 Ionic Bond: Transfer of electrons
2 Covalent Bond: Sharing of electrons

5. Acids, Bases and Salts

1 Acids release H+ ions
2 Bases release OH- ions
3 pH scale ranges from 0 to 14

6. Environmental Chemistry

1 Air Pollution
2 Water Pollution
3 Land Pollution