Chemistry

---

The world is made up of a variety of substances. Some of these occur naturally in our environment, others are made through the combination of naturally occurring substances to form new materials. The study of chemistry can lead us to a better understanding of our material world and the processes by which materials can change and be changed.

• Section 2A: Classification of substances
  
  
• Section 2B: Air, oxygen, carbon dioxide and water
  
  
• Section 2C: Atomic structure, reactions and compounds