Introduction
Everything around us is matter—solid, liquid, or gas. In Class 9 Chemistry (Chapter 1 – Matter in Our Surroundings), CBSE students learn about the properties and interconversion of states of matter.
Key Topics Covered:
- Characteristics of Matter
- Particles have space, attract each other, and move.
- States of Matter
- Solid (Fixed shape, high density)
- Liquid (No fixed shape, flows)
- Gas (Highly compressible)
- Change of State
- Melting, Boiling, Sublimation (Dry Ice)
- Evaporation & Factors Affecting It
- Temperature, Surface Area, Wind
- Latent Heat & Humidity
Exam Tips:
- Focus on diagrams (e.g., arrangement of particles in solids/liquids/gases).
- Learn real-life examples (e.g., sweating cools us due to evaporation).
Conclusion
This chapter forms the basis for understanding physical and chemical changes in higher classes.
