CBSE Class 9 Science Notes
Chapter 1: Matter in Our Surroundings (Ultimate Exam Revision Guide)
Board: CBSE / NCERT Subject: Chemistry (Class 9) Target: Mid-Terms, Unit Tests & Finals
1. MASTER CONCEPT MAP
CLASSIFICATION OF MATTER
MATTER (Anything that has mass and occupies space/volume)
SOLIDS LIQUIDS GASES
• Fixed Shape & Volume • Fixed Volume, No Shape • No Fixed Shape or Volume
• Strongest attraction • Intermediate forces • Negligible attraction
• Rigid & Incompressible • Fluid (Can flow easily) • Highly Compressible
2. KEY DEFINITIONS & FUNDAMENTALS
• Matter: Anything that occupies space (volume) and has mass. (Note: Sound, light, and feelings are NOT matter).
• Diffusion: The spontaneous intermixing of particles of two different substances on their own.
◦ Rule: Rate of diffusion increases rapidly with temperature due to higher kinetic energy.
• Sublimation: Direct transition from Solid → Gas without passing through the liquid phase.
◦ Key Examples: Camphor, Ammonium Chloride (NH Cl), Naphthalene balls, Anthracene, Solid CO (Dry Ice).
4 2
• Deposition: Direct transition from Gas → Solid without becoming liquid.
3. CHARACTERISTICS OF PARTICLES OF MATTER
Characteristic Key Observation / Activity Exam Explanation
Sugar particles fit directly into the
Dissolving sugar or salt in water without
1. Particles have spaces microscopic intermolecular spaces of
increasing total volume.
liquid water.
Particles possess Kinetic Energy.
2. Particles are continuously Smell of unlit vs. lit incense stick; ink
Higher temperature increases energy and
moving spreading in water.
particle speed.
Inability to cut a continuous stream of Intermolecular attraction force: Solids >
3. Particles attract each other
water with a finger. Liquids > Gases.
4. MASTER COMPARISON: STATES OF MATTER
Property Solid Liquid Gas
Shape Fixed Not fixed (takes container shape) Not fixed
CBSE Class 9 Science • Chapter 1 Notes Page 1 of 3
Chapter 1: Matter in Our Surroundings (Ultimate Exam Revision Guide)
Board: CBSE / NCERT Subject: Chemistry (Class 9) Target: Mid-Terms, Unit Tests & Finals
1. MASTER CONCEPT MAP
CLASSIFICATION OF MATTER
MATTER (Anything that has mass and occupies space/volume)
SOLIDS LIQUIDS GASES
• Fixed Shape & Volume • Fixed Volume, No Shape • No Fixed Shape or Volume
• Strongest attraction • Intermediate forces • Negligible attraction
• Rigid & Incompressible • Fluid (Can flow easily) • Highly Compressible
2. KEY DEFINITIONS & FUNDAMENTALS
• Matter: Anything that occupies space (volume) and has mass. (Note: Sound, light, and feelings are NOT matter).
• Diffusion: The spontaneous intermixing of particles of two different substances on their own.
◦ Rule: Rate of diffusion increases rapidly with temperature due to higher kinetic energy.
• Sublimation: Direct transition from Solid → Gas without passing through the liquid phase.
◦ Key Examples: Camphor, Ammonium Chloride (NH Cl), Naphthalene balls, Anthracene, Solid CO (Dry Ice).
4 2
• Deposition: Direct transition from Gas → Solid without becoming liquid.
3. CHARACTERISTICS OF PARTICLES OF MATTER
Characteristic Key Observation / Activity Exam Explanation
Sugar particles fit directly into the
Dissolving sugar or salt in water without
1. Particles have spaces microscopic intermolecular spaces of
increasing total volume.
liquid water.
Particles possess Kinetic Energy.
2. Particles are continuously Smell of unlit vs. lit incense stick; ink
Higher temperature increases energy and
moving spreading in water.
particle speed.
Inability to cut a continuous stream of Intermolecular attraction force: Solids >
3. Particles attract each other
water with a finger. Liquids > Gases.
4. MASTER COMPARISON: STATES OF MATTER
Property Solid Liquid Gas
Shape Fixed Not fixed (takes container shape) Not fixed
CBSE Class 9 Science • Chapter 1 Notes Page 1 of 3
