Summary Best handwritten chemistry notes class 9 matter in our surroundings CBSE NCERT+study tips+important questions coming in exams

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Matter in our surroundings
Chemistry class 9 NCERT CBSE




1. What is Matter?
Anything that occupies space and has mass is called matter.

 Examples: Solids, liquids, gases.
 Mass – quantity of matter in an object.
 Volume – space occupied by an object.


2. States of Matter
 Three main states:

, 1.Solid

 Fixed shape & volume
 Particles are closely packed and vibrate in place
 Example: Ice, wood

2.Liquid
 Fixed volume, takes shape of container
 Particles are less tightly packed than solids; can move/slide
 Example: Water, milk

3.Gas
 No fixed shape or volume, fills container completely
 Particles are far apart and move freely
 Example: Oxygen, nitrogen

Important: Some NCERT questions ask differences between states → always remember in table
form.

3. Properties of Matter

Elasticity: Ability to regain original shape after force.

Density (ρ): Mass/Volume

Compressibility: Solids & liquids – low, gases – high

Diffusion: Gases mix quickly; liquids – slower; solids – very slow

Quick Tip: Remember solids < liquids < gases for diffusion rate.



4. Change of State

Melting: Solid → Liquid

Freezing: Liquid → Solid

Vaporisation: Liquid → Gas



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