CLASS 9 SCIENCE CHAPTER 4 STRUCTURE OF THE ATOM NOTES ⬆️ TOP EDUCATION ⬆️ structure-atom-notes-classnine-science

  

          ⬆️ TOP EDUCATION ⬆️                  

                                   CBSE

                        CLASS 9 SCIENCE

       CHAPTER 1 MATTER IN OUR SURROUNDINGS

                                        NOTES

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

👉Matter is composed of tiny particles called atoms and molecules.

2. States of Matter:

👉Solid: Definite shape and volume, particles are closely packed and have strong intermolecular forces.

👉Liquid: Definite volume but no definite shape, particles are close but can move past each other.

👉Gas: No definite shape or volume, particles are far apart and have weak intermolecular forces.

3. Change of State:

Melting: Solid to liquid.

Freezing: Liquid to solid.

👉Evaporation: Liquid to gas at any temperature.

👉Condensation: Gas to liquid.

👉Sublimation: Solid directly to gas or vice versa without passing through the liquid state.

4. Physical Properties of Matter:

👉Colour, odor, taste, hardness, density, boiling point, melting point, etc.

5. Characteristics of Particles of Matter:

👉Particles of matter have space between them.

👉They are constantly moving and have kinetic energy.

👉The particles of matter attract each other due to intermolecular forces.

6. The Particle Nature of Matter:

👉Matter is made up of particles.

👉Particles of matter are very small and can't be seen with the naked eye.

👉Particles have spaces between them.

7. The Effect of Change of Temperature:

👉Increase in temperature causes particles to move faster.

👉Decrease in temperature causes particles to move slower.

8. The Effect of Change of Pressure:

👉Increase in pressure compresses the particles and reduces the space between them.

👉Decrease in pressure expands the particles and increases the space between them.

9. Evaporation:

👉The process of conversion of a liquid into vapor at any temperature.

👉Evaporation occurs from the surface of a liquid.

👉Factors affecting evaporation: temperature, surface area, wind speed, humidity.

10. Condensation:

👉The process of conversion of a gas into a liquid.

👉It occurs when a gas loses heat energy and converts into a liquid.

11. Sublimation:

👉The process of conversion of a solid directly into a gas or vice versa without passing through the liquid state.

👉Examples: ammonium chloride, camphor, dry ice (solid carbon dioxide).

12. Diffusion:

👉The process by which particles of a substance move from an area of higher concentration to an area of lower concentration.

👉Diffusion occurs due to the random motion of particles.

⭐Remember to refer to your textbook and class notes for detailed explanations, diagrams, and examples related to each topic.