🧱 Chapter 7 Revision Notes

Particulate Nature of Matter

1. [cite_start]Matter and its Particles [cite: 99-100]

Matter: Anything that occupies space and has mass (e.g., stones, water, air).
Matter is not continuous (like a block of wood) but is made up of tiny particles.
Breaking chalk or sugar crystals into finer powder shows that they are made of smaller and smaller particles.

2. [cite_start]Characteristics of Particles of Matter [cite: 101-103]

Space between particles: When sugar dissolves in water, the water level does not rise. This shows sugar particles take up the spaces between water particles.
Continuous Motion: Particles are always moving.
- Diffusion: The intermixing of particles of two different substances on their own. (e.g., smell of incense stick spreading).
- Temperature affects motion: Higher temperature → Faster motion → Faster diffusion.
Forces of Attraction: Particles attract each other. This force keeps them together. The strength of this force varies (Strongest in solids, weakest in gases).

3. [cite_start]States of Matter [cite: 105-110]

Solids: Have fixed shape and fixed volume. Particles are tightly packed with strong attraction. Negligible compressibility.
Liquids: Have fixed volume but no fixed shape (take the shape of the container). Particles are less tightly packed than solids and can move/slide past each other.
Gases: Have neither fixed shape nor fixed volume. Particles move freely at high speeds. Highly compressible (e.g., CNG, Oxygen cylinders).

Class 8 Science - Ch 7 Practice Test

Particulate Nature of Matter

This test contains 20 questions.

Note on Marking:
• Word Limits: SA > 30 words, LA > 55 words.
• Step Marking: Marks for SA/LA are awarded based on matching key scientific terms from the textbook.
(If keywords are missing, you will receive 0 marks even if the word count is met).

Time Left: 01:00:00

Test Progress: 0/20

Test Results 📊

Total Questions:

Total Marks:

Your Score:

Percentage: %

Status:

Solutions & Explanations