MATTER IN OUR SURROUNDINGS

CBSE Class 9 Science Chapter 1, “Matter in Our Surroundings”, introduces students to the fundamental concept of matter — the basic building block of the universe. In this chapter, learners explore the nature, characteristics, and states of matter (solids, liquids, and gases), how matter can be classified based on its properties, and how it changes state under varying conditions of temperature and pressure. From understanding particle behavior to the significance of diffusion, this chapter forms the foundation for more advanced topics in chemistry. This article provides comprehensive, easy-to-understand notes, examples, and important questions from the CBSE Class 9 Science syllabus, making it an ideal resource for students seeking clarity and a strong conceptual understanding of matter in its various forms.

What is substance?

A substance is a specific type of matter that cannot be separated into other kinds of matter by any physical process. In simpler terms, a substance is a material with a fixed composition and distinct properties.

For example:

Sugar dissolved in water can be separated from water by evaporation, which is a physical process. In this case, sugar itself is a substance, because it cannot be broken down further by any physical method.
Similarly, sodium chloride (table salt) and lime (calcium oxide) are also examples of substances, as they have a fixed composition and cannot be split into other components using ordinary physical techniques.

The Physical Nature of Matter

To understand substances better, it is important to first recognize the physical nature of matter. All matter — be it solid, liquid, or gas — is made up of tiny, indivisible units called particles.

Key Point:

These particles have spaces between them, and they are always in motion. The nature and behavior of these particles determine the state and properties of the matter.

Concept	Definition	Examples
Substance	A material that cannot be separated into other matter by physical means.	Sugar, Salt (NaCl), Lime (CaO)
Physical Process	A method like filtering or evaporation that separates mixtures but doesn’t change the nature of a substance.	Evaporation of water from sugar solution
Matter	Anything that has mass and occupies space, made of tiny particles.	Solids, liquids, gases
Particles	Tiny units that make up matter, always in motion and with spaces between them.	Molecules, atoms

Frequently Asked Questions (FAQs)

Q1. What is a substance?

A1. A substance is a form of matter that has a fixed composition and can’t be separated into other matter by physical methods, like salt or sugar.

Q2. How is a substance different from a mixture?

A2. A substance has a fixed composition and properties throughout, whereas a mixture can be separated into its components by physical means.

Q3. What are examples of substances?

A3. Examples of substances include sugar, sodium chloride (table salt), and lime (calcium oxide).

Q4. What is matter made of ?

A4. Matter is made of tiny, invisible units called particles, which have spaces between them and are always in motion.

Q5. What is the physical nature of matter?

A5. The physical nature of matter is that it is composed of particles that have spaces between them and are constantly moving.

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