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Tamil Nadu (TNBSE)Class 9 Science★ 4-5 marks in assessments

Matter Around Us

Samacheer Kalvi (TN State Board) Class 9 Science — Chemistry Chapter 10, Matter Around Us. Matter exists in pure forms (elements, compounds) and mixtures. Understanding how to classify matter and separate mixtures using techniques like chromatography and distillation is vital for water purification, metallurgy, and drug testing. Notes, worked examples, common mistakes, and quick revision.

⏱ 19 min readEasy difficulty✓ Free · NCERT-aligned

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The chapter at a glance

Every concept and exam-favourite branch — revisable in 5 minutes.

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Study Guide

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Key points, glossary and the questions most likely to show up.

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By the end of this chapter you'll be able to…

1Classify matter into elements, compounds, and mixtures
2Distinguish homogeneous and heterogeneous mixtures
3Perform separation techniques like sublimation, distillation, and chromatography
4Identify properties of true solutions, suspensions, and colloids

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Why this chapter matters

Matter exists in pure forms (elements, compounds) and mixtures. Understanding how to classify matter and separate mixtures using techniques like chromatography and distillation is vital for water purification, metallurgy, and drug testing.

Before you start — revise these

A 5-minute refresher here will save you 30 minutes of confusion below.

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Class 8 Science — Matter Around Us

Basic elements and compounds.

Matter Around Us — Class 9 Science (Samacheer Kalvi)

TN State Board (Samacheer Kalvi) Class 9 Science, Chemistry — Chapter 10. Matter exists in pure forms (elements, compounds) and mixtures. Understanding how to classify matter and separate mixtures using techniques like chromatography and distillation is vital for water purification, metallurgy, and drug testing.

1. About this chapter

This chapter deals with classification of matter, properties of solutions, colloids, suspensions, and physical vs chemical changes.

2. Classification of Matter

Pure Substances: Elements (cannot be broken down) and Compounds (chemically combined elements).
Mixtures: Physically combined substances. Homogeneous (uniform composition, e.g. salt water) and Heterogeneous (non-uniform composition, e.g. sand and iron filings).

3. Solutions, Colloids and Suspensions

True Solution: Solute size < 1 nm, homogeneous, does not show Tyndall effect.
Colloid: Solute size 1–100 nm, heterogeneous, shows Tyndall effect (e.g. Milk, fog).
Suspension: Solute size > 100 nm, heterogeneous, particles settle down.

4. Separation Techniques

Sublimation: Separates a sublimable solid (e.g. Camphor, ammonium chloride) from non-sublimable solids.
Distillation: Separates miscible liquids with large boiling point differences.
Chromatography: Separates solutes based on solubility in a solvent.

Key formulas & results

Everything you need to memorise, in one card. Screenshot this for revision.

Concentration of a Solution

(Mass of solute / Mass of solution) × 100

Mass of solution = Mass of solute + Mass of solvent.

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Common mistakes & fixes

These are the exact errors that cost students marks in board exams. Read them once, save yourself the trouble.

WATCH OUT

✗ Confusing compounds and mixtures.

✓ Compounds consist of chemically combined elements in a fixed ratio (e.g. water). Mixtures consist of physically mixed substances in any ratio (e.g. air).

WATCH OUT

✗ Dividing solute mass by solvent mass instead of solution mass.

✓ For concentration calculations, always use the total mass of the solution in the denominator.

NCERT exercises (with solutions)

Every NCERT exercise from this chapter — what it covers and how many questions to expect.

Multiple Choice Questions

Questions on separating techniques, colloids, and mixtures.

Questions

Short Answer Questions

True solutions vs colloids, Tyndall effect, and fractional distillation.

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Practice problems

Try each one yourself before tapping "Show solution". Active recall > rereading.

Q1EASY· Numerical

A solution contains 40 g of common salt in 320 g of water. Calculate the concentration of the solution.

▶ Show solution

Solute mass = 40 g, Solvent mass = 320 g. Solution mass = 40 + 320 = 360 g. Concentration = (40 / 360) * 100 = 11.11%.

Q2MEDIUM· Concept

State three differences between a physical change and a chemical change.

▶ Show solution

1. Physical change is temporary and reversible; chemical is permanent and irreversible. 2. No new substance is formed in physical; new substances form in chemical. 3. Little or no heat change in physical; significant energy change in chemical.

5-minute revision

The whole chapter, distilled. Read this the night before the exam.

•Elements and compounds are pure substances.
•Suspensions settle down; colloids do not, but scatter light.
•Distillation separates miscible liquids with different boiling points.
•Tyndall effect is shown by colloids and suspensions.

Tamil Nadu (TNBSE) marks blueprint

Where the marks come from in this chapter — so you can plan your prep.

Typical chapter weightage: 4-5 marks in assessments

Question type	Marks each	Typical count	What it tests
MCQ	1	1-2	Base concepts and definitions
Short Answer	2-3	1-2	Descriptive and application points

Prep strategy

Understand core definitions and solve standard textbook problems.
Review common mistakes to avoid losing easy marks.

Where this shows up in the real world

This chapter isn't just an exam topic — it lives in the world around you.

Petroleum Refining

Uses fractional distillation to separate crude oil into gasoline, diesel, kerosene, and other components.

Water Treatment

Sedimentation and filtration are used to clean drinking water supplies for cities.

Exam strategy

Battle-tested tips from teachers and toppers for this chapter.

Write definitions precisely as defined in the textbook.
Draw neat, labeled diagrams for biology and physics chapters.

Going beyond the textbook

For olympiad aspirants and curious learners — topics that build on this chapter.

Read advanced reference materials to explore concepts beyond the school syllabus.

Where else this chapter is tested

CBSE board isn't the only one — other exams test this chapter too.

Class 9 Annual ExamsHigh

NTSE Stage 1Medium

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Questions students ask

The real ones — pulled from the Q&A community and tutor sessions.

The scattering of a beam of light by colloidal particles, rendering the path of light visible (e.g., light beam in a dusty room).

It separates components based on their different rates of movement on a stationary medium (paper) through a mobile phase (solvent).

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Tamil Nadu (TNBSE) Class 9 mock tests

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