Hey there! We receieved your request
Stay Tuned as we are going to contact you within 1 Hour
One of our academic counsellors will contact you within 1 working day.
Click to Chat
1800-5470-145
+91 7353221155
Use Coupon: CART20 and get 20% off on all online Study Material
Complete Your Registration (Step 2 of 2 )
Sit and relax as our customer representative will contact you within 1 business day
OTP to be sent to Change
CBSE Class 9 Revision Notes for Chapter 2 Is Matter Around Us Pure are a study guide for students for understanding what mixtures and pure substances are. This is an important chapter from the exam perspective and includes many interesting topics that will help you in higher classes. askIITians Science teachers have created these revision notes based on the latest CBSE syllabus and exam pattern for Class 9 Science. So they are the perfect study material for exam preparation. The notes are pointwise so that you can revise or memorise the concepts quickly. With our online free revision notes for Class 9 Science Is Matter Around Us Pure, you can revise the whole chapter in just 20 minutes or less!
CBSE Science Revision Notes for Class 9 Science Chapter 2 Is Matter Around Us Pure include all the topics introduced in the chapter such as mixtures, solutions, homogeneous solutions, the concentration of solutions, colloidal solutions, suspensions, separating the components of a mixture, physical and chemical changes, types of pure substances, and compounds. You can revise all these concepts easily with our revision notes. They are available for free for all students.
askIITians Science experts have prepared different types of study resources for Class 9 Science. These include NCERT Solutions, NCERT Exemplar Solutions, mind maps, chapter-wise revision notes, flashcards, mnemonics, daily practice papers, tests and much more. We also provide class 6, 7, 8, 9, 10, 11, 12 notes for Science and Maths subjects. Check our study resources once you have done reading our revision notes for Class 9 Science Is Matter Around Us Pure.
A substance that consists of only one type of particle is called a Pure Substance. For Example, Diamond, Salt, Sulphur, Tin.
Water, Copper, Chocolate cake, Hydrogen, Soil, Air
Mixture – Chocolate cake, Soil, Air
Pure substance – Water, Copper, Hydrogen
There are two categories of mixtures: Homogeneous Mixtures and Heterogeneous Mixtures
Here are a few differences between homogeneous and heterogeneous mixtures –
Homogenous Mixtures
Heterogeneous Mixtures
They have a uniform composition throughout
They have a non-uniform composition
We cannot separate the components of the mixture through physical processes
We can separate the components through physical processes
Components cannot be seen through naked eyes
Components can easily be seen through naked eyes
The mixture is in single-phase throughout
The substances can be of two different phases and we may see separate layers of the substances
Example: A mixture of water and milk
Example: A mixture of oil in water
A solution is nothing but a uniform mixture of two or more substances. Homogenous Mixtures are solutions.
Solution of -
An alloy is a mixture of different metals or nonmetals and metals that cannot be separated from each other using physical methods. For Example
Brass – Copper with up to 50% zinc
Bronze – Copper with up to 12% tin
Solution consists of two types of substances, a solute and a solvent.
Solution = Solute + Solvent
Solvent – The substance in which another substance is mixed is called the Solvent. For Example, Water is a solvent in which we can mix different substances such as salt or sugar.
Solute – The substance that is added to the solvent to form a solution is called a Solute. For Example, Salt, when mixed in water, acts as a solute for the mixture.
A stable solution is a solution in which particles do not settle down if we leave the solution undisturbed for some time. This is because the particles of a stable solution are homogeneously spread.
Concentration refers to the amount of a substance per defined space or can be defined as the ratio of solute in a solution to either solvent or total solution.
To calculate the concentration consider the formulae below:
Where, Moles of solute = Given mass/molar mass
= Mass of solute / (equivalent mass * volume of solution in Litres)
A suspension is formed when two or more substances are mixed in a non-uniform manner. Heterogeneous mixtures are suspensions. The solute does not mix with the solvent and can be viewed through naked eyes.
A colloidal solution or a colloid is a uniform solution of two or more substances. The particles are relatively very small and the solution appears as a homogeneous mixture but it is not.
When a beam of light is passed through a colloid the particles of the colloid scatter the beam of light and we can see the path of light in the solution. For Example, when a ray of light enters a dark room it is scattered by the dust particles present in the air and we can see the path of light clearly.
Dispersed Phase – The dispersed particles or the solute-like components in a colloid
Dispersing Medium – The substance in which these solute-like particles are added
Based on the state of the dispersing medium colloids are classified as:
Example
Dispersing Medium
Dispersed Substance
Colloid Type
Fog, Aerosol sprays
Gas
Liquid
Aerosol
Smoke, Airborne bacteria
Whipped cream, Soapsuds
Foam
Milk, Mayonnaise
Emulsion
Paints, Clays, Gelatin
Solid
Sol
Marshmallow, Styrofoam
Solid foam
Butter, cheese
Solid emulsion
Ruby glass
Solid sol
We can separate the heterogeneous mixtures into their constituents by means of physical methods like
The components of a mixture can be separated from each other using several other techniques like
Method – Fractional Distillation
Method used – Crystallisation
In the crystallisation method, we can obtain a pure solid in the form of crystals from its solution
Simple evaporation is not better than crystallisation because
Physical Property of a Substance:
Properties of a substance such as rigidity, colour, fluidity, boiling point, melting point, density and hardness which we can observe are called Physical Properties.
Physical Change:
When the physical properties of a substance change it is known as a Physical Change. When we convert a substance from one state to another, such as a solid into a liquid or vice-versa, it is also a physical change as only the physical nature of the substance changes without affecting its chemical nature.
For Example, Change of ice into water. The chemical properties of water remain the same.
Chemical Property of a Substance:
The chemical nature of a substance is known as its Chemical Property such as its odour or its chemical composition.
Chemical Change:
When the chemical properties or chemical composition of a substance gets altered it is called a chemical change. It is also called a Chemical Reaction.
For Example, Burning paper
Pure substances are classified as elements and compounds
An element is the simplest form of matter. Elements cannot be broken down into further elements by chemical reactions. Elements are further characterised as Metals, Nonmetals and Metalloids
Metals – Silver, Mercury, Copper, Gold
Non-Metals – Carbon, Iodine, Chlorine, Oxygen, Hydrogen
Metalloids – Silicon, Germanium
They show some properties of metals and some of the non-metals.
Quick Facts –
It is a substance that consists of two or more substances. These substances are combined chemically with each other in fixed proportions. The properties of a compound are different from that of its constituents. For Example, Ammonium Sulphate, Sulphur Chloride, Water.
Properties of a mixture Reflect the properties of the materials it contains.
Different properties from that of the elements that make up the compounds.
No uniform composition
Definite composition. Definite ratio/formula
Can be separated by physical means.
Cannot be separated by physical means.
This chapter helps you understand what pure and impure substances are found in the environment. This chapter teaches you important concepts related to mixtures, solvents, heterogeneous and homogeneous solutions, colloids and much more. All these topics help you in daily life as well as in higher studies.
askIITians provides live, interactive classes for Class 9 Science students where our teachers use innovative teaching methods. This also includes regular online classes, doubt sessions, discussions and tests. We also provide study materials like NCERT Solutions, previous year questions, daily practice worksheets, chapter-wise Revision Notes for CBSE Class 9 Science, flashcards, mind maps and much more!
Get your questions answered by the expert for free
You will get reply from our expert in sometime.
We will notify you when Our expert answers your question. To View your Question
Matter in Our Surroundings CBSE Class 9 Science...
Force and Laws of Motion CBSE Class 9 Science...
Revision Notes on Structure of Atom Quick Revision...
Improvement in Food Resources CBSE Class 9 Science...
Gravitation CBSE Class 9 Science Revision Notes...
Natural Resources CBSE Class 9 Science Revision...
Motion CBSE Class 9 Science Notes Chapter 8 Do you...
Why Do We Fall Ill CBSE Class 9 Science Revision...
Diversity in Living Organisms CBSE Class 9 Science...
Revision Notes on Work and Energy Work The...
Tissues CBSE Class 9 Science Revision Notes...
Atoms and Molecules CBSE Class 9 Science Revision...
Sound CBSE Class 9 Science Revision Notes Chapter...
The Fundamental Unit of Life CBSE Class 9 Science...