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Is Matter Around Us Pure Notes: Class 9 CBSE Revision Material

Is matter around us pure notes

Is Matter Around Us Pure Notes:

Do you know you can save a lot of time by reading class 9 notes of science? The fully packed study material, as well as revision notes, are included in “is matter around us pure notes”. It includes pure and impure substances, mixture with its types, solutions, suspension, colloids and depuration of mixtures. Read and learn it to score better in the exams.

classification of matter is matter around us pure NCERT


Anything that occupies space and has mass and volume is matter.

There are mainly two types of matter:

  1. Pure substances
  2. Impure substances or Mixtures

Pure substances:

The material which is consisted of only one type of atoms or molecules throughout is said to be pure substances. Here in ‘is matter around us pure notes’ we will read more about pure substances.

Pure substances are of two types:


  • Elements are made up of only single type of atoms.
  • Each atom in the element is identical.
  • It is a basic form of matter that cannot be broken down into simpler substances by chemical reactions.
  • Different elements have different type of atoms.
  • Gold, silver, Iron are some examples.


  • Compounds are made up of only single type of molecules.
  • When two or more elements combine in a fixed ratio by mass then a compound is formed.
  • H2O (water), NO­2(Nitrogen dioxide) are its example.
  • There is little to read about compounds in is matter around us pure notes.

Properties of compounds:

  • Compound is considered as the homogeneous substance with definite composition.
  • It has fixed melting and boiling point.
  • During the formation of compound energy is evolved in the form of heat or light.
  • By applying suitable chemical methods we can split compounds into its constituent elements.

Impure substances (Mixtures):

When two or more different types of atoms and molecules which do not react with each other are mixed randomly (any proportion) then the material formed is said to be a mixture. there are categories of impure substances mentioned in is matter around us pure notes.

Properties of mixtures:

  • It can be Homogenous as well as Heterogeneous.
  • There is variable composition of a mixture.
  • Melting and boiling point of a mixture is not fixed in a mixture.
  • During the formation of mixture, there is neither release nor absorption of energy.
  • The property of mixture is defined by the properties of its constituents.

Mixture is of two types: 

  1. Homogeneous Mixture
  2. Heterogeneous mixture

Homogeneous Mixture

  • It has fixed (uniform) composition.
  • There are no visible boundaries of separation between the mixed components.
  • Mixture of salt and water is the example of homogenous mixture.

Heterogeneous Mixture:

  • It’s composition is not uniform they are not uniformly mixed.
  • There are visible boundaries of separation between their components.
  • Mixture of oil and water or sand and water is the example of heterogeneous mixture.
  • Is matter around us pure notes contains all the information you should know.


  • The homogeneous mixture of two or more substances is said to be solution.
  • Lemonade, soda water is the examples of solution.

Properties of solutions:

  • Solution is homogeneous mixture.
  • Solution has particle size (diameter) less than 1nm (10-9m).
  • We can’t see particles of a solution even with a simple microscope.
  • Scattering the light (Tyndall effect) is not observed in a true solution.
  • The best thing about solution is that it is stablee. when left undisturbed, solute particles doesn’t settle down.
  • By simple filtration, we can’t separate solute particles from solution.
  • What information is essential for the notes is given here in is matter around us pure notes.

Components of solution:

There are two components of a solution:

  1. Solute: The component of solution which is dissolved and is present in less amount as compared to the solvent is said to be solute. Sugar, salt etc. are solute.
  2. Solvent: That component of the solution which dissolves the solute in it and is present in a large amount is said to be solvent. Water (universal solvent), alcohol etc. are examples of solvent.

We will read more about solvent in higher classes however is matter around us pure notes is sufficient for now.

Types of solution:



Solid in liquid Salt in Water
Liquid in liquid Alcohol in water
Gas in liquid Compressed CO2 in
carbonated drinks
Solid in Solid Different metal alloys
Gas in Gas Environmental air
Liquid in Solid Amalgams
Gas in solids Adsorbed gases on the
surface of different metals.
Solid in gas Camphor in air
Liquid in gas Clouds and fogs



Solubility can be defined as the maximum amount of solute that can be dissolved in 100 grams of a solvent at a definite temperature to make it a saturated solution.

Factors affecting solubility:

  • As temperature is increased solubility of solids in liquids also increases but on the other hand solubility of gases in liquids decrease.
  • As Pressure is increased solubility of gases in liquids increase whereas the solubility of solids in liquids remains unaffected.
  • Is matter around us pure notes contains what you require now for your exams.

Concentration of a Solution:

Mass of the solute in grams present in 100 grams of the solution is concentration.

There are basically two methods of finding concentration of solution:

  1. Mass by mass percentage method: \(\frac{mass \:of\: solute}{mass\: of \:solution}\) x 100
  2. Mass by volume percentage method: \(\frac{mass \:of \:solute}{Volume\: of \:solution}\) x 100
  • Saturated solution: At a given temperature when no more solutes can be dissolved in a solvent then it is called saturated solution.
  • Unsaturated solution: At a given temperature when more solutes can be dissolved in a solvent then it is called unsaturated solution.


  • A heterogeneous mixture when solute particles remain suspended in the medium (do not dissolve in it) is said to be suspension. Hence is included in is matter around us pure notes.

Properties of suspension:

  • First thing, it is heterogeneous mixture.
  • size
  • We can see the particles of suspension through our naked eye (at STP Standard Temperature Pressure).
  • Scattering of light is observed in suspension. i.e. No Tyndall effect is seen.
  • Suspension is unstable as when left undisturbed its particle settles down.
  • By simple filtration we can separate their components.


  • The solution in which the particles size lies in between those of true solutions and suspensions are said to be colloidal solutions.

Properties of colloidal solution:

  • Colloid is also a heterogeneous mixture.
  • We can’t see particles of colloid from our naked eye.
  • Colloid is stable as it doesn’t settle down when left un-shake.
  • We can’t separate its components by simple filtration.

Terminology related to colloids:

  • Tyndall Effect: The phenomenon of scattering of white light when it passes through a colloidal solution is said to be Tyndall effect.
  • Dispersed phase: It is solute like component or the dispersed particles are said to be dispersed phase.
  • Dispersion medium: The components of a colloid in which the dispersed phase is suspended is said to be dispersion medium.

Types of colloids:

We have provided here a list of phases and medium in is matter around us pure notes to ease your understandings.

Dispersed Phase Dispersion Medium Type Examples
Liquid Gas Aerosol Fog, clouds, mist
Solid Gas Aerosol Smoke, automobile exaust
Gas Liquid Foam Shaving cream
Liquid Emulsion Milk, Face cream
Solid Sol Milk of magnesia, Mud
Gas Solid Foam Foam, Rubber, Sponge
Liquid Gel Jelly, Cheese, butter
Solid :” Solid Sol Colored gemstone, milky glass

This informative table is exclusively added to is matter around us pure notes.

Separation of Mixtures:

There are various methods involved in separation of components of a mixture. In ‘is matter around us pure notes’ almost all the methods are mentioned. We can separate the components from the heterogeneous mixture by simple physical methods like sieving, hand-picking filtration. For a dense mixture to be separated into its constituents we use various components such as

  • Sublimation
  • Filtration
  • Centrifugation
  • Evaporation
  • Crystallization
  • Chromatography
  • Distillation
  • Fractional distillation
  • Separating funnel

Let’s discuss some important modes of separation of mixture components included in ‘is matter around us pure notes’:

1.  Sublimation:

  • The process in which a substance directly changes to gaseous state from solid state is said to be sublimation.
  • Sublimes are the solids which undergo sublimation.
  • Some common examples of sublimes are of camphor, ammonium chloride, naphthalene etc.


2.  Filtration:

  • In this method we use filter paper to separate the components.
  • Solubility is considered for separation by this process.
  • We filter insoluble substance from mixture by this process. The insoluble substance (residue) remains aside on the filter paper and the other components get filtered out called
  • We can separate sand & water by the process of fltration.
  • Refer is matter around us pure notes for good score in boards.


3.  Evaporation:

  • This method is used to separate the substance having different boiling points.
  • This process is also based on the fact that liquid vaporise easily than solid.
  • We can separate ink and water by this method.


4. Crystallization:

  • The process of cooling a hot concentrated solution of a substance to obtain crystals is said to be crystallization.
  • It is used to remove impurities from solid.
  • We can separate salt from sea water or crystals of alum from impure mixtures from this method.
  • This method is considered better than evaporation as there are various impurities which remains stick to the solid after evaporation.

5. Chromatography:

  • The process of separation of different solutes which dissolves in the same solvent.
  • It is used for separation of colours.
  • We can separate colors in a dye, pigments from natural colours, drugs from blood.

6. Separation of two immiscible liquids:

  • It is the separation of two liquids which don’t mix to each other.
  • Separating funnel is used in this separation process.
  • The separation of these immiscible liquids depends upon the densities of both the liquids.
  • We can separate oil and water by using the separating funnel.

seperation of immicible liquids

7. Distillation (Separation of two miscible liquids):

  • This process is used to separate miscible liquids having difference in their boiling points.
  • In this method the mixture is heated and the vapour is condensed into the other vessel.
  • The condensed vapour is called
  • Thus both the liquids are separated.


8. Fractional distillation:

  • This method is used to separate the components of mixture of miscible liquids.
  • In this method, the distillate is collected in fractions at different temperatures.
  • We use fractional distillation when the boiling point is less than 25 K.
  • This is enough for you as per is matter around us pure notes.

9. Centrifugation:

  • The process used for separating the suspended particles of a substance from the liquid.
  • We generally separate cream from milk by the process of centrifugation.
  • Centrifuge is a machine where centrifugation process is carried out.
  • The mixture is rotated rapidly so that the heavier particles in the mixture settle down in the bottom.
  • The principle of centrifugation is that the denser particles settle down and the lighter particles comes up.
  • Centrifugation is also a considerable under is matter around us pure notes.

Physical and chemical change:

  1. Physical change: The change which indulge only the change of physical properties are said to be physical change. No new substance is formed in case of physical change.
  2. Chemical change: Those changes in which new substances are formed and it is totally different from the previous one are said to be chemical change.
Physical Change Chemical Change
Only physical properties change. There is change in chemical properties.
Chemical composition of a substance
doesn’t change during physical change.
Chemical composition of a substance
always change during chemical change.
There is no new substance formation. Always there is formation of new substances.
It is reversible change. Chemical change is irreversible change.
It is temporary change. It is permanent change.

This tabular information from is matter around us pure notes will help you in better understanding.

Classification of elements:

Elements are broadly classified into three categories, they are:


  • Metals are lusturous (shiny suface).
  • These are of silvery-grey or golden-yellow colour.
  • It conducts heat and electricity.
  • Metals are ductile (can be drawn into wires).
  • It is malleable (can be hammered into thin sheets).
  • Also metals are sonorous (make a ringing sound when hit).
  • Gold, silver, copper, iron, sodium, potassium etc. are some examples of metals.
  • However a little about metal is there in class 9 is matter around us pure notes.


  • Non-metals show multiple colours.
  • They are bad conductors of heat and electricity.
  • They are non-lustrous, non-sonorous or non-malleable.
  • Hydrogen, iodine, oxygen, carbon (coal, coke), bromine, chlorine etc. are some examples of non-metals.


  • Metalloids possess properties of metals as well as non-metals.
  • Boron, silicon and germanium are some examples of metalloids.
  • Is matter around us pure notes has given you standard information about metalloids.

Difference between metals and non-metals:

Metals Non-Metals
They are lustrous. They are not lustrous.
Often metals are silvery-grey or
Non-metals have multiple colours.
Metals can be beaten into thin sheets
i.e. they are malleable.
They deform after being beaten.
They are ductile (drawn to thin wires). Non ductile
Metals are sonorous (produces sound). Non-sonorous

These tabular differences are often asked in boards so we added in is matter around us pure notes.

 Take a look at solved question and answer related to this chapter:

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