notes on is mattr around us is pure of book s chand class 9th
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IS MATTER AROUND US PURE
In our daily life whatever we see around is Matter. But is matter around us pure? A matter is defined as something which occupies space and has mass. Mass is a fundamental property which shows the amount of substance in an object.
How can we define the term purity? Many times we would have come across sentences like this water is pure or the milk used in making this tea is pure. Is this right? What is the basis for saying that a substance is pure? Can we say any substance is pure if it is smooth or soft or it is white? NO.
According to scientists, a substance is said to be pure if we take a substance and put it at a place and pick a particle from one corner and another particle from some random corner we get the identical particle despite the number of attempts made. In other words, a pure substance is made up of only one kind of elements or molecules. But if a substance is composed of different kind of elements or molecules then that substance is known as an impure substance. For example: When we were children, we would have played playpen with balls in which we have a large number of small balls. In this, we can have different colours of balls or all the balls can be of the same colour. If all the balls are of the same colour, then we can pick two balls from anywhere and it will be identical. This type of substance in which if we pick particles from any corner of the substance and it is same, then it is pure substance. But if the balls are of different colours in the playpen, then now if we pick balls from different corner they will not be identical always. This case in which if we pick particles from some random corners and are not identical then it is known as impure substance. The impure substance are often known as mixture.
Characteristics of pure substance:
They are perfectly homogeneous in nature.They are made up of only one kind of atoms or molecules.They have fixed composition.It have fixed density, melting point and boiling point etc.
Characteristics of impure substance:
It does not have any specific properties, the properties of mixture are result of the average of properties of all the constituents.It is formed as a result of physical change.They have variable composition.The mixtures are homogeneous as well as Heterogeneous Mixture in nature.
In our daily life whatever we see around is Matter. But is matter around us pure? A matter is defined as something which occupies space and has mass. Mass is a fundamental property which shows the amount of substance in an object.
How can we define the term purity? Many times we would have come across sentences like this water is pure or the milk used in making this tea is pure. Is this right? What is the basis for saying that a substance is pure? Can we say any substance is pure if it is smooth or soft or it is white? NO.
According to scientists, a substance is said to be pure if we take a substance and put it at a place and pick a particle from one corner and another particle from some random corner we get the identical particle despite the number of attempts made. In other words, a pure substance is made up of only one kind of elements or molecules. But if a substance is composed of different kind of elements or molecules then that substance is known as an impure substance. For example: When we were children, we would have played playpen with balls in which we have a large number of small balls. In this, we can have different colours of balls or all the balls can be of the same colour. If all the balls are of the same colour, then we can pick two balls from anywhere and it will be identical. This type of substance in which if we pick particles from any corner of the substance and it is same, then it is pure substance. But if the balls are of different colours in the playpen, then now if we pick balls from different corner they will not be identical always. This case in which if we pick particles from some random corners and are not identical then it is known as impure substance. The impure substance are often known as mixture.
Characteristics of pure substance:
They are perfectly homogeneous in nature.They are made up of only one kind of atoms or molecules.They have fixed composition.It have fixed density, melting point and boiling point etc.
Characteristics of impure substance:
It does not have any specific properties, the properties of mixture are result of the average of properties of all the constituents.It is formed as a result of physical change.They have variable composition.The mixtures are homogeneous as well as Heterogeneous Mixture in nature.
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hy
___
pure substance❓
made up of only kind of atoms or molecules
matter around us is of two types
__________________________
pure substance
mixture
mixture ❓
it contains two or more pure substances mixed together !!
pure substances are of two types.
elements ❓
which cannot be broken itno simpler substances by usual chemical method by supplying heat , light , energy !!
compounds ❓
it is a substance made up of two or more elements chemically combined in a fixed proportion
mixtures are of two types
homogenous ❓
in which substances are completely mixed and are indistinguishable from one another
heterogenous ❓
in which substances are not completely mixed with each other
alloys ❓
are homogenous mixtures of metals and nonmetals
solution ❓
a solution is homogeneous mixture
it consists
solute ❓
substance dissolved in solvent to make a solution
solvent ❓
which dissolves solute in it
properties of solution ❓
homogenous mixture.
particles are less than 1nm
they are stable
doesnot show tyndall effect
suspension ❓
in which solid substances are spread throughout the liquid without dissolving in it
properties ❓
heterogenous mixture.
are unstable
size if particles is 100nm
shows tyndall effect
colloids ❓
in which the size of solute particles is intermediate between those in true solution and suspension
properties❓
heterogenous mixture
particles size is intermediate between those in suspension and true solution
are unstable
shows tyndall effect
tyndall effect ❓
scattering of light by colloids
types of colloid ❓
sol
solid sol
aerosol
emulsion
foam
solid foam
gel
saturated solution ❓
a solution in which no more solute can be added at that temperature
unsaturated solution ❓
a solution in which more quantity of solute can be dissoved without raising its temperature
solubility ❓
maximum amount of solute which can be disdolved in 100 g of solvent at a specufic temperature
physical change ❓
in which no new substance is formed
its a temporary change
chemical change ❓
in which new substance is formed
its permanent change
filteration ❓
used to seperate insoluble substance from a liquid
crytallisation❓
process of cooling a hot concentrated solution to get the pure crystals
centrifugation ❓
un which suspended particles of a substance from a liquid un which mixture is rotated in a centrifuge machine
chromatography ❓
in which two or more solid substances present in solution in very small quantity is seperated
distillation❓
process in which heating the liquid to get vapours and cooling the vapours to get liquid back
evaporation ❓
is a surface phenomenon in which liquid is heated ti form vapours below its boiling point
hope helped❗
___
pure substance❓
made up of only kind of atoms or molecules
matter around us is of two types
__________________________
pure substance
mixture
mixture ❓
it contains two or more pure substances mixed together !!
pure substances are of two types.
elements ❓
which cannot be broken itno simpler substances by usual chemical method by supplying heat , light , energy !!
compounds ❓
it is a substance made up of two or more elements chemically combined in a fixed proportion
mixtures are of two types
homogenous ❓
in which substances are completely mixed and are indistinguishable from one another
heterogenous ❓
in which substances are not completely mixed with each other
alloys ❓
are homogenous mixtures of metals and nonmetals
solution ❓
a solution is homogeneous mixture
it consists
solute ❓
substance dissolved in solvent to make a solution
solvent ❓
which dissolves solute in it
properties of solution ❓
homogenous mixture.
particles are less than 1nm
they are stable
doesnot show tyndall effect
suspension ❓
in which solid substances are spread throughout the liquid without dissolving in it
properties ❓
heterogenous mixture.
are unstable
size if particles is 100nm
shows tyndall effect
colloids ❓
in which the size of solute particles is intermediate between those in true solution and suspension
properties❓
heterogenous mixture
particles size is intermediate between those in suspension and true solution
are unstable
shows tyndall effect
tyndall effect ❓
scattering of light by colloids
types of colloid ❓
sol
solid sol
aerosol
emulsion
foam
solid foam
gel
saturated solution ❓
a solution in which no more solute can be added at that temperature
unsaturated solution ❓
a solution in which more quantity of solute can be dissoved without raising its temperature
solubility ❓
maximum amount of solute which can be disdolved in 100 g of solvent at a specufic temperature
physical change ❓
in which no new substance is formed
its a temporary change
chemical change ❓
in which new substance is formed
its permanent change
filteration ❓
used to seperate insoluble substance from a liquid
crytallisation❓
process of cooling a hot concentrated solution to get the pure crystals
centrifugation ❓
un which suspended particles of a substance from a liquid un which mixture is rotated in a centrifuge machine
chromatography ❓
in which two or more solid substances present in solution in very small quantity is seperated
distillation❓
process in which heating the liquid to get vapours and cooling the vapours to get liquid back
evaporation ❓
is a surface phenomenon in which liquid is heated ti form vapours below its boiling point
hope helped❗
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