Grade -8 (Science ): Mixture

                        Unit :-12                  Mixture

Mixture :

The substance in which two or more than two substances  are mixes with each other any proportion by weight is called mixture .For example :Air ,milk, water ,sand ,sugar etc.

Types of mixture on the basis of nature of components of mixture :They are two type:

a)Homogenous mixture :The mixture in which components of mixture are equally distributed and component particles of mixture can not be seen init by naked eye is called homogenous mixture .For example :Salt water solution, alcohol water solution ,soda water etc.

b) Heterogeneous mixture : The mixture in which components of mixture are equally  not distributed and component particles of mixture can be seen init by naked eye is called heterogeneous mixture .For example :Muddy water ,Oily water ,Milk ,Blood etc.

Types of mixture  and method to separate the components of those mixture :

Types of Mixture	Methods of separation of mixtures
1.Homogenous mixture
A)Solid +Solid	-Evaporation i.e. Salt from salt solution -Crystallization i.e. Salt from salt and water -Centrifuging i.e. Cream from milk
B)Liquid +Liquid	-Simple distillation i.e. Salt +water -Fractional distillation i.e. Component of petroleum from crude oil, mixture of alcohol and water .
2. Heterogeneous Mixture
A)Solid+ Solid       B)Solid +Liquid	Winnowing i.e. Sand and rice -Sieving i.e. Wheat  grains from its floor +rice -Sublimation i.e. Sand + Camphor -Magnetic separation i.e. Iron dust + sand   -Sedimentation i.e. Sand + rices -Decantation i.e. Sand+ mud + water -Filtration i.e. Sandy water
C)Liquid +Liquid	Using separating funnel i.e. Kerosene water
-Coloured mixture	-Chromatography

Separation of Mixture :The process by which the component of mixture are separated from each other is called separation  of mixture .

Principle  of separation of mixture :The separation of the components at a mixture depend on the principle that “Different substances have different properties “

Distillation :The method of separation of solution in which one or more components of solution change into gas by heating and gas is condensed at another place by cooling is called distillation .For example :Separation of water from salt and waters solution .

Types of distillation :They are 2 types :

1.)Simple distillation :The process of converting a liquid into vapour on heating up to its boiling points and converting the vapour into liquid again on cooling is called simple distillation .For example :to separate salt from sea water ,to separate salt and water from salt water solution .

2.)Fractional distillation :The distillation process which is carried out by using fractional column is called fractional distillation .For example :This method is used to separate liquid having different boiling point from their mixture .i.e. mixture of alcohol and water

 .Chromatography :The method of separating different colours from their mixture  is called chromatography .For example :This method is used to separate various colours from their mixture and chemicals  present in urine and blood .

Principle of chromatography :Different colours move with different speed when they are passed through the same medium i.e. filter paper,silica gel, alumina etc. different colour move with different speed through the medium .Therefore, It is  possible to separate the mixture of various colours by chromatography .

Uses of chromatography :

i)It is used to separate various colours from their mixture .

ii)It is used to identify and separate medicine  mixed in blood and urine .

iii.)it is used to separate various colours from the mixture of natural and artificial coloring agents .