CBSE Class 9 Chemistry Is Matter Around Us Pure?
Classification of Matter
Separation of Solid Mixtures
Sublimate substances can be separated from non - volatile substance like common salt, sand, iron filings, chalk etc. by the process sublimation.
Any mixture with iron as one of its constituent can be separated by using a magnet.
Separation of Liquid Mixtures
Simple distillation: Constituent has a huge difference in boiling point.
Fractional distillation: Difference in boiling point of constituents is less than 25K.
Separating funnel is used to separate the mixture if constituents differ in the densities.
Separation of Soluble Solids
Crystallisation method is used to obtain pure crystals of copper sulphate, sugar and common salt.
Chromatography is commonly employed to get dyes from ink, components of chlorophyll and detecting poison in contents of bladder.
Separation of Insoluble Solids
The solid particle which remains behind on the filter paper are called residue and clear liquid obtained is called filtrate.
Fine suspended particles in a liquid are separated by rotating at very high speed. The method is called as Centrifugation.
Types of Changes
A process in which one substance reacts with another substance to undergo a change in chemical composition is known as chemical change.
Chemical changes are generally irreversible and can only be reversed under extreme conditions.
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