Question 1 What are pure substances. Give examples?
Question 2 What are the two types of pure substances. Give example of each?
Question 3 What are mixtures. Give example?
Question 4 What are the characteristics of pure substances?
Question 5 What are the characteristics of impure substances?
The matter around us is of two types:
(1) Pure Substance
A pure substance is one which is made up of only one kind of particles (atoms or molecules)
For Example:(1) Sulphur element is made up of only one kind of sulphur atom.
(2) Water is made up of only one kind of water molecules. All the elements and compounds are pure substances because they contain only one kind of particles.
For Example : Hydrogen, Oxygen, Nitrogen, Chlorine, Iodine, carbon, Iron, Copper etc. are pure substances(elements).
Water, sodium chloride, Hydrochloric acid, Camphor etc. are pure substances (compounds).
Pure substances are homogenous throughout its mass, they cannot be separated into other kind of matter by physical processes
A mixture is one which contains two or more different kinds of particles(atoms or molecules).
For Example : Salt Solution(salt and water), milk (fats, proteins and water), sugar solution, petroleum, LPG, tea, coffee etc.
A mixture may be homogeneous or heterogeneous, does not have fixed composition, have fixed melting and boiling point.