Question

Differentiate between pure and impure substances with examples.

Answer 1

Pure substance	Impure Substance
A substance that contains only one kind of atom or one kind of molecule is described as a pure substance.	A substance that contains two or more different kinds of particles is described as an impure substance.
They are all homogenous(i.e, composition is uniform throughout their mass).	They may be homogeneous or heterogeneous(i.e, the composition is not uniform throughout their mass).
It cannot be broken down or separated into new products.	It can be separated using different separation methods.
A pure substance has a sharp melting and boiling point.	The temperature of impure substances has aIt can be separated using different separation methods. range at which they melt or boil.
It can not be separated by physical method.	It can be separated by physical method.
For example: all elements Oxygen$\left({\mathrm{O}}_2\right)$, Nitrogen $\left({\mathrm{N}}_2\right)$and compounds water $\left({\mathrm{H}}_2\mathrm{O}\right)$.	For example: seawater, air, tea, etc.