The matter around us, irrespective of its nature, is not pure. The matter is of two types.
- Pure substances like Elements and Compounds; and
- Impure substances like Mixtures
An element is a substance, which contains only one kind of atoms. For example – Copper, Hydrogen, Gold, Oxygen, etc are all elements.
Compound is a substance, which is made up of two or more elements, which are chemically combined together in a fixed ratio. For example – Water contains Hydrogen (2) and Oxygen (1), Carbon Dioxide contains Carbon (1) and Oxygen (2) etc.
Element react to form New compounds.
The composition of each new substance is always fixed.
The new substance has totally different properties.
The constituent can be separated only by chemical or electrochemical reaction.
A mixture consist of two or more elements or compounds, which are combined together in any ratio. However, no new compound is formed when the elements or compounds are so combined. For example – Air is a mixture. Mixture has a variable composition and it shows the properties, of the substance of which it is formed. Generally, the constituents of a mixture can be separated easily through physical method.
Types of Mixtures
Mixtures are of two types:-
1. Homogeneous Mixture
Homogeneous Mixture are mixtures in which, the constituent substances completely mix with each other such that they cannot be distinguished from one another. For example, in a sugar solution, which is made of sugar and water, once these are combined, the sugar and water cannot be distinguished from each other.
2. Heterogeneous Mixture
Heterogeneous Mixture are mixtures in which, the constituent substances remain separated. For example – Mixture of soil in water and mixture of chalk powder in water.