Matter is simply defined as anything that has mass and occupies space. Our bodies as well as all the things around us are examples of matter. The Chemistry studies all types of matters that can exist in any of three physical states; solid, liquid or gas.
A piece of matter in pure form is termed as a substance. Every substance has a fixed composition and specific properties or characteristics. Whereas impure matter is called a mixture; which can be homogeneous or heterogeneous in its composition.
Every substance has physical as well as chemical properties. The properties that are associated with the physical state of a matter are called physical properties; like colour, smell, taste, hardness, shape of crystal, solubility, melting or boiling points etc. For example, when ice is heated, it melts to from water. When water is further heated, it boils to give steam. In this entire process only the physical state of water changes whereas its chemical composition remains the same.
The chemical properties depend upon the composition of the substance. When a substance undergoes a chemical change, its composition changes and a new substance is formed. For example, decomposition of water is a chemical change as it produces hydrogen and oxygen gases. All materials may either be substance or mixture. The simple classification of the matter into different forms is as follows: