1. The reason for this property of gases is that there is very large intermolecular space between gas molecules. On mere applying pressure, they are easily compressed.
2.In liquids intermolecular force is weaker than that of solids. So molecules in a liquids can slip over one another and liquids can flow uniike solids.
3 .We need to classify things in order to distinguish them. In this way, things can be categorized and can be easily studied.
4. Pure substances consists of only one kind of matter. All the particles of a pure substance are alike. It has a definite composition and similar properties. This is the reason that pure substances have fixed melting or boiling points.
5. Electricity neither has mass nor it occupies space. Beside it can not be seen by our eyes. This is why electricity is not considered mattet.
