MATTER, STATES OF MATTER

MATTER

Anything which has mass and occupies space is called matter. Examples are pencil, water, air, book, pen, all living beings etc.

STATES OF MATTER

Matter can exist in three physical states viz. solid, liquid and gas. The constituent particles of matter in these three states can be represented as shown below

 

1. Solid; Particles are held very close to each other in solids in an orderly fashion and there is not much freedom of movement.

2. Liquid; In liquids, the particles are close to each other but they can move around.

3. Gas; However, in gases, the particles are far apart as compared to those present in solid or liquid states and their movement is easy and fast.

Characteristics of Matter

I. Solids have definite volume and definite shape.

II. Liquids have definite volume but do not have definite shape. They take the shape of the container in which they are placed.

III. Gases have neither definite volume nor definite shape. They completely occupy the space in the container in which they are placed.

States of matter are interconvertible by changing the conditions of temperature and pressure.

                             Solid ↔ Liquid ↔ Gas

On heating, a solid usually changes to a liquid, and the liquid on further heating changes to gas (vapour). In the reverse process, a gas on cooling liquifies to the liquid and the liquid on further cooling freezes to the solid.