States of Matter: Matter exists in four states, i.e., solids, liquids, gases and plasma. General Properties of Gases: 1. Gases do not have a definite volume and occupy all available space. The volume of the gas is volume of the container. 2. They do not have a definite shape and take the shape of the container like liquids. 3. Gases have low densities. They can bubble through liquids and tend to rise up. 4. Gases can diffuse and effuse. Liquids also show this property where it is negligible in solids. 5. Gases can be compressed by applying pressure because there are large empty spaces between their molecules. 6. Gases can expand on heating or by increasing the available volume. 7. When sudden expansion of gases takes place, cooling is produced. It is called Joule Thomson effect. 8. Molecules of gases are in state of random motion. They can exert certain pressure on the walls of the container due to the collisions of gas molecules. 9. The intermolecular forces in gases are very weak. General Properties of liquids: 1. Liquids have a definite volume, but no definite shape. 2. The molecules of the liquids evaporate from the surfaces of the liquids at all temperature. 3. The molecules of a liquid diffuse into each other due to collisions and random motion. 4. The densities of liquids are high as compare to gases. 5. Molecules of liquids possess Kinetic energy due to their motion. The molecules of liquids can exchange energy among themselves. 6. Intermolecular forces of liquids are greater than those of gases. 7. The spaces among the molecules of the liquids are negligible, just like solids. General properties of solids: 1. Solids have definite shape and definite volume. 2. The solid particles possess only vibrational motion. 3. There are strong attractive forces which make the solids rigid and hard, 4. The particles of the solids are closely packed and are non compressible. 5. The solid particles cannot diffuse into each other.
