By changing the temperature and pressure, matter can be changed from one form to another. Lowering temperature or increasing pressure moves the molecules of matter closer to each other, making them more compact. The following phase changes can be done through this process:
Vapour is formed by boiling a liquid and the process is known as evaporation. It is a transition state from liquid phase to gas. It can co-exist with a liquid or solid when they are in the equilibrium state. Vapours of water and vapours of mercury are good examples. Water vapour refers to water in a gaseous form which is formed after boiling or evaporation. Aerosol is a suspension of particles of solid, liquid or both within a gas.
The gas is classified as one of the four states of matter; they have distinct feature of occupying the available space regardless of the shape and volume. This feature is because of the presence of very little intermolecular attraction between the molecules. The other three states of matter are solid, liquid and plasma. The solids have fixed shape and volume, whereas the liquids have fixed volume but lack the fixed shape feature; they take the shape of the container they are poured in. The gaseous molecules are constantly moving independently due to the weak force of attraction present between the molecules. So, the gas can fill out the container of any size as the gaseous molecules are constantly on the move. The compounds which even remain in the gaseous state are classified as the gas. For example, the carbon dioxide is classified as gas, that is because it remains gas even in the room temperature.
|Vapours are in solid or liquid state in ordinary conditions, but change into gaseous state under specific conditions. It is not a state of matter.||Gases are in gaseous state under ordinary conditions (at room temperature and one atmospheric pressure). Gas is a state of matter.|
|Vapours experience a phase change, i.e., from liquid to vapour form or from solid to vapour form.||Gases do not experience a phase change. Any change in phase will change the state of gas into liquid.|
|Natural state of vapour is not gaseous, but can be solid or liquid.||Natural state of a gas is the gaseous form.|
|Vapour is a substance that is a combination of gaseous and liquid phase in ordinary conditions.||Gas is a substance that has a single thermodynamic state in ordinary conditions.|
|Vapour is made of atoms and molecules that move randomly||Gases are made of atoms and molecules that move randomly|
|Examples: Iodine exists in a solid form under ordinary conditions, but upon heating, it changes to the vapour form.||Examples: Oxygen, Nitrogen, and Argon.|