About Physics - Gas & Vapour

Gas is a specific state/form of a material.
A material has 3 states - Solid, Liquid and Gas.
Liquid can change to gas by vapourization and boiling.
Vapour is the gaseous state of a material that is in solid or liquid form in room temperature as vapourization takes place below the boiling point of a liquid.



Quoted from wikipedia:

Vapor or vapour (see spelling differences) is the gaseous state of matter that is a solid or liquid at normal room temperature.

Although vapor and gas are frequently (incorrectly) used interchangeably, vapor refers to a gas phase in a state of equilibrium with identical matter in a liquid or solid state below its boiling point, or at least capable of forming solid or liquid at the temperature of the vapor. The term gas refers to a compressible fluid phase, as in common usage. Fixed gases are gases for which no liquid or solid can form at the temperature of the gas (such as air at standard temperature). A liquid or solid does not have to boil to release a vapor. The atmospheric boiling point of a liquid is the temperature at which the vapor pressure is equal to one atmosphere (unit). See the entry on vapor pressure for more information on this topic.

The vapor pressure is the equilibrium pressure from a liquid (or solid) at a specific temperature. The vapor pressure of a liquid or solid (pure or a mixture) is not affected by the pressure in contact with the liquid or solid.

Gas is a state of material. All elements in earth can form gas state when enough energy is applied to break the bond within particles. It is used to discribe any material which the particles arrangements are so loose that cannot form liquid or solid phase.

While vapour is specilaized to describe the gas state of water. There is no orange juice vapour or alcohol vapour, etc in the world.