States of Matter - The Gaseous State

Gas is a state of matter characterised by particles that are far apart, move quickly, and are not organised in any structured pattern. Gases are present all around us; the atmosphere is a mixture of gases such as oxygen, nitrogen, carbon dioxide, ozone, and water vapour. Despite being a simple state of matter, only 11 gases from the periodic table naturally exist as gases under standard temperature and pressure (STP: 1 atm pressure and 273 K temperature). These are called pure gases, and examples include helium, neon, argon, krypton, xenon, radon, hydrogen, nitrogen, oxygen, fluorine, and chlorine.

Exert pressure in all directions: The molecules in a gaseous element scatter by forces in all directions due to the negligible force of attraction between them. Therefore, the molecules exert pressure in all directions.

Mix Evenly: They mix evenly without the help of any mechanical change. The gaseous elements are more susceptible to reactions and admixtures. The huge gap between molecules gives the molecules of other elements an ease to mix with each other. This property of gases makes them highly reactive chemical elements.

1. High Compressibility: Gases can be easily compressed because the particles are spread out and there is a lot of empty space between them.
2. Large Intermolecular Distances: The particles in a gas are much farther apart than those in liquids or solids, resulting in minimal attractive forces between them.
3. No Definite Shape or Volume: Gases do not have a fixed shape or volume. Instead, they expand to fill the entire volume of the container they are in.
4. Occupy Full Space of Container: Gases spread out uniformly to occupy all the available space within a container, regardless of the container's shape or size.
5. Exert Pressure: Gas particles constantly move and collide with the walls of their container, exerting pressure on it. This pressure is measurable and depends on factors such as temperature and volume.
6. Minimal Attractive Forces: The weak intermolecular forces in gases allow the particles to move freely and rapidly, which is why gases easily mix and spread out.