The word gas was coined in 1650–60 by J. B. van Helmont (1577–1644), a Flemish chemist. It comes from the Greek word for chaos.
The name gas comes from the word chaos. Gas is a swarm of molecules moving randomly and chaotically, constantly colliding with each other and anything else around them. Gases fill any available volume and due to the very high speed at which they move will mix rapidly into any atmosphere in which they are released. Different gases are all around us in everyday life. The air we breathe is made up of several different gases including Oxygen and Nitrogen. Vehicle engines combust fuel and Oxygen and produce exhaust gases that include Nitrogen Oxides, Carbon Monoxide and Carbon Dioxide.
The table gives the sea-level composition of air (in percent by volume at the temperature of 15°C and the pressure of 101325 Pa). reference, honeywell gas detection systems, book
There are three main types of gas hazard: Flammable | Risk of fire, or explosion, e.g. Methane, Butane, Propane, Hydrogen, Toxic, | Risk of Poisoning e.g. Carbon Monoxide, Chlorine, ammonia, Asphyxiant, | Risk of suffocation e.g. Oxygen deficiency, Oxygen can be consumed or displaced by another gas Gases. Gases can be lighter, heavier or about the same density as air. Gases can have an odour or be odourless. Gases can have colour or be colourless. If you can’t see it, smell it or touch it, it doesn’t mean that it is not there, Natural, Gas Methane, is used in many homes for heating and cooking. reference, honeywell gas detection systems, book