Oxygen Facts
Chemical Symbol O
Atomic number 8
Atomic weight 15.999
Colorless gas
Has no smell or taste
The word oxygen comes from the Greek word "oxys", meaning sharp.
Oxygen is slightly heavier than air.
Oxygen is slightly soluble in water. Because of this property of oxygen, aquatic plants and animals can live in water.
Oxygen is the third-most abundant element by mass in the universe, after hydrogen and helium.
Oxygen is the most abundant element by mass in the Earth's crust, making up almost half of the crust's mass.
Oxygen makes up 21% of the atmosphere by volume and 23% by mass.
Oxygen is a highly reactive nonmetallic element and forms compounds with most elements except the noble gases Helium and Neon.
Oxygen is vital for life and constitutes most of the mass of living organisms.
Oxygen is exchanged between organisms and the environment in a continuous process. It is known as the oxygen cycle.
There are several known allotropes of oxygen. The most familiar is molecular oxygen (O2) and ozone (O3).
The common allotrope of elemental oxygen on Earth, O2, is generally known as oxygen, but may be called dioxygen or molecular oxygen.
Triatomic oxygen (Ozone, O3), is a very reactive allotrope of oxygen. It is a poisonous, colorless, tasteles gas with a strong smell.
Ozone is formed in stratosphere, the upper layer of the atmosphere. It prevents harmful ultraviolet radiations from reaching Earth's surface.
Ozone (O3) named for the Greek word for smell.
Chemical Properties:
In the lab, xygen can be generated by the decomposition of hydrogen peroxide. To increase the rate of this reaction, catalysts like manganese dioxide can be used.
For example:.
- hydrogen peroxide water + oxygen
Oxygen supports combustion. A combustion reaction is commonly referred to as “burning”. During a combustion reaction, oxygen combines with many other elements to form oxides.
As heat is produced in this reaction, this is an exothermic reaction.
For example:.
- Element + Oxygen Oxide of Element + Heat
- carbon + Oxygen carbon dioxide + Heat
- C (s) + O2(g) CO2(g) + Heat
For industrial purposes, oxygen can be obtained by fractional distillation of liquid air.
It is a very reactive oxidising agent.
Liquid oxygen is also slightly paramagnetic.