Why is oxygen not combustible?

Answer 1

oxygen is combustible, carbon dioxide isnt

Whomever wrote the above answer obviously never took basic science classes.

OXYGEN IS NOT A COMBUSTIBLE GAS!! It is an oxidizer.

The danger of compressed O2 cannisters is that they are under high pressure. O2 in & of itself will not burn. It is a major component of the "Fire Triangle"; the 3 things needed for fire to exist (1. a fuel source 2. heat 3. Oxygen). Take away any one of these items and it is impossible for a fire to exist.

You bring a stream of compressed O2 near an open flame, the flame will burn hotter but the Oxygen itself WILL NOT IGNITE.

http://www.newton.dep.anl.gov/askasci/chem00/chem00325.htm

Answer 2

Hydrogen gas in pure form is 2 hydrogen atoms connected together (H-H)<=Lewis drawing

Oxygen gas in pure form is 2 oxygen atoms connected together (O=O)

Water is a completely different chemical. Water is one oxygen connected to two hydrogens. (H-O-H*) This molecule is much more stable than either pure oxygen or hydrogen.

A chemical is not just a sum of all the elements in it. Due to the unique way the electrons are shared, each chemical has different properties.

These gasses are bonded with covalent bonds. This means that the electrons are shared between the atoms. Enough atoms are shared so that each atom has 8 electrons in its highest shell (or 2 electrons in the case of hydrogen) This is why Oxygen has 2 bonds/shared electrons in my Lewis drawings, while hydrogen only has one.

* this is not a completely accurate Lewis drawing. Water actually has 2 lone electron pairs, which force the molecule into a bent shape. But that is irrelevant for this discussion. If you look up water on wikipedia and look at the picture of the molecule you will see what a bent molecule looks like.

Answer 3

Oxygen is not combustible because it is an oxidizer, meaning it helps other substances burn. While oxygen itself supports combustion, it cannot burn on its own. Combustion requires a fuel source, such as wood or gasoline, to react with oxygen and release energy in the form of heat and light.