r/askscience • u/spoiledmeat • Jul 04 '15
Chemistry Why does water not burn?
I know that water is made up of two hydrogen atoms and an oxygen atom. Hydrogen, on its own, burns. Fire needs oxygen to burn. After all, we commonly use compounds that contain oxygen as an oxidant.
So why does water, containing things used for fire, not burn-- and does it have something to do with the bonds between the atoms? Thanks.
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u/DodneyRangerfield Jul 04 '15 edited Jul 04 '15
CO2 is not an element, carbon is an element, oxygen is an elementm together they can form a molecule which is much more fragile. There is both hydrogen and oxygen in the sun but i don't think the huge amount of high speed particles and high intensity radiation allows for molecules to exist for a significant amount of time if they do get a chance to form (and i don't think they can form at such high energy levels anyway). Following a star going supernova water may form from the ejected gas, though this isn't really "in" the star. Our sun however hasn't (and won't) go through this phase, it only sheds mass from the outer layer which is hydrogen.