Always wondered this. Why doesn't water create fire, as opposed to put it out?

Question

I love science a lot, but I haven't been able to figure this one out. Why on earth would hydrogen, (a combustable element) and oxygen (An element fire needs) chemically create a compound that does the exact opposite. I know it's a new chemical, and isn't neither hydrogen or oxygen anymore, but still... always bothered me.

Answer 1

Do not assume that just because a molecule has hydrogen atoms in it, it is reactive or combustible. Molecules can have very different properties from their individual atoms or even from molecules with the same atoms arranged in different ways.

Elemental sodium "burns" in water. Elemental chlorine (as two-atom molecules of chlorine gas or Cl2) is corrosive and deadly to breathe. But combine them and you get tame, unreactive table salt.

You can speak in terms of "chemical potential". The elements I mentioned above like hydrogen, sodium and chlorine are reactive because they have a high energy potential related to the exchange of electrons or the formation of bonds. Once those bonds are formed, though, the product has a low chemical potential and you will have a hard time finding anything new to react it with. Water is of a low chemical potential; in almost all situations except for combining with reactive metals like sodium, it will not react or create any fire.

That is why you should not believe anyone who says he has developed a car that can run on water. Chemically, there are almost no reaction products with a lower chemical potential than water and therefore you can't get any useful heat energy to power an internal combustion engine. To get useful, energetic hydrogen gas out of water, you have to zap it with lots of electricity (which is a good way to store electric current in a chemical form and get ALMOST all the energy back efficiently.) Also, over millions of years our Earth has stabilized chemically. Almost any rock or liquid you touch will be inert, it will not eat away at your hand. Anything that could react, did.

Answer 2

In water, the hydrogen is already "combusted" -- it's oxidized maximally to H2O, so it cannot burn any further. In fact, when hydrogen burns, it turns into H2O. Anyway, it's not so much the chemistry of water that puts out fires, but the physical effect. It lowers the temperature and snuffs out the supply of gaseous oxygen.

Answer 3

Because fire needs three components: heat, oxygen, and fuel.

Water deprives the combustion process of two of those components: heat and oxygen.

Answer 4

i think water is created through combustion of both hydrogen and oxygen. thus think of water charcoaled oxygen and hydrogen

Answer 5

H2O extinguishes fire by depriving it of O2. To create a fire you need a combustible material and heat- H2O is not combustible.

Answer 6

Water is a form of fire, I've heard. When the Hydrogen and Oxygen atoms collide, they explode.

Answer 7

Heat makes water boil, water puts out fire

Answer 8

Substances which have affinity with oxygen will burn. Substances which does have affinity to oxygen will put off the fire e. g. CO2, water , Dry inert powders etc.