Why doesn't fire burn in water?

Question

There's oxygen in water, so why doesn't fire burn in it?

Answer 1

Steve is perfectly correct. "Burning" as you understand it, requires free oxygen O2. Now, water has immense amounts of oxygen, but it is locked up in H2O. There is some free oxygen that gets trapped by the churning of the water, not to mention the plant life under that water producing it as a byproduct... however, these don't provide the large amounts to "burn" most items.

However, fire does burn underwater. Some compounds require only a small amount of free oxygen to burn. These flames are then fed by intense heat that allows water to free some of its oxygen to help keep the flames going.

Think underwater welding. Acetylene torches require so little "free oxygen" to burn, that underwater welding can occur.

Now, (as any Vietnam veteran can attest to) white phosphorus is another compound that can burn underwater. In fact, the small amount of free oxygen required to start the reaction in almost insignificant. Then the water takes over.

Do me a big favor, Steve is perfectly correct. If you like my answer, vote his the best. He answered it correctly first.

Answer 2

I will have to agree more with the first guy, the second guy doesn't know what he's talking about since over 99.9% of flame reactions use oxygen in the -2 oxidation state (example: thermite- a military grade flame maker)

Its only because the water suffocates the fire of an oxygen source, however that isn't always the case, thermite will burn underwater if compressed into pellets before hand, potassium + water = violent flaming ball underwater, same with sodium, lithium, any metal in the first period of the periodic table plus water can produce a flame underwater

for a better example, if you manage to send a bubble of hydrogen and oxygen up through water and ignite it, the resulting reaction will produce an rising fireball under water- I got this to happen once, looks cool but by the time the bubble reaches half way up trough the water the flame has ran out of fuel by then and goes out

Answer 3

Fire is "rapid oxidation accompanied by noticeable heat and light". The key word here is "oxidation", which is the process of elements and/or compounds combining with oxygen to produce more chemically-stable compounds. In water, hydrogen has been oxidized to form H2O, so the hydrogen has, in effect, already burned. Similarly with carbon dioxide, the carbon in CO2 has already oxidized or burned. (Coal is an example of elemental carbon which can be burned in air and forms CO2.)

In the case of hydrocarbons, such as propane (C3H8), both the carbon atoms and the hydrogen atoms will oxidize when propane burns, to make CO2 and H2O. When gasoline is burned in car engines, the temperatures get so high that even the nitrogen in the air is oxidized to NO and NO2. (Normally, you can't burn nitrogen gas.)

Answer 4

The water keeps air oxygen from getting to the burning material. The oxygen in water is in oxidation state -2, already "used up." The oxidation state of oxygen in air is 0, "ready to go."

Answer 5

Water does not allow things to using its oxygen burn because the oxygen has already been used up to burn the hydrogen in it.

Answer 6

Water does burn in water. However, because it is a different kind of liquid, it does not manifest itself as burning like gasoline or kerosene would. However, the effect of burning is shown in some other ways -water gets hot, or becomes a steam and evaporates. It is not a fuel like other liquids are (gasoline or kerosene) so it does not "retain" the flame in its body.

Answer 7

i thought you could have fire in water if you used gas, but you need oxygen to have something burn...

Thermite can burn in water.

Answer 8

there a total of five elements. i use the thing that u mensioned, which is wind, fire and water. wind make the fire bigger and water is used to extinquish fire

Answer 9

case you us water to put it out