water is made of h2 and o2. both support combustion. then how is that water puts off fire?

Question

hydrogen and oxygen support fire combustion really well

Answer 1

There's no O2 in wata

Answer 2

Hydrogen will not support combustion at all. It is combusted but only if oxygen is present. Water is a compound which is composed of the elements hydrogen and oxygen. It is very common for a compound to have entirely different properties than the elements that it is made from. Another example is the compound sodium chloride or common table salt. It is not like sodium (a flammable metal) or chlorine (a deadly gas) at all. Water can cool a fire, which can put it out, but in that process it remains as water, albeit probably in the gaseous state as steam.

Fire requires 3 things: an oxidizer, usually oxygen; something to burn (fuel) such as hydrogen gas, or paper, or oil; and finally heat. Remove any of the 3 and you put out the fire.

Answer 3

Good question. Hydrogen gas and oxygen gas combust easily for different reasons: oxygen gas doesn't technically "combust", because the definition of combustion is an exothermic reaction with oxygen. This is why an oxygen rich environment helps things burn, because there's more oxygen for the fuel to react with.

You're right, water is made of H2 and O2, and that's exactly why it doesn't burn. When hydrogen gas combusts, like everything else, it reacts violently with oxygen. When it does this, it combines with the oxygen to create water. A chemical reaction equation would look like this:

2H2 + O2 --> 2H2O

Because hydrogen gas reacts so readily with oxygen gas, this reaction is called spontaneous, which basically means that the hydrogen and the oxygen "want" to combine together to form water. If the equation were written backwards:

2H2O --> 2H2 + O2

This is not spontaneous. This is what prevents water from leaping out of your bathtub and turning back into hydrogen and oxygen. In fact, because hydrogen and oxygen prefer to be together like that, you have to add energy to split them apart (a process known as hydrolysis).

Hope this helps.

Answer 4

Oxygen supports combustion. Hydrogen burns explosively. Burns means combine with oxygen giving off heat. Hydrogen does not support combustion. H2O is a compound of O and H. It puts out fires because it cools them, and snuffs out the oxygen. To have a fire you need oxygen, fuel, and heat.

Answer 5

Water is made up of 2 parts Hydrogen (H) and one part Oxygen (O2 in its free form). Hydrogen is combustible while oxygen is needed to support combustion. Water puts out fire because it gets rid of one (temperature) of the three requirements for fire to occur - temperature, oxygen (air) and fuel (combustibles).

Answer 6

to start a fire u needs three things,
Fuel
Air (O2)
Ignition source (spark)
Water does not belong to either of the three groups. H2 and O2 may support combustion but the reaction between these two substances form a new substance with different chemical properties.

Answer 7

Actually water is 2 hydrogens and 1 oxygen, which is different than 2 hydrogens and 2 oxygens. While both, as separate entities, are combustable, together as H2O they create something totally different than they would if they were separate.

Answer 8

Well, water doesn't put out all fires. It puts out some fires. Water puts out some fires by shutting off the oxygen supply to the combustion process... Also, another attribute of the water application to a fire is its cooling capability. If the water cools off the hot materials below their combusion temperature, then the fire will also go out.

Answer 9

Water is made of hydrogen and oxygen as u said, but the fire extinguishing properties are to certain extent only. If there is sodium metal exposed to air it catches fire. Even if u pour water it will not extinguish. Basically the fire caused by wood, paper, clothes etc are extinguished due to the decrease in temperature caused by the water. Here the physical prperty works. But chemically it is different.

Answer 10

for starters ,water is NOT made up of h2 and o2 ,it s actually madeup of 2 positive H+ ions and 1 negative O(-2) ions.Know the basics before asking such a question.Ions have properties which differ from the molecules like h2 and o2

Answer 11

separately h2/02 would help a fire but when they are combined it changes there chemical reactions to certain if not all substances that it reacted w/ before. example the nitrogen in air. nitrogen is normally flammable but the are doesn't suddenly explode every time some 1 lights a match now does it. if it did we would all be dead. since it the other compounds and substances in the air it creates a null effect and nothing happens.