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Fire+water = ?

  1. Apr 9, 2009 #1
    how water extinguishes fire? i mean..what is the chemical reaction taking place when water combines with fire??
     
  2. jcsd
  3. Apr 9, 2009 #2
    I think fire is a visual representation of heat + burnt fuel. Does water actually react with fuel? I guess water only brings the heat down so that ignition of the fuel can't happen anymore.
     
  4. Apr 9, 2009 #3
    No chemical reactions. Water cool down the flame, but essentially water vaporizes and this vapour creates a barrier between the flame and air's oxygen, so the flame cannot be provided with oxygen anylonger.
     
  5. Apr 9, 2009 #4
    is there any chemical formula for fire?
     
  6. Apr 9, 2009 #5
    It depends on which kind of fire you have. An oil fire, a paper fire?
     
  7. Apr 9, 2009 #6
    formula of paper fire???
     
  8. Apr 9, 2009 #7
    The best I can find is:

    C8H18 + (25-x)/2 * O2 => 9 H2O + (8-x) CO2 + x CO

    for benzine fire.

    Be aware that fire is just warm gas+matter. When you see warm metal it will also be red and yellow but in a solid state.
     
  9. May 2, 2009 #8
    water doesnt react with anything in this regard, in fact no chemical reactions are taking place it's essentially a mechanical reaction: the water acts as a barrier between oxygen and the other reactant(s)
     
    Last edited: May 3, 2009
  10. May 3, 2009 #9

    Borek

    User Avatar

    Staff: Mentor

    While I understand the general idea behind your post, and I agree with it, this is a huge overstatement :smile:
     
  11. May 3, 2009 #10
    All common combustion reactions are of the form:

    Fuel + O2 --> CO2 + H2O

    Fire is just a visible manifestation of the energy of the combustion reaction. The energy given off by the conversion of paper into ash, or oil into carbon dioxide, etc. results in the heating of the air around the reaction epicenter, which can cause it to glow. Fire has no chemical formula because it is not a substance; it is an observation.

    Water puts out fire because water essentially stops oxygen from reaching the fuel by smothering the source.
     
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