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Explosive pressure in a vessel

  1. Feb 26, 2009 #1
    Hi,
    I have no chemistry background and my head is swimming with heat of formation heat of combustion heat of explosion enthalpy ideal gas law and so on

    What I'm trying to find out is how would I go about calculating the maximum pressure produced inside a vessel when a known amount of combustible gas was ignited?

    i.e a hydrogen/air mixture inside a sealed 100ml container with a starting temperature of 25 deg C

    Any examples or at least a point in the right direction is greatly appreciated.

    Thank You.
     
  2. jcsd
  3. Feb 26, 2009 #2

    mgb_phys

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    For the steady state end point (ie. ignoring any shockwaves etc)
    You would need the number of moles of gas at the start and the end - so if you were burning a solid/liquid fuel and ending up with a gas you are goign to have more pressure at the end just because there is more gas.
    Then from the energy change you have to work out what temperaure increase the resulting gas is going to have.
     
  4. Feb 27, 2009 #3
    Thank You for the response,
    Lets see if I understand this at all.
    Hydrogen reaction with oxygen 2H2 + O2 --> 2H20
    heat of formations 2H2 = 0 02 = 0 --> 2H20 2(-241.8) so the energy change is 483.6kj/mol ?
    What formula(s) to I use to convert that to temperature?
    once i have the temperature am I correct that
    P = (number of moles * gas constant {8.314}* temp(k))/volume (100ml) and that pressure is in torr?

    Thank you again.
     
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