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What will be the equilibrium state in the liquid N2 chamber?

  1. Nov 2, 2016 #1
    Suppose there is a test chamber containing liquid nitrogen. The container is insulated and only a small opening is there so that chamber is exposed to atmospheric condition. As the saturation temperature of liquid nitrogen is -196 degree Celsius at 1 atm pressure. chamber will remain at -196 till depletion of liquid nitrogen. Now my question is; somehow that opening to the chamber is closed. What will happen to the temperature and pressure of the chamber?

    I can answer the question if the chamber is not insulated. The chamber will attain the room temperature. But I cannot guess about phenomenon occurring inside. What will be the phase and so on?

    So please explain in both the cases; insulated and non insulated chamber when chamber is closed after being exposed to atmosphere.
     
  2. jcsd
  3. Nov 3, 2016 #2
    Hello Ravi.
    Would you please explain how you came to that conclusion.
    Bear in mind the chamber is insulated, with which I presume you mean no heat flow is occurring into the chamber from the surroundings.
    And that the hole is a very tiny pinhole.
     
  4. Nov 3, 2016 #3
    Suppose I was given a liquified nitrogen but it is exposed in the atmosphere so it will absorb latent heat of energy to change its phase. During that process temperature will remain same at the saturation pressure. From the table saturation temperature of liquid nitrogen is -196 C at 1 atm pressure.
     
  5. Nov 3, 2016 #4
    For an un-insulated chamber . But what about the insulated chamber?
     
  6. Nov 3, 2016 #5
    For insulated chamber there is no source of thermal energy coming to the chamber. As we close the chamber the pressure will remain same as atmospheric(same amount of matter is there). System will be behave as isolated system; nothing will happen macroscopically I think.
     
  7. Nov 3, 2016 #6
    That is also the way I see it.
     
  8. Nov 3, 2016 #7

    JBA

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    You are assuming a perfectly insulated chamber but in reality there will be some heat flow across the insulation so the increase in chamber temperature and pressure will be time dependent. Commercial dewar flasks for cryogenic storage and transport of liquid gases are always equipped with pressure relief valves to deal with this issue.
     
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