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Homework Help: Propane in a Container finding pressure and energy

  1. Sep 7, 2010 #1
    1. The problem statement, all variables and given/known data

    An aluminum bottle weighs 10 kg when empty and has an internal volume of 20 liters. It is filled with 5 kg of propane (C3H8) at 24 °C. The aluminum bottle is rated for a maximum pressure of 35 bar at which point a relief valve is opened.

    a) What are the initial pressure, quality, and internal energy?
    b) What temperature will the bottle reach at maximum pressure as it is heated? What
    is the quality at this maximum pressure state?
    c) The relief valve remains opened until the pressure falls back to 14 bar. If the mass
    of propane remaining in the bottle is tenth of its original value, what is the temperature of the propane upon shutting of the relief valve?

    3. The attempt at a solution
    All I want are the equations I need and how to set the problems up
  2. jcsd
  3. Sep 11, 2010 #2


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    Homework Helper

    For the first part you can use PV=MRC3H8T to get P.

    Neglecting the weight of the Al, if it weighs 10 kg when empty (no C3H8), and then is filled with 5kg of C3H8, how much air is in it? You should now be able to find the quality.
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