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Deoderant/pressurised container why does the liquid/gas come out

  1. Aug 28, 2006 #1
    Hi, While using a deoderant/pressurised container why does the liquid/gas come out while we press the knob? And is a high-pressure and low-temp situation possible together?
  2. jcsd
  3. Aug 28, 2006 #2
    well I would imagine that when the knob is pushed a path from the inside pressureized cannister and the outside is created, then because of the pressure differential the gas/liquid is 'forced' out.

    as for a high pressure, low temperature situation, these are entirely possible. The level of difficulty in creating these depends on the amount of pressure and how low of a temperature one would like. If you think of the basic equation PV=nRT (ignoring the fact that at really high pressures this equation doesn't hold exactly, but still the same principles apply) then at high pressure and low temperature in theory one would just need a small volume with many molecules. In practice this is hard to make. Industrial compressed air cylinders are usually around room temperature and highly pressured (the ones we use are 2500 psi when fresh).
  4. Aug 30, 2006 #3
    Yes a high pressure-low temperature condition is possible. But remember that this simply means that P is simply higher than T; P is always direclty proportional to T.
    Last edited: Aug 30, 2006
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