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Homework Help: Effect of degassing on particle size

  1. Jan 25, 2009 #1
    The specific surface area of polluting dust particles has been determined by gas adsorption:

    Treatment__________________Asp (m2g-1)
    4 h under vacuum at 200 °C_____5.61
    8 h under vacuum at 25 °C_____2.81

    Assume that they are monodisperse spheres of density r = 2.2 g/cm3. Calculate the radius of the particles.
    Propose an explanation for the effect of degassing on particle size.

    The radia are 243 nm and 485 nm, but what is the explanation?
  2. jcsd
  3. Jan 25, 2009 #2


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    You know the rules. What thoughts do you have on the question?
  4. Jan 25, 2009 #3
    When particles adsorb gas particles, they grow larger?
    Last edited: Jan 25, 2009
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