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Does temperature affect mass in chemistry

  1. Oct 31, 2004 #1
    I asked this question in the physics general forum and didn't get a solid answer. They say temperature won't really matter here, so what would be a reason to let the substance cool, from a chemistry point of view?
  2. jcsd
  3. Oct 31, 2004 #2
    Don´t get surprised about it.

    It´s just a problem of convection flux in air. If the sample is hot, the air surrounding it is warmed and it starts going upwards. Due to the non-zero viscosity of the air this can lead into an ascending force in the sample, altering the measure.
  4. Oct 31, 2004 #3
    Temperature does not affect mass but it does effect the instrument measuring mass. Analytical balances are calibrated at room temperature.
  5. Oct 31, 2004 #4
    Perhaps in your case the reason is to avoid the sample reabsorbing water (hot things that are getting cooled tend to absorb water). And you´re working with an higroscopic salt, so the cooling must be done in dry atmosphere before measuring.
  6. Oct 31, 2004 #5
    Thanks for your replies!
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