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Terminology, pressure of gas in fluid (quick question)

  1. Jan 1, 2017 #1
    Would it be correct to say the following...

    CO2 for example can change the surface tension of water from 72 mN m−1 to 57 mN m−1 as its pressure changes from 1 to 11 bar.

    I'm used to dealing with concentrations, in fact I would like to change bar to volume percent if anyone has a free moment and might suggest a method and the values I would need.

    Thanks for any help with this.
  2. jcsd
  3. Jan 1, 2017 #2


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    Check the context (reference?): it seems to me they may refer to the CO2 pressure above the water.
  4. Jan 1, 2017 #3
    Hm, here is the paper (info given about 1/4 down the abstract):



    It does say 1 to 11 bar absolute, would that that give any indication as to whether it's the pressure in the water or above? I assumed (which is why I wasn't sure of the context) that if a liquid is pressurised with gas then that would indicate how much is in there (partial pressure?) is that incorrect?
  5. Jan 1, 2017 #4


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    I'm convinced it's the pressure of CO2 above the liquid. "how much is in there" isn't expressed in terms of a pressure but in molality, molarity or some similar concentration (e.g. g/100 g solvent). Check out Henry's law.
  6. Jan 2, 2017 #5
    Ok thanks very much for the help!
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