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Vapour Pressure at Dew Point

  1. May 29, 2016 #1
    THERE IS NO TEMPLATE BECAUSE GHIS HOMEWORK WAS PLACED IN AN INCORRECT FORUM

    Equimolar benzene and and toluene form essentially ideal solutions. At 20degC the vapour of benzene and toluene are 9.866kPa and 2.933kPa respectively. The solution is boiled by reducing the external pressure below the vapour pressure.

    What is the vapour pressure when only a few droplets of liquid remain? Assume still at 20degC.

    I know I need to use Dalton's/Raoult's Law, but can't work out how to start really. Help would be appreciated, thanks.
     
    Last edited by a moderator: May 30, 2016
  2. jcsd
  3. May 30, 2016 #2
    From your problem statement info, what are the vapor pressures of pure toluene and pure benzene at 20 C?
     
  4. May 31, 2016 #3
    When most of the liquid has boiled away, which of the two species remains?
     
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