1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Vapor pressure curve for carbon dioxide

  1. Mar 9, 2015 #1
    Hello to everyone.

    I would like to ask a question: I'm analyzing the properties of CO2 for a project and I have noticed that for temperatures between 220 -300 K the Clasius Clapeyron curve is linear on 1/T, that is in the Antoine equation of the form logP = A-B/(T+C), C is almost 0. In my report I stated that this is due to the fact that the heat of evaporation can be considered indipendent from temperature, but my professor answered me that this assumption is not justified and I have to look for another reason, but what's this reason? Thank you very much
  2. jcsd
  3. Mar 10, 2015 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Coincidence. It's not any sort of general principle that you can apply. What else is going on that might contribute to such a numerical coincidence?
  4. Mar 10, 2015 #3
    The Clausius Clapeyron equation is based on the assumptions that the vapor obeys the ideal gas law, and that the molar volume of the liquid is negligible compared to the molar volume of the vapor. Maybe these assumptions are what your professor had in mind.

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted

Similar Threads for Vapor pressure curve
Constant-Pressure Calorimetry question
Gas Pressure - Fluid Column