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!

Calculating isothermal copressibility and expansion coefficient

  1. Sep 19, 2009 #1
    1. The problem statement, all variables and given/known data
    Calculate the isothermal compressibility and the expansion coefficient of a van der waals gas. Then show using Euler's chain relation that KR = alpha(Vm-b)

    2. Relevant equations
    isothermal compressibility K = (-1/V) (dv/dp)t
    isothermal expansion alpha= (1/v)(dv/dt)p

    3. The attempt at a solution
    I realize it has to do with partial derivatives. But beyond this i'm lost.
  2. jcsd
  3. Sep 19, 2009 #2


    User Avatar
    Homework Helper
    Gold Member

    Hi Zcuttlefish, welcome to PF!:smile:

    Hint: You might start by looking up the equation of state for a Van Der Waals gas!:wink:
  4. Sep 19, 2009 #3
    I did (p+ a/V2)(v-b) = RT
    (not including n because it should be constant)

    my answer for dv/dp ended up looking like
    Then i used the product rule and took the derivative dv/dp of the terms. I'm still unsure of why or if i've even gotten closer to the answer.

    I seem to be missing an R on top.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Calculating isothermal copressibility and expansion coefficient