1. Not finding help here? Sign up for a free 30min 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!

Mole fraction

  1. Dec 19, 2004 #1
    does anyone know how to do this problem?
    The total vapor pressure above a solution of [tex]C_6H_6(l)[/tex] and [tex]C_7H_8(l)[/tex] is 0.485 atm. What is the mole fraction of [tex]C_6H_6(l)[/tex] in the liquid solution?
    [tex]P^o C6H6(l) = 0.526 atm[/tex]
    [tex]P^o C7H8(l) = 0.188 atm[/tex]

    the answer is 0.879 but i'm not sure how to get that using the formula [tex]P_A = (X_A)(P^o _A)[/tex]
    Last edited: Dec 19, 2004
  2. jcsd
  3. Dec 19, 2004 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    It's a direct substitution problem.

    [tex]P_{tot} = P_A + P_B = (X_A)(P^o _A) + (X_B)(P^o _B) = (X_A)(P^o _A) + (1-X_A)(P^o _B)[/tex]

    Now just plug in the given numbers and solve for [itex]X_A [/itex]
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Mole fraction
  1. Help with moles (Replies: 5)

  2. The concept of mole (Replies: 4)