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: Urgent Help Needed (gases)

  1. Oct 10, 2006 #1
    Urgent Help Needed!! (gases)

    I need some urgent help with figuring out how to find the distance which 2 gases will meet in this question..

    Given: Samples of HBr gas and NH_3 gas are placed at opposite ends of a 1.80 m tube.
    Question: If the two gases are allowed to diffuse through the tube toward one another, at what distance from each end of the tube will the gases meet and form solid NH_4Br?

    Thank you to anyone who can help me with this, or at least set me in the right path.

    The distance must be in Cm as well..
  2. jcsd
  3. Oct 11, 2006 #2


    User Avatar
    Staff Emeritus
    Science Advisor

    One may assume that the gases are at the same temperature.

    Apply kinetic theory of gases and determine the mean velocity which is a function of molecular mass.

    If one gases travels distance d in time T, then the other must travel 1.8m-d in the same time.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook