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: Pressure and force

  1. Dec 16, 2009 #1
    Hello, I am studying for an exam that I am taking in January, and I am doing practice problems. I have not taken physics in over 2.5 years... and I dont remember half of it pretty much. I'm trying to learn it again as I practice.

    1. The problem statement, all variables and given/known data
    Here is the problem:
    There is a 1 cubic meter container filled with 4 gases: He, O2, CO2, N2. There are equal molar quantities of all 4 gases, and are assumed to be ideal. The pressure inside is 1 atm, or 10^5 Pa. The temperature is 25 degrees C.
    What I want to know is, does the partial pressure of each gas increase at different rates? Or does the partial pressure of the gases increase at the same rate... If they are different, does it depend on the size of the gas molecule?
    Actually, I'm not sure if this should be in physics section or in the chemistry section.

    2. Relevant equations

    Honestly I dont even know.

    3. The attempt at a solution

    I tried reading about partial pressures, but could not find anything relevent :/
  2. jcsd
  3. Dec 16, 2009 #2


    User Avatar

    Staff: Mentor

    What do you mean by "pressure increase rate"? What force is behind this pressure increase?

    I suppose you mean something like "do all partial pressures go up at the same time if we heat the mixture?" If so the answer is yes, each gas behaves ideally independent of what other gases do.
  4. Dec 16, 2009 #3
    Thank you Borek!
    Yes that is what I meant.
    The temperature was increased from 25C to 50C.


    Now I'm up to a problem that deals with FM radio waves and the magnetic field generated by the waves.... :/
    I have to relate the direction of the magnetic field that accompanies the FM signal. I definitely did not learn this in my physics courses.
    I know that FM radiowaves are electromagnetic, they have a certain frequency and an amplitude. But I do not know anything about the magnetic field caused by it.... :(


    Ok so I found out that the magnetic field is perpendicular to the radio wave.
    Last edited: Dec 16, 2009
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook