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Finding what fraction of molecules have speeds over a certain value

  1. May 13, 2013 #1
    1. The problem statement, all variables and given/known data
    A sample of oxygen gas with molar mass 32 g/mol contains 5.0 moles and is at a temperature of 500 K. How many moles of the gas have speeds between 375 m/s and 380 m/s?

    2. Relevant equations
    Maxwell Boltzmann Distribution:
    f(v) = 4[itex]\pi[/itex][[itex]\frac{M}{2pi RT}[/itex]]^(3/2) * v^2 * e^[(-Mv^2)/(2RT)]

    3. The attempt at a solution
    I know that this function gives the probablility of having the molecules at some speed v, but I'm not sure how to translate this over a range or how to calculate the number of moles over this range.
     
  2. jcsd
  3. May 14, 2013 #2

    SteamKing

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    Do you know how to use the M-B distribution to find out how many molecules have a speed greater than 380 m/s?

    Do you know how to use the M-B distribution to find out how many molecules have a speed greater than 375 m/s?
     
  4. May 14, 2013 #3
    I figured it out, thanks!
     
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