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Homework Help: Ideal gas question(thermal physics)

  1. Jan 12, 2008 #1
    1. The problem statement, all variables and given/known data

    estimate the number of air molecules in an average sized room

    2. Relevant equations

    possible equation: N=n*N(a) , N(a) being avogradro number. N being the number of molecules. PV=RTn
    3. The attempt at a solution

    So should I guesstimate what n should be and the multiply that by avogradro number to get my total number of molecules. Or maybe I should apply the Ideal gas equation to find n and then multiply n by N(a) to calculate N
    Last edited: Jan 12, 2008
  2. jcsd
  3. Jan 12, 2008 #2


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    What is the P,V and T in an ordinary room?
  4. Jan 12, 2008 #3
    Room temperature is around 21 degrees celsius, P=1.01*10^5 pascals, and I guess in order to get the volume, I assume the room is equal to the shape of a cube and the length of an average room is around 25 meters. I can now calculate my volume by cubing the length of the side of the room./
  5. Jan 12, 2008 #4


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    Check what you just wrote.. temp must be in kelvnin, and preassure in Si-units. And you have a VERY large room :P biggern than my house :)

    let T = 300K, P = 1*10^5 N/m^2, and an average room is like 2.5m from floor to ceiling and 5m x 5m.
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