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Homework Help: Ideal Gas Question

  1. Aug 1, 2009 #1
    1. The problem statement, all variables and given/known data
    A house has a volume of 770 m^3. (a) what is the total mas of air inside the house at 20 Celsius? (b) If the temperature drops to -10 Celsius, what mass of air enters or leaves te house?

    2. Relevant equations

    PV = nRT

    3. The attempt at a solution
    I found the solution for part a which I think 924 kg. I found this answer by multiplying 770 m^3 by 1.2 kg (density of air at 20 Celsius: 1.2kg/m^3).
    But I do not know how to find the answer to part b. I read the whole chapter but still did not know how. Please help me.
  2. jcsd
  3. Aug 1, 2009 #2


    User Avatar
    Homework Helper

    Using the formula
    V1T1 = V2/T2
    find V2.
    Then find the change in volume. Multiply it with density to get the mass air entering the room.
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