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Homework Help: Ideal Gases Problem

  1. Sep 21, 2009 #1
    1. The problem statement, all variables and given/known data
    Hg is spilled in a laboratory which measures 15.2m long, 6.6m wide, and 2.4m high. Find mercury vapor in grams at 20C room. Given vapor pressure of Hg = 1.7E-6 atm.

    2. Relevant equations 3. The attempt at a solution
    Volume= 15.2*6.6*2.4 =240.768 m^3 = 240768 L
    Temp = 20 + 273.15 = 293.15 K
    P = 1.7E-6 atm

    PV =nRT
    n= PV/RT
    n= (1.7E-6)(240768 L)/ (0.08206 L atm/mol K)(293.15K)
    n= 0.017 mol
    0.017 mol*200.6g/mol
    = 3.4 g Hg

    I'm not quite sure if this is how you calculate the mass of Hg. the next part of question asks if concentration of Hg exceed air quality reg. (0.050 mg Hg/m^3). According to my answer, it does exceed b/c 3.4g=3413mg/240.768m^3 = 14.2 mg Hg/m^3.

    can someone check my work plz, thanks in advance. I have a feeling that the mass of Hg is a bit too high......
  2. jcsd
  3. Sep 21, 2009 #2


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    Science Advisor
    2017 Award

    I didn't check the math, but the setup for the calculations looks correct.
  4. Sep 21, 2009 #3
    are the numbers i used correct?
  5. Sep 22, 2009 #4


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    Staff: Mentor

    Looks OK.


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