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Homework Help: Ideal Gas law and mole conversions

  1. Feb 1, 2012 #1
    1. The problem statement, all variables and given/known data

    You have several identical balloons. You experimentally determine that a balloon will break if its volume exceeds 0.900L . The pressure of the gas inside the balloon equals air pressure (1.00 atm). The air inside the balloon has a constant temperature of 22 C. How many grams of oxygen can be blown into the balloon before it explodes? Helium?

    2. Relevant equations

    .9L = .0009m^3
    22C = 295.15
    1 atm = 1.013 x 10^5
    PV = nRT

    3. The attempt at a solution

    (1.013 x 10^5)(.0009) = n(8.31)(295.15)
    n = .03717 moles

    .03717 moles = .593 grams of oxygen

    I don't know if I've forgotten something with chemistry or I've missed something in the calculation, but that answer's being spit out as incorrect (automated grading). Obviously I can't do the helium part until I figure out what's wrong with this part.

  2. jcsd
  3. Feb 1, 2012 #2


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    Homework Helper

    Hi Cfem,

    Oxygen is a two-atomic gas, two atoms make a molecule, its molar mass is 32 g/mol. But helium is noble gas, its molar mass equals the atomic mass.

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