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Mass of helium

  1. Feb 4, 2007 #1
    1. The problem statement, all variables and given/known data

    A balloon 20 m in diameter is filled with helium at a gauge pressure of 2.0 atm. A man is standing in a basket suspended from the bottom of the balloon. A restraining cable attached to the basket keeps the balloon from rising. The balloon (not including the gas it contains), the basket and the man have a combined mass of 150 kg. the temperature is 24oC that day and the barometer reads 760 mm Hg.

    What is the mass of helium?

    2. Relevant equations

    pV = nRT

    3. The attempt at a solution

    (3 atm x 101325 Pa/atm)(4/3*pi*(10^3)) = (m/0.004)(8.314)(297.15)
    m = 2061 kg

    But the correct ans is 2050 kg. Anyone pls help? thanks
    Last edited: Feb 4, 2007
  2. jcsd
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