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Homework Help: PV=nRT question

  1. Jun 23, 2005 #1
    A tank having a volume of .100 m^3 contains helium gas at 150 atm. How many ballons can the tank blow up if each filled balloon is a sphere of .300 m in diameter at an absolute pressure of 1.2 atm?

    Here is what I have so far: Assuming no gas is lost to the atmosphere, n is constant. R is constant (8.314 J/mol K) by definition. The final volume of the gas must be a multiple of (4/3)pi(.3/2)^3. So

    ((150 atm)(1.013*10^5 Pa/atm)(.1 m^3))/T1=(x(4/3)(pi)(.15)^3(1.2))/T2

    But this equation contains three variables x,T1,T2...please help...
  2. jcsd
  3. Jun 23, 2005 #2


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    If you assume isothermal flow of molecules,then you only have "x" which you must round to the nearest integer.

  4. Jun 23, 2005 #3
    Try using PV = a constant, rather than PV = nRT
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