Test: MCAT Physical


Air is composed of about 78% nitrogen (molecular mass = 28 g/mole), 21% oxygen (molecular mass = 32 g/mole), and 1% argon (40 g/mole). The weighted average of these numbers leads to the approximation that if air was a pure gas, its “molar mass” would be about 29 g/mole. Helium has a molar mass of 4 g/mole.  What is the volume of helium gas required to lift a balloon carrying a 100 gram sensor?

  1. about 20 liters
  2. about 50 liters
  3. about 90 liters
  4. about 120 liters
  5. about 166 liters






1/2 questions


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