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How to calculate mass of air in mass balance?

  1. Oct 18, 2015 #1
    What is the general procedure for calculating the mass of air in mass balance problems?
    what assumptions must be made? How do i convert this into mass from a percentage, e.g 21% oxygen & 79% nitrogen?
  2. jcsd
  3. Oct 20, 2015 #2


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    Hello Mo, welcome to PF :smile: !

    No responses so far, so let me give it a try:

    (don't know if this question is for continuous flow or batch, though).

    With 21 mass% of O2 and 79% of N2 any mass flow is fully described.
    For the volume flow you need a density for which you use the ideal gas law in most cases (and a state equation for extreme situations).
    The ideal gas law is in terms of moles, so you'll also neet he molar weights (32 and 28, respectively).

    Does this help /

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