How can the molar flow rate of a two-gas mixture be calculated?

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Discussion Overview

The discussion revolves around calculating the molar flow rate of a two-gas mixture when the individual molar flow rates of each gas are known. Participants explore concepts related to averaging, mass balance, and the implications of gas composition on flow rates.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions whether the molar flow rate of the mixture can simply be the average of the two individual flow rates, suggesting that averaging may not accurately represent the situation.
  • Another participant proposes that the average does not work due to the percentage flow of each gas, indicating that the composition affects the calculation.
  • A suggestion is made to consider mass balance, emphasizing that mass conservation is a fundamental principle in physics and chemistry.
  • One participant attempts to apply mass balance by suggesting a formula that incorporates the molar flow rates and molar masses of the gases, although there is confusion about the mixture's composition.
  • Another participant expresses uncertainty about the implications of the mixture's composition, highlighting the need for clarity on whether the percentages refer to volume or weight.
  • A participant asserts that the total molar flow should be the sum of the individual molar flow rates, while noting that conservation of mass and moles are equivalent unless a chemical reaction alters the number of moles.

Areas of Agreement / Disagreement

Participants do not reach a consensus on how to calculate the molar flow rate of the gas mixture, with multiple competing views on the role of averaging, mass balance, and the significance of gas composition.

Contextual Notes

There is ambiguity regarding the definitions of the gas mixture's composition (volume vs. weight) and how this affects the calculations. Additionally, the application of mass conservation principles is not fully resolved in the context of the discussion.

vishnu123
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TL;DR
Is there any way to calculate the molar flow rate of the mixture of gaseous?
I have two Gases where i know the molar flow rate of each gas. Is there any way to calculate the molar flow rate of the two gases together or is it just the average of the two molar flow rates?
 
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Why average?

If there is 1 mole/min of one gas, and 1 mole/min of other gas, average is 1 mole/min also, and it would tell you individual flows are 0.5 mole/min for both gases - yet we assumed there is 1 mole/min. So in some way and for some reason average doesn't work. Can you think why?
 
thank you for your reply. i think the average won't work because of the percentage flow of each gas.
 
What about mass balance?
 
ok, I don't know much about that, can you please explain it in detail.
 
Basically: mass is conserved (this is one of the most basic principles governing classical physics and chemistry), mass can't disappear, whatever gets in, must get out.
 
so what you say is it has to be divided by the molar mass of the individual gas?
for example 60%of Hydrogen and 40%of nitrogen to calculate it
(.6*molar flow of H2/molar mass of H2)+(0.4*molar flow of N2/molar mass of N2)
is it right?
 
You have lost me. Initially you said you know individual molar flows, now you have 40/60 mixture that can be either v/v or w/w. I have never tried to address the other problem.

What mass conservation tells you is that the mixture of 40/60 is 100% in total.
 
Total molar flow should be the sum of the individual molar flow rates.

AND...conservation of mass and conservation of moles is essentially the same thing unless there is a reaction happening which produces a different number of moles of product vs reactants.
 

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