What is the final pressure of helium and neon gas mixture in this case?

Update:

I wrongly selected incorrect answer as favourite answer. Another answer final pressure p=6.67 bar is the correct and favourite answer with 5 stars.  

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  • 2 months ago
    Favorite Answer

    ((10.0 mol x 5.00 bar) + (5.00 mol x 20.0 bar)) / (10.0 mol + 5.00 mol) = 10.0 bar

  • 2 months ago

    We can treat noble gasses as ideal gasses, which means we can use the formula pV=nRT, which is independent of the actual type of gas.

    Let the first container have n₁ moles, pressure p₁, and volume V₁.

    Let the second container have n₂, p₂, and V₂.

    Let the temperature be T, and let the final pressure be p.

    Then we have:

    p₁V₁=n₁RT

    p₂V₂=n₂RT,

    p(V₁+V₂)=(n₁+n₂)RT

    Since we do not know the volumes, we will eliminate them from the equations:

    V₁=n₁RT/p1

    V₂=n₂RT/p2

    p(V₁+V₂)=(n₁+n₂)RT

    ⟹p=(n₁+n₂)RT/(V₁+V₂)=(n₁+n₂)RT/(n₁RT/p₁+n₂RT/p₂)

    =n₁+n₂/(n₁/p₁+n₂p₂)

    =10.0+5.00/(10.0/5.00+5.00/20.0)=6.67bar

    The final pressure should be p=6.67bar.

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