Ok so I am doing this problem and it is making me insane. The problem states that you have a container, the container has a partition and in compartment A you have an ideal gas at 5 atm and 400K. In compartment B you have another ideal gas at 8 atm and 400K. The partition is removed and the gasses are allowed to mix together. The molar fraction for gas A is found to be 25/43. The total volume of both of the compartments is 29 liters. Find the original volumes of compartments A and B.(adsbygoogle = window.adsbygoogle || []).push({});

So here is how I approached it.

the molar fraction is [Nk/Ntotal] = [Pk/Ptotal].

Using this formula the total number of moles is 43 and using PV=nRT you get the total pressure equal to 48.669 atm. Plugging this number back into the molar fraction formula gives you a partial pressure for gas A of 28.30 atm.

Now it may just be me but from the get go this does not make a lick of sense as you originally had pressure for gas A of 5 atm and pressure for gas B of 8 atm. If the container is not flexible and the total volume of the container is 29 liters I personally would not expect the combined pressure of the two gasses to be more than 3.5 times greater than the sum of their individual pressures. I have gone on to try and figure out what has gone wrong several different ways but am at a total loss. The only thing I can think of is that the container is flexible, but we have not started studying that and it does not mention it anywhere in the text. I am sure it is something glaringly obvious and if anyone would like to point it out to me I would be eternally grateful. My homework is not due until next friday but this is making me insane.

Thanks

Rachael

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# Homework Help: Pressure, Volume, Temperature, etc.

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