A qvault gen chem question please

[Qtn2x]

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The solubility of dissolved oxygen in water is 1.25 x 10-4 M at 25°C, where the mole fraction of oxygen is 0.21 and atmospheric pressure is 1.0 atm. In a pure oxygen atmosphere at the same pressure, what would the solubility be?


I have no idea how to approach this problem and the explanation qvault provided didn't help either. I don't think Chad has ever covered Henry's law? Could someone please explain to me how to solve this problem using what formula? Thank you.

 

[Illfavor]

Henry's law tells us the solubility of a gas is proportional to the partial pressure aka mile fraction of that gas. So what's the partial pressure of oxygen in a pure oxygen atmosphere?

 

[jHoon]

I don't know the exact answer, but the way I would approach the problem is to realize that it is asking for the solubility of PURE oxygen. So the assumption you could make is that the solubility they are giving you is impure oxygen. Since the partial pressure of the impure oxgen is given as 21% (of what would normally be 100% if it were pure oxygen) you simply divide the solubility by 0.21 to give you the solubility of 100% pure oxygen.

It's almost like a QR question where they ask you "1.25 x 10-4 is 21% of what number?"

Hope that helps.