If O2 is heavier than air, why does it float in air? [duplicate]








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[Why don't heavy and light gases separate in the atmosphere?](/questions/61140/why-dont-heavy-and-light-gases-separate-in-the-atmosphere)

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Closed 10 months ago.



If the molecular weight of air is 28.96 G/mol and O2 is 32 G/mol,
does O2 float in air? If yes, then why?




O2 and N2 are essentially idea gas in everyday condition. Suppose there is only O2 ideal gas, then it will distribute throughout the whole atmosphere. Now lets add N2 to the atmosphere as well. The mixture is still essentially ideal gas (ie, the atoms barely interact between different species as well as barely interact within the same species). Therefore, the spacial distribution of the two ideal gas is independent with each other and O2 is still distributed throughout the whole atmosphere.
The situation is different with two types of liquid, since liquid are not ideal gas (not close-to-none interaction). Their interactions within (or across) species can potentially segregate the two liquid.


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