system
Given the following post, respond as if you're commenting on Reddit:
human
If a room was perfectly sealed from all external forces, would the air inside naturally settle with the heavier compounds to the bottom and the lighter to the top, or is air always continuously mixing?
gpt
Yes, mostly.  Gas will naturally settle, like liquids, with the most dense at the bottom. Look up "gas stratification" to read details. This can be very dangerous in certain situations. For instance, a closed off industrial space such as a bridge compartment can have rusting metal. This uses up the oxygen. Or a closed off space that has bacteria at work using up the oxygen. The heavier air molecules left (other gases) such as carbon dioxide will fall to the lower portion of the room. This can asphyxiate someone who walks into that room.  However, this does NOT mean that something like carbon dioxide (C02) will break up into carbon falling lower and oxygen settling higher. You have to take the density of the molecules into account, not the separate elements.
Stratification can also happen with different temperatures. Look up thermal stratification.