gas question

davidj

I think the following is false but my brain is scrambeled from too much cramming so just though I'd get a second opinion

in air, the pressure exerted by oxygen is constant, regardless of the altitude at which its partial pressure is measured

Kevster

I cannot think of any reason why it would remain constant anyway... ...

ApeXaviour

I don't really get what you're saying. Pressure is related to force. If you cram a load of air molecules into a tight space, they'll exert more force on the boundaries of this space. Cramming the same amount into a larger space, they'll exert less force. Similarly for heating, you're giving the individual molecules more thermal energy so they'll push the sides more.

Air can also weigh on itself, so as you go higher in altitude, the density of the gas and hence the pressure decreases. Think of a giant soft bath sponge that goes many metres in the air. It's own weight will squeeze the bottom of it closer together, making it denser. But this density will decrease as you go up.

Also air is mostly nitrogen