Oxygen has a boiling point of 90K, and nitrogen has boiling point of 77K. Which is a liquid and which is a gas at 80K?

Question

I tried to look into the phase diagrams, but I still don't understand. Can somebody please help and explain to me??? THANKS A LOT!!!

Answer 1

gas
|
|
90K b.p.O2
|
|
80K
|
|
77K b.p.N2
Anything above 90 K is a gas. So at 91K, O2 is a gas; N2 is a gas. At 89K, O2 is a liquid (it boils at 90K) but N2 is a gas(because it boils at 77K). At 88K, O2 still a liquid; N2 still a gas. At 87 K, O2 still a liquid; N2 still a gas. etc. So at 76K, both O2 and N2 are liquids. 80K is below the boiling point of O2 but above the boiling point of N2.
Draw a diagram, something like I've done above, for this type question and you can SEE where you are on the drawing.

Answer 2

I HATE THIS WEBSITE