An airplane is pressurized to 650mm Hg, which is the atmospheric pressure at a ski resort at 13,000ft altitude.

a. if air is 21% oxygen, what is the partial pressure of oxygen on the plane?

b. If the partial pressure of oxygen drops below 100mm Hg, passengers become drowsy. If this happens, oxygen masks are released. What is the total cabin pressure at which oxygen masks are dropped?

3 answers

The mole fraction of oxygen is 0.21
a. PO2 = 650 x 0.21

b. Ptotalx0.21 = 100
solve for Ptotal
Check my thinking.

476.2

A.136.5 or 137
B. 476