The mole fraction of oxygen in air is 0.209. Assuming nitrogen is the only other constituent,

what are the partial pressures (in torr) of oxygen and nitrogen when the barometer reads 780
torr?

1 answer

XO2 = 0.209
XN2 = 1-0.209 = ?

pO2 = XO2*780 = ?
pN2 = XN2*780 = ?