A sample of dry air at 28 degress celcius in a sealed flask has a pressure of 90kPa. Which is the most likely the partial pressure of Oxygen, O2(g) in the flask?

a) 70kPa
b) 19kPa
c) 3Pa
d) 0.8kPa
Can you explain how you got this answer?

2 answers

The mole fraction of oxygen molecules in dry air is 0.2095.

Daltons Law:
Po2/90=.2095

Po2=18.8 kPa
How did you get the mole fraction?