Atmospheric pressure at sea level is equal to a column of 760 mm Hg. Oxygen makes up 21 percent of the atmosphere by volume. The partial pressure of oxygen (PO2) in such conditions is ________.
A) 160 mm Hg
B) 16 mm Hg
C) 120/75
D) 21/760
E) 760/21

Question

Quizplus · Accepted Answer

The total pressure at sea level is 760 mm Hg. As oxygen makes up 21% of the atmosphere by volume, the partial pressure of oxygen (PO2) would be 21% of 760 mm Hg. 
= (21/100) x 760 mm Hg 
= 160 mm Hg

Atmospheric Pressure at Sea Level Is Equal to a Column