Atmospheric pressure at sea level is equal to a column of 760 mm Hg. Oxygen makes up 21% 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

Since Oxygen makes up 21% of the atmosphere by volume, the partial pressure of oxygen (PO₂) can be calculated as follows:
PO₂ = 21% of 760 mm Hg 
PO₂ = (21/100) x 760
PO₂ = 160 mm Hg.

Atmospheric Pressure at Sea Level Is Equal to a Column