The air pressure in Denver, Colorado, is about 83% of the air pressure in Miami Beach, which is about sea level. Given that the air pressure in Miami Beach is 760 mm Hg and oxygen makes up 21% of the air in Miami Beach, what is the percentage of oxygen and the partial pressure of oxygen in Denver, respectively?
A) 17.4%; 21 mm Hg
B) 21%; 21 mm Hg
C) 21%; 132 mm Hg
D) 17.4%; 132 mm Hg

Question

Quizplus · Accepted Answer

If the air pressure in Denver is 83% of that in Miami Beach, then it is:
0.83 × 760 mm Hg = 631 mm Hg
This is the total air pressure in Denver.
Since oxygen makes up 21% of the air in Miami Beach, the partial pressure of oxygen in Miami Beach is:
0.21 × 760 mm Hg = 160 mm Hg
To find the percentage of oxygen in Denver, we need to find the partial pressure of oxygen in Denver. Since the total air pressure in Denver is 631 mm Hg, the partial pressure of oxygen is:
0.21 × 631 mm Hg = 132 mm Hg
Therefore, the percentage of oxygen in Denver is also 21%. The answer is (C).

The Air Pressure in Denver, Colorado, Is About 83% of the Air