An airplane is pressurized to 650mm Hg, which is the atmospheric pressure at a ski resort at 13,000ft altitude.

a. if air is 21% oxygen, what is the partial pressure of oxygen on the plane?

b. If the partial pressure of oxygen drops below 100mm Hg, passengers become drowsy. If this happens, oxygen masks are released. What is the total cabin pressure at which oxygen masks are dropped?

The mole fraction of oxygen is 0.21

a. PO2 = 650 x 0.21

b. Ptotalx0.21 = 100
solve for Ptotal
Check my thinking.

A.136.5 or 137

B. 476

476.2

To find the partial pressure of oxygen on the plane, we need to multiply the atmospheric pressure by the fraction of oxygen in the air.

a. The partial pressure of oxygen on the plane can be found using the formula:

Partial Pressure = Total Pressure × Fraction of Gas

Given:
Total Pressure = 650 mm Hg
Fraction of Oxygen = 21% = 0.21

To calculate the partial pressure of oxygen, we need to multiply the total pressure by the fraction of oxygen:

Partial Pressure of Oxygen = 650 mm Hg × 0.21

Therefore, the partial pressure of oxygen on the plane is 136.5 mm Hg.

b. In order to find the total cabin pressure at which oxygen masks are dropped, we need to determine the cabin pressure at which the partial pressure of oxygen drops below 100 mm Hg.

To get the total cabin pressure, we need to determine the partial pressure of oxygen when it reaches 100 mm Hg. We can set up the following equation to find the total cabin pressure:

100 mm Hg = Total Pressure × Fraction of Oxygen

Since the fraction of oxygen remains the same (0.21), we can rearrange the equation and solve for the total pressure:

Total Pressure = 100 mm Hg / 0.21

Calculating this, we get:

Total Pressure = 476.19 mm Hg

Therefore, the total cabin pressure at which oxygen masks are dropped is approximately 476.19 mm Hg.