When the air in a testing chamber is specially mixed so that its oxygen content is 10% and its overall air pressure is 400 mm Hg, then PO2 is . When the air in a testing chamber is specially mixed so that its oxygen content is 10% and its overall air pressure is 400 mm Hg, then PO2 is . 400 mm Hg 82 mm Hg 4 mm Hg 40 mm Hg

PO2 is 40 mmHg

Explanation:

PO2 is the partial pressure of oxygen in the testing chamber

Total air pressure = 400 mmHg

% by weight of oxygen = 10%

Partial pressure of oxygen = % by weight of oxygen × total air pressure = 10% × 400 mmHg = 0.1 × 400 mmHg = 40 mmHg

altitude, density, pressure

air gets less dense the higher the altitude and also the air pressure is less as altitude rises.