Final answer:
When the air pressure in a testing chamber is 400 mm Hg and the oxygen content is 10%, the partial pressure of oxygen (PO2) is calculated as 40 mm Hg.
Step-by-step explanation:
When the air pressure in a testing chamber is 400 mm Hg and the oxygen content is mixed to be 10%, the partial pressure of oxygen (PO2) can be calculated using the formula:
PO2 = (Total pressure of the gas mixture) x (Oxygen content in the mixture)
Therefore, the partial pressure of oxygen in this scenario is:
PO2 = (400 mm Hg) x (0.10) = 40 mm Hg.
This means that the PO2 in the testing chamber is 40 mm Hg when the oxygen content is specially mixed to be 10% of the overall pressure at 400 mm Hg.