Answer:
322 mmHg
Step-by-step explanation:
Step 1: Given data
- Total pressure of the gaseous mixture (P): 756 mmHg
- Partial pressure of helium (pHe): 229 mmHg
- Partial pressure of nitrogen (pN₂): 205 mmHg
Step 2: Calculate the partial pressure of oxygen (pO₂)
The total pressure of the gaseous mixture is equal to the sum of the partial pressures of the individual gases.
P = pHe + pN₂ + pO₂
pO₂ = P - pHe - pN₂
pO₂ = 756 mmHg - 229 mmHg - 205 mmHg
pO₂ = 322 mmHg