265.2 mmHg is the partial pressure of oxygen in 780 mmHg of total pressure.
Explanation:
The partial pressure of a gas is defined as the individual pressure of the gas in total mixture. In an ideal gas all the constituent gases have partial pressure some of which will give total pressure of the gas.
The partial pressure of a gas is calculated by
total pressure x mole fraction of the gas.
Mole fraction of the oxygen present is 0.34 as it is 34% of the total gas.
= 0.34 is the mole fraction
Total pressure is given as 780 mm Hg
The partial pressure can be calculated using the above formula:
Putting the values in equation:
780 x 0.34
= 265.2 mm Hg is the partial pressure of oxygen.