Question

A mixture of three gases has a pressure at 298 K of 1380 mm Hg. The mixture is analysed and is found to contain 1.27 mol CO2, 3.04 mol CO, and 1.50 mol Ar. What is the partial pressure of Ar?

Answer 1

The partial pressure of Ar is 356.3 mmHg

Step-by-step explanation:

The concept of the molar fraction can be applied to calculate the partial pressure of a gas, in a mixture where the molar fraction is equal to the gas pressure, over the total pressure.

PCO2 / Total pressure = n° moles CO2 / Total moles

So we have the total pressure, the moles of Ar and the total moles

The sum of moles is moles Ar + moles CO + moles CO₂ =

1.27 + 3.04 + 1.5 = 5.81

1,5 moles of Ar / 5.81 moles = Partial pressure Ar / Total Pressure

1,5 moles of Ar / 5.81 moles = Partial pressure Ar / 1380mmHg

(1,5 moles of Ar / 5.81 moles) . 1380mmHg = Partial Pressure Ar

356,3 mmHg = Partial Pressure Ar