A tank holds a mixture of argon and helium gases. If the partial pressure of oxygen is 3.3 atm and the total pressure of the mixture is 15 atm; what is the mole fraction of helium gas?

Question

Quizplus · Accepted Answer

The mole fraction of helium gas can be calculated using Dalton's Law of Partial Pressures. The total pressure of the mixture is the sum of the partial pressures of the individual gases. Given that the partial pressure of oxygen is 3.3 atm and the total pressure is 15 atm, the partial pressure of the argon and helium mixture is 15 atm - 3.3 atm = 11.7 atm. Without information on argon's partial pressure, we assume the question intends to find the fraction of the mixture that is not oxygen, which would be 11.7 atm / 15 atm = 0.78. This suggests a misunderstanding in the question's phrasing, as it specifically asks for the mole fraction of helium, not the combined non-oxygen gases. However, based on the provided choices and the likely intent, 0.78 is selected.

A Tank Holds a Mixture of Argon and Helium Gases