With a gas mixture of N2 & He..?

Question

If the partial pressure of N2 is 300 torr and the partial pressure of He is 600 torr, what is the mole % of N2 in the mixture?

Answer 1

partial pressures of any gas are directly proportional to their mole fractions. So the ratio of the pressures will give you the ratio of the mole fractions, i.e: 1/2 (N2/He). So, % of N2 is 1/(2+1) = 1/3..

Answer 2

Partial pressures are proportional to the moles of each gas (Ideal gas law)

So the mole percent of N2 would be 300 torr over the total combined pressures of the 2 gases. (times 100 for percent)

Answer 3

50%