A 1.00-L gas sample at 100°C and 600 torr contains 50% helium and 50% xenon by mass. What are the partial pressures of the individual gas?

Answer 1

Pick any convenient number for the total mass, then half of that is He and half is Xe.
Now find the moles.
moles = grams/molar mass.

Calculate mole fraction He and mole fraction Xe.
mole fraction He = mol He/total moles and
mole fraction Xe = mol Xe/total moles.

Finally,
PHe = mole fraction He*total P (which is 600 torr).
PXe = mole fraction Xe*total P.

Answer 2

partial pressure for He: 582 torr & 18 torr for xe