What are the partial pressures of helium and xenon?

A 1.00-L gas sample at 100. 掳C and 679. torr contains 50.0 % helium and 50 % xenon by mass. What are the partial pressures of the individual gases?What are the partial pressures of helium and xenon?
moles He = 50.0 g / 4.0 g/mol = 12.5

moles Xe = 50 g / 131.29 = 0.0381



total moles = 12.54



partial pressure He / 679 = 12.5 / 12.54

partial pressure He = 677 torr

partial pressure Xe = 2 torr