Partial pressure of He in this gas mixture

[Levy98]

Homework Statement

A container at 0.877 atm contains only 0.500 g H2 (g) and 0.750 g He (g).


What is the partial pressure of He?

Relevant Equations

P(HE) = 0.877*0.75/(0.75+0.5) = 0.5262 atm

My progress:

P(HE) = 0.877*0.75/(0.75+0.5) = 0.5262 atm

is this right?

 

[Charles Link]

You need to work with the number of moles of each, rather than the mass of each.