Question

A gas mixture in a rigid container has a total pressure of 2.5 atm. One gas, lets call it X, has 0.85 moles and accounts for 1.2 atm of pressure. What is the mole fraction of the other gases (all gases that are not X) in the container?

Answer 1

The mole fraction of the other gases : 0.52

Further explanation

Given

P tot = 2.5 atm

P x = 1.2 atm, n = 0.85 moles

Required

mole fraction

Solution

P tot = P gas X + P other gases

mol fraction = mol x : mol total

P gas X = mol fraction gas X x P total

1.2 atm = mol fraction gas X x 2.5 atm

mol fraction gas X = 0.48

mol fractionof the other gases = 1 - 0.48 = 0.52

Or we can use

P other gases = 2.5 - 1.2 = 1.3 atm

mol fraction the other gases = 1.3 : 2.5 = 0.52