The partial pressures of CH4, N2, and O2 in a sample of gas were found to be 155 mmHg, 476 mmHg, and 669 mmHg, respectively. What is the mole fraction of nitrogen?

20.9

0.880

0.515

0.410

0.366

We’re being asked to **calculate the mole fraction of N**_{2 }in a **gas mixture containing CH _{4}, N_{2}, and O_{2}.**

Recall that the ** partial pressure of a gas (P_{Gas})** in a mixture is given by:

$\overline{){{\mathbf{P}}}_{{\mathbf{gas}}}{\mathbf{=}}{{\mathbf{\chi}}}_{{\mathbf{gas}}}{{\mathbf{P}}}_{{\mathbf{total}}}}$

where:

**χ**** _{Gas}** = mole fraction of the gas

**P _{total}** = total pressure of the gas mixture

Partial Pressure