# Problem: Air is about 78.0% nitrogen molecules and 21.0% oxygen molecules. Several other gases make up the remaining 1% of air molecules.What is the mole fraction of nitrogen in air? Assume ideal behavior.

###### FREE Expert Solution

Recall that the partial pressure of a gas (PGas) in a mixture is given by:

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

where:

χGas = mole fraction of the gas

Ptotal = total pressure of the gas mixture

The given percentages indicate the contribution of each gas to the total pressure, which means we can use percentages instead of mole fraction.

For N2: The gas mixture is 78.0% N2

90% (401 ratings)
###### Problem Details

Air is about 78.0% nitrogen molecules and 21.0% oxygen molecules. Several other gases make up the remaining 1% of air molecules.

What is the mole fraction of nitrogen in air? Assume ideal behavior.