Dry air consists of 78.1% nitrogen (28 g/mol), 20.9% oxygen (32 g/mol), 0.9% argon (40 g/mol), 0.03% carbon dioxide (44 g/mol), and 0.07% other gases by volume. Which gas has the largest mole fraction in the composition of air?

Question

Quizplus · Accepted Answer

The mole fraction of a gas in a mixture is the ratio of the number of moles of that gas to the total number of moles of all gases in the mixture. Since the composition of air is given by volume and assuming ideal gas behavior (where the volume fraction equals the mole fraction because equal volumes of gases contain equal numbers of moles at the same temperature and pressure), nitrogen, with 78.1% of the air's volume, also has the largest mole fraction.

Dry Air Consists of 78