What Is the Chemical Composition of Air?
What Is the Chemical Composition of Air?
What  Is the Chemical Composition of Air?
Elements in the Atmosphere
By Anne Marie Helmenstine, Ph.D.
Question: What Is the Chemical Composition of Air?
Nearly all of the Earth's atmosphere is made up of only five gases : nitrogen, oxygen, water vapor, argon, and carbon dioxide . Several other compounds also are present. Although this CRC table does not list water vapor , air can contain as much as 5% water vapor, more commonly ranging from 1-3%. The 1-5% range places water vapor as the third most common gas (which alters the other percentages accordingly).
Answer: This is composition of air in percent by volume, at sea level at 15°C and 101325 Pa.
Nitrogen -- N2 -- 78.084%