What two elements make up 99% of dry air?

What two elements make up 99% of dry air?

• A. Hydrogen and Oxygen
• B. Nitrogen and Oxygen
• C. Argon and Nitrogen
• D. Carbon Dioxide and Nitrogen

Answer: (B)

Dry air is dominated by two gases in nearly all measurements. By volume, nitrogen is the largest component, followed by oxygen, and together they total about 99% of dry air. The rest—trace amounts of argon, carbon dioxide, neon, and other gases—adds up to roughly 1%, and water vapor (not included in “dry air”) can change the amounts when it’s present. Hydrogen isn’t a significant part of the atmosphere, and argon or carbon dioxide alone don’t come close to 99% when combined with the other gases. That’s why nitrogen and oxygen are the best fit for making up 99% of dry air.

Dry air is dominated by two gases in nearly all measurements. By volume, nitrogen is the largest component, followed by oxygen, and together they total about 99% of dry air. The rest—trace amounts of argon, carbon dioxide, neon, and other gases—adds up to roughly 1%, and water vapor (not included in “dry air”) can change the amounts when it’s present. Hydrogen isn’t a significant part of the atmosphere, and argon or carbon dioxide alone don’t come close to 99% when combined with the other gases. That’s why nitrogen and oxygen are the best fit for making up 99% of dry air.