Multiple choice

Which of the following terms correctly defines air?

  1. Compound

  2. Element

  3. Mixture

  4. Atom
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Air is a mixture of various gases. The main gases present in air are nitrogen (78.1% by volume) and oxygen (20.9% by volume). These two gases together form 99% of the air. Besides these two, air contains small amounts of carbon dioxide (0.03 to 0.04%), water vapour (variable), noble gases (0.94%), and dust particles.

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