Multiple choice

Which of the following is the lightest gas?

  1. Nitrogen

  2. Hydrogen

  3. Ammonia

  4. Carbon dioxide
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Hydrogen (H2) is the lightest gas because it has the lowest molecular mass (2 g/mol) of all gases. All other gases like nitrogen (N2, 28 g/mol), ammonia (NH3, 17 g/mol), and carbon dioxide (CO2, 44 g/mol) are significantly heavier.

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