Why is the mass of the dihydrogen molecule TWICE that of the hydrogen atom?

1 Answer
Sep 2, 2016

You compare the #H_2# molecule with the #H# atom? Well, there are TWO hydrogen atoms in the molecule, and thus it REASONABLY should have TWICE the mass.

Explanation:

What should the mass of this molecule be compared to the constituent atom? The actual mass of a mole of atoms is given on the Periodic Table.