* Avogadro's Number: One mole of any substance contains 6.022 x 10^23 particles (atoms, molecules, etc.). This is known as Avogadro's number.

* Hydrogen Molecules: Hydrogen gas exists as diatomic molecules (H₂), meaning each molecule contains two hydrogen atoms.

Calculation:

1. Atoms per mole: Since each mole of hydrogen contains 6.022 x 10^23 molecules, and each molecule has 2 atoms, there are 2 * (6.022 x 10^23) = 1.2044 x 10^24 hydrogen atoms per mole.

2. Atoms in 2 moles: To find the total number of atoms in 2 moles, multiply the number of atoms per mole by 2: 1.2044 x 10^24 atoms/mole * 2 moles = 2.4088 x 10^24 atoms

Therefore, there are approximately 2.4088 x 10^24 hydrogen atoms in 2 moles of hydrogen gas.