1. Understand the chemical formula:

* H₂O represents one molecule of water. It contains 2 hydrogen atoms (H) and 1 oxygen atom (O).

2. Calculate the number of hydrogen atoms:

* 100 H₂O molecules contain 100 * 2 = 200 hydrogen atoms.

3. Convert atoms to moles:

* One mole of any substance contains Avogadro's number of particles (6.022 x 10²³).

* To find the number of moles of hydrogen, divide the number of hydrogen atoms by Avogadro's number: 200 atoms / (6.022 x 10²³) atoms/mol ≈ 3.32 x 10⁻²² moles

Therefore, there are approximately 3.32 x 10⁻²² moles of hydrogen in 100 H₂O molecules.