Here's how to figure out the number of moles of hydrogen atoms in one mole of phosphoric acid (H₃PO₄):

1. Chemical Formula:

* Phosphoric acid has the chemical formula H₃PO₄.

2. Subscripts:

* The subscript "3" after the hydrogen (H) indicates that there are 3 moles of hydrogen atoms in every mole of phosphoric acid.

Therefore, there are 3 moles of hydrogen atoms in one mole of phosphoric acid.