To determine the number of moles of oxygen atoms in a sample of ammonium phosphate (NH\(_4\))\(_3\)PO\(_4\) containing 3.18 moles of hydrogen atoms, we need to understand the composition of the compound and use stoichiometry.
- First, identify the chemical formula of ammonium phosphate: (NH\(_4\))\(_3\)PO\(_4\).
- Determine the number of each type of atom in one formula unit of ammonium phosphate:
- 3 nitrogen atoms (from 3 NH\(_4\) groups)
- 12 hydrogen atoms (4 hydrogen atoms per NH\(_4\) group × 3 NH\(_4\) groups)
- 1 phosphorus atom
- 4 oxygen atoms
- According to the question, the sample contains 3.18 moles of hydrogen atoms.
- The stoichiometric ratio between hydrogen atoms and oxygen atoms in one formula unit of ammonium phosphate is 12:4 or 3:1.
- Calculate the moles of oxygen atoms:
- If there are 3 moles of hydrogen atoms, this would imply 1 mole of oxygen atoms.
- Given 3.18 moles of hydrogen atoms, use the ratio to find the oxygen atoms: \[ \text{Moles of O-atoms} = \frac{3.18 \, \text{moles of H-atoms}}{3} = 1.06 \, \text{moles of O-atoms} \]
Thus, the number of moles of O-atoms in the sample is \(1.06\). Therefore, the correct answer is 1.06.