A sample of ammonium phosphate `(NH_(4))_(3) PO_(4)` contains 3.18 moles of hyrogen atoms . The number of moles of oxygen atoms in the sample is

Options

A. 0.265
B. 0.795
C. 1.06
D. 4

Answer

To solve the problem, we need to determine the number of moles of oxygen atoms in a sample of ammonium phosphate `(NH₄)₃PO₄` given that it contains 3.18 moles of hydrogen atoms.

### Step-by-Step Solution:

1. **Identify the Composition of Ammonium Phosphate**:
The chemical formula for ammonium phosphate is `(NH₄)₃PO₄`. This indicates that:
- There are 3 ammonium ions `(NH₄)`, and each ammonium ion contains 4 hydrogen atoms.
- There is 1 phosphate ion `(PO₄)` which contains 4 oxygen atoms.

2. **Calculate the Total Number of Hydrogen Atoms in One Mole of Ammonium Phosphate**:
Each ammonium ion contributes 4 hydrogen atoms. Therefore, in 1 mole of ammonium phosphate:
\[ \text{Total hydrogen atoms} = 3 \times 4 = 12 \text{ hydrogen atoms} \]

3. **Determine the Ratio of Hydrogen to Oxygen**:
From the formula, we see that for every 12 moles of hydrogen, there are 4 moles of oxygen in ammonium phosphate.

4. **Set Up a Proportion to Find Moles of Oxygen**:
We know that:
\[ 12 \text{ moles of H} \rightarrow 4 \text{ moles of O} \]
We need to find how many moles of oxygen correspond to 3.18 moles of hydrogen:
\[ \text{Let } x \text{ be the moles of oxygen.} \]
The proportion can be set up as:
\[ \frac{12 \text{ moles of H}}{4 \text{ moles of O}} = \frac{3.18 \text{ moles of H}}{x \text{ moles of O}} \]

5. **Cross-Multiply and Solve for x**:
Cross-multiplying gives us:
\[ 12x = 4 \times 3.18 \]
\[ 12x = 12.72 \]
Now, divide both sides by 12:
\[ x = \frac{12.72}{12} = 1.06 \text{ moles of O} \]

### Conclusion:
The number of moles of oxygen atoms in the sample is **1.06 moles**.