0.66 g of a compound gave 112 ml of nitrogen at STP in the Dumas method. The percentage of Nitrogen in the compound is

Answer

To find the percentage of nitrogen in the compound, we can follow these steps:

### Step 1: Identify the given data
- Mass of the compound = 0.66 g
- Volume of nitrogen at STP = 112 mL

### Step 2: Convert the volume of nitrogen to moles
At standard temperature and pressure (STP), 1 mole of gas occupies 22.4 L (or 22400 mL). We need to convert the volume of nitrogen from mL to L:
\[ \text{Volume of nitrogen in L} = \frac{112 \text{ mL}}{1000} = 0.112 \text{ L} \]

Now, we can calculate the number of moles of nitrogen (N₂):
\[ \text{Moles of nitrogen} = \frac{\text{Volume of nitrogen}}{22.4 \text{ L/mol}} = \frac{0.112 \text{ L}}{22.4 \text{ L/mol}} \approx 0.004464 \text{ mol} \]

### Step 3: Calculate the mass of nitrogen
The molar mass of nitrogen (N₂) is approximately 28 g/mol. Therefore, the mass of nitrogen can be calculated as:
\[ \text{Mass of nitrogen} = \text{Moles of nitrogen} \times \text{Molar mass of nitrogen} = 0.004464 \text{ mol} \times 28 \text{ g/mol} \approx 0.125 \text{ g} \]

### Step 4: Calculate the percentage of nitrogen in the compound
The percentage of nitrogen in the compound can be calculated using the formula:
\[ \text{Percentage of nitrogen} = \left( \frac{\text{Mass of nitrogen}}{\text{Mass of compound}} \right) \times 100 \]
Substituting the values:
\[ \text{Percentage of nitrogen} = \left( \frac{0.125 \text{ g}}{0.66 \text{ g}} \right) \times 100 \approx 18.94\% \]

### Final Answer
The percentage of nitrogen in the compound is approximately **18.94%**.

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