The number of moles of nitrogen present in one litre of air containing 16% nitrogen by volume, under standard condition, is:

Explanation

To find the number of moles of nitrogen present in one liter of air containing 16% nitrogen by volume under standard conditions, we can follow these steps:

### Step 1: Determine the volume of nitrogen in one liter of air.
Given that air contains 16% nitrogen by volume, we can calculate the volume of nitrogen in one liter of air.

\[ \text{Volume of Nitrogen} = \frac{16}{100} \times 1 \text{ L} = 0.16 \text{ L} \]

### Step 2: Use the ideal gas law to find the number of moles of nitrogen.
Under standard conditions (STP), one mole of an ideal gas occupies 22.4 liters. We can use this information to find the number of moles of nitrogen in the 0.16 liters we calculated.

\[ \text{Number of moles of Nitrogen} = \frac{\text{Volume of Nitrogen}}{\text{Volume occupied by 1 mole at STP}} = \frac{0.16 \text{ L}}{22.4 \text{ L/mol}} \]

### Step 3: Calculate the number of moles.
Now we perform the calculation:

\[ \text{Number of moles of Nitrogen} = \frac{0.16}{22.4} \approx 0.00714 \text{ moles} \]

### Final Answer:
The number of moles of nitrogen present in one liter of air containing 16% nitrogen by volume under standard conditions is approximately **0.00714 moles**.

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