How many molecules of `SO_(2)` are present in 11.2 L at STP?

Answer

To find out how many molecules of \( SO_2 \) are present in 11.2 L at STP, we can follow these steps:

### Step 1: Understand the relationship between volume and moles at STP
At Standard Temperature and Pressure (STP), 1 mole of any ideal gas occupies 22.4 liters.

### Step 2: Calculate the number of moles of \( SO_2 \) in 11.2 L
To find the number of moles of \( SO_2 \) in 11.2 L, we can use the formula:

\[ \text{Number of moles} = \frac{\text{Volume (L)}}{\text{Molar volume at STP (L/mol)}} \]

Substituting the values:

\[ \text{Number of moles of } SO_2 = \frac{11.2 \, \text{L}}{22.4 \, \text{L/mol}} = 0.5 \, \text{mol} \]

### Step 3: Convert moles to molecules
We know that 1 mole of any substance contains \( 6.022 \times 10^{23} \) molecules (Avogadro's number). Therefore, to find the number of molecules in 0.5 moles of \( SO_2 \):

\[ \text{Number of molecules} = \text{Number of moles} \times \text{Avogadro's number} \]

Substituting the values:

\[ \text{Number of molecules of } SO_2 = 0.5 \, \text{mol} \times 6.022 \times 10^{23} \, \text{molecules/mol} = 3.011 \times 10^{23} \, \text{molecules} \]

### Final Answer
Thus, the number of molecules of \( SO_2 \) present in 11.2 L at STP is \( 3.011 \times 10^{23} \) molecules.

---