The molecules present in L 6.5 of sulphur dioxide at STP is

Options

A. `1.5 xx 10^(23)`
B. `1.5 xx 10^(-23)`
C. `4 xx 10^(23)`
D. `0.15 xx 10^(23)`

Explanation

To find the number of molecules present in 6.5 liters of sulfur dioxide (SO₂) at standard temperature and pressure (STP), we can follow these steps:

### Step 1: Understand the relationship between moles and volume at STP
At STP (Standard Temperature and Pressure), 1 mole of any ideal gas occupies 22.4 liters. This means that if we know the volume of gas, we can calculate the number of moles.

### Step 2: Calculate the number of moles of SO₂ in 6.5 liters
To find the number of moles (n) of SO₂ in 6.5 liters, we can use the formula:
\[ n = \frac{\text{Volume (L)}}{\text{Molar Volume (L/mol)}} \]
Here, the volume is 6.5 L and the molar volume at STP is 22.4 L/mol.

\[ n = \frac{6.5 \, \text{L}}{22.4 \, \text{L/mol}} \]

### Step 3: Perform the calculation
Calculating the number of moles:
\[ n = \frac{6.5}{22.4} \approx 0.289 \, \text{mol} \]

### Step 4: Convert moles to molecules
To find the number of molecules, we use Avogadro's number, which is \( 6.022 \times 10^{23} \) molecules/mol. The number of molecules (N) can be calculated using the formula:
\[ N = n \times N_A \]
Where \( N_A \) is Avogadro's number.

\[ N = 0.289 \, \text{mol} \times 6.022 \times 10^{23} \, \text{molecules/mol} \]

### Step 5: Perform the final calculation
Calculating the number of molecules:
\[ N \approx 0.289 \times 6.022 \times 10^{23} \approx 1.74 \times 10^{23} \, \text{molecules} \]

### Final Answer
The number of molecules present in 6.5 liters of sulfur dioxide at STP is approximately \( 1.74 \times 10^{23} \) molecules.

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