6.4 gm of `SO_(2)` will contain how many
(i) Moles of `SO_(2)`
(ii) Number of `SO_(2)` molecules

Answer

To solve the problem of how many moles and how many molecules are contained in 6.4 grams of \( SO_2 \), we will follow these steps:

### Step 1: Calculate the Molar Mass of \( SO_2 \)
The molar mass of \( SO_2 \) can be calculated as follows:
- The atomic mass of Sulfur (S) = 32 g/mol
- The atomic mass of Oxygen (O) = 16 g/mol
- Since there are 2 oxygen atoms in \( SO_2 \), the total mass of oxygen = \( 16 \times 2 = 32 \) g/mol

Thus, the molar mass of \( SO_2 \) is:
\[ \text{Molar mass of } SO_2 = 32 \, \text{g/mol (S)} + 32 \, \text{g/mol (O)} = 64 \, \text{g/mol} \]

### Step 2: Calculate the Number of Moles of \( SO_2 \)
Using the formula for calculating the number of moles:
\[ \text{Number of moles} = \frac{\text{Weight (g)}}{\text{Molar mass (g/mol)}} \]
Substituting the values:
\[ \text{Number of moles} = \frac{6.4 \, \text{g}}{64 \, \text{g/mol}} = 0.1 \, \text{moles} \]

### Step 3: Calculate the Number of Molecules of \( SO_2 \)
To find the number of molecules, we use Avogadro's number, which is approximately \( 6.02 \times 10^{23} \) molecules/mol. The formula is:
\[ \text{Number of molecules} = \text{Number of moles} \times \text{Avogadro's number} \]
Substituting the values:
\[ \text{Number of molecules} = 0.1 \, \text{moles} \times 6.02 \times 10^{23} \, \text{molecules/mol} \]
Calculating this gives:
\[ \text{Number of molecules} = 6.02 \times 10^{22} \, \text{molecules} \]

### Final Answers:
(i) The number of moles of \( SO_2 \) in 6.4 grams is **0.1 moles**.
(ii) The number of \( SO_2 \) molecules in 6.4 grams is **\( 6.02 \times 10^{22} \) molecules**.

---