Calculate :
Number of moles in 8.0 g of `O_(2)`

Answer

To calculate the number of moles in 8.0 g of \( O_2 \), we can follow these steps:

### Step 1: Calculate the Molar Mass of \( O_2 \)
The molar mass of an element is the mass of one mole of that element. For oxygen (\( O \)), the atomic mass is approximately 16 g/mol. Since \( O_2 \) consists of two oxygen atoms, we calculate the molar mass as follows:

\[ \text{Molar mass of } O_2 = 16 \, \text{g/mol} \times 2 = 32 \, \text{g/mol} \]

### Step 2: Use the Molar Mass to Find the Number of Moles
We know that 1 mole of \( O_2 \) weighs 32 grams. To find the number of moles in 8.0 g of \( O_2 \), we can use the formula:

\[ \text{Number of moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}} \]

Substituting the values we have:

\[ \text{Number of moles} = \frac{8.0 \, \text{g}}{32 \, \text{g/mol}} = \frac{1}{4} = 0.25 \, \text{moles} \]

### Final Answer
The number of moles in 8.0 g of \( O_2 \) is **0.25 moles**.

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