The number of `O_3` molecules in 16 g of ozone is approximately.

Options

A. `2xx10^(23)`
B. `3xx10^(23)`
C. `4xx10^(23)`
D. `6xx10^(23)`

Explanation

To find the number of O₃ (ozone) molecules in 16 grams of ozone, we can follow these steps:

### Step 1: Determine the molecular mass of O₃
The molecular formula for ozone is O₃. To calculate its molecular mass, we need to know the atomic mass of oxygen (O), which is approximately 16 g/mol.

\[ \text{Molecular mass of O}_3 = 3 \times \text{Atomic mass of O} = 3 \times 16 \, \text{g/mol} = 48 \, \text{g/mol} \]

### Step 2: Calculate the number of moles of O₃ in 16 grams
The number of moles can be calculated using the formula:

\[ \text{Number of moles} = \frac{\text{Given mass}}{\text{Molecular mass}} \]

Substituting the values we have:

\[ \text{Number of moles} = \frac{16 \, \text{g}}{48 \, \text{g/mol}} = \frac{1}{3} \, \text{moles} \]

### Step 3: Convert moles to molecules
To find the number of molecules, we use Avogadro's number, which states that 1 mole of any substance contains approximately \(6.022 \times 10^{23}\) molecules.

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

Substituting the values we have:

\[ \text{Number of molecules} = \frac{1}{3} \, \text{moles} \times 6.022 \times 10^{23} \, \text{molecules/mole} \]

Calculating this gives:

\[ \text{Number of molecules} \approx 2.007 \times 10^{23} \, \text{molecules} \]

### Step 4: Round to appropriate significant figures
Finally, we round the result to two significant figures:

\[ \text{Number of molecules} \approx 2.00 \times 10^{23} \, \text{molecules} \]

### Final Answer
The number of O₃ molecules in 16 g of ozone is approximately \(2.00 \times 10^{23}\) molecules.

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