Number of atoms present in 224 `dm^(3)` of oxygen gas at STP is :-

Options

A. `6.0xx10^(23)`
B. `1.2xx10^(23)`
C. `6.0xx10^(24)`
D. `1.2xx10^(25)`

Explanation

To find the number of atoms present in 224 dm³ of oxygen gas (O₂) at standard temperature and pressure (STP), we can follow these steps:

### Step 1: Understand the Volume at STP
At STP, 1 mole of any gas occupies 22.4 liters (or 22.4 dm³).

### Step 2: Calculate the Number of Moles
To find the number of moles of oxygen gas in 224 dm³, we use the formula:
\[ \text{Number of moles (n)} = \frac{\text{Volume (V)}}{\text{Molar volume at STP (22.4 dm³)}} \]
Substituting the values:
\[ n = \frac{224 \, \text{dm³}}{22.4 \, \text{dm³/mol}} = 10 \, \text{moles} \]

### Step 3: Calculate the Number of Molecules
Using Avogadro's number (Nₐ = \(6.02 \times 10^{23}\) molecules/mol), we can find the number of molecules in 10 moles of O₂:
\[ \text{Number of molecules} = n \times Nₐ = 10 \, \text{moles} \times 6.02 \times 10^{23} \, \text{molecules/mol} = 6.02 \times 10^{24} \, \text{molecules} \]

### Step 4: Calculate the Number of Atoms
Since each molecule of oxygen gas (O₂) contains 2 oxygen atoms, the total number of atoms is:
\[ \text{Number of atoms} = \text{Number of molecules} \times 2 = 6.02 \times 10^{24} \, \text{molecules} \times 2 = 1.204 \times 10^{25} \, \text{atoms} \]

### Final Answer
Thus, the total number of atoms present in 224 dm³ of oxygen gas at STP is:
\[ \text{1.204} \times 10^{25} \, \text{atoms} \]

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