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 of gas at STP
At STP, 1 mole of any ideal gas occupies 22.4 liters (or 22.4 dm³).

### Step 2: Calculate the number of moles in 224 dm³ of oxygen gas
To find the number of moles of oxygen gas in 224 dm³, we can use the formula:

\[ \text{Number of moles} = \frac{\text{Volume of gas at STP}}{\text{Volume occupied by 1 mole at STP}} \]

Substituting the values:

\[ \text{Number of moles} = \frac{224 \, \text{dm}^3}{22.4 \, \text{dm}^3/\text{mole}} = 10 \, \text{moles} \]

### Step 3: Calculate the number of molecules in 10 moles of oxygen gas
Using Avogadro's number, which is \(6.022 \times 10^{23}\) molecules/mole, we can calculate the number of molecules in 10 moles:

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

Substituting the values:

\[ \text{Number of molecules} = 10 \, \text{moles} \times 6.022 \times 10^{23} \, \text{molecules/mole} = 6.022 \times 10^{24} \, \text{molecules} \]

### Step 4: Calculate the number of atoms in oxygen gas
Since each molecule of oxygen gas (O₂) contains 2 oxygen atoms, we can find the total number of atoms by multiplying the number of molecules by 2:

\[ \text{Number of atoms} = \text{Number of molecules} \times 2 \]

Substituting the values:

\[ \text{Number of atoms} = 6.022 \times 10^{24} \, \text{molecules} \times 2 = 1.2044 \times 10^{25} \, \text{atoms} \]

### Final Answer
The number of atoms present in 224 dm³ of oxygen gas at STP is \(1.2044 \times 10^{25}\) atoms.

---