Find the no. of moles of `O_2` present in 1.20x`10^24` molecules of oxygen gas?

Options

A. 0.199
B. 1.99
C. 19.9
D. 19

Explanation

To find the number of moles of \( O_2 \) present in \( 1.20 \times 10^{24} \) molecules of oxygen gas, we can follow these steps:

### Step 1: Understand the relationship between moles and molecules
One mole of any substance contains \( 6.02 \times 10^{23} \) molecules (Avogadro's number).

### Step 2: Set up the formula
To find the number of moles (\( n \)) from the number of molecules (\( N \)), we can use the formula:
\[ n = \frac{N}{N_A} \]
where \( N_A \) is Avogadro's number (\( 6.02 \times 10^{23} \) molecules/mole).

### Step 3: Substitute the values
In this case, \( N = 1.20 \times 10^{24} \) molecules. Therefore, we can substitute the values into the formula:
\[ n = \frac{1.20 \times 10^{24}}{6.02 \times 10^{23}} \]

### Step 4: Perform the calculation
Now, we can perform the division:
\[ n = \frac{1.20}{6.02} \times \frac{10^{24}}{10^{23}} = \frac{1.20}{6.02} \times 10^{1} \]
Calculating \( \frac{1.20}{6.02} \):
\[ \frac{1.20}{6.02} \approx 0.199 \]
Now multiply by \( 10^{1} \):
\[ n \approx 0.199 \times 10 = 1.99 \text{ moles} \]

### Step 5: Conclusion
Thus, the number of moles of \( O_2 \) present in \( 1.20 \times 10^{24} \) molecules of oxygen gas is approximately \( 1.99 \) moles.

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