How many moles of `O_(2)` are there in `1.20 xx 10^(22)` oxygen molecules ?

Answer

To determine how many moles of \( O_2 \) are present in \( 1.20 \times 10^{22} \) oxygen molecules, we can follow these steps:

### Step 1: Understand the relationship between moles and molecules
We know from Avogadro's law that one mole of any substance contains \( 6.02 \times 10^{23} \) molecules. This is a constant known as Avogadro's number.

### Step 2: Set up the conversion
We want to convert the number of molecules into moles. The formula to convert molecules to moles is:
\[ \text{Number of moles} = \frac{\text{Number of molecules}}{6.02 \times 10^{23}} \]

### Step 3: Substitute the given values
Now, we substitute the number of molecules given in the question:
\[ \text{Number of moles} = \frac{1.20 \times 10^{22}}{6.02 \times 10^{23}} \]

### Step 4: Perform the calculation
Now we calculate the above expression:
\[ \text{Number of moles} = \frac{1.20}{6.02} \times \frac{10^{22}}{10^{23}} = \frac{1.20}{6.02} \times 10^{-1} \]
Calculating \( \frac{1.20}{6.02} \):
\[ \frac{1.20}{6.02} \approx 0.1997 \]
Thus,
\[ \text{Number of moles} \approx 0.1997 \times 10^{-1} = 0.01997 \]

### Step 5: Round the answer
We can round this to two decimal places:
\[ \text{Number of moles} \approx 0.02 \]

### Final Answer
Therefore, there are approximately \( 0.02 \) moles of \( O_2 \) in \( 1.20 \times 10^{22} \) oxygen molecules.

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