How many molecules of `O_(2)` are present in 1 L air containing 80% volume of `O_(2)` at STP?

Explanation

To determine how many molecules of \( O_2 \) are present in 1 L of air containing 80% volume of \( O_2 \) at STP, we can follow these steps:

### Step 1: Calculate the volume of \( O_2 \) in 1 L of air
Given that the air contains 80% volume of \( O_2 \):
\[ \text{Volume of } O_2 = 80\% \text{ of } 1 \text{ L} = 0.80 \text{ L} \]

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