Here's how to calculate the moles of air in the container:

1. Ideal Gas Law:

The ideal gas law describes the relationship between pressure (P), volume (V), temperature (T), and the number of moles (n) of a gas:

PV = nRT

Where:

* R is the ideal gas constant (0.0821 L·atm/mol·K)

2. Rearrange for 'n':

To find the number of moles (n), we rearrange the equation:

n = PV / RT

3. Plug in the values:

* P = 1 atm

* V = 3 L

* T = 293 K

* R = 0.0821 L·atm/mol·K

n = (1 atm * 3 L) / (0.0821 L·atm/mol·K * 293 K)

4. Calculate:

n ≈ 0.124 moles

Therefore, there are approximately 0.124 moles of air in the 3 L container.