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To determine the internal energy of the air in a room that measures at 1 atmospheric pressure, we can follow these steps using the properties of a diatomic gas:

The volume of the room, , is calculated as:

For a diatomic gas like air, the internal energy is given by the formula:

Where:
is the number of moles,
is the molar heat capacity at constant volume,
is the ideal gas constant, and
is the temperature in Kelvin.
Using the ideal gas law, , we can substitute for :

Therefore, the internal energy becomes:

Substituting the given values for atmospheric pressure (1 atm) and volume

Thus, the internal energy of the air in the room is .