The change in internal energy of the air inside the container can be calculated using the first law of thermodynamics, which states that the change in internal energy (ΔU) of a system is equal to the amount of heat added (Q) minus the work done (W) on the system.
In this case, the heat added to the air is 140 cal, and the work done on the air is 30 cal. Therefore, the change in internal energy of the air inside the container is:
ΔU = Q - W
= 140 cal - 30 cal
= 110 cal
So, the internal energy of the air inside the container changed by 110 calories.