Answer:
the change in the internal energy of the balloon is 3,300 J
Explanation:
Given;
heat gained by the balloon system, Q = 6,400 J
work done on the surrounding air by the balloon, W = 3,100 J
The change in the internal energy of the system is calculated from the first law of thermodynamics;
ΔU = Q - W
where;
ΔU is the change in the internal energy of the balloon;
ΔU = 6,400 J - 3,100 J
ΔU = 3,300 J
Therefore, the change in the internal energy of the balloon is 3,300 J