Posted by Jasmine on .
You hold an inflated balloon over a hot air vent in your house and watch it slowly expand. You then remove it and let it cool back to room temperature. During the expansion, which was larger: the heat added to the balloon or the work done by the air inside? explain. (assume that air is an idea gas.) Once the balloon has returned to room temperature, how does the net heat gained or lost by the air inside it compare to the net work done on it by the surrounding air?
Physics conceptual -
During the heating, heat energy added to the balloon results in both expansion work and an increase in the internal energy of the balloon air.
Therefore the heat added exceeds the work done by gas inside. The second law of thermodynamics also prevents you from converting all of the heat to work.
In the second part of your question, if you are including the expansion and contraction in the "net", both are zero.