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 it? Explain. (Assume that air is an ideal 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 or by the surrounding air?
Solution 7DQ Introduction Here we have figure out whether the energy supplied to the balloon during inflation is greater than the work done by the balloon. Step 1 When we are holding the balloon over a hot vent, all the energy supplied to the balloon is coming from the vent as heat, since there are no other source of energy. So the energy required for the work done by the gas during the expansion will also be supplied by the heat we are supplying from the vent. But the heat will also be used to increase the temperature of the gas. Hence total energy supplied to the balloon as heat is greater than the work done by the balloon.