Question

A partially inflated balloon is heated over the open end of a glass beaker that contains water. The beaker is placed over a flame, which heats the water and causes a balloon to expand. What are the correct signs for the heat and work changes to the beaker and balloon system?

a) Heat absorbed by the beaker, work done on the balloon
b) Heat absorbed by the balloon, work done on the beaker
c) Heat released by the beaker, work done on the balloon
d) Heat released by the balloon, work done on the beaker

Answer 1

The correct signs for the heat and work changes in the beaker and balloon system are heat absorbed by the balloon and work done on the beaker.

Step-by-step explanation:

The correct signs for the heat and work changes to the beaker and balloon system are: b) Heat absorbed by the balloon, work done on the beaker.

When the balloon is heated over the open end of the glass beaker, the heat is transferred from the flame to the balloon, causing the balloon to expand. This indicates that heat is absorbed by the balloon.

At the same time, as the balloon expands, it pushes against the surrounding air inside the beaker. This results in work being done on the beaker by the expanding balloon.

Therefore, the correct signs for the heat and work changes are as follows: Heat absorbed by the balloon (+Q), work done on the beaker (-W).