In chemistry, work is most often performed when a gas expands. Open the Work: A Molecular Understanding Learning Tool. to explore this phenomenon.

Click the balloon to see the gas particles inside. Then, pump air into the balloon by clicking the handle of the pump. What happens to the balloon?

Question for Thought

Consider what happens to the balloon in the Work: A Molecular Understanding Learning Tool.. Is work performed? If yes, does the system perform work on the surroundings or does the surroundings perform work on the system?