To accurately describe the work performed in the Work: A Molecular Understanding Learning Tool., it is important that we carefully define our system. For Image of the Work: A Molecular Understanding learning toolour purposes, let’s define the system to be the balloon plus the gas particles inside the balloon. As gas particles are added to the balloon, the balloon and, therefore, the system expands. Since it is expanding, what must the balloon be doing? To expand, the balloon must push back all the surrounding air and make room for the system’s increasing volume. When pushing back the surrounding air, the system exerts a force over a distance on the atmosphere; therefore, the system has performed work on the surroundings.
How do we know?
In chemistry, work is commonly performed as gas molecules push against the surrounding air. This type of work is referred to as the work of expansion and occurs whenever the volume of a system increases. Because the system exerts a force over a distance, work must have been performed by the system on the surroundings.