In an ideal gas, which of the following assumptions is made regarding gas molecules?

In an ideal gas, one of the fundamental assumptions is that gas molecules are in continual motion. This means that the molecules are constantly moving in straight lines until they collide with either each other or the walls of the container. This motion is random and varies in speed, contributing to the pressure exerted by the gas as the molecules hit the surfaces of the container.

The assumption of continual motion is central to the kinetic molecular theory, which describes how gas pressure arises from the collisions of rapidly moving particles. As the temperature of the gas increases, the average kinetic energy and, therefore, the speed of the molecules also increases, leading to higher pressure if the volume is kept constant.

Other choices do not align with the ideal gas model. For instance, gas molecules do not attract each other strongly; instead, the forces between them are considered negligible to simplify calculations. Likewise, in the ideal gas assumption, the volume that gas molecules occupy is minimal compared to the volume of the container, and gases do not have a defined shape but rather expand to fill their container.