What term is used to describe the spread of gas molecules into occupied space?

The term that describes the spread of gas molecules into occupied space is diffusion. This process occurs when gas molecules move from an area of higher concentration to an area of lower concentration, resulting in a uniform distribution of the gas throughout the available volume. It is a fundamental concept in the study of gases and is crucial in understanding how different substances interact, as well as in biological systems where gas exchanges, such as oxygen and carbon dioxide, take place.

In contrast, the other terms refer to different physical processes. A condenser is a device used to convert gas into liquid through cooling but does not describe the behavior of gas molecules in space. Evaporation refers to the transition of a substance from the liquid phase to the gaseous phase, while condensation refers to the transition from gas to liquid. These processes are related to phase changes rather than the dispersion of gas molecules in a given volume.