photo.jpg

## The Kinetic-Molecular Theory of Matter - **Main Idea:** The kinetic-molecular theory explains the constant motion of gas particles. ### Key Terms - Diffusion - Effusion - Real Gas The kinetic-molecular theory can help you understand the behavior of gas molecules and the physical properties of...

## The Kinetic-Molecular Theory of Matter - **Main Idea:** The kinetic-molecular theory explains the constant motion of gas particles. ### Key Terms - Diffusion - Effusion - Real Gas The kinetic-molecular theory can help you understand the behavior of gas molecules and the physical properties of gases. The theory provides a model of what is called an **ideal gas**. An ideal gas is a hypothetical gas that perfectly fits all the assumptions of the kinetic-molecular theory. The kinetic-molecular theory of gases is based on the following five assumptions: 1. Gases consist of __large numbers of tiny particles that are far apart relative to their size__. These particles, usually molecules or atoms, typically occupy a volume that is about 1000 times greater than the volume occupied by an equal number of particles in the liquid or solid state. Thus, molecules of gases are much farther apart than molecules of liquids or solids. Most of the volume occupied by a gas is empty space, which is the reason that gases have a lower density than liquids and solids do. This also explains the fact that gases are easily compressed. 2. __Collisions between gas particles and between particles and container walls are elastic collisions__. An elastic collision is one in which there is no net loss of total kinetic energy. Kinetic energy is transferred between two particles during collisions. However, the total kinetic energy of the two particles remains the same as long as temperature is constant.