Difference Between Molecular Motion and Diffusion

Thekey differencebetween molecular motion and diffusion is that themolecular motion is the movement ofmolecules内部没有任何外部影响的物质，而扩散是分子从高浓度区域到较低浓度区域的运动。

分子运动和扩散非常重要，因为解释了物质分子的行为。所有物质都包含颗粒；atoms, ions或分子。大多数情况下，我们可以找到分子而不是原子或离子，因为分子更稳定。而且，所有形式的物质总是在三个中states of matter; gas, liquid or solid state. The movement of the molecules in these three states are described by molecular motion and diffusion.

1.Overview and Key Difference
2.What is Molecular Motion
3.What is Diffusion
4.Side by Side Comparison – Molecular Motion vs Diffusion in Tabular Form
5.概括

What is Molecular Motion?

Molecular motion is the movement of molecules inside a substance without any external influence. This means it is the movement of particles inside a substance here and there randomly. This movement occurs only inside the boundary of the substance. These movements cause molecular collisions, in which molecules colloid with each other. These collisions cause the bouncing of molecules.

Since the molecules of a solid are well-packed, the molecular motions in the solids are very limited. But in liquids, there are more movements and collisions when compared with solids. In gases, molecules have a large space for molecular movement and also there is a high degree of collisions. If we use an external influence on a substance, the movements change accordingly. Ex: If we increase the temperature of a gas, the speed of movement increases, thus the collisions are also high.

What is Diffusion?

Diffusion is the movement of molecules from a region of high concentration to a low concentration via a concentration gradient. These movements occur in the same solution. The factors that affect the concentration gradient affects the diffusion as well.

Difference Between Molecular Motion and Diffusion

Figure 01: Diffusion in a Simple Diagram

This motion terminates when the concentrations of the two regions become equal at every point. This means this motion occurs until the concentration gradient disappears. Then the molecules spread everywhere inside the solution.

What is the Difference Between Molecular Motion and Diffusion?

Molecular motion is the movement of molecules inside a substance without any external influence. It is a random motion. In addition, external factors can affect this motion, i.e. temperature and pressure. Diffusion is the movement of molecules from a region of high concentration to a low concentration via a concentration gradient. Therefore, it is not a random motion. The factors affecting the concentration gradient affects the motion of molecules. This is the main difference between molecular motion and diffusion.