how can molecular movement bring about diffusion?

Question

I need serious answers "adults", thanks!!

Answer 1

Molecular movement is the only REAL cause of diffusion. Concentration gradients are things that we as scientists have made up, because as you know, atoms, ions, and molecules have no idea that there is higher or lower concentration on the other side of a pore.

So, we understand the concept of random, Brownian motion. Molecules like to move, and be completely chaotic and random. Well, if we have 50 molecules on one side of a container, separated by a pore permeable to that molecule, with NOTHING on the other side, what is going to happen? We know that the container will probably end up close to 25 molecules on each side. It is important to note that although the concentrations are equal, molecules are still changing sides, but at an equal rate!!

Ok, so why did they go from higher concentration to lower concentration? The answer is simple chance. The side with more molecules is more likely to have a randomly moving molecule hit the pore and go through it, than the side with fewer moving particles. And basically, when the concentrations are equal, there is an equal chance that particles will hit the pore from each side of the container, and they will cross sides, but at pretty much equal amounts.

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Answer 2

Molecular Movement

Answer 3

Molecules are in constant motion, and so they tend to evenly distrubute themselves, given enough time. Diffusion can occur very rapidly, or a substance may diffuse very slowly. It depends on the molecules velocity, which mainly depends on its mass. For example, lighter gases such as hydrogen have a higher velocity than heavy gases such as chlorine, and hydrogen would diffuse more quickly. It is a random process, just as shaking a can of marbles of different colors. The marbles would tend to mix up and become more or less evenly distributed.