## Chem – Molecules and States of Matter

What are the states of matter?
VIDEO Molecules and States of Matter

The states of matter that we commonly interact with are solid, liquid, and gas. An example of a solid is the wood of a tree. An example of a liquid is the water that you drink. An example of a gas the air that you breath. What are the differences between these states on a small scale (molecular level)? Before we answer that question we need of a good way to think of molecules. The best way to think of a molecule at any state is like a tiny sphere shaped object. We can then picture how two molecules (two spheres) interact in two critical ways. 1) The amount of space between two molecules of the same state and 2) How two molecules of the same state move next to or around each other. First letÂ us talk about the amount of space.

What are the differences between the states of matter?

If you have two molecules of SOLID they are a SHORT distance from one another. If you have two molecules of LIQUID they are a MEDIUM distance from each other. If you have two molecules of GAS they are a LARGE distance from one another. Now lets us talk about how the molecules move next to or around each other. Two solid molecules will only be allowed to vibrate next to each other and bump one another. Solid molecules cannot pass around or between any of the neighboring molecules. Two liquid molecules can vibrate next to each other but they also have the ability to tumble over and past each other. Two gas molecules can vibrate next to each other but they also have the ability to tumble over each other or violently bounce off one another to move away from their neighbor at tremendous speeds. In fact gas molecules are always in motion, shooting away from and knocking into one another similar to soccer players on a field. This description of how molecules move relative to one another is what is called the Kinetic Molecular Theory. Lets break down the word Kinetic Molecular to give ourselves a simple description. Kin or Kinetic means the movement or motion of. Molecular means molecule. So the Kinetic Molecular Theory simply describes the movement or motion of molecules. There is one state of matter that we did not describe here that they do talk a lot about in chemistry. That state is Aqueous represented by ( aq ).

Video demonstration of how solid molecules act

Video demonstration of how liquid molecules act

Video demonstration of how gas molecules act