States of Matter

The three classical states of matter are solids, liquids and gases. First we’re going to look at solids and we’re going to look at some of the characteristics of a solid.

Solids have a definite volume and density, so we would say they have definite volume and density at a given temperature and pressure.

Mini-test: STATES OF MATTER 

Question 1: Which of the following is characteristic of a gas?
A.  
B.  
C.  
D.  
Question 2: Which state(s) of matter have a definite volume and density?
A.  
B.  
C.  
D.  

 

The next lesson for you: Nonpolar Covalent Chemical Bonds; these lessons are included in the Math practice tests.

The following transcript is provided for your convenience.

Like this whiteboard, for example, is a solid, so the volume of this whiteboard isn’t changing and the density of this whiteboard isn’t changing. Then the second point of a solid is it has a degree of structural rigidity and a constant shape. Notice that this whiteboard has a structural rigidity and a constant shape, so the structure isn’t changing. It also has a resistance to flow. Now some solids are just model and clay and can flow and then they go deformation under pressure, so I’m just to going to write here, there are exceptions, but for the most part, solids have a resistance to flow.

Now the second state of matter is the liquid and like solids at a particular temperature and pressure, it has a definite volume and density. The reason I say at a certain temperature and pressure is because, at a different temperature and a different pressure, this whiteboard may have a little bit of a different volume and a little bit of a different density. But as long as it stays at the same temperature and pressure, then it’s going to stay the same and the volume and the density are going to stay the same, the same thing with a liquid.

Now a liquid does flow readily, so that makes it a lot different than a solid, but it does not expand to fill a container. It’s going to flow readily if you spill water on the ground it wouldn’t all just stack up in one spot, it would flow all over the place. Well, if you were to pour water into a glass, the water isn’t going to expand to fill up that whole glass, it’s going to keep the same volume.

Now that’s different than the third state of matter, which is gas, because the main thing about a gas is that it will expand to fill a container, so also if a gas was exposed in this room, it wouldn’t all stay in one spot, it would eventually move to fill the entire room. Now the molecules are spread much farther apart and they move more rapidly and randomly than in a liquid. Basically, the molecules move the slowest in the cell, they move a little faster in the liquid and then they move the fastest in a gas. That’s why gases are spread apart, because they’re moving around so much and bumping into each other and pushing away from each other. The liquid has more moveability to it, it can move more because the molecules move more.

A solid, the thing about ice, it’s not really doing anything it’s just sitting there, because it’s a solid, the molecules are moving really slowly and so gas is far more dispersed than even a liquid, because it will expand to fill an entire container and so that’s a look at the three states of matter.

The next lesson for you: Non-polar Covalent Chemical Bonds; these lessons are included in the Math practice tests.

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