mixtures. So this is the second video for this chapter and this video will talk about mixtures. A mixture is a combination of two or more pure substances that are not chemically bonded. So they're made up of two or more atoms or compounds mixed together, but are not chemically bonded. So if you look on the left picture, the red and the white atoms are not bonded. They're just hanging out beside each other. In the picture on the right, there are red atoms hanging out next to the red and white compounds. They're not touching their space between all of the different types of atoms and compounds. Mixtures are held together by physical forces like gravity or electrostatic charges. Not chemical bonds will learn more about electrostatic charges later, but for now we just need to see that there's clear space between the different types of atoms and compounds. They're not bonded together. There are spaces between the atoms and the drawings. So if you look on the left, that's an example of a compound because of the regular pattern of gray and black atoms that are clearly touching. On the right, that's a mixture because the gray and black compounds have spaces between them. Each substance retains or keeps its physical properties in the mixture because there aren't any changes in the chemical bonds. If you look on the left, the salt is inside the water. It's still salt. It's just hanging out in the water. The picture to the right is cream and coffee. The cream still stays like cream. It's just sitting in the coffee. They keep their chemical properties because the chemical bonds don't change. Mixtures can be physically separated because there are no chemical bonds between the substances. For example, I can pick out the butter flavored jelly bellies that I don't like. That's a mixture and I can pick out the ones I don't want. The water filter will filter out all the impurities of the water. Any evaporating, you can see that you're left with the red atoms and all of the yellow atoms escape out of there. You can separate all of those different things without being in the chemistry lab. First, let's talk about homogenous mixtures. A homogenous mixture is when the molecules are mixed up in an even distribution and appear to be a single substance when looking at it. If we look at the picture on the left, the black and white atoms are next to each other in a regular pattern. You can see that they're not touching, so there are no chemical bonds there, but it's a regular pattern. There are no separations between them. Examples of homogenous mixtures would include coffee with cream, where we can't see any layers, or a bar of chocolate without any chunks of other stuff. Now let's talk about heterogeneous mixtures. In a heterogeneous mixture, the molecules are not mixed up in an even distribution. We can clearly see layers or chunks. So if we look in the picture on the left, the green and the red atoms are not together. There's a clear separation there. Another example would be the Coca-Cola with the ice, or that ice cream that we can see peanuts and marshmallows and other chunks of things. Sample problem is this a heterogeneous or homogenous solution. That's heterogeneous because we can see all the stuff floating in it in all the different layers. Is this a heterogeneous or homogenous cookie? That's homogenous. There are no chunks or separations of anything in there. It's all looks like a cookie. There's no other particles in there. It's just all evenly distributed. That's heterogeneous or homogenous. That's heterogeneous. We can see the separation between the purple and the green atoms. That's homogenous because the purple is mixed in with the green. To review, matter can be separated into pure substances or mixtures. This video only talked about mixtures. Mixtures can be separated into homogenous or heterogeneous. Homogenous is all one layer. They're all mixed together evenly. heterogeneous has a clear separation between the two.