Hi, this is Mrs. Hollick, and this is your podcast on classification of matter. Matter can be classified into mixtures and pure substances. A pure substance is either an element or a compound.
These would be things like oxygen or table salt, with the formula NaCl. A mixture is a physical combination of two or more substances, like salt water or air or maybe sand. when you have different things in the same place but they're not chemically combined.
Let's look at the definition of pure substances. Elements, like oxygen and carbon, are found on the periodic table. Compounds are made up of two or more elements bonded together. An example of a compound would be H2O.
An example of an element would be oxygen and hydrogen, and when you put them together, you make a compound H2O. There are two types of mixtures, heterogeneous and homogeneous, and you can see they have very different properties. Look at the difference in these two pictures versus these two.
Let's discuss the differences. Heterogeneous mixtures are not evenly mixed. You can see the separate parts.
There are three types of heterogeneous mixtures. The first one is called a basic. heterogeneous mixture.
The parts can easily be seen. You can sometimes pick them out. Some examples would be granite or vegetable soup, or if you took a scoop of sand at the beach, you might see sand, you might see rocks, seashells, maybe even a crab.
The second type is called a suspension. All suspension, all suspensions have tiny particles that settle out. They either sink or they float. Examples would be muddy water.
If you took a scoop of muddy water, you would see that the mud would settle out and the water would kind of come to the surface. Orange juice with pulp, you can see in the right-hand picture. Orange juice with pulp, the pulp tends to settle towards the bottom, and you can see it kind of gets a little bit clearer towards the top here. Italian salad dressing or oil and vinegar.
You can see here's an example of oil and vinegar, and you can see the oil sitting on the top and the vinegar sitting on the bottom. You can shake this up, and all the particles seem to come together. but after a few minutes they eventually settle out.
So suspensions settle out. The third type of heterogeneous mixture is a colloid. Colloids have tiny particles that do not settle out. So you want to remember that colloids do not settle out. And the particles actually scatter light.
This is called the Tyndall effect. I'm going to show you a couple of pictures of that effect. Some examples of colloids are milk, whipped cream, gelatin or jello.
and fog. Here's a picture of gelatin or jello. And here you can see the light coming through the trees on a foggy morning.
You see these beams of light? This is the scattering of light by a colloid, because you have the fog down here. That's called the Tyndall effect. Here's another example of the Tyndall effect.
You can actually see the scattering of the light. And once again, here's the lights from, I believe this is an airplane. or some kind of light and you can see how it's scattered from the fog. The second type of mixture is a homogeneous mixture.
Homogeneous mixtures are evenly mixed. You cannot see the parts. Another name for a homogeneous mixture is a solution. So you want to remember all homogeneous mixtures are called solutions and you can see some examples to the right. Kool-Aid, cranberry juice, sodas, here's a picture of soda, salt water, here's salt water here, any kind of metal alloy, so here's a picture of a wheel.
Their homogeneous mixtures are also solutions. Air, the air that you breathe, is also a homogeneous mixture. When you think about this, air is made up of, the main component is nitrogen, and then we have oxygen in there, and we have water vapor, and different other minute gases.
So it's a mixture. They're not chemically bonded. They're just all existing in the same place and you have the same phase throughout. They're all gases, so that's why it's homogeneous. Homogeneous mixtures or solutions contain two parts, a solvent and a solute.
The solvent is the substance that does the dissolving. The solute is the substance that gets dissolved. So very commonly, we dissolve.
sugar in water, we dissolve salt in water. Water would be a solvent. Water is considered the universal solvent. And then the solute would be salt or sugar or tea or coffee.
Now it's time for a quiz. So you can see on your podcast notes that you have a list of substances. What I would like you to do, I'm going to go through each picture and let you answer whether it's an element, a compound, or a mixture.
And then I'll go back and review the answers. So I'll give you a moment. on each slide. If you need to pause it at each slide, please pause the video so you can look at it and think about it and look through your notes.
I'm going to go through them fairly quickly, not too quickly, but enough that we keep the video moving. Lasagna. Is it an element, a compound, or a mixture?
Air. Is it an element, a compound, or a mixture? Calcium.
Element, compound, or mixture. Sugar. Element, compound, or mixture.
Coffee. Element, compound, or mixture. Water.
Element, compound, or mixture. Blood. Element, compound, or mixture. toothpaste element compound or mixture baking soda is it an element a compound or a mixture okay now i'm going to go back and we'll go through the answers lasagna you should have said that it's a mixture let's meet let's be more specific is it heterogeneous or homogeneous if you said heterogeneous you're correct And now we have three types of heterogeneous mixtures.
Is it basic, suspension, or colloid? It is a basic heterogeneous mixture. We can see the different parts.
Air. Air is a homogeneous mixture. It's a solution. Calcium.
Notice we have a symbol here. This should let you know it's an element. Sugar.
I also gave you a hint with sugar. You can see a chemical formula down here. When you see a chemical formula, that should give you a clue that it is a compound. Coffee. Coffee is a mixture.
More specifically, homogeneous mixture. It's a solution. Water. A lot of times we want to think of water as a solution, but it is not. That's why I gave you the hint of putting the formula down here.
Water is a compound. Blood. Blood is a mixture. Is it heterogeneous or homogeneous? Blood is actually a heterogeneous mixture.
More specifically... A suspension. If you've ever seen blood after it's sat for a little while, it will actually separate into the platelets and then the plasma.
You kind of see like a yellow liquid on the top. So it is a heterogeneous mixture, a suspension. Toothpaste. Toothpaste, this, looking at it, I would consider this a heterogeneous mixture because we can see the separate parts. You see the different parts here.
And I'd consider it basic. Baking soda. Notice the chemical formula on the bottom.
That would be a compound. So I hope you scored well on that quiz. There will be more practice in your packet on the different classification of matter practice. And please review your vocabulary. There are lots of terms in this podcast.
And be ready to use them on your quizzes and your activities in the classroom. Thanks. Have a great day.