hello in today's video we're going to be discussing uh quite a number of topics uh we're going to first discuss uh this idea of mixtures and the two types of mixtures that chemists generally come in contact with then we'll move on to the three math Mass laws that we use uh and you will be using for the rest of your semester and then we'll finish with starting to talk about the the first theory about atoms and so we're going to cover three very different Topics in this video and we're going to move through it very quickly however tomorrow in class we're going to work with a lot of problems about different mixtures as well as as using these Mass laws and something known as mass percent and then I just wanted to introduce the the atom because in the next video we're going to be talking extensively about it so let's Jump Right In let's first start talking about the two types of mixtures that chemist generally come in contact with the first one I want to I want to consider is uh called a heterogeneous mixture and this type of mixture has more has one or more visible boundary lines so what's a boundary line well let's think about a simple example let's take a glass of water and pour some oil in it and if you've ever done this you can go home and do this in your kitchen tonight uh the water will be on the bottom of the glass and the the oil will be floating on top of the water and there's clearly a a boundary condition between the oil and the water so this would be called or considered a heterogeneous mixture there there's definitely two phases here so we're going to be calling it heterogeneous another example of that would be uh let's say this picture of candy what you can see here there's all different types of candy that are easy to pick out we could separate this out by physical means we could go in visually and just pick out um different different candies and say okay this was uh this was this red type of candy this was an orange type of candy and we can separate that out just through Visual process alone so a heterogeneous mixture can be separated by physical means uh any type of physical means this is filtration we can we can use melting points we can do things like that that are that are related to physical properties so let's move on to the second type of mixture that CH has come in contact with those are called homogeneous mixtures this is where there is no phase uh pres two-phase presence so there is no phase there's no boundary between the two phases so let's see what would look like let's take Kool-Aid I'm assuming that all of you have H have drank Kool-Aid or made Kool-Aid at some point in your life so this is clearly a mixture we have water we have sugar and we have the the little package of Kool-Aid that we put in uh to make the to add the flavor but once we add all of that together into a container what happens is the water dissolves all of the all of the solids and there is no um you can't tell that there are two different phases there's no solid chunks of sugar floating around or there shouldn't be at least there's no the the the packet of of flavor has been mixed all the way through so you can't tell that this is composed of multiple types of components and so this is considered a homogeneous mixture now a homogeneous mixture if it's if it's a liquid form is called a solution and we're going to be calling those aqueous Solutions um from here on out we'll be talking about aquous Solutions a little bit later on in in later chapters however I wanted to show you what a homogeneous solution would look like and Kool-Aid is a good example of that so let's talk about some of the tools that we can use in laboratory to separate out uh to separate out mixtures so the first one there are five different separation techniques that I want to talk about the first one is going to be considered a filtration this is using uh any type of Civ such that that when we pour in a mixture only certain particles are allowed to move through the SI so this is this is based solely on the difference in particle size now these are all five of these are just separation techniques but there're words that you should know every chemist knows these words and every chemist should be able to use these words in a in a laboratory setting so we'll be using a few of these in lab uh throughout the semester so filtration it's based on the particle size crystallization sometimes is beneficial to dissolve out a salt and we know table salt if you pour it in water it dissolves out and it becomes the solution but if you if you heat out if you heat up that liquid you can actually crystallize that sodium chloride which is table salt back into its crystallin form and so this on a lot of in a lot of occasions uh makes the crystal more pure to this is a purification technique so crystallization uh has it its foundation in the difference in solubility now what solubility means some things will be able to be dissolved in in water and uh and then if we add to that solution a new element sometimes we can crash out a crystal out of that solution so crystallization is is a way of separating out different components in the solution distillation you've all seen this in in a movie at one point or another this is where people are making moonshine they have all this glass wear and there's this there's this nice flask and it has a glasswar that's connected like this and as you heat up that flask um you get vapor and then it condenses and so this is this is the process of distillation and we use this a lot in making alcohol so distillation uh uses the difference in volatilities so if you have a a mixture of solutions one of the solutions is going to boil quicker than the other one and you generally use distillations when the boiling points are very very different so the one that boils faster the one that has higher volatility boils off quicker and we can separate that out through this idea of distillation um extraction this is if we had a solid mixture and it's composed of different uh different components different elements and compounds some of them will be able to be dissolved in certain solvents which is the liquid that we can add to this and some of them won't so what that would be is if we had a a mineral let's say we had quartz and it was covered in table salt we wanted to separate out the two the two mixtures this is a a heterogeneous mixture but we want to we want to be able to separate these two things out well we know table salt dissolves in water while quartz doesn't and so we could just pour water on this and the salt the table salt would go with the water while this the solid quartz crystal would remain solid quartz crystal so extraction this is difference in solubility and then we have chromatography this is also a difference in solubility and what this is um You probably have seen this on CSI if you've ever watched CSI they always talk about thin layer chromatography or a gas chromatograph stuff like that these all have use this utilize this idea of difference and solubility so we can uh separate out the different components by using different solvents so these are the five types of of Separation techniques that chemist come in contact with in laboratory all of the time