Understanding Pure Matter and Mixtures

hey everyone welcome to homeschool and welcome back to class 9 science series we are with the second chapter is matter around us pure already one part is completed on this chapter where I covered everything about the classification of matter the importance of mixtures meaning of the word mixture types of mixtures and then i discussed everything about solutions solution what are the two components of solution what do you mean by concentrated solution dilute solution how to calculate concentration of a solution mass percentage all that we have discussed right now And in today's video, let us talk about suspensions and colloidal solutions. And we will also start the separating techniques of mixtures. Okay, so let us start with the topic suspensions. So what do you mean by the word suspensions? So this is very simple guys. We observe carefully if you have a beaker of water. So this is a beaker. of water and I will add a spoon of sand right. So when I add sand to this water how will the solution look? Here and there you will find the big particles right and after some time when you keep this particular solution without shaking without shaking when you keep this solution without shaking it will start to melt. After 5 minutes or 10 minutes, you will find your sand particles being settled at the bottom. Isn't it? So when you drop a sand and nicely mix it, you know, the big big particles will stay all over the water. But after 10 minutes, when you keep it as such without shaking, all your sand particles will come at the bottom and settle. You know, this particular solution is called as suspension, right? So sand in water is a suspension. So now how do you define a suspension? Is it a homogeneous or heterogeneous mixture? Definitely heterogeneous. We understood the meanings of these words in my previous video, right? So what do you mean by heterogeneous? Heterogeneous. is the one where one component do not gets mixed up with another component. Sand is one component, water is another component or I can say substance. Sand is one substance, water is another substance, sand will not get mixed up with water, right? So, such a solution is called, you know, suspension. So, how will I write a definition here? Heterogeneous mixture, heterogeneous mixture, it's a kind of mixture, what type? Heterogeneous mixture where solute do not gets, do not gets mixed up, mixed up with solvent. Okay, clear. And here, you know what, if I have to talk about properties of suspensions, properties of suspensions. So the first point you can mention is it is heterogeneous mixture. Okay, second point is solute particles can be seen with your naked eye. What do you mean by solute? The component which is present in a smaller amount. See, I just added one spoon to a large amount of water. So the substance which is there in a smaller quantity is called solute. And the substance which I took it in a large amount is called solvent. So here what I am telling you is solute particles can be seen with the naked eye. So what will I write? Solute can be seen with naked eye. You can see when you put a sand in water definitely you can see sand particles with your eye right and you know what separation of solute and solvent is easy. Separation of solute from solvent. from solvent is easy. So, you can easily separate the sand from water, right? Okay. So, the second one, I mean, the next point that we have to write is Since the size of solute is bigger, so size, size of solute is bigger. Since the size is bigger, you know, it will scatter the light. It will scatter the light. It means spreading of light is called scattering. Okay. So, these solute particles can spread the light to a surrounding region. Right? So that is the reason path of light, path of light through suspension, through suspension is visible. is visible. So what do you mean by this point? For example, you take a glass of suspension. So you have a suspension and you are passing light. So this is light that you are giving from top. okay so when you stand you know here is a glass you are passing a light and when you stand here and watch the path of light is visible inside a suspension how light goes you know can be seen with your eyes okay so it is because the particles of suspension is spreading the light since it is spreading the light you know the path how it travels inside a solution can be seen with your eyes okay so that is what the meaning of this last point right and another property is particles will settle at the bottom if you do not disturb the suspension right so this is all about the suspension that we have learned and now you Let us try to learn about colloidal solution. Okay. So the third type of solution is colloidal solution. So what do you mean by a colloidal solution here? For example, first let me give an example for colloidal solution that is milk. Okay, say can you see a particles of milk with your naked eyes? Is milk transparent? If it is a transparent liquid, you call it as a solution, right? So here the solute particles are very very small and they will completely gets mixed up, right? Whereas here solute particles are not very small like you know solution. and the solute particles are not very big like suspension. Okay. Say I can differentiate the three solutions here. Say in solution, the solute particles are very, very small. Okay. Whereas in case of colloidal solution, colloidal solution, the solute particles are quite big. Okay. Whereas in case of suspension, the solute particles are very big. Okay. So this difference you have to understand between solution, suspension and colloidal solution. In case of solution, you see solute particle, the component which is there in a smaller amount, the particle size is very, very small. Colloidal solution, much big. Suspension much much big. So what do you call colloidal solution as? It is also heterogeneous solution. Where the solute is dispersed in solvent. So what is the definition I can write here? It is also heterogeneous. Heterogeneous mixture where solute. Solute particles. Particles are dispersed throughout the solvent. Okay, so this is what the definition you have to remember, right? Say if you take a glass of milk, you know milk contain certain amount of water. Normally in a milk you have one of the component as water. Okay. So here the milk solids, the milk protein, whatever the solid component is there in a milk and those particles will uniformly, they randomly disperse. They keep moving all over the solution. See this is one milk solid. It will not stay only in this place. It can go here or it can come here or again it goes here. One single particle continuously randomly, irregularly moves throughout the solution. Okay, so carefully you watch the starch solution or milk solution. Okay, so when you watch it through microscope, usually you cannot see the particles with your naked eye. They are... quite small than our suspension okay but when you see from microscope what you will observe is the solute particles will not stay in their own place they keep moving all over the solution okay so such a type of mixture is called as colloidal solution okay so usually in a colloidal solution we don't use the words like solute and solvent you Solute is the component of a mixture present in a smaller quantity, right? Solvent is the component of mixture present in a larger quantity. But in case of colloid, solute is called with the name dispersion, called with the name dispersion phase. And solvent is called with the name, you know, dispersion medium. Okay, so there are two terms that you have to remember here. Solute is called with the name dispersion phase and solvent is called with the name dispersion medium. Okay, and actually you have different types of colloidal solution. You know what, if you are dispersion phase is solid, if you are solvent that is dispersion medium is liquid. you know such a colloidal solution is called with the name sol okay sol is a type of colloidal solution where dispersion phase that is solute component exist in solid form and solvent component exist in liquid form okay so the best example for sol is milk and you can give another example that is paints Okay, so remember the meaning of the word sol. Sol means dispersion phase is solid and dispersion medium is liquid. Okay, and another type of colloidal solution you have that is emulsion. So, in emulsion dispersion phase is liquid and dispersion medium is also liquid. Okay, so So both are liquids. One liquid mixed with another liquid. But one of the liquids particle is small and they randomly move all over the mixture. Okay. So such a colloidal solution is emulsion. The best example for emulsion is actually milk. Sorry milk is not the example for salt. Milk is example for emulsion. For salt the example is paints. Okay. And even. the fluids or the liquids which are present in cell that is also an example for sol only okay so like this there are many types of colloidal solutions where actually you study about them in a detailed way in higher classes that is in class 11 and 12 okay so as of now i think this much knowledge is enough so remember solute is called with the name dispersion phase solvent is called with the name dispersion medium Okay fine. So now let us try to understand the properties of colloidal solutions. So what are the properties you have? So the first property that I can list is it is heterogeneous solution. It is heterogeneous. solution where solute is continuously moves throughout the solvent. Solute particle will not stay at one place. It continuously moves throughout the solvent randomly every time. Only then you call that solution as colloidal solution. And most importantly, You know, colloidal particles, colloidal particles in the sense the solute particles, the dispersion phase particles, you know, scatter, scatter a beam of light, a beam of light. okay say when you take a glass of milk you can do this experiment even at your home and you take a torch light and you on the torch light you know light rays will you know fall and you know they can actually pass through the milk and they'll come up and this path the path where light is passing through the milk can be visible with your eye when you stand the right angle and look at okay so keep keep a glass keep a glass in front of you on a table and just pass the torch light through the glass of milk and your eye must be right angles to the glass okay the path the path of light is there no to that path your eyes position must be right angles okay only then you can see the light which is passing through the glass of milk. So this is called Tyndall effect. So there is a new word that you have to learn that is Tyndall effect. So what is Tyndall effect? Scattering of light, scattering of light by colloidal particles. by colloidal particles is called Tyndall effect very very important the best example of Tyndall effect I'll tell you see early in the morning the moment you open the window you know sun rays you you can see the sun rays right with your eyes like if you are sitting in right angles to the sun rays that are coming into your room you can see the light actually what's happening there in the atmosphere dust particles or smoke particles would be there. They are actually colloidal particles. They scatter the light. That's the reason you can see that path of light coming into your room. Okay. Say for example, you have a dark room. Okay. And you have a small hole, right? Imagine you are sitting in that dark room and somebody, he's passing a light through a hole so the the light ray that is coming into a room can be visible to your eye right so that is another example for tyndall effect or in the movie theaters you know you are sitting down right your your seatings are down but somewhere on top actually They will focus the light onto a projector, right? So that path of light which is coming from backside, it is moving on top of your heads, right? And it is hitting the screen, right? So when you look up that path of light in that atmosphere, you can see with your naked eye. So that is another example for Tyndall effect. So there are so many live examples for Tyndall effect. In the movie theaters, that path of light that is hitting the projector, right? So that is an example. Actually in that hall, you have a dust particles, so they are actually scattering the light. Tyndall effect is a very very important phenomenon shown by this colloidal particles. Okay. So that's all about the colloidal solution. So we have studied three types of mixtures that is solutions, suspensions and colloidal solutions. Right. Okay. Now let us study about the separation techniques of mixture. So we may have homogeneous mixture, heterogeneous mixture. Heterogeneous mixtures you can separate easily right because particles are very big. Heterogeneous mixture example it is suspension. Particles are very big just by normal filtration you can separate one component from another component. Whereas in homogeneous mixture one component is complete. Completely mixed up with another component where it's a separation is quite difficult. So let us learn different ways of Separating techniques to separate the components of homogeneous mixture So let us start studying the separating techniques of mixtures. So guys listen carefully This is the most important topic of this chapter separating components of mixture Separating components of mixture. So there are actually 8 techniques that we study in a chapter. So in this video I am going to explain you 4 simple techniques and in my next video I will explain you remaining 4 techniques. So separating components of mixture. So as I already told you there are 8 techniques that you have to learn with example. Under that, the first technique is very simple evaporation. So, it is evaporation. So, what do we do in evaporation? Let us understand with one example. So, here the example that they have mentioned in your textbook is separating. separating colored component from blue or black ink. Colored component. Okay. This colored component is actually called as dye from blue or black ink. Okay. So how do we separate? First let us understand what exactly we mean by ink. So when you take ink say for example you are taking an ink in a bowl right. So ink is available in the form of a liquid right. It is available in the form of a liquid. So if I take blue ink right in this particular bound so it is available in the form of liquid this blue ink contains two components one is color okay which color blue color that color is actually solid okay so this particles which are responsible for color is actually solid okay so those colored small small solid particles which are there in a milk in a ink is called dye and the other component is water. Okay, so here water is present in a larger amount guys. So that's why water is called solvent and this color, blue color which is a solid and that can also be called as a dye is actually solute that is present in a smaller amount. Even if it is present in a smaller amount, it can give you that thick blue color for that ink solution okay so now how do i separate this dye that is color from this water path so what we have to take is you know let me explain that in a diagrammatic way say this is what we call bunsen burner which can give you a flame you will observe this in chemistry laboratories if you have labs in your school you can observe this a bunsen burner from which a flame comes and here you should actually keep a beaker of water a beaker of water okay so upon this beaker you should keep a watch glass okay so what is this watch glass so watch glasses some you know plate like structure made up of glass okay so you are taking water in a beaker on that you have to keep the watch glass and then take some amount of ink okay so this is your ink and you start burning it. I mean to say you are not directly heating the ink. Okay. So if you directly heat the ink solution, what will happen? It will get charred. Okay. So you know, you are taking some watch glass and you're keeping it on a beaker containing water and you are actually indirectly heating this ink. Okay. So you are going to heat it up. you are boiling this water, water will boil and that heat will reach the watch glass. And so that way you are actually boiling the ink. So when you boil the ink, what happens is all the water part will evaporate. Water evaporates. After water gets evaporated, the leftover solid is your dye. So this way you separated dye from water. So the leftover blue solid particles you will observe that is what the dye and when you heat whatever the water component is there. everything will go into atmosphere. So this process of separating two components by heating is called as evaporation. So you are separating the two components based on heating. So what is evaporation? Separation of two components by heating. by heating okay so here what actually happens is volatile volatile component evaporates evaporates. Okay, so what do you mean by volatile component? The component that can easily escape to atmosphere by heating. What is volatile component? That can easily escape escape to atmosphere is called volatile component. Water is volatile because on heating actually water very quickly, very easily evaporates. Okay, the component that easily evaporates, I can say that easily evaporates is called as volatile component. Okay, so volatile component evaporates and non-volatile component, non-volatile component is left behind. Is left behind. Okay. So, this is what we call evaporation. So, whatever the dye stuff, solid stuff which is responsible for blue color that is left in a watch glass whereas the water component is completely evaporated to atmosphere. Okay. So, this is how With the help of evaporation technique, you can solve the two components of a mixture very very easily. But one condition you have to remember is among the two components, at least one component must be volatile. That means it must have easy escaping nature to atmosphere. Okay, so here among water and color, which one is volatile? Water is volatile. If this one was not volatile, then you cannot use this evaporation technique for the separation. So this is a very, very important point that you have to keep in mind. If you are using this evaporation technique, you know, one of the component must be volatile, while other one must be volatile. to be non-volatile only then you can use this heating technique to separate one component from another component so this is all about evaporation and now let us learn about centrifugation So guys, our second method centrifugation is very very easy. Centrifugation. Okay, so remember the word centrifugation. So here we study the example separation of cream from milk. So how do we separate cream from milk? Milk. So this you must have observed even at your home. Say for example you want to make a buttermilk. So what do you take? You will take a curd. So you will take a curd in a container and you will nicely churn with this kind of instrument right. So you have a wooden stick and a steel bottom curved bottom at the end and you will nicely churn. the curd so what would happen that nice butter will stay on topmost layer leaving behind the liquid that is buttermilk right so we have observed making buttermilk from curd similarly cream part that fat part from a milk can be separated by churning okay so this churning process is nothing but centrifugation what is centrifugation churning churning process is called centrifugation, okay, so What happens on churning is the denser Component will stay at the bottom and lighter particles will come at the top. Okay. So what is centrifugation on churning on churning Okay, so what happens? Denser particles, denser component will go to bottom and lighter lighter component or lighter particles are collected collected on top okay so when you nicely churn the liquid the component which has got less density will come up and settle leaving behind the particles which have more density so based on the density gradient you are actually separating the two components of mixture that's what we call it as centrifugation so in the centrifugation what we are observing based on density based on density components are getting separated. So this is very very important components are separated. Actually this is the principle of centrifugation I can say. Okay and where do we use this centrifugation? So this is widely used technique in hospitals we use this. Okay hospitals. okay or hospital labs i can say right so when you give your blood samples for testing say half an hour you stay there and observe what they are doing with your blood you know they'll put it in a machine which we call it as centrifuge there is a machine called centrifuge okay so in this machine they will keep that blood and they'll they'll on the switch and it will rotate okay so your blood will you know nicely gets churned i can say and you will observe that there are two layers separated in your blood okay so what they do initially is in a test tube they will take a blood and they'll nicely churn it they'll keep it in a centrifuge and centrifuge is a machine that rotates uh you know rapidly uh fastly and you know at the end after five minutes or ten minutes of centrifuge centrifuge you will see the colorless part of the blood will stay up and the red color solids will stay at the bottom actually they are your blood cells and the topmost colorless liquid is plasma of the blood okay same to separate the two things based on the densities always centrifugation is preferred so this technique is used in hospital labs And second one, as I told you, to separate cream from milk, right? From milk. To make buttermilk, we use this centrifugation technique, right? So, in various other, you know, industries, this centrifugation technique is widely used. Is that clear? And even this technique, you will observe in washing machines too. Washing machines. You must have seen washing machines. You know, they at the end, they spin, right? They continuously spin, right? So, why do they spin? It is to squeeze out water from the cloth, right? So, that spinning technique is a part of centrifugation, right? So, this is our second technique called centrifugation. And now, let us go for separating the two liquids by an instrument called separating funnel. So separation by separating funnel is our third technique. So third method is also very very important guys and here we are actually separating two immiscible liquids. So here you must understand what do you mean by immiscible liquids. Okay so it's very important to understand its meaning. immiscible liquid in the sense one liquid not getting mixed up with another liquid so they have a property of staying separately with each other okay when you combine water with kerosene what would happen water stays separately kerosene likes to stay separately right so that mixture we can call it as immiscible mixture okay so immiscible means what one one Does not gets mixed up with another. Okay. Does not completely gets mixed up with another. So what I can say in normal language is not. Mixed up, not mixed up with each other, with each other. The components not gets mixed up with each other is called immiscible liquids. So, how do we separate immiscible liquids? It is by a special instrument called separating funnel, separating funnel. Okay. So how does a separating funnel looks like? So just observe the shape guys. So this is how a separating funnel looks like. Say it has not come properly. But then something like this it looks. Say you have this shaped funnel where here there is something to get stopped. Okay. Some stopper. And this is a knob. Say now I have a mixture of mixture of. Water plus kerosene. Okay, I need to separate water from kerosene. So I will take water and kerosene mixture inside this separating funnel. So you allow it to stand for some time. What you will observe is water layer will come at the bottom and this is our kerosene layer, right? So this is kerosene. And this is water. They get separated. When you allow it to stand for some time, kerosene layer stays up, water layer stays down. So on what basis water is staying down and kerosene is staying up? It is based on the density. Water is more denser, right? So water stays down. So here we are separating immiscible liquids based on densities of liquids. based on densities only guys okay so water is more denser it has more density it's more heavier right so it is coming at the bottom so now you just on this knob slowly this water comes from this hole and you keep a beaker here you can collect till water level goes down the entire water level you can open this knob the moment kerosene comes to the tip you can stop this knob so kerosene only stays in this instrument water entire water would go down and it gets collected in a separate beaker okay so this is how we can use the separating funnel to separate two immiscible liquids what is the principle involved here Based on the densities. Okay. Two liquids must have different densities. Only then you can use this separating funnel to separate. Right. So very simple and beautiful technique. Right. Separating immiscible liquids with the help of separating funnel. Okay. And now coming to our fourth technique. That is sublimation. sublimation. So how do you separate the mixture using sublimation? Here there is one condition guys in sublimation one of the component any one of the component Must sublime. Okay, it should have sublimation property. What do you mean by sublimation? Sublimation in the sense on heating, on heating solid directly gets converted to vapor. Yes or no? So usually when you heat solid first converts to liquid. Again on further heating that liquid gets converted to vapor but sublimation there are certain components on heating they will directly become vapor. For example camphor or ammonium chloride when you heat it. You know they become vapor directly. Intermediate liquid state will not be found. So such components can be separated using sublimation. Okay. So here let us study the example when you have a mixture of mixture of salt plus ammonium chloride. Ammonium chloride. Okay. So somehow salt and ammonium chloride mixed up. You have to separate salt from ammonium. ammonium chloride. Both look white in color. Both have same sized crystals. Okay. So here salt and ammonium chloride. Ammonium chloride has a property of sublimation. It has got a property of sublimation. That means when you heat ammonium chloride, it quickly becomes vapor. Whereas salt is not having a property of sublimation. So you can use this. So this is the condition. This is the principle for sublimation. You can use the sublimation technique on Only if one of the component can become vapor on heating. Okay, only if one of the... component can sublime only then this technique is used. So how do you separate salt from ammonium chloride? So initially what you have to do is you take a Bunsen burner for heating. So heat will come right. So here what you will do you take a watch glass. So here you take a mixture. So what is there in it? Salt plus ammonium chloride formula NH4Cl. Okay and you you cover this with one funnel okay so you cover this with one funnel you start heating it what happened whatever ammonium chloride is there in this particular mixture everything will become vapor right so those vapors will you know evaporate and to evaporate you know we are not living into atmosphere we want it back. So we are keeping a glass funnel here. So the vapors will go to the walls of the funnel and there it will get condensed to solid. So all your ammonium chloride vapors are actually going going and they are hitting the walls of this glass funnel. There again the vapor is becoming condensed. So what do you mean by condensation? Vapor becomes you know liquid or solid right. So the moment these vapors touches this walls of a glass funnel you know there it gets collected as a solid or it can get collected as a liquid. First it becomes a liquid then there only it becomes a solid and it gets stuck on the walls of funnel. Okay so here whatever left out is a salt. How much ever ammonium chloride that is there in a mixture everything goes into vapor it will touch the walls and there it gets condensed and stays as a white solid. So later you can take it out the funnel whatever the white stuff stuck on the funnel is ammonium chloride and whatever the liquid or solid that is there in this watch glass left out residue is salt. so that's how you can separate the two solids using sublimation keeping in a mind that one of the component must have a property of sublimation otherwise you cannot use this method okay so using this method we can also separate cancer And we can also separate naphthalene, you know, camphor. If you want to purify camphor or if you want to purify naphthalene, right? You can always use this sublimation method. This has a property of sublimation. This also has a property of sublimation. So if any impurities are there in camphor, you can always go for this method to purify, right? So this is our fourth method sublimation. So we have covered four simple methods in this video. And in my next video, I will cover remaining four methods of separating components of a mixture. Along with that, we will finish the chapter by discussing the importance of element compound, their meanings, physical change, chemical change, etc. Okay. So I am. going to complete this chapter by next video. So keep watching, keep revising and keep learning. Share the videos with your friends also and do subscribe our channel to learn the concepts in a easiest way. Thank you so much.

We observe carefully if you have a beaker of water. So this is a beaker. of water and I will add a spoon of sand right.

So when I add sand to this water how will the solution look? Here and there you will find the big particles right and after some time when you keep this particular solution without shaking without shaking when you keep this solution without shaking it will start to melt. After 5 minutes or 10 minutes, you will find your sand particles being settled at the bottom. Isn't it? So when you drop a sand and nicely mix it, you know, the big big particles will stay all over the water.

But after 10 minutes, when you keep it as such without shaking, all your sand particles will come at the bottom and settle. You know, this particular solution is called as suspension, right? So sand in water is a suspension. So now how do you define a suspension?

Is it a homogeneous or heterogeneous mixture? Definitely heterogeneous. We understood the meanings of these words in my previous video, right?

So what do you mean by heterogeneous? Heterogeneous. is the one where one component do not gets mixed up with another component. Sand is one component, water is another component or I can say substance.

Sand is one substance, water is another substance, sand will not get mixed up with water, right? So, such a solution is called, you know, suspension. So, how will I write a definition here? Heterogeneous mixture, heterogeneous mixture, it's a kind of mixture, what type? Heterogeneous mixture where solute do not gets, do not gets mixed up, mixed up with solvent.

Okay, clear. And here, you know what, if I have to talk about properties of suspensions, properties of suspensions. So the first point you can mention is it is heterogeneous mixture.

Okay, second point is solute particles can be seen with your naked eye. What do you mean by solute? The component which is present in a smaller amount. See, I just added one spoon to a large amount of water.

So the substance which is there in a smaller quantity is called solute. And the substance which I took it in a large amount is called solvent. So here what I am telling you is solute particles can be seen with the naked eye. So what will I write?

Solute can be seen with naked eye. You can see when you put a sand in water definitely you can see sand particles with your eye right and you know what separation of solute and solvent is easy. Separation of solute from solvent. from solvent is easy. So, you can easily separate the sand from water, right?

Okay. So, the second one, I mean, the next point that we have to write is Since the size of solute is bigger, so size, size of solute is bigger. Since the size is bigger, you know, it will scatter the light. It will scatter the light. It means spreading of light is called scattering.

Okay. So, these solute particles can spread the light to a surrounding region. Right? So that is the reason path of light, path of light through suspension, through suspension is visible.

is visible. So what do you mean by this point? For example, you take a glass of suspension. So you have a suspension and you are passing light.

So this is light that you are giving from top. okay so when you stand you know here is a glass you are passing a light and when you stand here and watch the path of light is visible inside a suspension how light goes you know can be seen with your eyes okay so it is because the particles of suspension is spreading the light since it is spreading the light you know the path how it travels inside a solution can be seen with your eyes okay so that is what the meaning of this last point right and another property is particles will settle at the bottom if you do not disturb the suspension right so this is all about the suspension that we have learned and now you Let us try to learn about colloidal solution. Okay.

So the third type of solution is colloidal solution. So what do you mean by a colloidal solution here? For example, first let me give an example for colloidal solution that is milk. Okay, say can you see a particles of milk with your naked eyes? Is milk transparent?

If it is a transparent liquid, you call it as a solution, right? So here the solute particles are very very small and they will completely gets mixed up, right? Whereas here solute particles are not very small like you know solution.

and the solute particles are not very big like suspension. Okay. Say I can differentiate the three solutions here.

Say in solution, the solute particles are very, very small. Okay. Whereas in case of colloidal solution, colloidal solution, the solute particles are quite big.

Okay. Whereas in case of suspension, the solute particles are very big. Okay. So this difference you have to understand between solution, suspension and colloidal solution.

In case of solution, you see solute particle, the component which is there in a smaller amount, the particle size is very, very small. Colloidal solution, much big. Suspension much much big.

So what do you call colloidal solution as? It is also heterogeneous solution. Where the solute is dispersed in solvent.

So what is the definition I can write here? It is also heterogeneous. Heterogeneous mixture where solute. Solute particles. Particles are dispersed throughout the solvent.

Okay, so this is what the definition you have to remember, right? Say if you take a glass of milk, you know milk contain certain amount of water. Normally in a milk you have one of the component as water. Okay. So here the milk solids, the milk protein, whatever the solid component is there in a milk and those particles will uniformly, they randomly disperse.

They keep moving all over the solution. See this is one milk solid. It will not stay only in this place. It can go here or it can come here or again it goes here.

One single particle continuously randomly, irregularly moves throughout the solution. Okay, so carefully you watch the starch solution or milk solution. Okay, so when you watch it through microscope, usually you cannot see the particles with your naked eye.

They are... quite small than our suspension okay but when you see from microscope what you will observe is the solute particles will not stay in their own place they keep moving all over the solution okay so such a type of mixture is called as colloidal solution okay so usually in a colloidal solution we don't use the words like solute and solvent you Solute is the component of a mixture present in a smaller quantity, right? Solvent is the component of mixture present in a larger quantity. But in case of colloid, solute is called with the name dispersion, called with the name dispersion phase.

And solvent is called with the name, you know, dispersion medium. Okay, so there are two terms that you have to remember here. Solute is called with the name dispersion phase and solvent is called with the name dispersion medium. Okay, and actually you have different types of colloidal solution. You know what, if you are dispersion phase is solid, if you are solvent that is dispersion medium is liquid.

you know such a colloidal solution is called with the name sol okay sol is a type of colloidal solution where dispersion phase that is solute component exist in solid form and solvent component exist in liquid form okay so the best example for sol is milk and you can give another example that is paints Okay, so remember the meaning of the word sol. Sol means dispersion phase is solid and dispersion medium is liquid. Okay, and another type of colloidal solution you have that is emulsion. So, in emulsion dispersion phase is liquid and dispersion medium is also liquid.

Okay, so So both are liquids. One liquid mixed with another liquid. But one of the liquids particle is small and they randomly move all over the mixture.

Okay. So such a colloidal solution is emulsion. The best example for emulsion is actually milk.

Sorry milk is not the example for salt. Milk is example for emulsion. For salt the example is paints.

Okay. And even. the fluids or the liquids which are present in cell that is also an example for sol only okay so like this there are many types of colloidal solutions where actually you study about them in a detailed way in higher classes that is in class 11 and 12 okay so as of now i think this much knowledge is enough so remember solute is called with the name dispersion phase solvent is called with the name dispersion medium Okay fine.

So now let us try to understand the properties of colloidal solutions. So what are the properties you have? So the first property that I can list is it is heterogeneous solution. It is heterogeneous. solution where solute is continuously moves throughout the solvent.

Solute particle will not stay at one place. It continuously moves throughout the solvent randomly every time. Only then you call that solution as colloidal solution.

And most importantly, You know, colloidal particles, colloidal particles in the sense the solute particles, the dispersion phase particles, you know, scatter, scatter a beam of light, a beam of light. okay say when you take a glass of milk you can do this experiment even at your home and you take a torch light and you on the torch light you know light rays will you know fall and you know they can actually pass through the milk and they'll come up and this path the path where light is passing through the milk can be visible with your eye when you stand the right angle and look at okay so keep keep a glass keep a glass in front of you on a table and just pass the torch light through the glass of milk and your eye must be right angles to the glass okay the path the path of light is there no to that path your eyes position must be right angles okay only then you can see the light which is passing through the glass of milk. So this is called Tyndall effect. So there is a new word that you have to learn that is Tyndall effect. So what is Tyndall effect?

Scattering of light, scattering of light by colloidal particles. by colloidal particles is called Tyndall effect very very important the best example of Tyndall effect I'll tell you see early in the morning the moment you open the window you know sun rays you you can see the sun rays right with your eyes like if you are sitting in right angles to the sun rays that are coming into your room you can see the light actually what's happening there in the atmosphere dust particles or smoke particles would be there. They are actually colloidal particles.

They scatter the light. That's the reason you can see that path of light coming into your room. Okay. Say for example, you have a dark room. Okay.

And you have a small hole, right? Imagine you are sitting in that dark room and somebody, he's passing a light through a hole so the the light ray that is coming into a room can be visible to your eye right so that is another example for tyndall effect or in the movie theaters you know you are sitting down right your your seatings are down but somewhere on top actually They will focus the light onto a projector, right? So that path of light which is coming from backside, it is moving on top of your heads, right?

And it is hitting the screen, right? So when you look up that path of light in that atmosphere, you can see with your naked eye. So that is another example for Tyndall effect.

So there are so many live examples for Tyndall effect. In the movie theaters, that path of light that is hitting the projector, right? So that is an example. Actually in that hall, you have a dust particles, so they are actually scattering the light.

Tyndall effect is a very very important phenomenon shown by this colloidal particles. Okay. So that's all about the colloidal solution. So we have studied three types of mixtures that is solutions, suspensions and colloidal solutions. Right.

Okay. Now let us study about the separation techniques of mixture. So we may have homogeneous mixture, heterogeneous mixture.

Heterogeneous mixtures you can separate easily right because particles are very big. Heterogeneous mixture example it is suspension. Particles are very big just by normal filtration you can separate one component from another component. Whereas in homogeneous mixture one component is complete. Completely mixed up with another component where it's a separation is quite difficult.

So let us learn different ways of Separating techniques to separate the components of homogeneous mixture So let us start studying the separating techniques of mixtures. So guys listen carefully This is the most important topic of this chapter separating components of mixture Separating components of mixture. So there are actually 8 techniques that we study in a chapter. So in this video I am going to explain you 4 simple techniques and in my next video I will explain you remaining 4 techniques. So separating components of mixture.

So as I already told you there are 8 techniques that you have to learn with example. Under that, the first technique is very simple evaporation. So, it is evaporation. So, what do we do in evaporation? Let us understand with one example.

So, here the example that they have mentioned in your textbook is separating. separating colored component from blue or black ink. Colored component.

Okay. This colored component is actually called as dye from blue or black ink. Okay.

So how do we separate? First let us understand what exactly we mean by ink. So when you take ink say for example you are taking an ink in a bowl right. So ink is available in the form of a liquid right. It is available in the form of a liquid.

So if I take blue ink right in this particular bound so it is available in the form of liquid this blue ink contains two components one is color okay which color blue color that color is actually solid okay so this particles which are responsible for color is actually solid okay so those colored small small solid particles which are there in a milk in a ink is called dye and the other component is water. Okay, so here water is present in a larger amount guys. So that's why water is called solvent and this color, blue color which is a solid and that can also be called as a dye is actually solute that is present in a smaller amount. Even if it is present in a smaller amount, it can give you that thick blue color for that ink solution okay so now how do i separate this dye that is color from this water path so what we have to take is you know let me explain that in a diagrammatic way say this is what we call bunsen burner which can give you a flame you will observe this in chemistry laboratories if you have labs in your school you can observe this a bunsen burner from which a flame comes and here you should actually keep a beaker of water a beaker of water okay so upon this beaker you should keep a watch glass okay so what is this watch glass so watch glasses some you know plate like structure made up of glass okay so you are taking water in a beaker on that you have to keep the watch glass and then take some amount of ink okay so this is your ink and you start burning it.

I mean to say you are not directly heating the ink. Okay. So if you directly heat the ink solution, what will happen?

It will get charred. Okay. So you know, you are taking some watch glass and you're keeping it on a beaker containing water and you are actually indirectly heating this ink. Okay. So you are going to heat it up.

you are boiling this water, water will boil and that heat will reach the watch glass. And so that way you are actually boiling the ink. So when you boil the ink, what happens is all the water part will evaporate.

Water evaporates. After water gets evaporated, the leftover solid is your dye. So this way you separated dye from water.

So the leftover blue solid particles you will observe that is what the dye and when you heat whatever the water component is there. everything will go into atmosphere. So this process of separating two components by heating is called as evaporation. So you are separating the two components based on heating.

So what is evaporation? Separation of two components by heating. by heating okay so here what actually happens is volatile volatile component evaporates evaporates.

Okay, so what do you mean by volatile component? The component that can easily escape to atmosphere by heating. What is volatile component? That can easily escape escape to atmosphere is called volatile component. Water is volatile because on heating actually water very quickly, very easily evaporates.

Okay, the component that easily evaporates, I can say that easily evaporates is called as volatile component. Okay, so volatile component evaporates and non-volatile component, non-volatile component is left behind. Is left behind. Okay. So, this is what we call evaporation.

So, whatever the dye stuff, solid stuff which is responsible for blue color that is left in a watch glass whereas the water component is completely evaporated to atmosphere. Okay. So, this is how With the help of evaporation technique, you can solve the two components of a mixture very very easily.

But one condition you have to remember is among the two components, at least one component must be volatile. That means it must have easy escaping nature to atmosphere. Okay, so here among water and color, which one is volatile? Water is volatile.

If this one was not volatile, then you cannot use this evaporation technique for the separation. So this is a very, very important point that you have to keep in mind. If you are using this evaporation technique, you know, one of the component must be volatile, while other one must be volatile.

to be non-volatile only then you can use this heating technique to separate one component from another component so this is all about evaporation and now let us learn about centrifugation So guys, our second method centrifugation is very very easy. Centrifugation. Okay, so remember the word centrifugation.

So here we study the example separation of cream from milk. So how do we separate cream from milk? Milk. So this you must have observed even at your home.

Say for example you want to make a buttermilk. So what do you take? You will take a curd.

So you will take a curd in a container and you will nicely churn with this kind of instrument right. So you have a wooden stick and a steel bottom curved bottom at the end and you will nicely churn. the curd so what would happen that nice butter will stay on topmost layer leaving behind the liquid that is buttermilk right so we have observed making buttermilk from curd similarly cream part that fat part from a milk can be separated by churning okay so this churning process is nothing but centrifugation what is centrifugation churning churning process is called centrifugation, okay, so What happens on churning is the denser Component will stay at the bottom and lighter particles will come at the top. Okay.

So what is centrifugation on churning on churning Okay, so what happens? Denser particles, denser component will go to bottom and lighter lighter component or lighter particles are collected collected on top okay so when you nicely churn the liquid the component which has got less density will come up and settle leaving behind the particles which have more density so based on the density gradient you are actually separating the two components of mixture that's what we call it as centrifugation so in the centrifugation what we are observing based on density based on density components are getting separated. So this is very very important components are separated.

Actually this is the principle of centrifugation I can say. Okay and where do we use this centrifugation? So this is widely used technique in hospitals we use this. Okay hospitals. okay or hospital labs i can say right so when you give your blood samples for testing say half an hour you stay there and observe what they are doing with your blood you know they'll put it in a machine which we call it as centrifuge there is a machine called centrifuge okay so in this machine they will keep that blood and they'll they'll on the switch and it will rotate okay so your blood will you know nicely gets churned i can say and you will observe that there are two layers separated in your blood okay so what they do initially is in a test tube they will take a blood and they'll nicely churn it they'll keep it in a centrifuge and centrifuge is a machine that rotates uh you know rapidly uh fastly and you know at the end after five minutes or ten minutes of centrifuge centrifuge you will see the colorless part of the blood will stay up and the red color solids will stay at the bottom actually they are your blood cells and the topmost colorless liquid is plasma of the blood okay same to separate the two things based on the densities always centrifugation is preferred so this technique is used in hospital labs And second one, as I told you, to separate cream from milk, right?

From milk. To make buttermilk, we use this centrifugation technique, right? So, in various other, you know, industries, this centrifugation technique is widely used. Is that clear? And even this technique, you will observe in washing machines too.

Washing machines. You must have seen washing machines. You know, they at the end, they spin, right? They continuously spin, right?

So, why do they spin? It is to squeeze out water from the cloth, right? So, that spinning technique is a part of centrifugation, right? So, this is our second technique called centrifugation. And now, let us go for separating the two liquids by an instrument called separating funnel.

So separation by separating funnel is our third technique. So third method is also very very important guys and here we are actually separating two immiscible liquids. So here you must understand what do you mean by immiscible liquids.

Okay so it's very important to understand its meaning. immiscible liquid in the sense one liquid not getting mixed up with another liquid so they have a property of staying separately with each other okay when you combine water with kerosene what would happen water stays separately kerosene likes to stay separately right so that mixture we can call it as immiscible mixture okay so immiscible means what one one Does not gets mixed up with another. Okay. Does not completely gets mixed up with another. So what I can say in normal language is not.

Mixed up, not mixed up with each other, with each other. The components not gets mixed up with each other is called immiscible liquids. So, how do we separate immiscible liquids?

It is by a special instrument called separating funnel, separating funnel. Okay. So how does a separating funnel looks like?

So just observe the shape guys. So this is how a separating funnel looks like. Say it has not come properly. But then something like this it looks. Say you have this shaped funnel where here there is something to get stopped.

Okay. Some stopper. And this is a knob.

Say now I have a mixture of mixture of. Water plus kerosene. Okay, I need to separate water from kerosene.

So I will take water and kerosene mixture inside this separating funnel. So you allow it to stand for some time. What you will observe is water layer will come at the bottom and this is our kerosene layer, right? So this is kerosene. And this is water.

They get separated. When you allow it to stand for some time, kerosene layer stays up, water layer stays down. So on what basis water is staying down and kerosene is staying up? It is based on the density.

Water is more denser, right? So water stays down. So here we are separating immiscible liquids based on densities of liquids.

based on densities only guys okay so water is more denser it has more density it's more heavier right so it is coming at the bottom so now you just on this knob slowly this water comes from this hole and you keep a beaker here you can collect till water level goes down the entire water level you can open this knob the moment kerosene comes to the tip you can stop this knob so kerosene only stays in this instrument water entire water would go down and it gets collected in a separate beaker okay so this is how we can use the separating funnel to separate two immiscible liquids what is the principle involved here Based on the densities. Okay. Two liquids must have different densities. Only then you can use this separating funnel to separate.

Right. So very simple and beautiful technique. Right. Separating immiscible liquids with the help of separating funnel.

Okay. And now coming to our fourth technique. That is sublimation.

sublimation. So how do you separate the mixture using sublimation? Here there is one condition guys in sublimation one of the component any one of the component Must sublime. Okay, it should have sublimation property. What do you mean by sublimation?

Sublimation in the sense on heating, on heating solid directly gets converted to vapor. Yes or no? So usually when you heat solid first converts to liquid.

Again on further heating that liquid gets converted to vapor but sublimation there are certain components on heating they will directly become vapor. For example camphor or ammonium chloride when you heat it. You know they become vapor directly. Intermediate liquid state will not be found. So such components can be separated using sublimation.

Okay. So here let us study the example when you have a mixture of mixture of salt plus ammonium chloride. Ammonium chloride. Okay.

So somehow salt and ammonium chloride mixed up. You have to separate salt from ammonium. ammonium chloride. Both look white in color. Both have same sized crystals.

Okay. So here salt and ammonium chloride. Ammonium chloride has a property of sublimation.

It has got a property of sublimation. That means when you heat ammonium chloride, it quickly becomes vapor. Whereas salt is not having a property of sublimation. So you can use this. So this is the condition.

This is the principle for sublimation. You can use the sublimation technique on Only if one of the component can become vapor on heating. Okay, only if one of the... component can sublime only then this technique is used.

So how do you separate salt from ammonium chloride? So initially what you have to do is you take a Bunsen burner for heating. So heat will come right. So here what you will do you take a watch glass.

So here you take a mixture. So what is there in it? Salt plus ammonium chloride formula NH4Cl. Okay and you you cover this with one funnel okay so you cover this with one funnel you start heating it what happened whatever ammonium chloride is there in this particular mixture everything will become vapor right so those vapors will you know evaporate and to evaporate you know we are not living into atmosphere we want it back. So we are keeping a glass funnel here.

So the vapors will go to the walls of the funnel and there it will get condensed to solid. So all your ammonium chloride vapors are actually going going and they are hitting the walls of this glass funnel. There again the vapor is becoming condensed.

So what do you mean by condensation? Vapor becomes you know liquid or solid right. So the moment these vapors touches this walls of a glass funnel you know there it gets collected as a solid or it can get collected as a liquid. First it becomes a liquid then there only it becomes a solid and it gets stuck on the walls of funnel.

Okay so here whatever left out is a salt. How much ever ammonium chloride that is there in a mixture everything goes into vapor it will touch the walls and there it gets condensed and stays as a white solid. So later you can take it out the funnel whatever the white stuff stuck on the funnel is ammonium chloride and whatever the liquid or solid that is there in this watch glass left out residue is salt. so that's how you can separate the two solids using sublimation keeping in a mind that one of the component must have a property of sublimation otherwise you cannot use this method okay so using this method we can also separate cancer And we can also separate naphthalene, you know, camphor. If you want to purify camphor or if you want to purify naphthalene, right?

You can always use this sublimation method. This has a property of sublimation. This also has a property of sublimation. So if any impurities are there in camphor, you can always go for this method to purify, right? So this is our fourth method sublimation.

So we have covered four simple methods in this video. And in my next video, I will cover remaining four methods of separating components of a mixture. Along with that, we will finish the chapter by discussing the importance of element compound, their meanings, physical change, chemical change, etc.

Okay. So I am. going to complete this chapter by next video.

So keep watching, keep revising and keep learning. Share the videos with your friends also and do subscribe our channel to learn the concepts in a easiest way. Thank you so much.

Transcript for:Understanding Pure Matter and Mixtures

Transcript for:
Understanding Pure Matter and Mixtures