Matter in Our Surroundings Class 9 Science (Chemistry) One Shot Concepts+MCQs | CBSE Class 9 Midterm

[Music] [Music] hey everyone a very warm welcome to this class in ithaca hey prasad prachi saloni good evening all of you hey dilip hello again yes oh you attended the timetable session good to know that hobbies and crafts what's your name bacha hey good evening all of you so yes we want all of you to pass the exam with flying colors and that's why we have a mission that is mission mid terms so why are we having this session why why is this session one shot being placed here for all of you see it's not the quantity that matters it's the quality so what we've done is we've sorted everything for you all the important topics from this chapter in next 30 to 40 minutes you will be able to revise learn and practice practice why i'm saying is because you know i'll keep telling you the important questions in between yes absolutely guys so you will understand all the topics in this one session everything that's important from the exam point of view it's going to be here right now in this session in next you know say about 40 minutes you will be able to master this chapter and these are the topics that you just cannot miss from the exam point of view and that makes it very important session after a long time yes so a lot of you were asking maternal surroundings one shot cup hoga so there you go and here we are hey kia i'm doing really well thank you [Music] hey shavanch salman amir yes yes simpu yadav all right father father say give me a green signal that everything is working fine so that we get started you know the drill you know audio check video check ppd check smiley face i got a dick right clearly so give me loads of thumbs up growth of smileys i am doing really well i hope you all are doing extremely well and you people are all set for your exams yes so guys be very attentive because you know every topic that is going to be there that is very important from the exam point of view i'm repeatedly i'm you know restating the same thing so that you understand that this is something that needs to be reinforced in my second topic exam kelly we will not leave any single topic from this list of topics that i'm about to discuss with all of you yes simon thank you hey mona lisa hey nav need all right i can see you have given me loads of green signals so let's get started but before we dive straight into the session i hope all of you registered for anthony we have this opportunity for all of you but it's up to you to grab it right you know it that it's going to be very beneficial i am sure you must have heard from your seniors or your friends there is something that is you know there's something very good that's coming out of this and if you're actually aspiring to be a doctor or engineer you know what to do the link is there in the description box quickly go ahead register yourself and we will be supporting you at every step you're here to nurture your talent but first step today so go ahead and not just you know going to nasa a trip to nasa that's 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every important topic from this chapter right now let's do it together guys so four different topics you know four different types of topics i would say we have divided this chapter into char important topics the first very important topic is what is matter yes but a syllabus for anthony you have to go back and watch the video it's already there on the channel good evening good evening akshay now the first thing is to know about matter now further you need to know about definition of matter classification and characteristics we'll start with the definition that you people will tell me quickly what is matter we have to revise everything quickly right so that means your people have to be very attentive very interactive that matter has mass and volume so yes matter has mass it occupies space and it can be perceived by our senses now whatever say tell me look around and tell me anything around you that you can consider as matter so this will understand whether you've understood what matter is or not anything that's around you that's matter tv bed table biscuits books and this will get to know what's around you mobile air pencil box tab pen biscuits a lot of you are having biscuits table cheer yes all these things are matter somebody was saying everything around us is matter if everything is matter then what's not matter quick example in the chat box tell me what is not matter we know what matter is now you'll tell me what cannot be considered as matter emotions feeling sound are they water to matter yeah water cubicle thoughts anger sadness yes correct love hate correct correct correct all of you time thoughts feelings all these things are not matter so well done we know what is smart and we know what is not matter so if this question comes in the exam you know that one mark is in our pocket now the next important thing is classification now the classification can be given in terms of early classification and modern classification early classification [Music] you will tell me and then of course i'll reveal the answer according to indian philosophers matter is kind of made up of some basic elements rsv has been fire water earth wind acha five elements punya says agni is one of them namit says fire air water sky you're seeing five elements but you're stating four fire water earth wind sky still waiting still waiting for the correct answer fire water earth sky all right all right let me tell you the punch that were five elements that are there it's water sky earth fire air now i told you one easy way to remember i said you just have to remember this you have to remember that water that starts with w keeps us safe and this is actually easy way to remember all the five elements w for water s for sky a for air f for fire and e for earth must you will remember all the elements this is the early classification moving on to the next one modern classification now mata can be classified by physical nature of matter and the chemical nature of matter physical nature we will be discussing today solid liquid gases right chemical nature we would be doing in this grade itself but maybe a little later absolutely so physical nature currently discuss um and let's get started with this one physical nature of matter so what's the first thing that comes to your mind when i say the physical nature of matter so yes when we talk about matter it's made up of particles and these particles are tiny in nature now guys pay attention i want all of you to go through activity 1.1 and 1.2 that's given in your book because this is something that can be asked in your exam to understand the particulate nature of matter and to understand the fact that you know particles of matter are really small so for these two there are activities in your book so i'll keep telling you what you need to refer so activity one point one one point two hum definitely they thinking particularly and the fact that particles of matter are really tiny they are very small so this tells us about the physical nature of matter so there you go you know about the classification early b and modern as well next very very important thing is characteristics you will quickly tell me any one characteristic of matter that you remember akshay first one before i could finish my question they attract each other acha they are constantly moving punya says yes nav neet definitely it has volume they butcher that won't be a characteristic that is what matter is right they are very small yes space is correct so particles of matter have spaces between them they are constantly moving and they attract each other again what is important is the activities in the exam they can ask you a question based on this topic that is with the help of an activity explain the characteristics of matter they might give you one characteristic and ask you to support your answer with an activity in any case you need to know some examples for each say for example the first one particles of matter have space between them simple activity we have we take sugar we add it to water and we realize that the level of water is not going up that means there were spaces between the particles of water and in between those spaces particles of sugar have you know taken that place particles of the matter constantly moving just spray a perfume spray your deodorant and you'll be able to you know smell it from afar as well or maybe the kitchen food that we smell that is again because the particles are constantly moving particles of matter attract each other so if there's a stream of water and you try to cut it you can't really cut it you in a way redirect it why because the particles attract each other now these are very three very you know basic activities basic examples that i've told you but you can go ahead and you know mention so many others yes nominee that's a very important question that would be taken up in one of our sessions don't worry about this we would be discussing all the important exemplar questions bill cool cooling effect discussion absolutely guys now this another very important topic in the chapter that is diffusion this is super important quickly tell me what is diffusion you have heard about this term intermixing of particles okay yes into mixing of particles on their own is known as diffusion a lot of questions based on diffusion can be asked for example they can ask you you know how are aquatic organisms able to survive under water you know that the gases diffuse in water that's how they're able to survive or maybe you know they can ask you why is the rate of diffusion of liquids more or higher as compared to solids again you can in a way you know mention the answer based on the spaces yes a lot of diffusion questions could be asked hey do you think diffusion and temperature are kind of you know they are connected in some way yes correct a quick yesterday in the comment section i let's observe an activity some interesting activity over here so let's see the effect of temperature on diffusion if there is an effect or not so for this we have a glass which is filled with water and when we add food color to this you will see beautiful patterns are being formed can you see it's looking so wonderful but it's diffusion faster and hotter cold water let's figure out and for that we have some candies okay we've placed the candies in two plates in the first one we've added hot water and the second one we've added cold water and now the race begins the race to you know move towards the center of the plate have a look what's happening in case of hot water diffusion is definitely faster right why is this happening because of course hot water has more energy so they're moving faster now faster their speed higher would be the rate of diffusion so there you go hot water is winning the race of diffusion normal water so where would normal water be all right so what is happening is hot water rate of diffusion would be the fastest then normal water and then cold water yes harry potter it does to a very less extent yes diffusion in solids is very difficult it's very rare but in case they ask you this question you will say yes absolutely right so you could easily see that you know as temperature increases in a kinetic energy of the particles they would increase and rate of diffusion would also increase any question based on this i hope all of you will be able to answer yes great all right now talking about the force we know solids we know liquids we know gases now the force of attraction in case of solids you would notice that it's the maximum it's you know in a way more as compared to liquids in liquid it's more as compared to gases and the order of inter particle space is just the opposite it's just the reverse in space like if you talk in terms of space inter particle spaces are maximum in case of gases and it's decreasing as you go from gases to liquids to solids see obviously if the force of attraction is more in case of solids it would be very near the inter particle space would be very less lowest attractive force yes absolutely right guys all right so if you know everything about matter you know whatever your textbook says whatever is important from the exam point of view you know about the definition you know what's matter what's not matter characteristics classification so this is something that you need to know about matter moving on to the next very important topic or sub topic i would say is the states of matter yes akshay sponge is very soft because see in case of sponge you've got those air pores pores are there that have been filled with air now when you compress it it's the air that comes out yes now coming to the states so we've got solids gases we've got liquids and these are the states of matter that we have they're very much interchangeable also now let's discuss the properties a lot of questions based on the properties could be asked when you see something like this it's generally applicable okay this is generally true exceptions are there but generally solids they have definite shape liquids no fixed shape gases no fixed shape so just the solids have fixed shape coming to volume now solids and liquids they have fixed volume but gases they have no fixed volume coming to compressibility now gases are highly compressible can you tell me one advantage of gases being highly compressible yes akshay five states are there cng mona lisa says cng punima says gases can be filled easily stored lpg oxygen yes we've got lpg cylinders cng cylinders oxygen cylinders because of compressibility of gases they could be stored easily they could be transported in large volumes so correct if they ask you about the advantages of gases being compressible you know it all and coming to rigidity well solids are rigid see it's the property due to which particles kind of remain fixed in their position but that's not the case of liquid or gas so if i spill a liquid it's going to flow it's a fluid and gas gases they keep flowing right so they're also fluids but agar pin phone wherever you've kept your phone this is going to stay there it's not going to move here and there that's not the case with water or say oxygen for that matter yes see exceptions are there that's why i said generally all right so clearly if they ask you about packing you can have a look over here when we talk about solids in solids particles are closely packed in case of liquids you will notice that they are loosely packed and in case of gases they are very loosely packed so yes based on that a lot of properties can actually be decided for matter [Music] so you need to know about all these states of matter the three states in detail with their properties after that the next very important thing in this chapter is can matter change its states let's see let's take your vote what do you think can matter change its state yes i don't know all of you are saying yes definitely they can and we can change the physical state of matter by changing temperature and pressure how let's see let's quickly recall all the processes in one go now say suppose you have any solid substance now when you heat it it can be converted to liquid and this process of converting solids into liquids it's called melting or fusion important terms are coming up guys both important now liquids can also be converted back to solids on cooling and this process is known as solidification or it can also be known as freezing so melting fusion is the same solidification freezing it's the same vaporization solidification yes correct yes freezing is also right all right now something that is i think a very common mistake that you people sometimes do melting point so i'll write two terms over here melting and melting point so one term is melting point one term is melting but you're melting johanna that's a process and melting point jo that's a temperature a lot of you get confused when you know if there's a one marker about the definition of melting point you say it's a process melting process here melting point temperature if you write processor you lose marks so understand this thing boiling process a boiling point a temperature okay so melting point which is a temperature it's the minimum temperature at which solid melts to become a liquid at atmospheric pressure that is what is melting point atmospheric pressure we always force per unit area right that is exerted by atmosphere yes melting point see that's why we say melting point of ice is zero degrees celsius melting point zero degree celsius so that's a temperature right that's not a process melting is a process now this melting point actually it indicates the strength of force of attraction so this you have to remember melting point boiling point they actually indicate the strength of force of attraction as well difference between boiling and evaporation butcher will come to this don't worry another very important term in this chapter is the latent heat of fusion latent basically hidden heat right it's the heat energy that's required to change one kg of solid into liquid fusion liquid yoga and the amount that we're taking is 1 kg heat energy required to change 1 kg of solid into liquid add atmospheric pressure at its melting point now you'll notice that you know when something is melting at certain point of time the temperature remains constant even though constant heat is being provided same happens you know when something is being boiled as well there this latent heat plays road because all the heat that we are supplying it gets used up in changing the state of the substance yes ash i can read your comment yes we come to latent heat of vaporization don't worry yes yes without coming to the liquid state we'll come to that worry about that all right now i saw somebody was writing about vaporization as well bill cool critical temperature eventually don't worry about that all right nikhil but now liquid to gas what is this process called what efforts in the comment section what is this process called sublimation think again vaporization liquid to gas okay vaporization vaporization vaporization vaporization all right yes this is called vaporization so liquid when it's you know it's being heated it converts to vapor that is vaporization or gas so gas can always be converted back to liquid on cooling which is known as condensation so similarly we have another very important point that is boiling point you all know boiling point is a temperature and you know boiling is a process so boiling point actually it's a temperature at which liquid starts boiling at atmospheric pressure again this is also an indication of the strength of force of attraction so suppose they give you two substances with two different boiling points now the one which has higher boiling point that means that the force of attraction would be more in that case so a lot of application based questions can be asked out of this vaporization they could either be it could actually mean that either we're talking about boiling or we're talking about evaporation yes saloni when you talk about vaporization it could be boiling also it could be evaporation also all right so for water it is 100 degrees celsius or 373.15 kelvin that's the boiling point next latent heat of vaporization now late need a vaporization just like fusion we all know it's the heat energy required to change 1 kg of a liquid into gas at atmospheric pressure at its boiling point so suppose i say latent heat of vaporization of water is two to six kilojoules per kilogram what do you mean this what do you think this means let's see what quickly guys evaporation liquid latent heat of vaporization of water is 226 kilojoules per kilogram that means how much amount of energy is being absorbed it's 226 kilojoules of heat that is being absorbed to actually you know convert one kilogram of water to water vapor of course at atmospheric pressure at its boiling point so mark this question important this can definitely be asked as a one marker they might give you the latent heat of vaporization value of any substance or latent heat or fusion value of any substance just mention that that's the amount of energy that's required to convert one kilogram of that substance correct yes all right yes now a lot of people think solids i think ours was asking so let's directly guess i want all of you to answer to this question like provide us the answer what do you think is it possible so let's say directly gas without coming in the intermediate liquid state yes practices yes sublimation correct yes see solid to directly vapor or gas on heating is known as sublimation the reverse is also present so in a way we can you know cool the vapors and get back the solid which is known as deposition now in your book only sublimation is mentioned but to be very precise when from vapors or gases we go back to solid that is actually known as deposition yes dry eyes yes that's the correct example in fact you can also mention naphthalene you can mention iodine you can mention ammonium chloride anthracene a lot of substances are there yes don't worry about this yes you're welcome ashad all right now guys i want all of you to pay attention right now because i'm going to ask you something very important i'll put a star mark here something very important that i'm going to ask you now this is something that is definitely going to come in your exam what is the physical state of say water at different temperatures now for water you know the freezing point is 0 degree celsius and the boiling point is 100 degree celsius this is the freezing point this is the boiling point now below the freezing point of any substance maybe water may be anything it will always be in the solid state in between the freezing and boiling point it will be in the liquid state beyond the boiling point it will be in the vapor state we all know that but what about at the freezing point at the melting point or at the boiling point at that point of time two states coexist so at the freezing or melting point of a substance you will have solid or liquid state and at the boiling point you will have liquid and gaseous state coexisting based on this i want all of you to tell me i'll remove everything and i'll write your answer at 100 degree celsius water exists in both gaseous and liquid state have you understood why this statement has been placed over you yes yes dry ice is also known as solid carbon dioxide true good all of you now i'll quickly tell you some temperatures and you will tell me um the physical state of water at that temperature okay minus 5 degree celsius what's going to be the physical state of water minus 5 degrees celsius is it going to be solid is it going to be liquid is it going to be gas solid solid solid solid solid correct okay 25 degrees celsius you've told about minus 5 degrees celsius the next is 25 degree celsius hey mukesh i'll come to your question really soon when we'll discuss about evaporation 25 degree celsius liquid all right what about zero degree celsius so at minus five degree celsius you people said it's going to be solid 25 degree celsius you said liquid zero degree celsius challah fattah say let's see who are the rock stars answering really quick gas zero degree sphere solid and liquid mayang says solid and liquid mukesh is also saying that nithya guy is also saying that yes correct so at zero degree celsius is going to be solid and liquid okay 250 degrees celsius what about 250 degree celsius i hope i'm not hiding it 250 degree celsius absolutely right so gaseous state for any substance all right last one i will write it over here 100 degree celsius what is going to be the physical state now we're talking with respect to water here hundred foot of water liquid and vapor correct so you've understood this thing all right good so at 100 degrees celsius it's going to be liquid and vapor moving on to the next topic that is conversion we are talking about conversions so let's talk about the inter-particle space as well i hope you all remember this by the way that in solids the spaces they were negligible in liquids it's a bit more and in gases we have large spaces and that's why we can actually compress gases and gases are highly compressible and i've already told you application based questions that can come out of this why you know it's very useful for us yes two states are coexisting because the conversion is taking place whatever energy you're providing it's being used up to change the state first correct punima you remember cng all right so if i ask you how can we actually compress gas we are saying it's highly compressible how can we compress it shallow for tougher it's in the chat box tell me hey radha we've discussed about sublimation you'll have to quickly go back and watch the video yes so some class or the other for grade nine would definitely happen every day if not chemistry it will be physics or maths or biology questions i see the answer right there by applying pressure by increasing pressure what about temperature temperature pressure increase smiley out there yes correct by decreasing temperature you people are right so by increasing pressure decreasing temperature you can actually liquefy gases you can actually liquefy gases correct all right now this is a question that's there in your ncrt as well so solid to liquid the process is fusion or melting liquid back to solid it's solidification of freezing liquid to gas vaporization gas to liquid its condensation solid directly to gas somebody was asking that sublimation and gas directly back to solid is deposition they might not give you these in the exam and this might come as a three marker so just imagine how easily you will get three marks or they might give you some and ask you for the rest no not at all if you work hard procure you will not find the exam very hard so there you go you know about the change of state now moving on to the next very important subtopic that is evaporation questions say first of all when we talk about evaporation it's the change of liquid into vapor at any temperature below the boiling point so if i ask you at 56 degrees celsius or at 60 degree celsius or at 90 degrees celsius what's happening to water when we provide heat it's evaporating right now what's the difference between evaporation and boiling because see in both liquid is getting converted to guys so this is one question hey casey that's okay yes so let's understand this correct very good mayank very good punya yes correct so evaporation it's a surface phenomena see surface particles have higher kinetic energy right as compared to the rest of the particles which are present in bulk so evaporation takes place from the surface basically at the surface of the liquid boiling it's a bulk phenomena that means it's happening throughout evaporation is happening at the surface boiling is happening throughout now evaporation does not produce bubbles but boiling produces bubbles when you you know a lot of you in the last session you were saying you eat maggi and also when you boil water it produces bubbles but evaporation bubbles produce liquid it's very difficult to compress a liquid okay rani noted you're welcome pranjal now evaporation occurs at all the temperatures below the boiling point that's very important this is happening below the boiling point but when we talk about boiling it occurs at the boiling point of the substance right another very important point is that when we talk about evaporation it causes cooling effect obviously and that's not being observed in case of boiling now talking more about evaporation there are certain factors that can actually change the speed at which evaporation is taking place let's see who will quickly tell me all those points the four factors whatever humidity correct what else temperature surface area wind speed good all of you so yes increase in temperature see when we increase temperature evaporation increases because now more number of particles will get the sufficient kinetic energy to convert to vapor next is surface area when you increase surface area evaporation increases because now more number of particles are exposed if you increase the surface next humidity when you increase humidity evaporation decreases see humidity is the amount of water vapor that's present if the amount of water vapor is already high in the air then of course rate of evaporation would be low so here you notice it's inversely proportional next increase in wind speed see as when speed increases particles or whatever they move away with wind in a way evaporation increases yes power shine world condensation aura correct absolutely right now i also said that evaporation causes cooling effect right so a lot of questions can be asked based on this see when we talk about acetone or when we talk about petrol or perfume they contain in a way volatile liquids that means easily converted into the vapor form now say suppose you have acetone on your palm you've spilled acetone or you put a drop over it now when this acetone which is a volatile liquid when it you know vaporizes what happens it takes heat from our pump that's why we feel cool in a way our palm is losing energy right similarly they can ask you questions based on earthen pots so earthen pots they have small pores through which evaporation constantly takes place and we all know evaporation causes cooling effect right or they can ask you what kind of clothes do we wear in summer well we all know when you talk about cotton it's a very good absorber of you know water or sweat and then it exposes it for easy evaporation as the sweat gets evaporated as water gets evaporated we feel that you know it's causing a cooling effect no no but not ignoring anyone some of the comments we read some of the comments we miss by chance yes absolutely right so you know cotton clothes why are they being you know worn during summers hey that's great akshay all right so if you have understood all these important concepts i want all of you to quickly hit the like button and give me a thumbs up here father say let me know if you've understood everything that we've discussed so these are the topics that you just cannot miss in you know kind of we've just sorted everything for you we've put it in one single session so that you are able to revise everything in one go good all of you well done guys because yes we keep telling you we've got you covered so we really value the trust that you have that you've shown always we value the love and support that you keep giving us and that's why we will keep coming up with amazing sessions for all of you to make sure that you people is the exam and guys before i leave before i close don't forget to register for auntie the link is right there in the description box go ahead and quickly register yourself and yes you know we are in a race right now raise to a is the exam race 200 in midterms we have a plan for you and if you feel that you know following the plan kind of becomes difficult for you don't worry we are here to make sure that you follow the plan as well we will be coming up with all kinds of sessions so stay tuned subscribe color of attack so that you do not miss any important session of us good drop super that is great good to know that and yes for the first thousand users we have the mini learning program that's absolutely free you just have to use the code yt first so this has come back on your popular demand you really wanted us to come you know come back with this mini learning program because you've thoroughly enjoyed it the first time so go ahead book the classes according to your convenience pick up the topics of your choice and experience superior learning and get wonderful results yes you will get the ppt on telegram for sure all right questions in the comment section i want all of you to convert 25 degree celsius to kelvin scale leave your answers this is again a one marker that can come we can change the value it could be celsius to kelvin kelvin to degrees celsius so i've given you 25 degrees celsius you have to convert it to kelvin scale i will wait for your answers and i hope you've hit the like share and subscribe button yes that's great hey don't don't post your answers here you know it will get lost in the live chat i will be waiting for your answers i hope you can see this 25 degree sessions all right guys keep working hard keep smiling please remember to do the homework question post your answers in the comment section and i'll see you on the next class take care bye you

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Keywords: matter in our surroundings, matter in our surroundings class 9, matter in our surroundings one shot, matter in our surroundings class 9 one shot, matter in our surroundings class 9 mcqs, matter in our surroundings class 9 questions, matter in our surroundings quiz, class 9 science chapter 1 mcq, matter in our surroundings question answer, matter in our surroundings class 9 questions answers, class 9 science matter in our surroundings, class 9 science, class 9 mid term exams

Id: BQ1tqT76A1k

Length: 51min 53sec (3113 seconds)

Published: Thu Aug 18 2022