 Good. So students hope all of you are doing good. And my name is Prabhat Karnani. Many of you have already seen me last year if you were in the Centre. Can you please let me know who all are new students here or okay fine. I'm just giving you okay. If you were a Sentom student in class 10 then please I'm putting one poll. I'm launching one poll. Just put yes. If you were a Sentom student on last year then select yes option. I just want to know who all are who all were in Sentom last year. Okay fine. As of now 18 students have answered. Three more students. Okay fine. 18 have already answered and 67% are okay fine. So few new students are also here. So I hope most of you know me. Okay nine not in 10. Okay fine. Oh very happy to see you all. Okay and fine. So first I would like to introduce myself. Those who are a new student they should know me first and I think okay I'm closing this poll here only. Okay fine. So students just let me know. Can you see my screen now? Can you see my screen? Yes no? Yes? Okay fine. So okay good. So my name is Prabhat Karnani. I have been teaching in Sentom for last four years and I have been teaching. I am having experience of more than five years in teaching chemistry for those who are preparing for JEE mains, advance, KVPY, NAIT, Olympiats and SAT. So I have done my graduation. I finished my graduation from IIT ISM Dhanbad. How many of you know IIT ISM Dhanbad? How many of you know that? Okay again I'm launching one poll. Just tell me how many of you know just select yes. Just select yes if you know IIT ISM Dhanbad or if you have heard about that. If you have heard about IIT ISM Dhanbad just select yes option. Okay fine. So okay fine. So three, two, one, polling over. Okay fine. So students, the IIT Dhanbad or earlier it was known as ISM Dhanbad. So ISM Dhanbad is known for its earth science branches okay. Earth science branches like mineral mining and all those. I have done my graduation in mineral engineering. So it is known for its earth science branches. So in Asia it is a very well known, reputed college. So I have a clear JEE exam then I got admission there. Okay fine next. So I have taught more than 2500 students here and earlier I got a job here only and I worked for one year in as a mineral process engineer, a plant design. I had a project of process designing and plant designing. So I worked for there. I worked one year. I worked for one year there and then I decided actually to switch off to this teaching profession. When I was in Kota at that time only I decided that sooner or later I will become a teacher somewhere. So after working for in a corporate I decided to switch my job. So after that I have been teaching and even in my college I started teaching chemistry in different areas. So I had a great interest earlier for teaching. Now I am enjoying this. So now I have produced these ranks. You can see 149, 575 in KVPY. Last year I think you must have seen the result of Centrum Academy. We circulated the results also. So there are top rankers like students under 100 rank were also there in KVPY. So it was a great result for all of us and in JEE, 515, 644 all these are ranks which I produced. So I am very happy to say all these things because it gives a lot of sense of satisfaction. So students this is a little introduction of mine and as time passes you will get to know more about me. So I think most of you know me. How many of I think most of you have attended my Centrum are also so you might be knowing because of Centrum are or I have taught you in class 10th that might be the reason. As I discussed with Akhil sir and Dheera sir also told me so I think most of you are preparing for JEE Mains, Advanced and KVPY and few of you are preparing for other competitive example also like NEET, CET and all. So fine students I want to tell you one thing like if you are preparing for all these competitive exams. So you must have some resources to ease these exams and get a good rank. So students what do you think? What all resources as far as chemistry is concerned? I am not going to talk about every subject. I think Akhil sir has given you a good idea about all these exams and all. I am going to talk about chemistry only. So as far as chemistry is concerned which all books are important? Which all books you should refer for preparing JEE and which all resources like other than the resources which are going from Centrum which all you can purchase and you can solve questions from that. We will discuss all those things in this in next slide. Fine so one minute students. Okay so here okay now here I am going to show you for some books or references which you can check for preparing JEE. Okay so here is the list of books. So students you can see here those who are preparing for JEE Mains, JEE Advanced, Neat, KVPY, Bitset, KCET and school exams also. These are the books which you all can refer. Okay now I am going to start with one by one by taking all the all these. We will discuss about all the exams and which all things are required for our for getting good ranks in this exam. First I want to start with JEE Mains. In JEE Mains as you all know that it is a have you need to prepare very well to get a good school to get a good college through JEE Mains exam. So first of all in chemistry I would want I want to tell you there are three parts. It's not like what we learned in class 10. Okay so here if you see in class 10 we had only one book which which has physics, chemistry and biology. So it is just a science subject but here in class 11 the syllabus is huge the portion is huge. It's not like we have just a one book or we have two books in class 11. Can you imagine two books in class 11? So now in these two books why there's what all chapters we are going to have we have a three topics. Actually chemistry is classified in three mainly three sections that is the organic chemistry. Okay so mainly it is three parts which we are going to discuss. Organic chemistry, organic chemistry, physical chemistry and inorganic chemistry, physical chem and inorganic chemistry, inorganic chemistry. So in these three parts we will we will be going to have different resources because there are three broad sections we have different resources, different books for tracking for understanding the concept of these three parts. Okay so now here if you see JEE Mains if we are going to if we discuss little bit about the JEE Mains here the one of the most important book which is followed nationwide in organic chemistry is Himanshu Pandey. So you can refer Himanshu Pandey. Okay first definitely you are going to get a centermodule centermodule you will get but if someone wants to do more questions centermodule NCRT is enough but if you want to improve your result if you want to improve your understanding of some concept you can refer you need to buy this you won't get this from a centerm but centermodule you will definitely get. So here you have a Himanshu Pandey and for the organic chemistry for inorganic chemistry you can refer JD Lee. JD Lee is also used for JEE advance also. Okay for JEE advance we also use JD Lee for inorganic chemistry so students feel like inorganic chemistry little tough that is why more and more practice is required in inorganic chemistry. Okay so now here one of the most important part I want to tell you for JEE mains you know what around 75 to 80% of the Christians in JEE mains are based on NCRT are based on NCRT so it is very very important to cover each and every small part of NCRT at least in chemistry. NCRT is Bible if there you know sometimes there is a contradiction okay if in the two textbooks or in the two resources answers are different they always follow NCRT okay so whatever things are given in the NCRT all those things are important last year only one question was asked from NCRT actually students left that question why because that chapter was very basic there is a one chapter chemistry in everyday's life generally students don't pay attention in that chapter but one question from asking JEE means from not one I think one or two questions were asked from JEE main from that chapter so it is very important to cover all topics from NCRT if you complete the NCRT then only you should move to the other resources okay for during just before the revision okay so for for most important thing is NCRT coming to the JEE advanced part okay JEE advanced part you can use the JD Lee that is for in organic chemistry again for organic chemistry you can use MS Johan book also that is also a good source of there are multiple type of Christians are there in the MS Johan you can refer that book also fine yes here NCRT you know this time if you ask me about the JEE advanced if you just follow NCRT you know it's not sufficient at all to crack JEE advanced it's fine for JEE means I told you it's very very important but if you follow NCRT you won't get any help from for JEE advanced yes that will build up your concept that is fine but you can't rely you look on that only that source so third thing is question may arise sir okay sir you have told about in organic chemistry organic chemistry what about physical chemistry okay for physical chemistry mostly I would tell you like refer centermodule centermodule NCRT that is fine for JEE means for JEE advanced also we I'm going to provide you the worksheets and module itself has a lot of questions related to JEE advanced okay but still if someone wants no sir I want book please refer something so you can go with the P Bahadur and all so there are books but I would recommend you to stick to the centermodule NCRT for physical chemistry now coming to the NEET exam those who are preparing for NEET yes again NCRT is a bible I want to tell you NCRT is very very important for physical chemistry you can refer OP Tandon also OP Tandon is also a very good book you can refer it for JEE means as well OP Tandon is followed again a nationwide so it is again a good source of physical chemistry now good resource of physical chemistry now MTG complete NEET guide chapter wise topic wise chemistry there MTG MTG books are actually it's a they have a good content and a very good type of question so you can refer MTG books also Ariant MTG you can refer all those books now for KVPY okay I think many many of you are preparing for KVPY at least in Bangalore people are very concerned about the results of KVPY and they they plan to go they plan to get the admission through KVPY so for KVPY again I want to say centermodule is must and KVPY chemistry stream essay by CP publication you can refer otherwise JEE main source also work for KVPY JEE main source will work for KVPY as well now then next is the BITSET those who are preparing for a BITSET exam they can refer the Ariant Publications book that is a good source of good resource for preparing BITSET so it is a good one those who are preparing those who are planning to write KCET okay so for KCET you can refer centermodule again you can refer objective chemistry MCQ by Disha publication again a good resource Disha publication books are good for many streams so you can refer Disha publications book now school exams NCRT I told you NCRT there are two parts volume 1 and volume 2 for all these exams I am again want to tell you one thing don't forget to skip don't skip a single topic in NCRT so that is the most important part this is the most important one okay so here this is most important fine so in NCRT you have a volume 1 volume 2 you can go with the textbook also NCRT textbook for 12th the that and NCRT exemplars exemplars have a some good questions it's not like a textbook they have a good level question so you can refer NCRT exemplar and for inorganic chemistry especially for inorganic chemistry NCRT's Bible for even for J.E.Mains and for any exam for inorganic chemistry I would like to tell you please refer NCRT okay so later you know when there will be and I will as I think Akhil sir has also told you this thing don't go for too many rest resources take one take one book complete it once you can repeat the same book after some time if you feel like your concepts are getting dull and you are not able to solve questions as soon as you were solving it earlier so you can do the same textbook same book you can solve that again and again so that would be good thing instead of going for more and more books it will pile up in your home only and you won't be you know you won't get satisfaction also because you can't finish two year is not a long time it's a very short time I'm telling you so you can't finish all the resources so students as of now whatever the idea I have given you about the textbook if you have any doubt please ask if you have any sort of doubts please ask no doubts do you have any doubt in this at least write yes no yes no say say say okay good okay nice to see all there are many known names okay fine fine fine so fine moving to the next so here we got the idea about the books like which all books we can refer now what we are going to do sir the question is you might you might be wondering sir these books are fine but sir we are still in class 10 how can we prepare for full on with the full allegedly for the class 11 we have our school exam left yes fine I understand that and we all have selected the topic such that it will just a bridge up between the so like chapters of class 10th and class 11 so it won't be that tough chapter first of all and second thing it is a very important chapter to understand the whole chemistry which we are going to learn in coming two years the chapters which I'm going to take in this bridge course will just just provide a connectivity between class 10th and 11th and it is helpful to understand all the concepts in all the chapters okay so that basic chapter I'm going to take so you might be thinking sir which all chapters I'm going to take so for that I just want to tell you okay so here one minute so the chapter which I'm going to take is mole concept that is the first chapter I think most of you have heard about mole concept I have taken so many classes on mole concept centermars yes so you must have seen all these chapters in you have heard about mole concept in centermar so students in front of you you can see that a list of topics which we are going to discuss and so first topic which I have taken is mole concept now this is or some basic concepts of chemistry sometimes we call it as a mole concept or basic concepts of chemistry now you might be wondering sir why you have chosen this concept only why you have taken mole concept okay so for that I want to tell you you know importance of this chapter is because of the it gives you the quantity it tells you about the quantity let's say you take a pinch of salt for the experiment but if you don't know how much salt how many salt particles are present in that how many salt units are present in that then there is no point of doing experiment with that salt also let's say some experiment gives some result also then how you will explain this thing I have taken a pinch of salt and this was the result no you need to explain in terms of what amount so mole concept will tell you okay what it will give the name to that you know that specification to that pinch of salt okay this pinch of salt is having these many salt particles or this let's say you have a bottle of H2SO4 let's say you have a bottle of H2SO4 so in that bottle of H2SO4 what is the what is the concentration of H2SO4 how you will tell whether it is safe for can we can we touch that H2SO4 or we should avoid touching that H2SO4 if it is that much diluted or it is that much concentrated all who all will answer these questions it's fine we have not started studying like what will happen with H2SO4 but at least we should know like what is the what things we should keep in our mind while we are dealing with H2SO4 or while we are dealing with any of such acids base or any chemicals in the laboratory so the point is the first chapter will give you the idea about the mole concept about the concentrations about the formula of compound so which all topics which we are going to learn in this so here we have introduction to mole concept calculation of mole I will tell you in detail what is mole as of now first we will see what our topics we are going to discuss average molar mass of substance what what is the mass of substance empirical formula chemical stoichiometry problems on mixture so empirical formula molecular formula you have a little bit idea of this and vapor density limiting reagent sorry POSC concentration terms question on concentration terms mixing of solution problem on mixtures so we are going to discuss all those things in this chapter so basic terms of organic chemistry important organic in the in the next okay so this is all about mole concept I would need four hours to complete this chapter okay we have total eight hours in this bridge course so four hour four hour I will take to complete this now coming to the next that is the nomenclature what is there in the nomenclature part nomenclature part means okay this chapter is related to organic chemistry this chapter is related to organic chemistry okay now here students have you heard something about nomenclature last year have you heard something about nomenclature in class 10th yes so here we are going to see in detail we just had a look on this subject it was like very basic which we didn't discuss much about nomenclature last year actually yes yes naming of compounds but in this year we are going to see so many compounds it's like thousands of compound but so sir are we going to remember thousands of names no no no there is a there is a logic behind the nomenclature there will be a logic behind the nomenclature if you if you have a some compound if you want to write the name of that compound there must there will be some logic in that okay so there is a rules and regulations there is a rules which we need to follow to write name of any compound there is a priority order there is a functional group order all those things we are going to discuss in that sequence of writing of iupc name how to write the iupc name what is the sequence which we are going to follow common name of alkanes and alkyl substituents iupc nomenclature of alkanes all those things we are going to discuss in this chapter okay so you might have heard we have discussed very little bit about the nomenclature let's say i have taken methane you know that this is methane and all those but what if there is a any another compound which is given to you and you have never seen that compound then how to name that we are going to discuss in this chapter so sir the question is sir why why you have taken this chapter fine nomenclature is fine but why in the bridge course so i would like to tell you see nomenclature chapter we won't come like a separate as a separate chapter anywhere okay in ncrt also there is nothing called as nomenclature so no one will we don't have any such chapters so what happens you know but this this topic is very important for j e mains and any any of the competitive exam so it is very important to understand this chapter thoroughly but because it does not come in any specific or we do not have any specific nomenclature chapter in ncrt it's better to take this and you know it is a if you understand this chapter then only you can understand the organic chemistry all the chapters because organic chemistry and organic chemistry you have phenols they're like one compound you will have so you will have all the reactions of phenol in that let's say you have a carboxylic acid then all the reactions of carboxylic acid so the point is if you don't know which carboxylic acid is this how can you tell the reaction of carboxylic acid how can you tell the preparation of carboxylic acid so the point is if you know the name then only you can proceed. It is same like when we meet someone, we just say, what's your name? Without name, how can you interact with him? How can you know more about him or her? So the point is nomenclature is a very important topic for organic chemistry and for it is a basic of all the chapters which are we are going to learn in organic chemistry. Students, do you have any doubt in this part and any questions related to topics which we are going to discuss in nomenclature? Anything related to this? No? Okay, for one important thing I want to tell you students, please feel free to ask any question. First of all, whatever you are going to write, only I can read that. For those who think like what others, should I ask this question or not? It is a silly question or something like that. There is nothing called as silly questions. You should ask questions. If you have any doubt, please ask and then only you can answer your questions with full of confidence in exam. So you should ask every question, whatever comes to your mind and I would be happy to answer all your questions. So let's start with some. So this is a overall idea of what we are going to do in this bridge course. We are going to discuss the mole concept. We are going to discuss the nomenclature part. Okay, so now we will start with the first topic which is called as mole concept. So students, before starting mole concept, how many of you remember about mole concept? You have learned this in class nine. Can anyone tell me what is there in mole concept or what is mole? What is mole? Any idea? Any idea about mole? You have learned in class nine. Then we have discussed a little bit about mole in class 11, 10th also. What is mole? Okay, Sharduli of any item is fine. Very good Sharduli. Anyone else? Yes, mole concept. Yes, it is just like a dozen. Very good. Very good Setu. Number of AMU which makes a gram. Number of AMU which makes a gram. No, my dear. Anything else? Okay, fine. No problem. It's a very good try. Later I will come to that. What is AMU and what is gram and what is the relation between these two? We will come to that. So students, to start the mole concept, it is just a number. First, I want to tell you it is just a number, a number which chemists use. Like if you go to market, you say, okay, I need one dozen bananas. Similarly, if chemists go to the lab or if a chemist go for the purchase, to purchase any chemical, he will say, okay, I need five moles of this. I'm just giving an example. The number is like five moles. Like mole is a number. So you might be wondering, sir, why not we say just give five dozen NaCl? Okay, fine. Why can't we directly say, okay, give, yes, let's say any number. Okay, we need 100 NaCl units. Why can't we say like that? Why we need mole for that? Any idea? Why can't we say, okay, I need 100 units of NaCl? Why we use the word mole? We can directly say, no, mole is big. Very good. So, so what? Mole is big. I understood. Then why can't we say I need just 1000 NaCl units, 1000 NaCl units? Why we say I need NaCl? Okay, fine. Students, I want to tell you. See, when you have a pinch of salt, if you have a pinch of salt, could you imagine how many NaCl units are present in that pinch of salt? Do you think there are millions of NaCl units present in your pinch of salt in just a pinch of salt? So if you ask for 100 units of NaCl, you even can't hold it. You can't even see that 100 units of NaCl. Even if it is a 1000 unit, you can't see it because 1000 unit itself is a very, very small that you can't see it with naked eyes. So the point is, there are so many particles in a pinch in a very small amount of salt or anything because we are talking in an atomic level like, okay, so NaCl is like NaAtom and CL Atom. They are combined. So the point is, we are talking in terms of atomic radius and atomic size. So the point is, you can't see 1000 units of NaCl with your naked eyes. If you take a smallest amount also, it will be in, which you can see, that will be in the millions in number. So the point is, to ease the calculation, to ease the calculation, to make this thing convenient for use, let's say otherwise, I can't say, okay, I need 10 to the power 14 units of NaCl. Why I should say for 10 to the power 14 units of NaCl, make some unit which will help you directly tell, okay, this is the number of moles. This is the number of units. So that is why mole concept has a great importance because it is just a number. Okay, so one mole actually is, one mole is something that is 6.022 into 10 to the power 23. Now, you might be thinking, sir, why this number only? Why not anything else? Is it something special in this number? Why is 6.022 into 10 to the power 23? Why not something like 10 into 10 to the power 20? So I will come to that. Why this number has a huge importance in few minutes, I will come. Before that, just note it down. Okay, so now, okay, so this is one mole. Now, how we will use it in the lab? Okay, and what is the origin of this world one mole? And it is also called as Avogadro's number. It is also called as Avogadro's number. Why Avogadro's number? Why Avogadro's number? Any idea? Yes? Why Avogadro's number? Avogadro's constant. Okay, fine. So what do you think? Avogadro's discovered this? He found that one mole has these many numbers? Did Avogadro find this? Or what? Okay, students, for that, I want to tell you one story, one small story. Okay, so to understand that story, we need to understand about what actually happened that time. So Avogadro's full name was this and the male is not famous for his striking good looks, but he's famous for solving a problem. And he would be wanted to know that he actually didn't find the Avogadro number. Avogadro didn't actually, didn't know that there is a one number called as Avogadro number based on his work or people honored him and they gave this number as a Avogadro number. Actually, Avogadro gave one law which helped to solve a lot of problem in chemistry. So to honor Avogadro, okay, after he died, to honor Avogadro, a number which is like a one mole was named after him that is Avogadro's constant. Avogadro actually didn't know that this thing will happen. So the point is here you can see, I have added one more slide where you can see what is actually, in 1966 to 1856, never knew this. His own number, it was named in his honor by French scientist in 1909. Actually, this was honored in 1909, but he died on 1856. Its value was first estimated by the, okay, so the point is to honor Avogadro. Now the question arises, okay, sir, what Avogadro did? So that the number, the name is like, what was his contribution in chemistry? Why Avogadro got so much importance in chemistry? Can anyone tell me what law came? What law he gave that is called as Avogadro law? Any idea? What is there in that Avogadro law? Yes, what is Avogadro law? He gave a law regarding gaseous volume. Exactly, but what was that law? Do you know that law? Okay, I will tell you, wait. So in the Avogadro law, he gave one hypothesis. He said, yes, he told that a very, very interesting thing, like if you have a hydrogen gas, if you have a hydrogen gas and if you have a methane gas, hydrogen has a molecular mass that is two, one and one. I will come to that molecular mass and all those things. Hydrogen has molecular mass to AMU, but methane molecule has a mass 12 plus 4, 16 AMU. Methane has 16 AMU, hydrogen has 2 AMU mass. Now the question was, okay, what law he gave? He said that if you take equal moles or equal particles, if you, let's say you are taking two hydrogen molecules, if you are taking two hydrogen molecules and if you are taking two methane molecules, methane is CH4, I am writing it like this, four atoms, around one atom, CH4. So if you take two molecules of methane, a hydrogen, and if you take two molecules of methane, both will occupy same volume. It doesn't matter whatever the size of the molecule is. But the point is, if they are same in number, if molecules are same in number, so what will happen? They will occupy same volume at standard, same temperature and pressure, at same temperature and pressure. So this was a great contribution in the chemistry because people got to know it doesn't matter if you have a five molecule of any gas, all gas will occupy same volume. It doesn't matter which gas you are talking about. If it is a five molecule at some temperature and pressure, they both will occupy same volume. Is it clear? Is it clear to all of you, what was the book Adro's law? That is why, you know, it was, there was a, people got to know about this. And finally, when they realized that it solved so many problems in chemistry, like which thing is heavier, you can directly tell if there are two molecules of methane and two molecules of hydrogen, they occupy same volume. You can directly predict the density of gas because density is mass by volume. Volume is same, mass is different, density will be different. So you can predict so many things using this. That is why Avogadro's law got a great, you know, importance in that time and still we use it. So the point is, that is why the number was given after Avogadro and it is called as Avogadro number. Let's talk about, okay, so let's talk about mole in detail. Now what is mole then? Avogadro law is fine. Any doubt in Avogadro law students? Any doubt in Avogadro law? No? Okay, fine. Now come to the, now come to the next thing that is how big the mole is. How big is the mole? Okay, the point is, if you want to know about the mole, it is that big number, okay, that, as I told you, the number is 6.02, 2 into 10 for 23. Okay, why this number came? Because I will come to that in a few minutes. So one mole of marble would cover an entire earth ocean included for depth of three miles. So you can understand that how big this number is, one mole, because it's 10 to the power 23 is a very big number. One mole of $10 bills staked up on top of one another, top of another would reach from Sun to Pluto and back 7.5 million times. So you can imagine like if you just put the, this money and the very, very thin you, you'll see that, that the note is thickness is very less, but still you can cover this much distance. So this mole is a very big number that is the important part for you to understand. Okay, so what I want to tell you, so what is the Avogadro number then? Avogadro number is nothing but mole. So how it is related in chemistry? This is fine. This is in general, we can say this is mole, this is that and number, mole represents a number. But how we are going to use this in chemistry. So for chemistry point of view, we are going to see how we utilize this. Okay, so here what is Avogadro number? A mole of substance, a mole of any substance, a mole of any substance, here you can see one minute, a mole of any substance contains as many elementary units. Okay, a mole one minute. Okay, a mole of any substance is contains as many elementary units and atom as number of 12 gram of isotope of C12. Why this carbon 12 was taken? Why mole is the number I told you that I will come to this point? Mole is what is one mole? It is a number of particles of carbon in a 12 gram of C12 isotope. I think you people know about isotope. Students, what is isotopes? What is isotopes? Let me see. Let me see what answer you are going to put. Write your answers. What is isotope? Same atomic number, but different mass number. Anyone else? What is isotope? Different atomic number, same atomic number, but different mass number, different neutron, same element, very good students. Yes, but I have seen that all of you have not answered. Answer it students. What do you think about? What do you think about? Isotope, yes. What do you understand by term isotope? Okay, fine. So here, just a minute. So isotope is something that a same atomic number. See, if two isotopes have a same atomic number, but different mass number. However, I remember I think I have told this trick. Isotope means it ends with P. So proton same. Here you have a same proton, but different neutron. But neutron number are different. Neutron numbers are different. Okay, so that is isotope. So carbon 12 was taken as isotope. Why carbon 12? Why not carbon 14? Why not carbon 14? Carbon 12 was taken as isotope. Why not carbon 14? Yes, because carbon 14 is a radioactive isotope. It won't stay for long time in nature. Means it is very less in nature first of all. And it is a radioactive, sorry, it is a radioactive, right? Actually, radioactive isotope means it will stay for very long time, but it keeps on radiating. You know, the age of fossils, age of rocks are found by carbon 14 isotope only. It is one of the important topic. As I told you, it is one of the important topic for your NTSC exams also. They used to ask question from carbon 14 or C-14 isotope. So the point is carbon 14 is a radioactive isotope. That is why it is not very stable. If it is not stable, then so we can't use it. So the question arises. So sir, why carbon was taken as reference? Why not hydrogen? Why not oxygen? Any idea? Why carbon was taken as reference for one mole? Why not hydrogen, oxygen? Any idea? Okay, fine. What else? What else? Highly stable. Okay, fine. Yes, highly stable thing you can say, but at the same time what is the actual reason? I would like to tell you. See, later we will see that we have atomic mass of all the elements in whole number, relative atomic mass in whole number. So carbon when taken was a reference, it gives a atomic mass in whole number. And second thing is, it's isotope as one of your friends said, it is a very stable atom. Its radioactive isotope is very less in amount in nature. Actually the carbon amount is itself an abundant. C12 is abundant in nature. So if C12 is abundant and radioactive isotope is less abundant, C12 was preferred. Second thing like for hydrogen and oxygen, the problem earlier it was taken, hydrogen was taken as reference earlier. Even oxygen was taken as reference, but later it was removed because if you take hydrogen and oxygen as reference, the point problem is one is having isotopic, good amount of isotope, so you can't take as a reference. If two atoms of same element having a different mass, then how can you take something as a reference? It should be unique for isotopic behavior due to isotopic behavior. And second thing, the mass which we are obtaining after taking these references were not in whole number. That is why hydrogen and oxygen was not continued as a reference for calculating atomic masses, carbon was taken as a reference. This number is called as the Avogadro number. The mass of one mole of substance is called as a molar mass symbolized by M M. So hydrogen molecular mass is 2 gram per mole, helium 4 gram per mole, nitrogen 28 gram per mole, oxygen. So these are molar masses. Molar mass means, molar mass means, tell me, what is molar mass? What is molar mass? Yes, molar mass is mass of one mole of substance in gram, mass of one mole of substance, mass of one mole of substance in gram. Is it clear? That is called as molar mass. So these are the, if you take a one mole of CO2, one mole of CO2 means, if you take 6.02 into 10 to the power 23, but molecules of CO2, if you take these many CO2, so the mass will be 44 gram. 44 gram, can you imagine? Just these many numbers having just a mass of 44 gram. So this is the importance of mole. So now moving to the next, this is about the Avogadro number. And now there is one more thing which I want to add here. There is one more thing. Here you can see, the mole is developed. If you have a one carbon atom, if you have a one carbon atom, the mass of carbon atom is 12. If you have one carbon atom, the mass of carbon atom is 12. You can see here, the mass of carbon atom is 12. See, this is the mass of carbon atom. But if you have two carbon atoms, 2 into 12, 10 carbon atoms, 10 into 12, 50 carbon atoms, 50 into 12. So if you have Avogadro numbers or any carbon atom, Avogadro number is also represented like Na. If you have any carbon atom, not sodium, it is Na. So Avogadro number is there. Then what will be the mass? 6.02 into 10 to the power 23 into 12. This is a one mole. This is one mole. And this is total mass, one mole into 12. So this will be the molar mass of carbon. And when you calculate this, later we will see what will come, not now. But actually the molar, if someone asked you what is the molar mass, means mass of one mole of that substance in grams is called as molar mass. Now, carbon was taken as reference. I will tell you how carbon was taken as reference and how the relative mass is calculated. Okay, students, if you have any doubt in this section, then please let me know. Do you have any doubt in this section? Please let me know if you have any sort of any doubt. Because now we are going to start writing a new topic, sir. Atoms make up molecules, exactly. Atoms make up molecule. It could be molecule could be from different atom, it could be from same atoms. Okay, H2O2 failed because the reason being, first of all, they exist in isotopic forms also. Isotopic form was one of the reason. And second is, the mass obtained by using these as reference was not coming as wool number. Mass of other atoms relative to these atoms was not coming as wool number. Understood. Okay. Okay, carbon majorly, there are three main isotopes, but mostly it is carbon 12 and carbon 14 we discussed. Okay. Okay. How was this number discovered? Okay. See, you know, actually when the 12 gram was that mass was taken as a reference. And you know, there was a mass spectrometry, using mass spectrometry, the number was calculated because we got to know about the, by that time, we got the idea of what is the mass of any atom or let's say, total mass we knew. And using the mass spectrometry, we got to know about that. Understood. Any other doubt? Okay. Is it clear? Okay, fine. So now let's start with, okay. Next heading is right relative atomic mass. Right heading, relative atomic mass, relative atomic mass, relative atomic mass. So now what do we have in relative atomic mass? First of all, it is dimensionless. It is dimensionless. Okay. So relative atomic mass is also called as relative atomic mass in bracket, you can write RM in bracket, you can write RM is equals to mass of, okay, try to understand mass of atom of an element mass of one atom of an element of an element divided by one AMU. Mass of one atom of an element divided by one AMU is called as relative atomic mass. Many people write that one AMU is equals, you all know, okay, fine. I will tell you, I think you people have forgotten this one AMU is called as atomic mass unit. First of all, atomic mass unit. And this atomic mass unit is nothing but it is like one by 12th of one by 12th of one by 12th of mass of one atom of C 12, one atom of C 12, one by 12th part of mass of one atom of C 12. Okay, so this is what we call as a one AMU. Is it clear? One AMU is one by 12th part. So sometimes, sometimes people write like this also, one by 12th of C 12, one by 12th into mass of C 12. Sometimes people write like this also, but I think you understood now. Okay, so this is how relative, why word relative? Because it is relative to some mass, mass relative to some mass, that is why it is relative atomic mass and it is a dimensionless quantity. Because on top it is AMU, on bottom it is AMU. So it is a relative atomic mass with no unit. Is it clear? What is AMU value? One AMU value in gram, that is 1.66 into 10 to the power minus 24 gram. This is a value used, that is relation between AMU and gram. AMU is atomic mass unit, but if you want to convert it into gram, so this one AMU is equals to 1.66 into 10 to the power minus 24 gram. Is it clear students? Did you understand till here? Any doubt in this? When we do calculation, you will get to know more about this. So the question is okay sir, you have explained the relative atomic mass. Then what is atomic mass? We have heard about atomic mass also. So now we are going to discuss about atomic mass. Atomic mass is, what is atomic mass? Atomic mass is mass of one atom in AMU. Mass of an atom, right atomic mass? Atomic mass is mass of one atom of an element of an element, mass of one atom of an element in AMU. That is atomic mass. Only thing, only difference in the relative atomic mass and atomic mass is, it is in AMU. But relative atomic mass is dimensionless. Okay. Relative atomic mass is dimensionless. Now we will do one thing. Let's say atomic mass of oxygen. Atomic mass of oxygen atom is, atomic mass of oxygen atom is 2LU. Can you tell me, can you tell me what is the relative atomic mass of oxygen atom? If atomic mass of oxygen is 2LAMU, can you find the relative atomic mass of oxygen atom? I have received two answers so far. If atomic mass of oxygen atom is 2LU, what is the relative atomic mass of oxygen atom? Fine. Okay. Very good. Relative atomic mass is just 2L. Why? Because it is 2LU divided by one U. U and U will get cancelled out. U and U will get cancelled out. Any doubt students in this? Any doubt in this? Relative atomic mass, it is just a mass of an atom in AMU divided by one AMU. Okay. It is just a relative mass. Okay. Fine. So, now next is gram atomic mass. Next heading is gram atomic mass. Okay. Very good. Siddhant, Siddharth, see. U and AMU are same. Both are same. Unit of atomic mass unit is represented by small U. Here I have written. Okay. U right here. One AMU, it is represented by U. Right here. Here, right here. AMU is represented by U. One AMU is represented by, represented by U. Did you understand now? AMU and U are same. Clear? Very good. So, actually it is just a unit. So, gram atomic mass. Next is gram atomic mass. What is gram atomic mass? In gram atomic mass, first you need to understand the definition. It is also, it is written like GAM. And mass of, what is the definition? Mass of one mole of atom. Please underline mass of one mole of an atom. Mass of one mole of an atom. Mass of one mole of an atom or atom or element in gram, in gram. Relative atomic mass is mass of one mole of an atom. Mass of one mole of an atom of an element in gram. Of an element in gram. This is gram atomic mass. Underline the word one mole. I will tell you why it is important. So, let's say you have a sulfur, sulfur atom. Let's say you have a sulfur atom. What is atomic mass of sulfur atom? What is atomic mass of sulfur atom? Any idea? Atomic mass? Atomic mass of sulfur atom is? Very good. 32 U. 32 U, not 16 U, my dear. 32. 16 is atomic number. Just multiply it with 2. Multiply it with 2, you will get. So, 32 is atomic mass. Can you calculate gram atomic mass? Can you calculate gram atomic mass of this? Can you calculate gram atomic mass? Very good. Can you do the calculation? Can you do the calculation? Prove it. Can you prove that, sir, gram atomic mass will be this? Can you prove this? By whatever data I have given you so far. The data which I have given you, can you prove this thing with the help of the data? No? Fine. Gram atomic mass is 32 U. Atomic masses, you need to calculate. So, gram atomic mass, how to calculate? That is equals to mass of atom, mass of one atom into one mole, into one mole, mass of one atom into one mole. And this all should be in grams. This all should be in grams. So, mass of one atom is 32 U. See here, atomic mass of sulphur is 32 U into one mole. One mole is 6.022 into 10 to the power 23. This is one mole. So, this is the mass of gram atomic mass. But the point is, gram atomic mass is always in grams. But the answer which we are going to get is in U. We need to convert it into gram. What is the relation between U and G? I think I have already informed you. What is the relation between U and G? We have written in last page, 1 U is equals to 1.66 into 10 to the power minus 24 G. 1.66 into 10 to the power minus 24 G. This is the one relation between U and G. Apply this thing. 32 U, 32 into 1.66 into 10 to the power minus 24 into 6.022 into 10 to the power 23 grams. Calculate this, students. Calculate this. How much it is? Calculate this and tell me what answer you are getting. Only one student has answered. After doing this calculation, what you are getting? Students, this will get cancelled out. You will get 32 grams only. You can calculate it. Gram atomic mass will come out to be 32 grams. Students, did you understand? Did you understand how we got 32 grams? So, what is the thing which you need to learn, which you need to understand? That whatever atomic mass we have, that is atomic mass is X gram, X U, atomic mass is X U or XAMU. Then, gram atomic mass is, gram atomic mass is X gram. Very, very important. Atomic mass is X U, then gram atomic mass will be X gram. Is it clear to all of you? Yes or no? Is it clear? I will give you some questions that will give you more clarity. First tell me, did you understand till here? Sir, can you repeat what you just wrote? I have written that if you have X gram of atomic mass of some element is X U or XAMU. X could be any value. Then, gram atomic mass of the same element is X gram. The only thing is, that U would be replaced with G. So, did you understand this part? Yes? So, see now the calculations become very easy. Whatever the number we had for 32 gram, whatever the number we had for let's say 32 U, the same number we will use for one mole of substance that is 32, that is 32 G. So, number will remain same, only the unit will change. Is it clear? Okay. See, I was converting, I was finding gram atomic mass of carbon atom. So, gram atomic mass of one atom into one mole, because gram atomic mass is mass of one mole of substance. Yes, yes, yes. We don't, yes, say it is same like atomic mass, gram atomic mass. See, there are two things, gram atomic mass is for atom, gram molecular mass is for molecule. If I am talking about sulfur, I will talk about atom only. I will say gram atomic mass, not gram molecular mass. Got it? Yes or no? Okay. So, 32 U is a mass of one atom of sulfur and one mass of one mole, one atom is molar mass. Yes, yes. Okay. But just let me finish this. I will come to your Prisha. Mass of an atom is 32 U. You have one mole of that atom. One mole means 6.022 into 10.23 and 32 U is one atom mass. So, total mass is 32 into 1.66 into 10 power minus 24, because U and G convert and we know. We have seen in last page, how to convert U and G. Understood? Anushka, in last page we have written relation between U and G. Okay. Fine. Now, coming to the Situ's question, Situ, this exactly gram atomic mass is like, see, it is defined for atom, not for molecule. So, you can't say, you can say molar mass of an atom is fine. Okay. You can say molar mass in grams is gram atomic mass. Molar mass in gram is gram atomic mass. Got it? Yes or no? Okay. Good. Now, this is all about the gram atomic mass, atomic mass. Now, do some questions. 1 G is equals to, no, no, no, no. One AMU is, yes, exactly. One AMU is how much? One AMU is 1.66 into 10 power minus 24 G. So, 1 G is equals to, 1 G is equals to 1 by, 1 G is equals to 1 by 1.66 into 10 power minus 24. So, it will become 10 to the power 23, 6.022 into 10 power 23. Is it clear? 1 G is equals to this many AMU. Any doubt? It's right. 1 G is equals to 1 mole AMU. Yes, you can say. You can say that. Understood? Yes? Very good. Fine. So, next point is 1 G is 1 point this AMU. Now, you need to do one question. Question is, you need to calculate gram atomic mass, relative atomic mass, atomic mass for sodium and helium. Quickly, tell me the answer for this. Gram atomic mass, relative atomic mass, atomic mass for sodium and helium. 1st one is sodium. Gram atomic mass, relative atomic mass and atomic mass for sodium and helium. Okay. I would give you some number. Otherwise, if you don't remember, Here sodium mass number is 23. Helium mass number is 4. Mass number is proton plus neutron. Gram atomic mass, relative atomic mass and atomic mass. These three terms are very much related. Gram atomic mass, relative and atomic mass. So sodium atomic masses, sodium atomic masses 23U. Because proton number is same and atomic mass is mass of atom in AMU, 23U, atomic mass. What is the relative atomic mass? What is relative atomic mass? That is 23. That's it. Just 23. Because relative atomic mass is atomic mass of an element in U divided by 1AMU. So relative atomic mass is 23. And what is gram atomic mass? What is gram atomic mass? Gram atomic mass is mass of an atom. Mass of one mole of an atom in gram is called as gram atomic mass. So that is 23 gram. Is it clear to all of you? Is it clear to all of you students? Yes, no. Yes, helium. Helium, helium. Coming to the helium, here it is. Same thing. Helium atomic masses, 4U. Relative atomic masses, it is relative mass. So unit less, 4. Gram atomic mass, same number but with gram, 4 gram. Because gram atomic mass tells you the mass of one mole of substance. So that is 4 gram. Did you understand students this part? Did you understand this? All of you? Okay, I would like to launch a poll now. Let us see how many of you understood this. So, okay, fine. So one minute, how many of you? Okay, anyone has any doubt? Please ask. No? Fine. So let's have a poll. If anyone has any doubt, then write no, otherwise put yes. Yes. Did you understand? Then say yes. If you didn't understand, say no. Okay. So nine. Okay, fine. Vote it fast. Four students. Vote it. Okay, good. So who has a doubt in this? Oh, sorry. One minute. Okay. Most of you, I put no because I thought no is for no doubt. Okay, okay, Kartik. Fine. So I think everyone has understood this. Sir, can you explain the definition of mole which you gave? The definition of mole, where? Which one minute? Okay, just a minute which you are asking. Charduli, which thing? Sorry, Setu. Mole is like, okay, here the first page you are asking. Okay, okay, okay. Okay, see here, when we say mole, mole is just the number of particles. So you can write it. Okay, write it here only. You write it. Write definition. So I told you, but if you want to write, you can write here. So what is the mole? Mole is, what is mole? It is a number of carbon atoms. Number of carbon atoms present in, present in 12 gram of C12 isotope. 12 gram of C12 isotope. This is called as mole. 12 gram of C12 isotope. Now, yes, yes, sorry, Charduli. Okay, fine. So now the very important topic I'm going to start that is called as calculation of moles. Calculation of moles. So there are three methods which, by which we are going to calculate the number of moles. I'm going to explain the three methods to you. Calculation of moles or the number of moles. First is when number of particles are given, when number of particles are given, when number of particles are given, then how to calculate moles. So here, let's say you have, I'm just giving you one example, 12.044 into 10 to the power 23 particles if you have. If you have these many particles, so can you calculate the moles? Can you calculate the moles? If you have these many particles, can you calculate the moles? Fine. Most of you have answered. Just think, if you have these many particles of anything, can you calculate the moles? How many moles? I told you moles is just a number. So if someone give you some number, can't you, if I give you 24 bananas and I will ask you how many dozen bananas are there, you can directly answer. Similarly, if these many numbers of particles are given to you and someone ask you how many moles, then how to calculate? Very good. Very good. Now I think many of you understood. If these number is given, you need to get very good. Most of you got the answer. It is nothing but it is two moles. Yes, exactly. It is two moles. Why? Because in one mole you have 6.022 into 10 to the power 23 particles. So in two moles you have 12.044 into 10 to the power 23 particles. Students, any doubt? Any doubt? So now write the formula. Number of moles. Number of moles is equals to given number of particles. Given number of particles. Number of moles is equals to given number of particles. Number of moles is equals to given number of particles. Divided by any. Divided by Avogadro number. Divided by Avogadro number. Students, did you understand this? Any doubt in this? If anyone has any doubt, no doubt sure. Very good. Very good students. I will move to the next topic. This is number of atoms I told you. What if the mass is given to you? So second heading right. When mass of substance in gram is given. In gram is given. Mass of substance in gram is given. Then what two will do? Example. Example. I will just give you example. I will see how many of you can answer. Let's say you have 48 gram of carbon. You have 48 gram of carbon. Can you calculate moles? If you have 48 gram of carbon. When mass of substance in gram is given. How to calculate moles? 48 gram of carbon you have. If you want to know gram atomic mass of carbon. I can tell you gram atomic mass of carbon is 12 U. Gram atomic mass of carbon is 12 U. Ah sorry 12 gram. Gram atomic mass. Ah yes. So answer for this question is what you can go like this. 12 gram is one mole. 12 gram is one mole of carbon implies 48 gram is 4 mole of carbon. Any doubt? 48 gram will be 4 mole of carbon. So how to write the formula? Number of moles of substance. Number of moles of substance is equals to. What should I write? Number of moles of substance is equals to given mass in gram. Given mass in gram divided by. Given mass in gram divided by. Yes. Given mass in gram divided by molar mass in gram. Very good. That is relative atomic mass. Okay molar mass in gram. Molar mass in gram. This molar mass could be relative atomic mass or relative molecular mass also. I will tell you relative molecular mass after this. So molar mass in gram. Actually if you see molar mass in gram is in gram per mole. Unit is gram per mole because molar mass is always defined for one mole of substance in grams. So gram per mole is the unit. And this is gram. So gram and gram will cancel out and you will get the number of moles. Did you understand students? Yes. No. Any doubt in this? I will give you questions that will give you more clarity. You can write note. You can write one note here. What is note? I am writing that. Notice relative molecular mass. RMM is relative molecular mass. Relative molecular mass. That is mass of one mole of molecule. Molecules in gram. RMM is relative molecular mass. Mass that is mass of one mole of molecules in gram. Mass of one mole of molecules in gram. Is it clear students? Did you understand this? Yes or no? Is it clear? Example. Example. Example. Here you can say example you have H2O. What is the mass of one mole of H2O? If you have one mole of H2O, what will be the mass? How to do? Can I write like this? One mole of water means two moles of hydrogen atom plus one mole of oxygen atom. Yes or no? Yes or no? Because one mole of water in one water there are two hydrogen. So in one mole of water there are two moles of hydrogen. Any doubt? Yes or no? One mole of hydrogen means two moles of hydrogen. Because in one molecule of water there are two hydrogen atoms. So if there are one mole molecule, there are two mole molecule of hydrogen. Mole is just a number. So two mole of hydrogen atoms if there is one mole of water. So what is the mass of two mole of hydrogen atom? Two into one hydrogen atom is one gram. One mole hydrogen atom is one gram plus one mole of oxygen atom. One mole of oxygen atom is 16 gram. So overall answer is 18 gram. Is it clear students? Is it clear to all of you? Yes. Any doubt in this? No doubt? Sure. This is about the relative molecular mass. Okay now next is right next heading. This is relative molecular mass. Okay so two ways we have seen how to calculate number of moles. If number are given then we can calculate number of moles. If mass is given. Sir RMM is for molecule and not for atoms right? Exactly. RMM is same like GAM but GAM is applicable for atom. RMM is applicable for molecule. Got it? Yes? RMM is relative molecular mass. You tell me very good question one of your friend has asked. Relative molecular mass. Whether it has a dimension or not tell me. Relative molecular mass will have some dimension. Okay I think he want to ask whether it's having some unit or not right? Does relative molecular mass having unit? Yes relative molecular mass has unit. See here I have written in grams. Understood? Is it clear? It has unit that is gram. Any doubt in this? No? Okay fine. Next is next point is okay here you write the heading when this is the gram mass is given. Okay one question do one question. Here if you have 64 gram of sulphur. If you have 64 gram of sulphur. Can you tell me moles of sulphur? Can you tell me moles of sulphur? If you have 64 gram of sulphur. Very good. Solution is? Solution is. So what can we write? Moles is equals to given mass divided by relative atomic mass. Given mass divided by relative atomic mass. Given mass is 64 gram. Relative atomic mass of sulphur is 32 gram per mole. So gram and gram will get cancel out answer is 2 mole. Students did you understand this part? Yes or no? Did you understand? Last question from this section then I will move to next. Question is if you have 36 gram of water. If you have 36 gram of water calculate mass of oxygen. Mass of oxygen in it. In 36 gram of water calculate mass of oxygen in it. In 36 gram of water calculate mass of oxygen in it. Relative atomic mass does not have unit. Ok. Ok. Gram atomic mass. Right. Absolutely right. G-A-M not relative atomic mass. G-A-M. Understood? Done. Wow. So many students have answered this. So it's very easy question. 36 gram of water means moles of water are. Moles of water are given mass divided by given atomic mass. Sorry. Gram atomic mass. Here I won't write gram atomic mass. Why? Because I have a molecule. So I would write gram molecular mass. I would write gram molecular mass. So gram given mass is 36 gram molecular mass is 36 gram per mole. Here it is gram. Is it clear? Gram molecular mass is 18 for water. 18 for water. Ok. So this is 2 mole. 2 mole of water you have. You have 2 mole of water. Now the question is if you have 2 mole of water you need to calculate mass of oxygen in it. So you can say 1 mole of water. 1 mole of water has 18 gram. 1 mole of water has 16 gram of oxygen. 16 gram of oxygen. Because 1 mole of water has 18 gram total. So it has 16 gram of oxygen implies 2 mole of water have 32 gram of oxygen. Any doubt students? 32 gram. Do you have any doubt? Any doubt in this? Sure. No doubt. Ok. Fine. Last point of this. One more thing which we need to discuss. So third point is we have discussed 2 things. One is when number of molecules are given then you can calculate moles. When mass is given then you can calculate moles. So the third is when volume of gas is given. So for gases if volume of gas is given then how to calculate moles? So in that case what we can say how to calculate moles? You can write if volume of gas is given under standard temperature and pressure condition under STP. STP is what? Standard temperature and pressure. Standard temperature and pressure. Ok. So that is 0 degree Celsius. 1 bar pressure. So volume of gas is given under STP. Standard temperature and pressure. 0 degree Celsius and 1 bar pressure. So here how to calculate the moles of any substance? So what to do? Moles of gas is equal to given volume of gas at STP. Given volume of gas at STP in litre. Given volume of gas at STP in litre. Divided by just given volume of gas at STP divided by molar volume of gas at STP. Molar volume of gas at STP in litre per mole in litre per mole. This is the most important one. How to calculate the moles of gas? If volume of gas is given how to calculate moles of gas in that container? So you need to do this thing. Ok. So it is in litre per mole. So how you can say? Just write molar volume at STP is 22.7 litre. Molar volume of gas at STP is 22.7 litre. Please remember this value. Ok. For any gas. For any gas no matter whatever you have. Yes students. One student has written 22.4. Sharduli. I want to tell. Ok 22.4 you will find it in many textbook. Many textbook because you know the definition of standard temperature and pressure condition has changed. Ok. Earlier when the definition was 1 atm pressure and 0 degree Celsius temperature. Then molar volume comes out to be 22.4 litre. But now the standard condition is 1 bar and 0 degree Celsius. Very small difference is there. 1 bar then it is 22.7 litre. So many textbook still has this. There is not huge difference. But if someone ask you what is the correct value you should be able to answer. Correct value is 22.7. In many textbook you will find 22.4 litre. Ok. But the actual it is given in NCRT also. You tell me what is the unit of molar volume. Molar volume is litre only. Molar volume is volume of one mole of substance. What is molar volume? Volume of one mole of substance. Molar volume is volume of one mole of substance. Volume of one mole of substance. Ok. See both are same. One minute sir. Then why have you written by mole? Where it is? Volume of one mole of substance. Same thing now. Litre per mole. Volume of one mole means litre per mole. Like if I am saying understood now. Litre per mole. Ok fine. Any other doubt students? Any other doubt? No. I want to give you one question. Then we will do some questions on three questions on Mentimeter. First I will give you one question. Then we will move to the Mentimeter. Question is if you have 90 gram of glucose. If you have 90 gram of glucose. Glucose formula is given to you. C6S2O6. And its molecular mass is given to you. Relative molecular mass of glucose is 180 gram per mole. Question is fine. Question is fine. Number of moles of glucose. Fine. Number of moles of glucose. And second is number of moles of carbon, hydrogen and oxygen. Do this. You need to calculate number of moles of glucose. And number of moles of carbon, hydrogen and oxygen. Number of moles of glucose. And number of moles of carbon, hydrogen and oxygen. One by two three. Fine. You need to calculate number of... Just apply the formulas which you learnt. Ok very good. I think all of you have given right answer. Very good. So moles of glucose. Moles of glucose is given mass. Given mass divided by... Given mass in gram. Divided by... One minute. Given mass in gram. Divided by... Since it is molecule. Since it is molecule. What should I write? Gram molecular mass. Gram molecular mass is in gram per mole. Given mass is 90. Gram molecular mass is 180 gram per mole. So what will be the answer? One by two mole. Did you understand students? Because... Relative molecular mass I have already given you. Yes? You can just change this small thing. It is gram molecular mass. Gram molecular mass. Gram molecular mass of glucose is given to you. You can calculate number of moles of glucose. Understood? Next. Second question. What is answer of second one? Now you got the moles of C. You can write like this. C6H12O6. Here you have 12 carbon. 12 hydro... 6 carbon 12 hydrogen. You have 6 carbon. 12 hydrogen. 6 oxygen. 6 oxygen. 1 molecule of glucose. 1 molecule of glucose. 1 molecule of glucose. 1 molecule of glucose. 1 molecule of glucose. 1 molecule of glucose. So can I say that... 6 carbon 12 hydrogen. 6 oxygen. 1 molecule of glucose. 6 mol of carbon. 12 mol of hydrogen. 6 mol of oxygen. 6 mol of oxygen. in one mole of glucose, in one mole of glucose, right, we have not written, yes, yes, write gmm, where, where should you, where do you want to write, okay, where, here, gram molecular mass we have written now, definition, in note, in note, I have shown you gram molecular mass, one minute, remember, as a note in previous section, okay, 6 mol of carbon, 12 mol of hydrogen, 6 mol of oxygen in one mole of glucose, one mole of glucose, but you have just half mol, you have just half mol, implies in half mol, what will be the amount of all these, in half mol, it is 3 mol of carbon, 6 mol of hydrogen and 3 mol of oxygen, it is just a unitary method in half mol of oxygen, in half mol of glucose, did you understand students, yes or no, just I have applied the unitary method, you can directly, why I have written all these steps, those who get confused, for them I have written, otherwise I could have directly told you, if you have glucose C6H12O6, 6 carbon, 12 hydrogen, 6 oxygen in one molecule, so in one mole, same number of moles of carbon, hydrogen and oxygen respectively, okay, then if it is a half mol, then 3 mol of carbon, 6 mol of hydrogen, 3 mol of oxygen, students, did you understand till this point, okay, one minute, just a minute, okay, then it is easy now, gram molecular mass is same thing, like gram atomic mass, similarly you can write gram molecular mass, yes Seethu, gram atomic mass is same like gram molecular mass, like we have written relative atomic mass and relative molecular mass, same way just atom will be replaced by molecule in the definition of gram atomic mass, understood, second question of glucose, one minute, see this is second part, done, okay students, now we will go to the mentee, can I move to, can I close this, could I close this, fine, so now we are going to do questions on mentee, be ready, this is the code, please join in fast, this is the code, please join in quickly, 91681210, join in fast students, should we start, should we start, right, yes, no, can you see my screen students, right, fine, I am starting the quiz, first question is in front of you, consider that is standard temperature and pressure conditions only, standard temperature and pressure conditions, STP, students you have 40 seconds left, 12 students have already answered last 11 seconds, okay, fine, don't worry I will explain, how to do this question, see, okay, so here 20 gram, 20 gram of ideal gas is given to you, 20 gram of ideal gas, contains only sulphur and oxygen or atoms occupy 5.6 litre, 5.6 litre, so calculate the moles of ideal gas, moles of ideal gas, how much it is, moles of ideal gas is volume, given volume, I would write like this, given volume in litre divided by molar volume in litre, molar volume in litre, so given volume is, given volume is 5.6 litre, molar volume is 22.4 or 22.7, we will put 22.4 because it will give a good calculation, but actually it's a 22.7, so how like, what we will get after doing this, so it is like, fine, so it is how much, around 4, 1 by 4, right, 1 by 4, now they are asking that, they are giving that 20 gram of ideal gas contains only sulphur and oxygen atom, so you got the moles, you got the mole, so what is the, what they have asked, molecular weight of the, okay fine, very easy question, now apply that formula, moles are given to you, moles is 1 by 4, given mass is 20 gram, given mass is 20 gram, yes, yes that information is useless, given mass is 20 gram, then you need to calculate gram molecular mass, so formula, apply that formula, what, apply that formula, what to do in this case, yes, apply that formula, moles is equals to, implies moles is equals to, given mass divided by gram molecular mass implies gram molecular mass is 80, students, did you understand this question, did you understand this question, that to both concepts are applied in this, did you understand, both are applicable here, yes, okay fine, moving to the next one, moving to the next question, okay, so here, let us see how many of you have done this right, good, two more questions, a sample of ammonium phosphate, a sample of ammonium phosphate contains six moles of hydrogen atom, the number of moles of oxygen atom in the sample is, ammonium phosphate given NH4 whole thrice PO4 contains six moles of hydrogen atoms, the number of moles of oxygen atom in the sample is, we have done that, few minutes back we have did, we did this type of question, when I explained the glucose one, C6S2O6, there we counted number of atoms for oxygen and carbon and hydrogen, same way, you need to use the same thing to find answer for this question, six moles of hydrogen atom it has, the number of moles of oxygen atom in the sample is, very good, fine, how to do this, okay students, so to understand this question, ammonium phosphate you need to write, this is ammonium phosphate, yes, ammonium phosphate, they are saying six moles of oxygen you have, six moles of oxygen, so you can do like this, you can do like this, right now in one molecule, four threes are twelve, twelve hydrogen you have in one molecule when four oxygen atoms are present, when four oxygen atoms are present, twelve hydrogen are present in that molecule, implies when there are six moles of oxygen, because the stoichiometry won't change, the ratio of atoms combining won't change, so six moles of oxygen when combined, this means 12 by 4 into 6, so 2, 2 to 4, 2, 3, 1, 6, 8, is it clear to all of you, can you show question again, okay, one minute, just a minute, I'll show you that question, just a minute, fine, so here question is this, just a minute, this is the question, a sample of ammonium phosphate, six moles of hydrogen atom was taken, okay, six hydrogen taken, I took six oxygen to solve the question, six hydrogen taken, so very easy, when 12 hydrogen are there, four oxygen used, six hydrogen is there, two oxygen is used, that's it, understood, understood, yes, no, should I explain this, again, very easy, see, yes, how to say, six, fourth, six hydrogen, six moles of hydrogen you have, but right now in ammonium phosphate, you can see 12 hydrogens are there, so actually 12 hydrogens are there when there are four oxygen atom, so when there is six hydrogen atom, there will be only two oxygen atom present in the molecule, but here it's a six mole, so it will be two moles of oxygen atom, stoichiometry balance you need to see, any doubt students, could I move to next, could I move to next question, last question, right, okay, fine, so next is, last question of today's class, okay, do this, which of the following contains the largest mass of hydrogen atom, which of the following contains the largest mass of hydrogen atom, these are the molecule C2H2O4, C3H8O3, C6H8O6, C2H4O2, largest mass of hydrogen atom, moles are given to you, just calculate moles of hydrogen and find the answer, very easy, calculate moles of hydrogen in all the four cases, okay, I would help you a little bit, in first case, in one molecule there are two hydrogen in one molecule of C2H2O4, but they are total five moles, so total moles of hydrogen are 10 moles, in A option total moles are 10 for hydrogen, likewise calculate for all the cases, whichever is having the highest moles of hydrogen atom, that will be the answer, last question is this, okay, fine, a very easy question, oh good, 11 have answered it right, very, this is very good result, okay, see it's not a tough question at all, you have C2H2O4, C2H2O4 means in one molecule of C2H2O4, in one molecule total four hydrogen, two hydrogen atoms, in one molecule two hydrogen atoms, so in one mole, two mole hydrogen atoms, so in, so in a five mole, 10 mole hydrogen atoms, so likewise 10 mole hydrogen atoms are there, in this case, here it is 1.1 into 8, here it is 1.5 into 8 and the last one is 4 into 4, so this is the highest number, 4 into 4, what I am doing, four moles of this and four hydrogen atoms are present in one molecule, so 4 into 4, 16 moles of hydrogen are there, that is why this is having the highest, highest mass of hydrogen, for this I have shown the calculation, you can apply the same calculation everywhere, here you can directly get by 5 into 2, 5 into 2, students did you understand this question? Yes, no, all of you, okay, one minute, which this is with steps only, see, okay, okay, see in one molecule two hydrogen atoms, so in one mole of, in one mole of C2H4, two mole of hydrogen atoms, in five mole of C2H4, C2H2O4, 10 moles of hydrogen atom, right, so should I write for all the steps, for all the, should I write for all the options, did you understand, C2, is it clear, or should I write, okay fine, so just multiply the number of, fine, I have kept questions in assignment also, same type of questions, one or two questions you will get like this, so you can solve that, okay students, thank you, anyone has any doubt, please ask, if anyone has any doubt in this today's session, please ask, no doubts, sure, yes, leaderboard, yeah, that is the important thing, one minute, so who is the winner for today's quiz, we are going to see now, the leaderboard says that winner of today's class, winner, winner of today's session is, it seems Sarduli has won the quiz, congratulations Sarduli, congratulations Siddharth, Adya, Ralf, Risham, Ranjani, very good, okay students, thank you, bye, take care, finish your assignment on time, okay, fine, thank you.