Mole concept part 1

Added: 2026-05-11

[00:00:00]now children I came to a very important part in chemistry that is your whole concept it's very very important it's very important many of the children they have a doubt in the MOL concept so please listen from the beginning very carefully and pay attention to it and make a note of it thoroughly so first of all what is a mole a lot go to the definition I have already given the definition in your notes here also I have you can say I've written a particular definition I am coming to again the concept first you understand always understand the concept definition in formula you can understand it you can learn it and you can understand it but you need to understand the concept first so what is a mole if somebody is asking me what is a mole sir mall I will say to him it is a chemist unit of counting particles chemists you know our chemist the person who study chemistry for it who is a master of chemistry we can say there sativas chemist so mole is a chemists unit of counting particles particles means particles means not that path or unconquered understood that's not particles here here the particles means atoms molecules ions electrons protons etcetera they are said to be us again I repeat if you ask me what is a mole I will say to you in simple words mole is a chemist unit of counting particles particles here are atoms molecules ions electrons protons etc they are known as the particles now you know in the next question I'm asked what is a what is the need necessary to count these particles why do why should I do so fine let me ask you again a question here for example when you go to a market to buy some let us say you are going to buy some super rice how do you buy how do you buy it what is a unit cell a byte in kg I buy it in grams okay you buy it in case your grams Rama that's clear now you want to buy some egg then how do you buy it in kg or in gram no we buy it in dozens correct now suppose you want to buy some oil how did suppose you want to buy mustard oil or you are going to a petrol pump and you are want to put oil in your vehicle how in what way you measure it kg doesn't know liter he measure in liter find correct we measure it in liter oil we measure in liter fine now you want to buy some pencils or some pen how do you buy it litter gram doesn't know byte in score score means what unit one score is 20 unit you read in the lower classes so in this way what we find is that in our day-to-day life we have got different units for different measurements different units and all are independent of each other independent they do not depend upon one another to buy eggs do you need to know the unit of oil or either the relations between oil and egg or is there in relations on egg and pen or pencil is the relations between pencil and rice no nothing all are independent of each other nothing there is no relationship at all you know day to day life it is not required also if suppose somebody is one-to-one to put petrol in his vehicle should you know that what is in it of egg in which we unity is buying or rice in which unit is buying or pencil in which unit is buying not necessarily not at all there is no relationship in our day-to-day life so hence these units are independent we buy it independently we see it independently but in chemistry in chemistry lab not it atoms molecules ions are eight electrons all these are not independent they are dependent upon one another you say how how it is dependent upon one another for example I am giving you an equation you write on take out a pen and copy and write zinc plus sulfuric acid Zn plus h2 so4 what it will give you ZN s so 4 plus h2 doesn't it it will give you hydrogen gas now I'm asking you you do one thing I have giving you 5 gram of zinc tell me the amount of hydrogen gas produced in liters what did I ask you I asked you that I gave you five gram of zinc you tell me how much hydrogen gas is produced in liter that means there is a relationship between mass and volume there is a relationship you have to now do it in unitary method this one what you need to do you have do you have to first find the atomic weight of zinc sorry you need to find that chemically weight of zinc so little static weight of zinc is 65 so 65 gram gives let us say 20 2.4 liter of hydrogen okay when you balance equation you will get it Zn plus it Joseph or gives at any so 4 plus h 2 so it's 2 means 1 that is nothing but what that is 1 molecule which is otherwise known as 1 mol you will come to know later on so one molecule or 1 mol what is the volume I told you already twenty two point four liter which is known as the molar volume of the gas at STP 22 point four liter so hence 65 gram of zinc gives 22 point four liter of hydrogen but I asked you five gram how much it will give five gram will give twenty two point four by sixty five into five so here you need to know the relationship between weight and volume the sentence which has said you we come to know how do we come to know this particular relationship by looking at the sentence we derive it we understand it that here zinc means one small body can say atom of zinc so what is the atomic weight of zinc it is 65 grams how much hydrogen we are getting it one molecule so what is the volume 21 per liter so 65 gram this one 2.4 liters of hi gram will give you how much similarly I may ask you also that tell me that the 5 gram of zinc requires how much of weight of sulfuric acid how much sulfur gas it requires so this is a relationship between weight and weight because I have given you the mass of zinc and I am asking you the mass of sulfuric acid so there is a relation Suton mass and mass in the previous case what we did we read the relation since between mass and volume so how do you find sulfuric acid same thing you find the molecular weight of sulfuric acid it is 98 so 65 gram of zinc requires 98 grammer sulfuric acid write it down students all these things you write in your copy if you just simply listen to the you will not understand it is a time to write now 65 gram of sing will give you 98 grammar sulfuric 68 65 gram of zinc requires 98 gram or sulfuric acid 5 gram requires how much 98 as 65 into 5 entry method in this so you can calculate so here there is a relationship now which particular unit now see here we are having a relationship in mass and volume we are having a relationship in mass and mass it can be volume on volume it can be number of atoms and masks anything so you need a unit a particular you need a standard unit which will establish the relationship between all these between mass and mass between mass and volume between volume and volume between mass and atoms so that unit that standard unit is known as what moles so hence I said you that is small is a chemist unit of counting that is particles for that reason I said you so remember that mole is that standard unit which establishes a relationship between mass volume atoms what you can say anything we can say that he did establish a relationship not it because when you when you are doing the mole concept questions you will see that when you are doing the mole concert question you will be getting an equation now in that equation zinc is in the form of solid sulfuric acid in the form of liquid zinc sulphate you got a solid and hydron is a gas so in one particular equation you can see solid is there liquid is there gas is there in our day-to-day life are we having this this sort of thing are we dealing with no but in chemistry we deal with so for that reason we require high unit a standard unit which will establish the relations between them and that standard unit is known as mole for that reason mole is required because more will establish the relations between that you can see the bottom akin is given you a particular art mind map I've given you to understand about the more in short did you get the idea of more now or it what is small it is nothing but a unit a standard unit we can say that now we will come to the definition which I have given you now this definition have learned in the lower class is also a mole is that amount of the substance which contains as many elementary entities as there are atoms in exactly 12 gram of carbon-12 isotope C - 12 isotope the elementary entities must be specified that is whether there are atoms molecules ions electrons or any other entity so we are going to compare this elementary entities that is adams molecule science with unknown what you can say entities of carbon that is carbon we take it because i said you that that carbon is the most stable isotope not it that is c 12 isotope because it can be stored easily it does not get deactivated it is it is generally available in the pure state it is readily available and so many other things are there not it so hence really you use carbon we can say that here so when we compare with the number of atoms and our number of molecules and number of ions or the volume of the carbon or the mass of the carbon with the unknown one which we have to find then we get the moles so let us come to that formula first so in your notes you can see I have given you the definition of moles in three ways I have given you in terms of volume I've given you in terms of number and I have given you in terms of weight I've given you how did the definition of mole you can see in terms of that is volume what is the definition of more in terms of volume in case of gases a mole is defined as that amount of the gas which has volume of twenty two point four liter at STP very simple it as I said you one mole our volume is how much twenty two point four liter of gas so one mole of any gas rumor that's gas it is gas you would say one mole of water water is not I guess but if its water vapor then it is a gas so don't say that that particular thing he would say one mole of sodium chloride is tendu 2.4 liter now sodium chloride is a gas No so when you say when you think of think logically and assume so it is for gas only twenty two point four liter or 2.4 decimeter you because remember that one liter is 1 decimeter cubed okay or it can be also 22,400 ml hot 20 2400 CC because one liter is thousand CC and one ml is 1 CC anything it can be it depends upon how the question is given to you whether it is given in terms of liter or decimeter cube or in CC CC means centimeter cube orange is given in ml so remember it 1 ml is 1cc please write down 1 li trees 1 decimeter cubes are twenty two point four liter is equal to twenty two point four decimeter cubed 22400 M L how do we get it because vonlee trees thousand ml you multiply thousand twenty two point four in two thousand a match will get twenty two thousand four hundred ml or twenty thousand four hundred cc so one mole of any gas at STP occupies this much twenty two point four liter for twenty two point four decimeter cube or 20 2014 ml or hundred thousand four hundred cc in terms of volume this is nothing but one mole of any gas mole is represented by small letter and see that I've given you next in terms of number how much is one mole in terms of number what is the definition I've given a mole is defined as that amount of the substance which contains Avogadro's number of atoms Avogadro's number is six point zero two three or six point zero two 2 into 10 to the power 23 atoms if the substance is atomic or molecule is the substances molecular or ions of the substance is ionic anything so hence I've given you in terms of number you can see six point zero two three 10 to power 23 atoms or ions or molecules in whatever way the question is given if the question is give me a form of elements then it will be atom if it is getting the form of compound or molecules it will be molecules six one zero two thin 10 to the 23 molecules and if it is going in the form of ions like na plus iron cl- ions then how how much is one mole six point zero two three in 10 to the power 23 I am sodium ions or six one zero two three 10 to power 23 chloride ions that is known as one mole so in terms of number from that one mole is this many number of particles together we call it as particles one mole is six point zero two three in 20 10 to the power 23 particles one mole remember that or it's one mole is this many particles one mol of molecule one mole of atoms one mole of iron is how much have a good rows number one more in terms of weights now it can be if it is element atomic weights if it is compound or molecules molecular weight if it is any compound and formula MIT so atomic weight one mole is how much like 12 gram of carbon see it is what one mole of carbon there is a weight of one mole of carbon so atomic weight is nothing but the weight of one mole of an element I've given a the example there 12 gram of carbon 23 gram of sodium what are they they are the atomic weight of the element 35.5 gram of chlorine atomic weight of chlorine got it 16 drama Fox in is the atomic weight of oxygen clear similarly molecular weight 44 gram of carbon dioxide is nothing but the weight of one mole one molecule what it 18 gram of water is a weight of 1 mole water is what molecule is a compound what it's a molecular weight is nothing but is equal to 1 mole atomic weight is nothing but is equal to 1 mole got it formula which I told you just now to you 58.5 gram of sodium chloride that is what the formula mass same as that of a molecular mass also off is nothing but the 1 mole of sodium chloride if I ask you what is the weight of 1 mole of sodium chloride 58.5 gram if I ask you what is a weight of 1 mole of glucose glucose is what glucose is what glucose is covalent compound so you find it out glucose formula is c6h12o6 so what is the weight of one mole molecular weight 180 gram got it so it depends upon if I say sodium atom equate you take that to me quit as one mole if I take glucose molecule compound you will take the molecular weight if I take potassium chloride it is a formula weight that is one mole so I think it's clear one mole it's how much now let me come to the formula thank you in the next one