Hello kids, today in the mole concept we will understand stoichiometry in which chemical equation is written and we have to tell how much volume, mass or molecules are formed to understand that, for the first 5-6 minutes, look carefully what we are going to tell by which you can find out the number of moles its relation with mass and its relation with volume the first formula which you will note is number of moles is equal to mass given divided by molar mass example we said find number of moles in 32 gram of methane. We have to find the moles of methane. Here is the methane. 32 grams of methane. Carbon's atomic mass is 12 and hydrogen's 1. So the formula for the number of moles is mass given.
How much mass is given? 32. Divide by molar mass. Ch4 molar mass. Carbon's 12 and hydrogen's 1 multiplied by 4. How much? 16. So this is molar mass.
How many moles are there? 2 moles. Whose 2 moles?
Methane's 2 moles. Let's take another example. Find number of moles of H2SO4 in 49 gm H2SO4. Hydrogen's atomic mass is 1, sulfur is 32, oxygen is 16. Mass given? How much mass is given?
49. Molar mass? Let's find out. H2SO4.
Hydrogen is 1, sulfur is 32, oxygen is 16. And how many atoms are there? 4. So, it becomes 2, 32, 34, 64. and 34, 60, 30, 90, 98 divided by 98, 49, 1, 0, 49, 2's are 98 0.5 moles Do you understand? Mass given, how do we divide it? Molar mass How do we calculate molar mass?
We will write the formula We will take the atomic mass of all and calculate Mass given upon molar mass Let's go around this question a little Now, you asked us Find Mass of 2 moles of sulfur dioxide Now we have asked about mass We don't know the mass given Let it be x What is the number of moles given? 2 What will we have to find? Molar mass So, Sulfur is 32 Oxygen is 16 So, we will find Molar mass 32 plus 16 into 2 32 is 64 divide by 64 x is equal to 2 into 64 how much is it?
128 grams, what is this? mass, so we asked for mass of 2 moles, we have to use this formula number of moles is equal to mass given upon molar mass ok, this time we gave moles and asked for mass so the first formula is this we will put this formula aside and start with the second formula, the second thing is Volume relation This formula we will write on the side Here we will write Number of moles We have written the first formula Mass given upon molar mass Formula no.2 Number of moles is equal to Volume given STP is standard temperature pressure divided by molar volume and molar volume is fixed at 22.4 L or 22.4 dm3 the volume given in the question is divided by molar volume which is the problem? number of pools let's start take an example find volume of Find volume of...
Find... Volume of 3 moles of carbon dioxide So, number of moles is given as 3 Volume to be found is x and cup to be found is at ST Molar volume 22.4 liters the x is equals to 3 into 22.4 liters 3 4s are 12 3 2s are 6 1 7 3 2s are 67.2 liters cub at STP How much volume will be occupied on the STP of carbon dioxide? formula Volume given upon molar volume molar volume 22.4 one more example find volume of 0.5 mol Nitric oxide at STP.
Volume asked, number of moles, 0.5. Volume given, this is asked, X. Molar volume, of any gas, of any gas, 32.4 liter.
on STP. Molar volume of any gas which can be any gas. From here x value will be 0.5 x 22.4 liters which will be So, this is the second formula of number of moles.
That means, number of moles can be related to volume and mass. How will volume be related to volume given? Upon 52.4. So, this is formula number 2. That's it.
I have kept it in two forms. Question start. I will not use the unitary method. You use the unitary method that this much gram is made of this much. No.
The name of the chapter is the basic concept. We will solve it with we will solve it in steps number of moles mass given upon molar mass number of moles volume given upon lets write it in short what is molar volume volume given divided by 22.4 L on STP or 22.4 decimetre Let's start the question Let's start the question Which one? Stochasticity In which equations are written Let's start the question Let's take easy question first CH4 plus O2 gives CO2 plus H2O Let's balance it Carbon is balanced You have to do for you do Now the question is, if 16 gm of methane is burned, find mass of CO2 produced. This is the stocking material. How much CO2 will be produced from 16g of methane?
You will ask, will you use this much from 16g? No, I will use the number of moles. The number of moles.
The mass of this is 16g. So, let's take out the moles. Number of moles.
What is the formula? Mass given divided by molar mass. How much mass is given? 16 upon molar mass. So how will molar mass be?
Carbon is 12. Hydrogen is 1, Oxygen is 16. So CH4, 12 plus 1 into 4, 16. How many moles are there? 1 mole. Now the question is, how much CO2 mass will be formed? Now I am not applying unitary.
Now pay attention to the mole concept and stoichiometry. Look at this equation carefully. The first condition is equation.
It should be balanced. This is a combustion equation. It doesn't matter.
Whatever chemical equation it is, it should be balanced. It is balanced. Cc is balanced, Oxygen is poor, and balance is hydrogen balance.
Now see what is written after this? Is it written as 1? What is written after this? It is written as 1. This means that 1 mole of methane gives 1 mole of CO2. This is written as 1 mole to 1 mole.
Kena coffee shoes Consider them as moles. For example, 1 mole of methane requires 2 moles of oxygen to give 1 mole of CO2 and 2 moles of water. So, 1 mole of methane is equal to 1 mole of carbon dioxide. How many moles are there?
1 mole. So, how much is carbon dioxide? How many moles will be formed? One mole. Question is over.
And what did we ask? Mass of CO2. So, we have got moles.
Now, let's apply the formula of number of moles. Mass given upon molar mass. What is the number of moles?
One. The mass of carbon dioxide is written as x divided by molar mass. This is the formula.
Let's write it here. number of moles is equal to mass given divided by molar mass this time we don't know mass, number of moles is 1 mass given x molar mass So CO2, carbon 12, oxygen 16 into 2, 32 or 12, 44, divided by 44, X is equal to 44 gram. So how much CO2 will be made? 44 gram. You could have done it in short.
but doing it in short is wrong because good questions are not done with short tricks ok, this is done let's change this question a little bit let's learn a new concept in this he asked me, fine volume of CO2 produced at STP started with 16 gm methane first of all what we have to find out is number of moles mass given upon molar mass mass given 16 molar mass carbon 12 hydrogen 1 oxygen 16 1 mole how much carbon dioxide is being made from 1 mole methane? 1 How many moles are there? There is only one, so how much will this be? One Now if we ask about volume So the formula for number of moles What is there for volume? Volume given upon molar volume which is 22.4 L and when it should be?
STP and question is also STP number of moles 1 volume given x divided by 22.4 L x is equal to 22.4 L volume also came ok so mass, volume, all the story could be done Let's change the question and bring a new one. And talk to you in a new way. Let's assume that they gave us an equation. They heated CaCO3.
Calcium carbonate is in the syllabus. Heating. calcium oxide plus carbon dioxide the equation is balanced calcium balanced carbon balanced oxygen 3 balanced the question is find volume of oxygen produced when 50 gram of CaCO3 is heated We have to find the volume of CO2 When 50 gm calcium carbonate is heated Calcium mass is 40 Carbon is 12 Oxygen is 16 So whose mass is given?
Calcium carbonate Let's find out the number of moles What will be the formula? Mass given upon molar mass Mass given is 50 divided by molar mass Calcium 40, Carbon 12, Oxygen 16 into 3 48, 12, 60, 40, 100 How much is it? 0.5 moles Now let's do the documentary If you don't write anything, write 1 this balanced, it should be balanced this number in balanced is called coefficient stoichiometric coefficient it represents moles means 1 mole calcium carbonate will give 1 mole carbon dioxide how much calcium carbonate we have 50 gram means how many moles? 0.5.
One mole makes one mole. So 0.5 will make 0.5 mole. But what is the question?
The question is volume of CO2. So we know the number of moles. What formula can we use?
Volume given upon 22.4 liters and the answer will be on STP the number of moles is 0.5 volume given is unknown and this is 22.4 liters so x is equal to 22.4 multiplied by 0.5 which is 11.2 liters the answer is 11.2 liters So, you are taking very easy questions. No, no, you will get good questions. First, let me teach you basics.
Now, let's raise the level of questions a little. Raise the level a little. We have C4H10.
CO2 plus O2 gives CO2 plus H2O. So the first thing is to balance the equation. This is butane. Char carbon is called butane.
balance it 3n plus 13 by 2 2nCO2 8CO2 by 10H2 this is the balance balance is given in exam question is find mass of carbon dioxide produced When mass of carbon dioxide produced, carbon dioxide mass is asking, when 5.8 gram of butane is burned this is combustion equation mass of CO2 produced what is given here 5.8 gram of putane so kids first of all number of moles what will you use mass given upon molar mass So, mass given is 5.8 We have to calculate molar mass Carbon 12, Oxygen 16, Hydrogen 1 So, 4 x 12 is 10 x 1 48 x 10 is 58 How many moles are there? 0.1 mole. So in the question, 5.8 gm of butane was given but how will we understand it? We will understand it as 0.1 mole of butane. Now comes the question.
What is this telling us? This is telling us the ratio of moles. 2 moles of butane gives 8 moles of CO2.
So, if I had 2 moles of butane, then I would have made 1 mole of butane. carbon dioxide if 1 mole of butane is there then it would be 1 divided by 2 4 mole carbon dioxide from 1 mole, we are getting 4 from 2, we are getting 8 question is, 5.8 gram means, 0.1 from 0.1 mole, how many moles will we get? from 1 to 4, 0.1 0.4 mole CO2 Answer is 0.4 moles CO2 This much CO2 will be produced from 5.8 gm but the question is mass of CO2 No problem, number of moles is equal to mass given upon molar mass Number of moles is 0.4 mass given x molar mass Carbon 12 oxygen 16 into 2 16 x 2 is 32 or 12?
44. Divided by 44. x is equal to 0.4 multiplied by 44. 4 x 4 is 16. 4 x 4 is 16. 17.6 grams. 17.6 grams of carbon dioxide. So, we have to solve this question. First, what do we get? Number of moles.
The mass of which we have given. Then, look at the coefficient. And then move on. Let's go around the question.
Find... Mass of Oxygen Required The same question, just a little change Mass of Oxygen Required when 5.8 gm of butane is burned Now we are talking about Oxygen So, how much Oxygen is being produced from 2 moles? 13 2 moles of C4H10 is being produced 13 moles of Oxygen 1 mole C4H10 will make 13.1 mole O2 We have 0.1 mole 0.1 mole C4H10 will make 13.2 into 0.1 mole O2 This will be 0.65 mole of O2 got the answer?
how much oxygen will be produced? 0.65 do you understand the method? who gave us the mass of butane?
We have taken the number of moles of butane, mass given, divided by molar mass and here it is. When we do all this, then there is no difference. When we do all this, then first take out the number of moles.
Now check the equation. How many moles are required for 2 moles? 13. How much is required for 1 mole? 13 by 2. So for 0.1, 13 by 2 into 0.1. How much is it?
6.5, 0.65. What did you ask? Mass of O2. So.
number of moles is equal to mass given upon molar mass so how much is the number of moles? 0.65 mass given x of 16 multiplied by 2 is 32 32 multiplied by 0.65 grams What are you doing? You! In the concept of moles, always find out the moles.
Don't worry about mass-vast, that you have to use so much of unity, no, no, no, no. No, you have to do it with moles. So, Hamze said 5.8 gm butane, so we won't work on mass. First, we will find out the number of moles given by butane.
Then we saw that 13 is required for 2 moles, so 1 mole is required, so 0.1 mole is required. These are the moles of oxygen. Now, we have to go back to mass. So, number of moles is equal to mass upon molar mass. Let's increase the level of the question Let's take another question Take care of it We gave the question Let's change the pattern of the question We gave the question CucO3 was heated and it became CuO plus Cu2 This is the reaction we gave We asked Find mass of CucO3 required To produce, to produce, to produce 11.2 liters of carbon dioxide at STP.
Up! The mass of CO2 is 11.2 L Carbon is 12, Oxygen is 16, Hydrogen is not there and Copper is also there So I am taking 63.5 of copper as 64 so that the calculation is correct This is what I have given in the exam How to start? This time I said 11.2 L of CO2 So we have to start the question with CO2 Is the equation balanced?
So, we have to start with 11.2 L CO2. Will we question the volume? No, we will question the moles. So, let's find the number of moles of carbon dioxide. Formula, volume given upon 22.4 L.
Volume given 11.2 L divided by 22.4 L Answer is 1 by 2 which is 0.5 moles So, he is telling us how many moles of carbon dioxide are there 0.5 moles What is the answer of copper carbonate? mass so we will not take out mass, what will we take out? moles here 1 here 1 here 1 if carbon dioxide had 1 mole then copper carbonate would have also become 1 mole 1 mole would have been made from 1 mole how many moles are there?
0.5 so how many moles will be there? 0.5 moles mole concept now we have asked mass so number of moles is equal to mass given upon molar mass number of moles 0.5 mass given is not known x molar mass so copper 64 carbon 12 oxygen 16 into 3 so this will be 64 plus 48 plus 12 so this will be 61 24 so X is equals to 0.5 into 124 this will be half that is 62 gram so 62 gram copper carbonate requirement will be there to make 11.2 liters of CO2 and you can solve the question with this So whatever is given in the form of volume or mass, first remove its base. then look at the equation how many moles are making 1 so 0.5 will be made 0.5 is here Now if we want mass, then the formula of number of moles is mass upon molar mass.
In this way, you can solve the question of stoichiometry. Shall I take one more question? Absolutely, brother, let's take one more question.
We will not stop, we will take one more question. Let's assume that we were given that, let's take this. CaNO3 whole twice. I am taking the reaction randomly of your syllabus.
When we heat calcium nitrate, then calcium oxide, nitrogen dioxide is formed. and oxygen is needed. We will balance it.
2,2,3,4,2,2,3,6,6,2,12,2,4,2,3,4,2,2,10,2,12. Ok, we have balanced it. Now the question is, find mass of calcium oxide produced when when 5.6 liters of NO2 is produced STP What is the mass of CO? This What is the DIA?
5.6 L of NO2 This is the mass of all the elements Calcium is 14 Nitrogen 14 Oxygen 16 Who else? Now, we have given 5.6 liter of NO2. So, first of all, we will calculate the number of moles of NO2.
These are of equation. Don't think that these are the moles. The moles which are given... what is the number of moles in this formula?
volume upon 22.4 volume is there so we will add volume volume 5.6 divided by 22.4 1 by 4 is 0.25 moles how many moles are there in this question? 0.25 moles. in question 5.6 L elementally a movement 0.25 Now the question will go towards calcium oxide. Here. So we have to come from here.
If it had 4 moles, the equation tells that if it had, this document tells that if it had, if it had 4 moles, then how many moles would calcium oxide have? 2 moles. So if I had 4 moles of NO2, then how many moles would calcium oxide have? 2 moles.
So if there is one mole of nanotube So, how much will be the amount of NO2K? 2 x 4 mols of calcium oxide. But, how much is the amount of NO2K?
0.25 mols. So, if the amount of NO2K is 0.25 mols, then it will be 2 x 4 into 0.25 mols of calcium oxide. Do you understand?
4 mols are 2. 1 mol is 2 x 4. 0.25 is 2 x 4 into 0.25. So you will get 2 into 0.25. So you have 0.125.
Calculation is a little fast, keep your mind on it. 4 would be 2, means this is half of it. See, instead of 4, 2. So, 0.25 is half.
0.125 mol of CaO. So, how much CaO is 0.125 mol? Did you get the answer?
What did you ask? Mass. We can get the mass.
We can get the mass. How will we get it? Kése nika lé ni maas.
How to find it? Let's apply this formula Number of moles is equal to mass given upon molar mass Let's apply this Number of moles of calcium oxide is 0.125 Mass given to x and molar mass of calcium oxide is Calcium 40, Oxygen 16, 56 Mass will be x is equal to 56 into 0.125 Whose mass is it? Calcium Oxide So we were asked the mass of calcium oxide produced when 5.6 L of NO2 is given So we changed 5.6 L of NO2 into the number of moles 5.6 upon 22.4, how many moles are there? 0.25 Now 4 moles are formed when it has 2 moles Means half of it, half So 0.25 will be formed when half of it is 0.25 Once the mole is found, it is easy to find the mass Number of moles, mass given upon molar mass No. of moles is this, mass given is unknown, molar mass is 40 plus... Don't multiply by 2 in molar mass, use molecular formula only in molar mass.
So, this way you can solve any question of mole concept which is related to this documentary. Take one more question, the more questions you ask, the stronger the topic. For example, C2H2 is acetylene in organic chemistry.
I will also close the equation. So, equation will be 2, 5, CO2, H2O, 4, 4 to the 8, F to the 10, 2. It is balanced. The question is, find mass of O2 required.
O2 required to produce to produce 44.8 L of carbon dioxide and STP 2 things are remaining O2 and carbon dioxide Now we will calculate the volume of carbon dioxide. Number of moles is equal to volume given 44.8 divided by 22.4. So, we have volume given upon molar volume.
How many moles are there? 2 moles. So, in the question, we have given 2 moles of carbon dioxide.
Now we have to calculate the mass of O2. So, let's run this way. Now we are getting to know from the balanced equation that 4 moles of CO2 is equal to 5 moles of O2.
So, 1 mole CO2 is equal to 5 by 4 mole O2. How many moles are there in the question? 2 moles. So, 2 moles CO2 is equal to 1 mole O2.
2 mol is equal to 5 by 4 into 2 mol O2 5 by 2 is equal to 2.5 mol Oxygen moles are 2.5 mol Question is mass of O2 Oxygen atomic mass is 16 is equal to mass upon molar mass we can write it number of moles is 2.5 mass is to be taken out x molar mass O2 16 x 2 is 32 when we take out molar mass we don't count it only molecular formula divided by 32 x is equal to 2.5 multiplied by 32 so this will be whatever it will be that will be what in grams Let's talk about this question in another way Find the mass of Acetylene required to produce 44.8 L of CO2 So, how do we convert 44.8 liters of CO2? In the number of moles, 44.8 divided by 22.4. How many moles are there? 2 moles.
Now, where do we have to go? Towards the acidity. 4 moles are made from 2 moles. Means, half of it. How many moles are there?
2. So, how will 2 be made? From 1 mole. Question is mass, number of moles is equal to mass given upon molar mass Carbon mass is 12, hydrogen 1, molar mass is 2x12 plus 1 1 x 2 is 24 x 2 is 26. I didn't multiply by this. Only this molar mass 26. So, 1 mole is formed.
The mass is unknown. Molar mass 26. x is equal to 26 grams. So, 26 grams of acetylene will be formed. 44.8 liters of CO2.
The question is solved. The question on the number of moles is easy. The question is broken.
It is a very big question. It will be broken in a very easy method. If we use which approach?
number of moles and use the number of moles in the equation So, these are the tabulations of this documentary Thank you