Hello kids, today we will understand stoichiometry in the mole concept in which chemical equation is written and we have to tell how much volume, mass or molecules are formed to understand that, watch carefully for 5-6 minutes of the beginning which 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 gram of methane Carbon's atomic mass is 12 Hydrogen's 1 So the formula of number of moles is mass given How much mass is given? 32 Divide by molar mass C H4 molar mass Carbon's 12 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, 2s 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, we were asked to find Mass of 2 moles of sulfur dioxide Now we have asked about mass We don't know the given mass Let it be x What is the number of moles?
2 What will we have to find? Molar mass So, Sulfur is 32 Oxygen is 16 So, let's find Molar mass 32 plus 16 into 2 How much 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 this time we gave moles and asked for mass so the first formula is this we will put this on the side and start with the second formula second thing is Volume relation This formula we will write on the side Here we will write We have written the first formula of number of moles 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 both are same the volume given in the question, divide it by molar volume this is molar volume whose problem is it? number of bolts let's start take an example find volume of Find volume of, find volume of three moves of carbon dioxide so number of moles given is 3 volume to find is x and when to find is at STP molar volume 22.4 L so x is equal to 3 into 22.4 L 3 x 4 is 12 3 x 2 is 6 1 x 7 is 67.2 L when at STP 3 moles On carbon dioxide's STP, how much volume will occupy 67.2? Volume given upon molar volume. Molar volume 22.4 One more example.
Find volume of 0.5 mol of nitric oxide at STP. volume asked number of moles 0.5 volume given asked x molar volume of any gas of any gas 22.4 liter when on STP when on STP molar volume of any gas which can be any gas from here x value will come 0.5 into 22.4 liters which will be 11.2 liters. So this is the second formula of number of moles That is, we can relate number of moles with 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 taken two formulas Question starts I will not use the unitary method You use the unitary method that this much is made from this gram and this much is made from this No The name of the chapter is mole concept We will solve the concept from the mole concept we will solve it with concept 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 of STP or 22.4 decimetre cube good two things for you lets start the question whose question of stock your mystery in which equations are written Lets start with easy question first. CH4 plus O2 gives CO2 plus H2O. Balance it. Carbon is balanced. Here 2, 4. 2, 2, 4. Balance.
Now what is the question? Question is, if 16 grams of methane is burned Find mass of CO2 produced. This is the stoichiometry. How much CO2 will be produced from 16g of methane? You will ask, will 16g produce this much?
No, I will ask the number of moles. The mass of 16g is given. So, let's find 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 is 12 plus 1 into 4 is 16. How many moles are there?
1 mole. Now we are asked how much CO2 mass will be created. Now I am not applying unitary. Now pay attention to what is the mole concept and what is stoichiometry. Look at this equation carefully.
First condition is that the equation should be balanced. This is a combustion equation. It doesn't matter if it is any chemical equation. It should be balanced.
Cc is balanced, Oxygen is poor, O is balanced, Hydrogen is balanced. Now see what is written after this? One is written. What is written after this? One.
This means that one mole of methane gives one mole of CO2. This is written as 1 mol to 1 mol. These coefficients, consider them as mols. For example, 1 mol of methane requires 2 mol of oxygen to give 1 mol of CO2 and 2 mols of water.
So, 1 mol methane to 1 mol carbon dioxide. How many mols are there? 1 mol. So, how much carbon dioxide will be made? 1 mol.
Question is over. But what did we ask? Mass of CO2.
So, Molesville Gang Let's write the formula for number of moles Mass given upon molar mass Number of moles is 1 Mass of carbon dioxide is x Divided by molar mass This is the formula Number of moles is equal to mass given Divided by molar mass This time we don't know the mass Number of moles is 1 Mass given is x Carbon 12, Oxygen 16 x 2, 32 and 12, 44, divided by 44, x is equal to 44 gm. So how much CO2 will be made? 44 gm.
You could have done it in short, but doing it in short is wrong because good questions are not done with short tricks. Okay, this is done. Let's change this question a little bit.
Let's learn a new concept in this. Hansen put up fine volume of CO2 produced at STP 16 grams of methane is the starting point so what is the number of moles of methane? mass given upon molar mass mass given 16 molar mass is carbon 12 hydrogen 1 oxygen 16 1 mole how much carbon dioxide is being produced from 1 mole methane? how many moles are there?
1 so how much will be produced? Now, let's talk about volume. The formula for number of moles is volume given upon molar volume which is 22.4 L and when it should be? STP and the question is STP number of moles 1, volume given x divided by 22.4 L x is equal to 22.4 L volume is also here 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 we are given an equation CaCO3 is heated Calcium carbonate is in the syllabus heating calcium oxide plus carbon dioxide Is the equation balanced? Calcium balanced, carbon balanced, Oxygen free, balanced The question is Fine.
Volume of Oxygen produced when 50 gm of CaCO3 is heated We have to extract volume of CO2 When 50 grams of calcium carbonate is heated Let's go Calcium mass 40 This is given in the question Carbon 12 Oxygen 16 So whose mass is given? Calcium carbonate Let's go Let's take out the number of moles Which formula will we use? Mass given upon molar mass Mass given is 50 divided by molar mass Calcium 40, Carbon 12, Oxygen 16 into 3 Calcium 48, Carbon 12, Oxygen 60, Calcium 40, Calcium 100 Calcium 40, Carbon 12, Oxygen 60, Calcium 100 Calcium 40, Carbon 12, Oxygen 60, Calcium 100 Calcium 40, Carbon 12, Oxygen 60, Calcium 100 Now let's do the documentary If you don't write anything in front of this, 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. 50 gram means how much mole?
0.5. Made from 1 mole, 1 mole. So, made from 0.5, 0.5 mole.
Question is, what is the number of moles? Volume given upon 22.4 L and the answer is STP So, the number of moles is 0.5 Volume given is unknown, so we have to find out the volume and this is 22.4 liters so x is equal to 22.4 multiplied by 0.5 which is 11.2 liters answer is here how much carbon dioxide will be produced? 11.2 liters so you are taking very easy questions no no you will get good questions too first let me teach you the basics let's raise the level of the question a little raise the level a little we have we have C4H2 plus O2 gives CO2 plus H2O so the first thing is to balance the equation this is butane, butane 4 carbon, so we call it butane rest of the things we know so we will balance it, so 3N plus 13 by 2 so we have 2, NCO2 2, 8CO2 10H2 this is balanced, ok Very good.
He gives balance in exam most of the time with these questions. What is the question? The 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 butane 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 there 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 8 divided by 2 4 mole carbon dioxide from 1 mole, how many moles are we getting? 4 from 2, we get 8 question is, 5.8 grams means how many moles? 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 such questions. First, what do we get? Number of moles.
The mass of which we have given. Then, look at the coefficient. And then, we will come.
Let's go and turn 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, from 2 moles, how much Oxygen is being made?
13 2 mol C4H10 is making 13 mol of oxygen means 1 mol C4H10 will make 13 by 2 mol O2 How many moles do we have? 0.1 So, 0.1 mole will be made from C4H10 13.2 x 0.1 mol O2 How much will it be? It will be 0.65 mol of O2 Got the answer?
How much oxygen will be made? 0.65 mol 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 two moles? 13. How much is required for one 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 put 0.65 here mass given x of molar mass of 0.16 multiplied by 2 is 32 mass will be 32 multiplied by 0.65 grams I'm saying this now. Now- In the concept of moles, always find out the moles.
Don't worry about mass-vast, that you have to use so much mass for unity. No, no, no, no. Use moles.
Do it with moles. So, Hamze said 5.8 gm of butane, so we won't work on mass. First, we will find out the number of moles for butane.
Then, we saw that 13 is required for 2 moles. So, 1 mole is enough. So, how much for 0.1 mole? 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 a question Let's change the pattern of the question We gave a question CucO3 was heated and it became CuO plus Cu2 We gave this reaction We asked Find mass of CucO3 required to produce 11.2 liters of carbon dioxide at STP Now, its mass is given as 11.2 liters of CO2 Here, carbon has 12, oxygen has 16, hydrogen has none, and copper has 63.5 I am taking 64 for the calculation I am giving this in the exam How to start?
This time we will talk about 11.2 L of CO2 So we have to start the question with CO2 Is the equation balanced? Yes it is balanced So we have to start with 11.2 L CO2 Will we start with the volume or the moles? So we will take the number of moles of carbon dioxide Formula is Volume given upon 22.4 L Volume given 11.2 L divided by 22.4 L, the answer is 1 by 2, which is 0.5 moles. So, he is telling us that how many moles of carbon dioxide are there in 0.5 moles.
What is asked? The mass of copper carbonate. So, we will not find the mass, what will we find? Moles. Here 1, here 1, here 1. If there was 1 mole of carbon dioxide, then 1 mole of copper carbonate would have been formed.
1 mole. It is made up of one mole. Here, how many moles are there?
0.5 So, how many moles will it have? 0.5 moles. Mole concept.
Now, we have asked about 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 so this will be half that is 62 gram so 62 gram copper carbonate requirement will be 11.2 liters co2 to make and you can solve the question with this.
So whatever thing is given in the form of volume or mass first, take out the modes then look at the equation that how many moles are making 1? so who will make 0.5? 0.5 comes till here Now if we want mass then the formula of number of moles is mass upon molar mass.
In this way you can solve stoichiometric questions. 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 are 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. We will balance it.
2,2,3,4,2,2,3,6,6,2,12 2,4,2,5,6,7,8,9,10 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 particles Calcium is 14 Nitrogen 14 Oxygen 16 and who else? Now, we have given 5.6 liter of NO2. So, first of all, we will calculate the number of moles of NO2. This is a part of the equation. Don't think that these are the moles.
The moles that are given are... what are the moles in this? number of moles is equal to which formula we have used?
volume upon 22.4 if we have used volume then we have used volume formula number of moles we will take out volume 5.6 divided by 22.4 this will be 1 by 4 means 0.25 moles how many moles are given in this question? 0.25 moles in question 5.6 liter we converted it into moles 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 of calcium oxide would there be? 2 moles. So if I had 4 moles of NO2, then how many moles of calcium oxide would there be? 2 moles. So if there is one mole of nanotube So, how much will be the value of NO2K?
2 by 4 moles of calcium oxide. But, how much is the value of NO2K? 0.25.
So, if NO2K is 0.25 moles, then it will be 2 by 4 into 0.25 moles of calcium oxide. Do you understand? 4 moles are 2, 1 mole is 2 by 4, 0.25 is 2 by 4 into 0.25. so you will get 2 into 0.25 they are the 0.125 of calcium oxide keep the calculations fast 4 So, 0.25 is equal to 0.125 mol of CaO. So, what is the answer?
What is the answer? Mass. We can calculate mass.
How can we calculate mass? Let's put this formula. Let's apply this. Number of moles is equal to mass given by mass. given upon molar mass can we apply this?
number of moles of calcium oxide is 0.125 mass given is x and molar mass is calcium oxide calcium 40 and oxygen 16 how much is it? 56 calcium 40 and oxygen 16 16 56 here the mass will be X is equal to 56 into 0.125 whose mass is here? calcium oxide so we will be asked the mass of calcium oxide produced when 5.6 liter of anode So we changed 5.6 liter NO2 into number of moles. 5.6 divided by 2.4 is 0.25. Now 4 moles are formed when it has 2 moles.
Means 0.25 will be formed when it has 0.25 moles. Once the mole is formed, it is easy to calculate the mass. Number of moles, mass given upon molar mass.
Number of moles is this. Mass given is unknown. Molar mass is 40 plus.
Don't multiply by 2 in molar mass. only use molecular formula 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 like we were given C2H2 this is acetylene from organic chemistry and I will also burn acetylene plus O2 so the equation will be 2 5 here will be CO2 here will be H2O so this becomes 4 and this becomes 4 to the 8 to the 10 so 2 balanced question is find mass of O2 required to produce To produce To produce 44.8 L of carbon dioxide and steam Two things are left O2 and carbon dioxide Now we will find 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 find the mass of O2. So, let's run this way.
Now, from the balanced equation, we know that 4 mol CO2 is equal to 5 mol O2. 4 mol CO2 is equal to 5 mol O2. That means 1 mol CO2 is equal to 5 by 4 mol O2. How many are there in the question?
2 mol. So 2 moles CO2 1 mole 2 mol is 5 by 4 into 2 mol O2 5 by 2 is 2.5 mol Oxygen moles are 2.5 mol Question is mass of O2 Oxygen atomic mass is 16 Do you know number of moles? So number of moles is equal to mass upon molar mass number of moles is 2.5 mass is x molar mass is O2 16x2 is 32 when we calculate molar mass we should not count it only molecular formula Thaidu.
x is equal to 2.5 multiplied by Thaidu. So this will be whatever it will be. That will be what in grams. Let's go around this question a little more.
Let's talk about this question in some other way. Let's talk about this question in another way. Find the mass of acetaminophen. find the mass of acetylene required to produce 44.8 liter of CO2 so what is the number of moles to convert 44.8 liter of CO2 into? 44.8 divided by 2.4 4 is equal to 2 moles.
Now where do we have to go? To the acidity. 4 moles are made from 2 moles. Means half of it.
How many moles are there? Two. So, how will two be made?
From one mole. Question is, what is mass? So, number of moles is equal to mass given upon molar mass. Carbon's mass is 12, hydrogen's mass is 12. 1, its molar mass 2 x 12 plus 1 x 2 24 x 2, 26 I didn't decline this, only this this molar mass 26 so 1 mole is made, we don't know the mass molar mass 26, x is equal to 26 grams of acetylene will be made from this 44.8 liters of CO2 So the question is solved Question on number of moles is easy Question is broken Very big question Will be broken in very easy method If we use which approach Number of moles Which approach?
Using number of moles So these are the definitions of this documentary Thank you