Hello everyone, I'm Susi and welcome to my channel. In this video we are going to work with the law of ideal gases, so let's get to it. Here we have the equation of ideal gases. P by V equals nRT. What is the equation of gases? Well, what do we do in this equation? We are multiplying P by V equals n by R by T. What is each letter? P, pressure, okay? And it is given in atmospheres. This is the unit that we use for pressure. V, volume, we are going to give it in liters, okay? The unit we give is liters. N is the number of moles, R is a constant of gases, we do not have to learn this. We have to learn, because we do not know that an atmosphere is 760 millimeters of mercury, okay? Well, we have to know this constant, 0.082, okay? And also the units, but come on, this is easy because they are the rest of the units that there are. Do you realize? Atmosphere per liter per mole per Kelvin, okay? So you will see that after using it so much, in the end you will end up memorizing it, so there is no problem. And then T is the temperature that we are going to give in Kelvin. Remember that to find the temperature in Kelvin we have to add to Celsius 273. Let's see now how we would apply this law of gases in a problem. We have this one that tells us that a cotton swab contains 12 kilos of gas and asks us to calculate the volume knowing that it is at an atmosphere of 25 Celsius. We are going to summarize the data, I have already summarized them, okay? We have this compound of which we have 12 kilos, 12 kilos is mass, okay? We must see that 12 kilos belongs to the mass. They ask us for the volume, the volume is going to be our unknown, they give us an atmosphere, an atmosphere. We must know that if that atmosphere is the unit of the pressure, okay? So an atmosphere is the pressure and they also tell us that they are 25 degrees Celsius and what is that? Temperature, okay? Well, we have all these data and they have also given us this data so that we can calculate, in which they tell us that the molar mass of the cotton swab is 58 grams mole, that is, a mole of this gas is 58 grams, okay? We are going to see now why we will use that data, but you will see that we are going to need it. Well, we have these data, let's see what we have from the formula, what we need to find, okay? We are going to find out if from the formula we have all the data, to lack the one they ask us, of course. Well, I have the pressure, I also have it in atmospheres, which is the unit of pressure. Do I have the volume? No, but that's what they ask me. Well, this is going to be my unknown. Do I have the mole number? I don't have it, I'm going to have to find it, okay? Well, that's where this data comes into play. The n, the mole number, if they already give me the mass, this is calculated, this is important, the mass between the molar mass, okay? Well, the mass, we are also going to try to put it in grams, because if they give me the mole mass data in grams, then I will have to have this data in grams. And 12 kilos, I know how many grams are, 12,000. This change is easy. Well, then we are going to find the mole number, the mass, which is 12,000 grams, between the molar mass, which is 58 grams mole. Grams with molar mass, and logically I'm going to have moles. If I calculate 12,000 between 58, I get that I have 206.9 moles. Well, I already have n too. I don't have the r, but I have to know it, because it's a constant, it's always the same, r is always going to be 0.082, okay? I'm not going to put it because now I'm going to put it in the formula. And the temperature, I have the temperature, yes, but I don't have it in my own unit, which are the kelvins, so we are going to pass it to kelvin. I have to add 273. Well, now I have all these data, I have all but the volume, because I can calculate it. Volume, I will have to clear the v, the v to clear it, as p is multiplying, it is dividing. Therefore, I would have the formula like this, n times r times t divided by the pressure, okay? And from this formula we are going to substitute all these data that we have. Volume equals n, how many moles does it have? How many moles are there in 12 kilos? There are 206.9 by r, which is 0.082, okay? Remember to put the units, if you get used to working with them, if at some point you are putting some unit wrong, you will also realize, it helps you. Temperature in Kelvin. Pressure, an atmosphere, great, if it is divided by 1 it will be easy. Well, now I am going to see the units first, mole, and here the mole is dividing, because it is going to go. Atmosphere, with the atmosphere that is here, it is going to go. Liter, it is going to stay because there is no other liter, Kelvin with Kelvin, it is going to stay liter, it is fine that I have a liter if I am going to calculate volume. Yes, well, that's where I'm going well. Now we are going to calculate how many liters, we are going to multiply 206.9 by 0.082 by 298 and divided by 1, well, that's it, I don't do it. I will finally have 5055.8, what unit? Liters. See? We have reached the end. Keys to doing this type of exercise well. First, know the formula. Second, know how to clear to know what they ask me. Corroborate what data I have, what data I lack and if I can get to them with what they give me. Also corroborate, that is, see if I have the units, the data I have in the units that I want to put in the formula. And finally, do the operations well, the operation, the whole issue of clearing, of multiplying the numbers well, of the units, okay? Keep it in mind and remember to give the solution, give the number that does not come out and the unit, okay? And so far today's video. If you liked the video, give it a like and share it. 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