Composition

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##### Top Chemistry 101 Educators ##### Stephanie C.

University of Central Florida  ##### Morgan S.

University of Kentucky

### Video Transcript

Okay, here we have 10 questions. So the 1st 1 is what isn't a m u. So am you is we've learned is an atomic mass units. So this is the unit that atomic mass is given in on the periodic table, General. And you know that it's also equivalent, um, two grams per mole toaster and agree. And okay, we know that one atomic mass unit ways Ingram's 1.66 times 10 to the negative 24 10 to these exponents. Negative 24 Gramps. So an extremely small number. That is the way it basically of one atomic mass unit. Next, if you were to have 1000 and eight, I am used. What? This that reminds us of basically, so we know that, um, this number 1008 is very similar to the atomic mass of hydrogen hydrogen. One hydrogen atom has an atomic mass unit of basically 1.0 eight. I am used or grams per mole. So then housing of 1000. An eight week until of this, Just 1000 of this. So then that means that we have this in this quantity 1008 AM use. We have 1000 hydrogen Adams. That is the weight of 1000 hydrogen atoms. You could We could have been a division 1008 divided by 1.8 would basically give us 1000. What's okay? Number three. Now, we have, um, mass of one Adam of any particular element. So well, parameter do we know gives us the mass of Adam of an element. Well, don't look too far. Atomic mass, right? Atomic mass, as I just described Here is the mass of one element of one Adam oven element. That's why were able toe, you know, do you work this division to see how many atoms fit in in this particular mass? See, atomic mass is like Roemer's, as the name suggests, Massive and Adam. So the atomic mass can a question for we have the number of carbons. Now we're looking for how many carbon? It's, uh, in 12.1, Gramps. Uh huh. All right, so this number should be very familiar. It's the molar mass of Karpin. So we know we have a mass here, and we have a molar mass and the equal the same thing. So Okay, what does that give us that. We know that moles is equivalent to mass over more mass. And in this situation, because Massimo nights or equivalent moles is equivalent to one. So what does that lead us to further so we know to find them number of atoms. We just We multiply moles by of a codgers number. So then, because and is one number, Adams is equivalent avocados number on A and that's also, however, Guardo's number is based is comes from it comes from specifically carbon and telephone. 01 grams of carbon. Oh, question five. If we have a gorgeous number, what else does that tell us? Okay, let's just look not too far again. Look up. We know that one of a guard row unit. So one clump of so one like 6.2 to time center of 23 quantity of a thing is a mole of a thing that's equivalent to one wall. Yes, a mole is six point old to two times 10 to the 23 of a quantity. Any particular one no Number six now were given basically a description, and we're tryingto qualitative. The our find the actual term that we're defining. So we have mass of a compound in just mass of a compound and just one mole of it of that particular compound so mass and one more. Oh, you have mass Permal. This is very obviously Connell hating Mullah Mats just as its name, you know, dictates the Moeller. So as in mole mass, the math of a mall? Yeah, question seven. It's also description, and we're trying to find the term we're defining. So here we have smallest entered your ratio of elements in the compound, so But, you know, very quickly. Um, if you wash my last video, bring up the term empirical formula, So yeah, that is what Trying to define, you know. So not the actual ratio of atoms in the compound, but the smallest one. Yes, which we term us. Empirical formula. Uh, impure, cool formula. Uh huh. Of it. What's go on to question number eight? So now push Number eight is seen actual ratio of each Adam in a particular compound. So seems similar to empirical formula, but we know this one as being molecular formula. So ratio is here that I am saying is re she of elements and ah compound or compounds in a compound or of Adams in the compounds molecular formula. It's the molecular formula is gonna do possibly for formula. We want to question number nine. So we have, um, gas that is being produced from carbon containing compounds. One, they're burnt. So the gas well from burning and in particular burning carbon containing compounds. So we should remind you of like combustion reactions. Because when you take any carbon containing source with some oxygen, oxidizer and heat and then we produce Theo too. Yes, carbon dioxide that's always being produced Now final question now is ah, compound that has the same empirical formula but different molecular formulas as each other. So must ones you have. See 686 versus C, two age too. So here they have same molecular formula. Are means started Same empirical formula. Just wait that over here. Same empirical formula. A suddenly would be this there or ch ch. Is there empirical formula? But obviously they have different molecular formulas. Empirical So the same empirical ch different molecular McMaster University

#### Topics

Composition

##### Top Chemistry 101 Educators ##### Stephanie C.

University of Central Florida  ##### Morgan S.

University of Kentucky