Composition

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

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

University of Kentucky ##### Jake R.

University of Toronto

### Video Transcript

All right. So here we have four nitrogen containing compounds and we are to find the mass of matter. Jim, this time given a total mass of each compound being, like, what, five grams? Yes, Why? Perhaps so we're going to use like, the previous video. It's simple. The last percent of nitrogen multiply that by this whole mass. Give us mass of just nitrogen. T is total and end this furniture. Okay, so last percent is going to be a massive nitrogen divided by mass of the molecule mass of a compound total minutes a compound. So masses moles, mortal problem, more mass. And in mass percent, we always like to work with one mole of compound, one wall most wanted then by the molar mass of the compound. So now one wolf compound could mean and usually does mean more. Mel's off the element neck surgeon who's gonna multiply this? This is a one not by one more, but just you know, whatever Moeller factor it is by the molar mass of nitrogen. That's an end. And this is the one for the time. I always working with one more compound on one month compound usually means a bit more moles of just nitrogen. So yeah, here we have gwai C, which was amino acid monomer in a protein. A protein walk that makes a protein. So here we actually I only have one metre gin making their just Yeah, one mole of nitrogen for, you know, relations small amounts just like 14. And then again, we no one will of compound and the molar mass of life scene is 75. Since we already multiplied by one, we can call this a grams. This is a grams promote. This is a bowl. So this woman lead us to the mass percent of 18. No, just don't really socialise once. But how we what we're gonna do this mass present to find massive nitrogen is take our total mass, which is five grams and multiply. Buy them percent. Just find 18% of five. You articulate that which will give us 0.93 93294 Well, I'm just gonna leave there. Not so too. I'm just gonna ready since that every rating just take off that Oh, this is the mass of nitrogen. Next up, we have magnesium nitrite. So for the last percent. So you can see we have two moles of, um, nitrogen in one for one mole of compound. There's gonna take double its mother mouse. And this Pelous years, my uneasy and I tried small mass as a whole is 100 0.9 grams per mole multiplied by one. Give us 100.9 grams. Now, if we 12 through with this division, we mass percent 27 just quite so long. So then that will give us a massive nitrogen. It's just 27% of five. Give us ah, massive nitrogen being 1.38 cramps. Yeah. Now here we have calcium nitrate. We're finding last percents. Okay, so it appears as though there's only one nitrogen. But don't forget to look outside the brackets to so two months off message in per one wall compound. It was always working normally, and this skies molar mass is 164 grams per mole multiplied by one more. Give us 164 grams giving us mass percent 17 than 17% of our total mass. Five grams gives us a massive nitrogen 0.8 five Gramps until now isn't going quite quickly. Like Good. Now, here, Dia, nitrogen touch oxide. Do the same thing by the last percent of nitrogen. Don't. Yeah. Apparently we have to most again of nitrogen for one wall of compound, and then one more multiple. The molar mass of the compound gives us 92 grams, which is then equivalent to 30 percent and then a massive nitrogen 30% of five. 1.5 Gramps, there we have. McMaster University

#### Topics

Composition

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

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

University of Kentucky ##### Jake R.

University of Toronto