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# Calculate the number of moles of the indicated substance present in each of the following samples.a. 21.2 g of ammonium sulfideb. 44.3 g of calcium nitratec. 4.35 g of dichlorine monoxided. 1.0 lb of ferric chloridee. 1.0 $\mathrm{kg}$ of ferric chloride

## a. 0.311 $\mathrm{mol}$b.0.270 $\mathrm{mol}$c. 0.0501 $\mathrm{mol}$d. 2.8 $\mathrm{mol}$e. 6.2 $\mathrm{mol}$

Composition

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##### Allea C.

University of Maryland - University College

##### Jake R.

University of Toronto

### Video Transcript

dear. We have five compounds and we have their mass. And we're trying to find their number of moles in the number of moles in each miles. So recalling the formula for moles, you know that it's mass over more mass. It's already do is take the masses given in divided by their more mass. All right, so let's get started here. We have ammonium sulphide, so the fine ammonium sulphide small a mask. We simply sum up the molar mass of each individual element in this compound. And we also have to take into account the number of Adams of the Children. Yeah. Then something that up, I found it to be 68 0.154 grams per mole. Mm. Okay. And if we do this division, the quotient comes up to being zero point 31106 If we were to have kept all the units, okay. This the routine. Next we have calcium nitrate. I only have 44.3 grams of it. So after calculating a mullah mass, I want it to be 164 0.0, 88 grams per mole. Huh? After this division, the more the number of most is zero 0.269 Yes. Okay. Next up we have, um, di quarry, the chlorine monoxide doc. Where monoxide. So emoluments of the Korean monoxide is 86 0.9 grams. Problem e. When we do this division, we get the number of moles coming out to be 0.5 nos. Next up, we have iron. Try glory, claret. So here we have £1 but we must work in Gramps. Everybody's more mass grams per mole. So let's do a nice unit conversion. So we need to multiply this quantity by one. And by Qandeel as equivalent to one is what I need. So we have pounds in the numerous. We must have pounds and denominator and grams up top, so should be given somewhere. But you know that 453 0.592 grams is equivalent to £1 so pounds will counsel well and we will be left with grams. And it's basically equals 40 or 53.592 Gramps. So then I will take this whole mess invited by the molar mass of iron core rights. I think I'm Florida. Yes, which, as a mullah math of 162 0.2 grams Permal. Okay, so try to keep up with all the units they're being tossed all around. Basically equals 2.79 Memphis. All right of us do a cloaking. An analysis to make sure we didn't make any mistakes. We have pounds in the numerator here, pounds login on near here. So that cancelled up. We have grams and the numerator and grounds and the denominator line on top. And I we have moles in the denominator, the denominator, which is basically the numerator, So all right, that works out. The last one we have is one he will ground off. I record one table. Graham, we know to me 1000 grams. So I already did this conversion already because one of the simplest ones. So we already calculated or very state of the molar mass are in quarried 162.2 grams per mole. Mush equals up, which equals 1.1652 moves. All right,

McMaster University

#### Topics

Composition

##### Allea C.

University of Maryland - University College

##### Jake R.

University of Toronto