Calculate the mass in grams of nitrogen present in 5.000 g of each of the following compounds. a

Calculate the mass in grams of nitrogen present in 5.000 g...

Key Concepts

Molar Mass Calculation

This concept involves summing the atomic masses of all the atoms present in a compound’s formula to obtain its molar mass. It is essential for converting a given mass of a compound into moles, which is a necessary step in quantitative chemical calculations.

Mole Concept

The mole concept links the mass of a substance to the number of particles (atoms, molecules, etc.) using Avogadro's number. It enables the conversion between mass and moles, making it possible to relate macroscopic amounts to the number of elementary entities present.

Stoichiometry

Stoichiometry deals with the quantitative relationships between reactants and products in chemical reactions or within a chemical compound. It allows you to determine the proportion of a specific element, like nitrogen, in a compound by using the ratios provided in the chemical formula.

Percentage Composition

Percentage composition is the calculation of the mass percentage of each element within a compound. It is used to determine what fraction of the total mass of a compound is due to a particular element, which is critical for problems that ask for the mass of a specific element in a given sample.

Transcript

00:01 All right, so here we have four nitrogen containing compounds and we are to find the mass of nitrogen this time.

00:12 Given a total mass of each compound being like what, five grams? yes, five grams.

00:28 So we're going to use like the previous video, that's simple, mass percent of nitrogen.

00:37 Multiply that by the total mass to give us.

00:40 Mass of just nitrogen.

00:44 T is total and n is for nitrogen.

00:49 Okay, so mass percent is going to be a massive nitrogen divided by mass of the molecule, mass of the compound, total mass of compound.

01:07 So mass is moles multiplied by molar mass.

01:12 And in mass percent, we always like to work with one mole of compound.

01:20 One mole multiplied then by the molar mass of the compound.

01:26 So now one mole of compound could mean, and usually does mean, more moles of the element nitrogen.

01:36 So we're just going to multiply this, this is a one, not by one mole, but just, you know, whatever molar factor it is by, you know, molar mass of nitrogen.

01:49 And that's an n.

01:55 And this is a one.

01:56 For the compound, we're always working with one mole compound, and one mole of compound usually means a bit more moles of just nitrogen.

02:05 So yeah.

02:07 Here we have glycine, which is an amino acid, a monomer in a protein.

02:16 Like a protein block that makes up a protein.

02:23 So here, we actually, only have one nitrogen.

02:31 Like there's just, yeah, one mole of nitrogen for, you know, nitrogen's molar mass, which is like 14.

02:43 And then, again, we know one mole of compound.

02:48 And the molar mass of glycine is 75.

02:54 And since we already multiplied by one, we can call this a grams.

02:58 This is a grams per mole, and this is a mole.

03:01 So this will lead us to the, mass percent of 18.

03:10 Now, i'm only going to show this once, but how we, what we're going to do with this mass pretend to find massive nitrogen is take our total mass, which is five grams, and multiply by them percent.

03:29 To just find 18 percent of five.

03:33 Just take it like that, which will give us 0 .9 .3.

03:45 93, nine three, two, nine four.

03:48 Well, i'm just going to leave it there.

03:50 That's a two...

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