And so, we can do a littleīit of dimensional analysis. Hey, let's convert this to grams of germanium. All right, so we started off with 15.4 milligrams of germanium. So, let me clear out some space the periodic table ofĮlements was taking up. To walk up to you and say, hey, you, I have a 15.4 So, let's use our newįound powers of the mole and Avogadro's number to startĭoing some useful things. That Avogadro's number is much hairier of a number than a dozen. Mole of lithium atoms, how many lithium atoms do I have? That means that I have 6.02214076 times 10 the to 23rd lithium atoms. If I say I've got a dozen of eggs, how many eggs do I have? Well, if I have a dozen of eggs, that means I have 12 eggs. Now, what does that mean? Well, think about the word dozen. Used by the German chemist Wilhelm Ostwald at theĮnd of the 19th century, and he came up with the word because of its relation to molecule. Actually, it is both of those things, but, in a chemistry context, a mole is just saying you Now, what is a mole? It is not a little mark on your cheek. That it's very useful to familiarize yourself with in chemistry, and that's the idea of a mole. Many significant digits, we will usually approximate it as 6.022 times 10 to the 23rd power. And, in most contexts,īecause you're not normally dealing with data with this There a name for this number, and there is indeed a name, and it is called Avogadro's number, named in honor of the earlyġ9th century Italian chemist, Amedeo Avogadro. Whatever its average atomic mass is in terms of unified atomic mass units, if you have that number of the atom, you will have a mass of that This number of lithium atoms, that sample is going to And, this number of atoms is 6.02214076 times 10 to the 23rd power. Number of atoms of lithium such that if I have that number, so times certain, certain number of atoms, then I will actuallyĮnd up with 6.94 grams, grams of lithium. We know its average atomic mass is 6.94, 6.94 unified atomic mass units Well, the chemistryĬommunity has come up with a useful tool. Masses at an atomic scale to the masses, masses of samples that you see in an actual chemistry lab, or in, I guess you could
You're more likely toĭeal with several grams of an actual substance. You're very unlikely to justīe dealing with one atom, or just a few atoms, or That we might actually see in a chemistry lab. But, what we're gonna do in this video is connect it to the masses Mass at an atomic level, or at a molecular level. Idea of average atomic mass, which we began to realizeĬould be a very useful way of thinking about a In a previous video, we introduced ourselves to the
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