00:01
So this question is asking us to determine whether the two atoms of lead or the 5 .1 times 10 to the negative 23 moles of helium has a greater mass.
00:11
So let's first start with the lead.
00:14
We know right now that we have two atoms of lead.
00:20
Now what we first need to do is convert the atoms into moles.
00:25
So we're going to use avogadra's number, which is up here.
00:28
And this conversion factor tells us that there are 6 .022 times 10 to the 23 atoms and one mole.
00:43
Perfect.
00:44
Now what we need to do is continue converting all the way to grams.
00:49
And to do this, we're going to use the molar mass of lead, which is 207 .2 grams per mole.
00:58
And so if we put this right into our equation, equation, we know that one mole equals 207 .2 grams of lead.
01:10
And now within our dimensional analysis table, we can see that atoms cross off, moles cross off, and so we're just left with grams, which is what we want.
01:20
And this equals 6 .8 times 10 to negative 22 grams...
