00:02
Hi there.
00:03
In this question, we are given an amount of copper in kilograms, and what we're trying to convert to is number of atoms.
00:15
Well, we don't have a way to convert directly from kilograms to atoms.
00:18
What we can do is get there by going through the mole.
00:25
And to get to the mole, we can use molar mass.
00:29
Molar mass is the mass of one mole of a substance in grams, and we get that from the periodic table.
00:35
So one mole of copper, looking at the periodic table, we see it is 63 .55 grams because numerically molar mass is the same as the atomic mass.
00:47
The atomic mass gives the mass of one atom in amu and the molar mass gives the mass of entire mole of atoms in grams.
00:55
Okay so that gives us a way to get from grams to moles.
01:01
We can use that molar mass.
01:04
But now in our little plan, we need to fill in our missing steps here.
01:09
We need to convert first from kilograms to grams, and we can do that because we know that one kilogram is equal to 1000 grams.
01:19
We're just using metric prefixes here.
01:22
And then we can get from mole to number of atoms by using avogadro's number.
01:31
Avogadro's number is the number of representative particles in one mole of anything.
01:35
Anything.
01:36
So in one mole of copper, there will be avogadro's number of atoms, which is 6 .02 times 10 to the 23rd.
01:48
All right, so we have a plan here to get from our starting point to our answer...