00:02
Hi there.
00:03
In this problem, we have 2 .24 grams of cobalt.
00:12
And we want to calculate how many grams of iron it would take so that we have the same number of atoms as this mass of cobalt.
00:22
Well, if we think about it, equal moles of substances contain the same number of atoms.
00:29
So if i convert this to moles and then use that number of moles as the moles of iron, i can calculate how many grams of iron would have the same number of atoms as this many grams of cobalt.
00:44
So that is my plan.
00:45
I'm going to convert this to moles, and then i'm going to use that number as my moles of iron and convert to grams of iron.
00:54
So to convert from grams to moles of cobalt, i need to use the molar mass.
00:59
Looking up the molar mass on the periodic table for cobalt, i see that there are 58 .9 .9.
01:06
3 grams of cobalt in every mole of cobalt.
01:14
The grams of cobalt will cancel, and i will have an answer in moles of cobalt.
01:19
That answer is 0 .0 380 moles of cobalt...