Look at the end of his post. It looks like he knows it a little too well because, of course, there's no need to use it in this problem. It appears he did something like 12.0107 * 6.022e23.
FlyBoy: The mass of 1 mole of atoms of any element is equal to its atomic weight in grams. ie, one mole of hydrogen atoms masses 1.022794 grams. (Although individual hydrogen atoms don't really occur in the real world, so this is perhaps a bad example)
See the link I posted above for more information.