N_A is simply another collective number like a dozen, or a gross, or a score. Admittedly, N_A is a VERY large number. We have 2.12xxN_A molecules of propane, H_3C-CH_2-CH_3.
If we have this number of propane molecules, there are clearly 3xx2.12xxN_A "carbon atoms", and 8xx2.12xxN_A "hydrogen atoms". It would be worth your while to get your head around these quantities; they are simply NUMBERS.
N_A has the property that such a number of ""^1H ATOMS a mass of 1 g, or such a number of ""^12C atoms has a mass of 12 g. N_A is thus the link between atoms and molecules, about which we can only theorize, and the macro world or g and kg and "litres", that which we can measure in the laboratory by mass or by volume. What is the mass of your quantity of propane molecules?
