How many atoms are in in 13.2 mol copper?

1 Answer
Jun 27, 2016

Answer:

#13.2xxN_A" copper atoms"#, where #N_A="Avogadro's number"#.

Explanation:

#N_A="Avogadro's number"=6.022140857(74)xx10^23*mol^-1#.

I may use #N_A# as I would use any other collective number: #"dozens, Bakers' dozens, scores, gross, etc."# Of course, #N_A# is an unfeasibly large number, and it happens that #N_A# #""^1H" atoms"# have a mass of precisely #1*g#. #N_A# is thus the link between the sub-micro world of atoms, and molecules, that which we can conceive of, and theorize about, and the macro world of #"grams"#, and #"litres"#, and #"kilograms"#, that which we measure in a lab.

In an exam, would you have to remember #N_A#? The answer is no, as it will quoted to you as supplementary material. You do have to be able to manipulate it, and to demonstrate its significance.