How many atoms are in 1.75 moles of zinc?

1 Answer
Jun 2, 2016

How many atoms in 1.5 dozen zinc atoms? Clearly, there are 18.

Explanation:

We know that 1 mol of stuff specifies Avogadro's Number, NA individual items of stuff. Avogadro's Number = 6.022×1023mol1.

So you have 1.75×NA atoms of zinc. You do the arithmetic, and tell us what is the mass of this quantity, this number, of zinc atoms?

The use of Avogadro's number as we use any other collective number, e.g. score, dozen, gross, is entirely legitimate. Why do use such an absurdly large number? It turns out that NA 1H atoms have a mass of 1g precisely. Avogadro's number is thus the link between atoms and molecules, the which we can't see, to the macro world of grams and litres, that which we can conveniently measure in the laboratory.