Question

How many moles of potassium are there in `2.4 \times 10^21` atoms K?

Answer 1

0.0040 mols of potassium.

Explanation:

In order to do the conversion:

`2.4*10^21 "atoms of K"*("1 mol of K"/(6.022*10^23 "atoms")) = 0.0040 "mols of K"`

Since there are `6.022*10^23` atoms in 1 mol of a substance (Avogadro's number), we use that conversion factor in the dimensional analysis.