Question

How many moles are in 1.20 x 10^24 atoms of copper?

Answer 1

There are 1.99 moles in 1.20x10^24 atoms of copper.

To solve the exercise we have to use the Avogadro's number (6.022x10^23). With the Avogadro's number we know that there are 6.022x10^23 particles in 1 mol, in this case, the particles are atoms of copper.

Now, with a mathematical Rule of Three we can calculate the number of moles in 1.20x10^24 atoms of copper:

$\begin{gathered} 6.022\cdot10^{23}atoms-1mol \\ 1.20\cdot10^{24}atoms_{}-x=\frac{1.20\cdot10^{24}atoms\cdot1mol}{6.022\cdot10^{23}atoms} \\ \\ x=1.99\text{ moles} \end{gathered}$

So, there are 1.99 moles in 1.20x10^24 atoms of copper.