Question

how many moles are in 7.12 x 10^21 atoms of iron?

Answer 1

To Find :

How many moles are in $7.12 \times 10^{21}$ atoms of iron.

Given :

We know, 1 mole of any element or compound contains exactly $N_A$ ( Avogadro's Number ) atoms/compound .

Now, $N_A = 6.022 \times 10^{23}$

So, number of moles in given number of atoms are :

$n = \dfrac{6.022 \times 10^{23}}{7.12 \times 10^{21}}\\\\n = 1.18 \times 10^{-2} \ mol$

Hence, this is the required solution.