Question

How many moles of cobalt (Co) atoms are there in 6.00 x 10° 6.00 billion) Co atoms? mol Enter your answer in scientific notation.

Answer 1

We have 6 $\times$ 10⁹ atoms

We Know that Avogadro's constant

One mole of substance = 6.022 $\times$ 10²³ atoms

So 1 mole of Co = 6.022 $\times$ 10²³ atoms   

then for 1 atom

1 atom of Co = (1 mole of Co / 6.022 $\times$ 10²³ atoms)

So for given number of atoms

1 $\times$ 6 $\times$ 10⁹ atoms = 6 $\times$ 10⁹ atoms $\times$ (1 mole of Co / 6.022 $\times$ 10²³ atoms) = 0.9963 $\times$ 10^-14

= 9.963 $\times$ 10^-15   Moles ( or approx =   1 $\times$ 10^-14 moles)

So Our Answer is = 9.963 $\times$ 10^-15   Moles