How many moles are in 1.0 *10^9 atoms

The number of moles in 1.0 x 10^9 atoms would be 1.66 x moles

According to Avogadro, 1 mole of a substance contains 6.022 x 10^23 atoms.

Hence, the number of moles that would be present in 1.0 x 10^9 would be:

           1 x 1.0 x 10^9/6.022 x 10^23

                                         = 1.66 x moles

More on Avogadro's number can be found here: link

1.66×10^-15 mole

Explanation:

6.02×10^23 atoms gives 1 mole

1.0×10^9 atoms gives X mole

X= 1.0×10^9/6.02×10^23

X= 1.66×10^-15 mole.

a is the correct answer