Question

How many atoms of potassium are in 0.250 mol of potassium carbonate, k2co3?

Answer 1

The  number  of  potassium  atom  that  are  in  0.25  moles   potassium  carbonate  is  calculated  as  follows

by  use  of Avogadro  contant

1  mole=  6.02  x10^23   atoms

what  about  0.25 moles,   
by  close  multiplication

{0.250 moles  x 6.02  x10^23}  /  1 mole  =  1.505  x10^23  atoms