Calculate the number of atoms in 8g of iron. Given iron= 56u??

mass  =  8g.              ,                atomic mass of iron 56u.
n = m / M
= 8 / 56
Therefore , = 0.1428 moles.
this means 0.1428 has 6.022 x 10²³ atoms of iron.
N = Atoms or Particles / Avogadro's Constant or 6.022x10²³ OR IN SHORT A.C
Therefore , Particles = NxA.C          
= 0.1428 x 6.022 x 10²³
= 1428 x 6022 x 10¹⁶
= 8599416 x 10¹⁶ atoms.