How many moles of ammonium sulfate contain 661025 atoms of N

How many moles of ammonium sulfate contain 6.6×1025 atoms of N ?

Solution

number of N atoms = 6.6 x 10^25 atoms

number of moles of N = 6.6 x 10^25 / 6.023 x 10^23

                                  = 109.6 mol

ammonium sulfate = (NH4)2SO4

1 mol (NH4)2SO4   ----------------> 2 mol N

       ??                  ----------------> 109.6 mol N

moles of (NH4)2SO4 = 54.79 mol

moles of ammonium sulfate = 54.79 mol