How many hydrogen atoms are in 4.40 mol of ammonium sulfide

 The number  of hydrogen  atoms  that are  in 4.40  mol  of ammonium sulfide is  2.12 x10^25  atoms

      calculation
 find the number of moles  of Hydrogen  in ammonium sulfide  (NH4)2S

that is  4.40  x  number of hydrogen atoms in (NH4)2S ( 4x2= 8  atoms)

moles is  therefore=  4.40  x8= 35.2  moles

by  use of  Avogadro's law  constant

that is  1mole =  6.02 x10^23 atoms
         35.2  moles=?

by  cross multiplication
  {35.2 moles x 6.02 x10^23} /1 mole  = 2.12  x10^25  atoms

The molecular formula for ammonium sulfide would be (NH4)2S. That means in one molecule of ammonium sulfide there will be 1 N + 4 H + 2 S molecules. 
Then the amount of hydrogen atoms in 4.4 moles of ammonium sulfide should be: 4.4 moles * 4/1= 17.6 moles 
If you are asked for atom count then the amount should be: 17.6 moles * 6.022x10^23 atoms/mol = 105.9872 * 10^23= 1.06 * 10^25