Question

How many grams of aluminum hydroxide are obtained from 16.2 g of aluminum sulfide?

Answer 1

Number of moles Aluminium sulfide
1 mole of sulfide contains 150 g
Therefore; 16.2/150 
               = 0.108 moles 
The mole ratio of Al2S3 : Al(OH)3 is 1:2
Therefore; moles of Aluminium hydroxide will be;
  = (0.108 × 2)
  = 0.216 moles 
But, 1 mole of  Al(OH)3 contains 77 g
Therefore, the mass of aluminium hydroxide is
   0.216 moles × 77
=  16.632 g