Aluminum sulfide is Al₂S₃, which shows that there are 3 sulfur atoms per formula unit.
In one mole there is Avogadro’s number of atoms and Avogadro’s number = 6.02 x 10²³
In 1.10 mole = 1.10 x 6.02x10²³ = 6.62 x 10²³ formula units
Now multiply with 3 to get number of sulfur atoms present in 1.10 mol of Aluminum sulfide;
3 x 6.62x10²³ = 1.99 x 10²⁴
So, the answer is 1.99 x 10²⁴ sulfur atoms.
