Question

1. How many moles are in 80.5g of Aluminum Sulfide?

Answer 1

Aluminium sulphide = Al2S3 with molecular mass of 150.158 (ref. Wiki, or add up individual elements)
Number of moles in 80.5 g
=80.5/150.158
=0.5361 mol
=0.536 mol (rounded to 3 significant figures)