Question

how many grams of aluminum metal are needed to completely react 55.0 grams of solid elemental sulfur in order to make solid aluminum sulfide

Answer 1

The reaction equation is:
2Al + 3S → Al₂S₃

Moles of sulfur: 55 / 32 = 1.72
Molar ratio of Al : S = 2 : 3
Moles of aluminium needed = 2/3 x 1.72
Moles of Al needed = 1.15
Mass of Al needed = 1.15 x 27
Mass of Al needed = 31.05 grams