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?

Question

unklerhaukus · Answer

First you need to determine how many atoms of each element appear in the compound, — use a periodic table to determine the valence of species

anonymous · Answer

Thank you.
What do I do after I find the molecular masses?

anonymous · Answer

Find how many moles (mass/molecular_mass) 55.0 grams of solid Sulfur:
"55/32" -> 1.71875...
Check relation of moles of sulfur and aluminum from chemical equation:
"2Al + 3S = Al2S3" -> 2/3
Calculate the number of moles alluminium you need for comletely react with 1.71875 mol Sulfur:
"1.71875/3*2" -> 1.14583...
Finally - count the number of grams 1.14583... mol alluminium is (mol * atomic_mass):
"1.14583 * 27" ->30.9375...