in the reaction Al2O3= Al+O2 if 742.5 grams of Al2O3 are used how many mols of Al will be produced?

2Al2O3 ==> 4Al + 3O2

mols Al2O3 = 742.5 g/molar mass Al2O3.
Now use the coefficients in the balanced equation to convert mols Al2O3 to mols Al.
Finally, g Al = mols Al x atomic mass Al.