calculez moli Al si S din ecuatia chimica
2mol.....3mol.....1mol
2Al + 3S-----> Al2S3
x.............y..............22mol
x=44molAl
y= 66molS----> m=niuxM,S= 66X32g= 2112 g S pur; calculez m,S impur ,din puritate
p=m,px100/mi---> m=2112x100/90g=...................calculeaza !!!!