Răspuns:
1.
MAl2S3=2x27+3x32=54+96=150g/mol
150g Al2S3......................54g Al
90gAl2S3......................x g Al
x=90x54/150=calculeaza
2.
MSO3=32+3x16=80g/mol
80gSO3..........................32gS
ygSO3..............................96gS
y=96x80/32=calculeaza
Explicație: