Răspuns:
MO2=2x16=32g/mol
MAl=27g/mol
4x27g........3x32g
4Al + 3O2 → 2Al2O3
108g.............xg
x=108x3x32/4x27=calculeaza
claculam in moli
n=m/M=108/27=4moli Al
4moli........3moli
4Al + 3O2 → 2Al2O3
4moli.............ymoli
y=4x3/4=calculeaza
Explicație: