Răspuns:
a)
100g Al......................80gAl pur
200.............................xgAl pur
x=200×80/100=160gAl pur
b)
MAl=27g
MAl2O3=2×27+3×16=102g/mol
4×27g 2×102g
4Al + 3O2→ 2Al2O3
160g xgAl2O3
x=160×2×102/4×27=302,22gAl2O3
c)
MAl=27g
MO2=2×16=32g/mol
n=160/27=5,92moli Al
4moli 3moli
4Al + 3O2 → 2Al2O3
5,92moli ymoli
y=5,92×3/4=4,44moli O2
Explicație: