Răspuns:
Explicație:
Na2O
1.
r.a.= 2 : 1
2.
r.m.= 2 . 23 : 16
=46 : 16
=23 : 8
3.
MNa2O= 2.23 +16=62-------> 62g/moli
62 g Na2O--------46g Na---------16 g O
100 g---------------------x----------------y
x= 100 . 46 : 62=74,19% Na
y= 100 .16 : 62=25,81% O