cati moli se cantaresc in 90 g H2O?​

Răspuns :

5moli, pt ca 90:18=5

MH2O=2+ 16=18-----> 18g/moli

n=m:M   ;     n=nr.de moli     m=masa subst.        M=masa molara

n=90g : 18g/moli=5moli H2O