Răspuns:
Explicație:
A Be=9-----> 9g/moli
n = m : M
n= 36g : 9g/moli= 4 moli Be
1mol de atomi de Be--------------6,023.10²³atomi
4moli---------------------------------------x
x=4 . 6,023.10²³=24,092 .10²³atomi Be
-se afla nr. de moli de Fe din 122g Fe
n= 122g : 56g/moli=2,18 moli Fe
1mol de atomi de Fe------------6,023.10²³atomi
2,18 moli--------------------------------y
y=2,18 . 6,023.10²³atomi Fe=