M= 56g/mol Fe
M=(2x56gFe+3x16gO)/mol=160gFe2O3
SE VEDE : 160g Fe2O3 contine 2x56gFe
480g...........................m= 6x56g=336gFe
calculez nr.moli Fe: 1mol..Fe........56g
x............... 336g---> x= 336/56 moli Fe calculeaza !!!!
calculez nr atomi:
1mol contine 6,023x10²³atomi Fe
336/56...............x calculeaza !!!!!!