CALCULEZ MASA de ZnO pur, din p=90%
p=m,px100/mi-------> m,p= 90x90/100g= 81gZnOpur
calculez moli oxid ,stiind M,ZnO= 81g/mol
niu=m/M= 1mol
calculez moli de substante, din ecuatia chimica
2mol.........1mol........2mol.......1mol
2ZnO + C----> 2Zn + co2
1mol........x=0,5 ,.......y=1........z=0,5mol
calculez masa de carbon
m= niuxN= 0,5X12g= 6g C