-calculez masa de Cu O pur
p= m,px100/ m,impur
80/100= m,pur/8----> m,pur= 6,4g CuO pur- M(miu)= (64gCu+16gO)mol
-calculez moli si masa H2 necesar in reactie
1mol 1mol
CuO + H2---> Cu+ H2O
80g.........1mol
6,4g.........x----> x=0,08molH2
m,H2= n,molxM,g/mol=> m= 0,08molx2g/mol=...................CALCULEAZA !!!