Răspuns:
C=49%
ms=400g
md=?
md=C×ms/100=49×400/100=196g
MZn=65g/mol
MH2SO4=2×1+32+4×16=98g/mol
65g.......98g
Zn + H2SO4 → ZnSO4 + H2↑
xg........196g
x=196×65/98=130g Zn se consuma in reactie
Explicație: