Calculam masa de zinc pur consumata in reactie
65 2·36,5
Zn + 2 HCl → ZnCl₂ + H₂ MHCi = 1+35,5 AZn = 65
x 7,3g =36,5
x = 65· 7,3/ 2 ·36,5 x = 6,5 gZn pur
Calculam puritatea zincului:
10g Zn impur ........................6,5gZn pur
100g Zn impur ........................y
y = 100·6,5/10 y = 65% puritate