M,Zn(OH)2= 99g/mol
M,sare= 155g/mol
-calculez moli hidroxid de zinc
n= m/M=19,8g/99g/mol= 0,2mol
-calculez moli si masa sare, di ecuatia:
1mol................................1mol
Zn(OH)2 + KOH---> K[Zn(OH)3]
0,2mol.............................x= 0,2mol
m= nxM= 0,2molx155g/mol=...............calculeaza !!!