Question

Ce masa de solutie de acid clorhidric cu concentratia 20% reactioneaza 6,5g Zn?

Answer 1

-calculez moli Zn
n=m/A,   unde A=65g/mol,din tabel
n= 6,5g/65g/mol=0,1mol
-calculez moli acid, din ecuatia:

1mol....2mol
Zn    + 2HCl---> ZnCl2  +   H2
0,1mol....x= 0,2mol
\
-calculez masa de acid dizolvat in solutie
m= nxM---> m=0,2mol(1gH+35,5gCl)/mol=7,3g HCl

calculez masa de solutie
c= mdx100/ms
20=7,3x100/ms---------------------------> calculeaza ms !!!!