Question

O solutie de HCl 40% reactioneaza cu 260g de Zn
a) scrie ec. reactiei chimice
b) calculeaza masa solutiei de HCl necesara
c) determina masa hidrogenului degajat

Answer 1

-calculez moli zinc
n=m/A
n= 260g/65g/mol= 4mol Zn
-deduc, din ecuatie,moli HCl si H2
2mol.......1mol..................1mol
2HCl  +  Zn----> ZnCl2 + H2
x=8...........4.....................y=4mol-
-calculez masa de aci si,apoi, masa de solutie de acid
m,HCl= 8molx36,5g/mol=292g
c= mdx100/ms;    40/100= 292/ms..............................> calculeaza ms !!!!
-calculez volumul H2, stiind volumul molar in c.n.=22,4l/mol
V= nxVm;   V= 4molx22,4l/mol=........................calculeaza !!!!