-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 !!!!