stehiometrija

Isidoraa's picture

200g rastvoora hloridne kiseline u reakciji sa cinkom pri normalnim uslovima daje 15.68 dm3 vodonika. Izracunaj maseni udio hloridne kiseline.
Zn+2HCl = ZnCl2 + H2
rjesenje: 25.55 %

milicaradenkovic's picture

Zn+2HCl-------------------->ZnCl2+H2

n(H2)=V(H2)/Vm=15.68/22.4=0.7 mol

n(HCl)=2*n(H2)=2*0.7=1.4 mol

m(HCl)=n(HCl)*Mr=36.5*1.4=51.1 g

w(HCl)=m(HCl)/m(rastvora)=51.1/200=0.2555=25.55 %

Isidoraa's picture

n(HCl)=2*n(H2)=2*0.7=1.4 mol
a tu sad zasto puta 2

milicaradenkovic's picture

Na osnovu hemijske jednacine imas 2 mola HCl i 1 mol H2.