Question

Un volum de solutie de HCl cu p=1,1 g/cm de concentratie 20% se dilueaza cu 5 volume de apa. Determinati concentratia molara. ​

Answer 1

1 volum = 1 L , p= 1,1 g/cm3 , c%= 20%

5 volume apa = 5 L apa

1 L = 1000 cm3

p = ms/Vs => ms = pxVs = 1000x1,1 = 1100 g

c% = mdx100/ms => md = msxc%/100

= 1100x20/100 = 220 g HCl

=> Vs.final = Vs + V.apa = 1+5 = 6 L

M.HCl= 36,5 g/mol

Cm = md/MxVs = 220/36,5x6 = 1 M