Question

sa se determine cantitatea de acid clorhidric necesara pentru a prepara 5l sol 0,5 M , 2l sol 0,2

Answer 1

CM=0,5M
V=5L n=?
CM=n/V => n=CMxV
= 0,5x5= 2,5 moli HCl
M HCl= 36,5 g/mol => mHCl= 2,5x36,5= 91,25g HCl

CM=0,2M
V=2L n=?
CM=n/V => n=CMxV
= 0,2x2=0,4 moli HCl
M HCl= 36,5 g/mol => mHCl= 0,4x36,5= 14,6g HCl

Answer 2

C = n/V => n = V x C
n= nr de moli, V= volumul, C= conc. molara

a) V = 5L, C= 0.5M
n= 5 x 0.5 = 2.5 mol HCl pur  = 91.25 g HCl pur

b) V = 2L , C = 0.2 M
n = 2 x 0.2 = 0.4 mol HCl pur = 14.6 g HCl pur