Exercice I :
b1) n = 2,00 × 10^-3 mol
b2) C = 2,00 × 10^-2 mol.L^-1

Exercice II :
n = C x V = 2,5 x 10^-3 mol
m = n x M = 0,395 g 

Exercice III :
m = C x V x M = 12,69 g

Exercice IV :
V _mère = C _fille × V _fille / C _mère = 5,0 × 10^-3 L = 5,0 m L