C1V1 = C2V2 is used to find either the volume or concentration of a solution that's already prepared to a known concentration, and dliute them to new concentration/volume as needed. Which is Titration I think?
eg. If 25.00 mol of a solution of concentration 0.3750mol/L was diluted to a new volume of 500.0mL, what is the concentration of the diluted solution?
C1V1 = C2V2
C1 = 0.3750mol/L
V1=25mL
C2 = ?
V2 = 500.0mL
So.. C2 = C1V1/V2
C2 = 0.375 x 0.025 / 0.5
C2= 0.01875 mol/L
C = n/v is a way of measuring the concentration of a solution (Molarity)
eg. Calculate the Molarity of a solution that has 0.4 moles of solute dissolved in 400mL of solutuion
C =?
n =0.4mol
V = 400mL = 0.4L
C = 0.4/0.4
C= 1 mol/L or 1M
Hope that helps