If a chemist wants to make 1.3 L of 0.25 M solution of KOH by diluting a stock solution of 0.675 M KOH, how many milliliters of the stock solution would the chemist need to use?

To solve this we use the equation,

M1V1 = M2V2

where M1 is the concentration of the stock solution, V1 is the volume of the stock solution, M2 is the concentration of the new solution and V2 is its volume.

.675 M x V1 =.25 M x 1.3 L

V1 = 0.48 L or 480 mL