Question

How would you prepare 2.15 L of a 8.00 M solution from a 12.0 M stock solution?

Answer 1

use M1V1=M2V2 where M1 is the molarity of the stick solution and M2 is the desired molarity. V2 is the disired Volume and then u solve for V1, which is how much water you dilute it with. so,
(12M)V1=(8M)(2.15L)

V1=((8)(2.15))/(12)

and finally V1 = 1.43L

To prepare a 2.15L soln of 8M concentration, mix the 12M stock solution with 1.43L of Water