How many milliliters of a 4.00M FeBr3 stock solution are needed to prepare 55mL of 1.25 M FeBr3 solution?

Question

How many milliliters of a 4.00M FeBr3 stock solution are needed to prepare 55mL of 1.25 M FeBr3 solution?

Answer 1

Use the dilution formula:

M₁V₁=M₂V₂

M₁ = 4.00M

V₁ = ?

M₂ = 1.25M

V₂ = 55mL

V₁= (M₂V₂)/M₁=(1.25 M x 55 mL)/4.00M = 17 mL (with the correct number of significant figures)