A biologist needs 500 mL of a 10 mM phosphate buffer.The stock solution of the buffer is 100 mM.How much stock solution should be used to make the 10 mM phosphate buffer?
A) 500 mL
B) 50 mL
C) 5.0 mL
D) 0.5 mL
E) 2.0 mL

Question

Quizplus · Accepted Answer

To prepare a 10 mM solution from a 100 mM stock solution, you use the dilution formula: C1V1 = C2V2, where C1 is the concentration of the stock solution (100 mM), V1 is the volume of the stock solution needed, C2 is the final concentration desired (10 mM), and V2 is the final volume of the solution (500 mL). Solving for V1 gives V1 = (C2V2) / C1 = (10 mM * 500 mL) / 100 mM = 50 mL.

A Biologist Needs 500 ML of a 10 MM Phosphate