How much of a 25 mg/ml chloramphenicol stock solution do we need to make 400 ml of growth media taht has final 25 ug/ml concentration of chloramphenicol

0.4mL of the stock solution is needed

Explanation:

This is simply a dilution analysis. From the question, the following were obtained:

C1 = 25 mg/mL = 25x10^-3g/mL

V1 =?

C2 = 25 ug/mL = 25x10^-6g/mL

V2 = 400ml

Applying the dilution formula, we have:

C1V1 = C2V2

25x10^-3 x V1 = 25x10^-6 x 400

Divide both side by 25x10^-3, we have:

V1 = (25x10^-6 x 400) / 25x10^-3

V1 = 0.4mL

Therefore, 0.4mL of the stock solution need.