Question

Calicheamicin gamma-1, C55H74IN3O21S4, is one of the most potent antibiotics known: One molecule kills one bacterial cell. Part A: Describe how you would prepare 25.00 mL of an aqueous calicheamicin gamma-1 solution that could kill 1.0×108 bacteria, starting from a 5.00×10−9M stock solution of the antibiotic. Part B:Complete the explanation.Calculate the volume of the antibiotic solution needed to kill the bacteria from Part A.

Answer 1

Part A)

Describe how you would prepare 25.00 mL of an aqueous calicheamicin gamma-1 solution that could kill 1.0 x 10⁸ bacteria, starting from a 5.00 x 10⁻⁹ M stock solution of the antibiotic.

The antibiotic solution needs to contain a minimum of 1 x 10⁸ molecules of drug which is equal to the number of bacteria.

Part B)

Calculate the volume of the antibiotic solution needed to kill the bacteria from Part A.

Moles of antibiotic = (1 x 10⁸)/ (6.023 x 10²³) = 1.66 x 10^-16 moles

Volume required = (1.66 x 10^-16 moles)/(5 x 10^-9 M) = 3.32 x 10^-8 L = 3.32 x 10^-5 mL

Volume required = 3.32 x 10^-5 mL