The nurse is preparing to administer streptomycin 0.25 g. The directions say to reconstitute with 9 mL of sterile water for a concentration of 400 mg/2 mL. How many mLs will the nurse give? Fill in the blank.

The nurse will give 1.3 mL.

Solution: Convert 0.25 g to mg: 0.25 g × 1000 = 250 mg. Set up a proportion to solve. Recall that the concentration is 400 mg streptomycin per 2 mL of solution: 250 mg/400 mg × 2 mL. Solve: = 1.25 mL. Round up to find the quantity in millileters: = 1.3 mL.