Final answer:
To make a penicillin solution with a concentration of 400,000 units per cc from a vial with 3 million units, one needs to dilute the entire amount in 7.5 cc of diluent, resulting in the desired concentration.
Step-by-step explanation:
To determine how much diluent is needed to make a solution containing 400,000 units of penicillin per cc from a vial containing 3 million units, you can use the concept of dilutions. The total amount of drug you have is 3,000,000 units, and you want to prepare a solution that has 400,000 units per cc.
First, calculate the number of cc that should contain the entire amount of penicillin:
- 3,000,000 units ÷ 400,000 units/cc = 7.5 cc
This means you need to dilute your total amount of penicillin in 7.5 cc of diluent to get the desired concentration. Since we assume no powder volume, the volume of diluent required will be equal to the final volume of the solution, which is 7.5 cc.