1) You have a stock of 100 mg/mL ampicillin in sterile water. You want to make a
ID: 206943 • Letter: 1
Question
1) You have a stock of 100 mg/mL ampicillin in sterile water. You want to make a 25 mg/mL stock in sterile water. What is your dilution factor?
2) You take 2 mL of spoiled chicken broth and add 3 mL of water. You vortex-mix that volume, and then sample 10 microliters of the mixture. You bring that 10 microliters up to 1 mL with water. You vortex-mix that second volume, and then plate 100 microliters onto a nutrient agar plate. The next day, you count 82 colonies. What was the original number of bacteria in the soup ?
Explanation / Answer
1) Concentration of the stock solution(C1) = 100 mg/mL.
Concentration of the solution(C2) = 25 mg/mL.
Then, the dilution factor(DF) = C1/C2.
= 100 mg/mL / 25 mg/mL.
= 4.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.