- Units & Notation
- Moles per litre
- Grams per litre
- Percent solutions
- Parts per million
- Practice problems
Serial dilution
Activity 1
You are a microbiologist and you have 10 mL of solution containing 2000 e.coli per mL. How many 1 in 10 dilutions would you need to make to achieve 10 mL of solution containing 2 e.coli/mL?
Try to attempt this problem yourself. You may wish to follow the steps identified in the example provided in the previous section to solve problems like these. Type-in your answer (number of dilutions in digits only) in the text box given below and then check your answer by clicking the 'Check Answer' button.
To achieve a dilution of 2 e.coli/mL from 2000 e.coli/mL, we need a dilution factor of 1000. A combination of 1:10 dilutions that can give a Final dilution factor of 1,000 can be 10 times 10 times 10 which is equal to 1,000. So we will need 3 1:10 dilutions of our starting solution to obtain a new solution with 2 e.coli/mL.
If you have got the answer right then try Activity 2, or else the video below shows a detailed step by step approach to solve the above problem.
This video contains sound.
