Question

Question 10. Bacterial density in a counting chamber A scientist needs to calculate the density of a bacterial culture in order to set up an experiment, but the laboratory spectrophotometer is broken and the only alternative is to use a counting chamber that she finds in a drawer of old equipment. The counting chamber has a glass to coverslip height of 0.02 mm and the instructions say that each square of the chamber measures 10 um x 10 um. She counts bacteria in 5 squares. The 5 squares contain 264, 287, 240, 267 and 251 bacteria. A. What is the volume of liquid corresponding to one square in um? B. What is the volume of liquid corresponding to one square in u!?

I need the answer to question B, thank you.

Answer 1

1 mm = 1000 um

0.02 mm = 1000 × 0.02 = 20 um

A. Volume in um^3 -

20 × 10 × 10 = 2000 um^3

B. 1 um^3 = 10^-9 uL

2000 um^3 = 2000 × 10^-9 = 2 × 10^-6 uL = 0.000002 uL

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