Question

essie is working with a 100% stock concentration of Clorox. She decides to add 150 µL of bacteria to a tube containing 2 mL of nutrient broth and then adds 200µL of the Clorox stock to the tube as well. What is the unknown concentration of the tube?

Answer 1

8.5%

Step-by-step explanation:

The unknown final concentration can be found out by the dilution formula C1V1 = C2V2

where,

C1 = Starting concentration = 100%

V1 = Starting volume = 200μL

C2 = Final concentration

V2 = Final volume = 2350μL ( 2000 + 150 + 200 )

So,

100 * 200 = C2 * 2350

C2 = (100 * 200) / 2350

= 20000 / 2350

= 8.5%