PLTW, MI Unit 1 Serial Dilution Practice

If 1 mL sample is put into tube #1 that has 9 ml diluent, what is the tube dilution? What is the final dilution?

• Tube 1/10

• Final 1/9

• Tube 1/9

• Final 1/10

If 1 mL sample form tube #1 with a tube dilution of 1:10 is placed in tube #2 with 9 mL of diluent, what is the tube dilution and what is the final dilution of tube #2?

• tube dilution 1:90

• tube dilution 1:10

• final dilution 1:100

• final dilution 1:90

If the concentration of tube 1 = 200 µg/ml (tube 1 is now the starting stock solution) and 0.5 ml of sample is moved each time into 9.5 ml of diluent to complete 3 dilutions from the first tube, what is the concentration in tube #4?

• 2.63 µg/ml

• 0.025 µg/ml

• 0.050 µg/ml

• 0.100 µg/ml

If 20 µL sample is put into tube #1 with 100 µL diluent, what is the tube dilution and final dilution of tube #1?

• tube dilution 20/100 or 1/5

• tube dilution 20/120 or 1/6

• final dilution 20/120 or 1/6

• final dilution 20/100 or 1/5

If 1 mL sample is put into tube #1 that has 49 mL of diluent, what is the tube dilution?

• 1/49

• 1/50

If 2 mL sample is removed from a tube with a dilution of 1/50 and placed into a tube #2 with 48 mL diluent, what is the tube dilution and final dilution for tube #2?

• tube dilution 2/48 or 1:24

• tube dilution 2/50 or 1:25

• final dilution 1:50

• final dilution 1:1250

If the concentration of the stock solution is 50 ng/ml, what is the concentration of the tube with final dilution of 1/1250?

• 0.2 ng/mL

• 50 ng/mL

• 0.04 ng/mL

• 2 ng/mL