Pipette And Micropipette (Mathematical Skills)

Question 1

In a P20 micropipette, how would you set the pipette to 13 ul?

Answer 1

130

Question 2

In a P1000, if the micropipette is set at 025, how many ul is that? And ml?

Answer 2

250; 0.250

Question 3

In a P200 micropipette, how would you set the pipette to 180 ul?

Answer 3

180

Question 4

In a P1000, if the micropipette is set at 010, how many ul is that? And ml?

Answer 4

100 ul; 0.100 ml

Question 5

20 ul = ___ ml = ____ g

Answer 5

.02; .02

Question 6

How do you calculate % error?

Answer 6

(Actual # - Expected #) / (Expected #) * 100

Question 7

A volume of 4.2L is equivalent to what volume in mL?

Answer 7

4200 mL

Question 8

Report a volume of 736 uL in units of mL.

Answer 8

0.736 mL

Question 9

To withdraw the sample from a microcentrifuge, depress the plunger to the _______ and hold it in this position.

Answer 9

First stop

Question 10

If you notice air space at the end of the tip or air bubbles within the sample in the tip, carefully _____.

Answer 10

expel the sample back into its microcentrifuge tube

Question 11

To expel the sample into the reaction tube, slowly depress the plunger to the first stop to expel the sample. Then ____.

Answer 11

depress to second stop to blow out the last bit of fluid

Question 12

To prevent cross-contamination of reagents, remember to

Answer 12

1- Always add a single reagent to reaction tubes;
2- Release each reagent drop onto a new location of the inside wall, near the bottom of the reaction tube;
3- Use a fresh tip for each new reagent to be pipetted;
4- If the tip becomes contaminated, switch to a new one

Question 13

How do you find the average error?

Answer 13

Take the average of all the errors.

Question 14

A scientist determines that a sample has a mass of 127 mg. What is the mass of the sample in ug? g? kg?

Answer 14

127,000 ug; 0.127 g; 0.000127 kg

Question 15

What is the concentration of a 36 uM pyruvate solution, in units of mM?

Answer 15

0.036 mM

Question 16

if a phosphate buffer has a concentration of 5 mM, what is its concentration in umol/mL?

Answer 16

5 umol/mL

Question 17

The molecular weights of sucrose and water are 342 gmol^-1 and 18.0 gmol^-1, respectively. 17.3 g of sucrose is dissolved to a final total volume of 246 mL.

a) Write the equation to find the total mol of sucrose used.
b) What is the molar concentration (mol*L^-1) of sucrose in the resulting solution?

Answer 17

a) 342g / 1 mol = 17.3g / x

b) Molar of conc. of sucrose = x / 0.246L

Question 18

What is M?

Answer 18

mol/L

Question 19

What is mol*L^-1

Answer 19

mol/L = M

Question 20

A 10 mL volume of a 5 mM lactic acid solution is mixed with 5 mL of water. Write the equation to find the concentration of the resulting mixture in uM.

Answer 20

(5000 uM)*(10 mL) = C_2 * (10 mL + 5 mL)

Question 21

1 ml = ___ ul

Answer 21

1000

Question 22

10 mM = __ uM

Answer 22

10000

Question 23

A 3 mL volume of a solution containing an unknown concentration of HCl is added to 7 mL of water. It is then determined that the concentration of the HCl in the diluted solution is 630 mM. Write an equation to find the concentration of HCl in the original solution?

Answer 23

(3 mL) * [HCl] = (10 mL) * (630 mM)

Question 24

Suppose you need 100 mL of a 0.15 M solution of NaCl.

a) Write equation to find the # of mol you need of NaCl.
b) Write the equation to find the mass needed for NaCl.

Answer 24

a) 0.15 mol / 1L = x / 0.1L

b) 58.44 g / mol * x = mass of NaCl