QUESTION 5 In this lab, you will carry out dilutions using a dropper to get qual

Question

QUESTION 5

In this lab, you will carry out dilutions using a dropper to get qualitative information about metal/ligand ratios. Two drops of hydroxylamine solution are placed in a 0.50-mL well. Then eight drops of ligand solution, and 4 drops of 5 mg L-1 iron solution are added. How many nanomoles of iron are in the well?

Useful conversion factors:

There are about 20 drops in 1 mL.

1 nanomole = 1x10-9 moles

QUESTION 6

A tissue culture plate experiment is done by adding 3 drops of hydroxylamine solution, 4 drops of ligand solution, and 8 drops of iron solution to a well in the plate. If you want to repeat the experiment on a larger scale, what is the conversion factor from plate to cuvette assuming that you need to make 2.2 mL of total solution volume?

QUESTION 7

A properly done graph of your results will look something like this. The ideal ratio of ligand to iron can be determined from the volume of iron solution where the two lines intersect, that is, where they have the same x and y values. The volume of iron is on the x axis, and absorbance is on the y axis. The x value can be determined by setting the equations of the lines equal to each other, and solving for x. What is the volume of iron in mL at the ideal ratio for the results pictured here?

Explanation / Answer

2 drops of Hydroxylamine solution

V = 0.5 ml

8 drops of ligand solution

4 drops of 5 mg/L iron solution

We must add all volume

Drops = 2+8+4 = 14 drops

since 20 drops = 1 ml

then

14/20 drops = ml = 0.7 ml

find the amount of Iron solution

4 drops = 4/20 = 0.2 ml of solution

we have 5 mg/L

5 mg / L * 0.2 ml / 1000 ml/L = 0.0001 mg of Iron is present

MW of Iron = 55.8 g/gmol

mol of Iron = mass*MW = (0.0001 mg)(1 g / 1000mg)*(55.7 g/gmol) = 5.57*10^-6 mol of Iron

moles of Iron = 5.57*10^-6 mol of Iron

nanmo moles = 5.57*10^-6 /( 10^-9 ) = 5570 nanomoles

NOTE:

consider posting question 6 and 7 in another set of Q&A, we are not allowed to answer to multiple questions

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