Based off of a Beer\'s Law Chart, how can I find these values? 1. Calculate the

Question

Based off of a Beer's Law Chart, how can I find these values?

1. Calculate the concentration (M) of Fe2+ in the saturated solution of iron(II) oxalate.

a. Calculate your experimental Ksp value and compare it to the literature value found in Table 1. Calculate a percent error.

b. Calculate pKsp for your experimental Ksp and pKsp for the literature value of Ksp. Calculate a percent error in pKsp. Note: pKsp = -log(Ksp)

c. Calculate the solubility of iron(II) oxalate in units of grams per liter.

d. Calculate the number of grams of iron(II) oxalate that will completely dissolve in 100 mL of water.

Here are the steps we took:

1. Prepare a new standard 2.00 mM iron solution for your own use. Dissolve the appropriate amount of Fe(NH4)2(SO4)2*6 H2O in 50 mL of water containing 1 mL of concentrated H2SO4.

2. Transfer the solution to a 1-L volumetric flask and dilute to 1 Liter. Mix well.

3. Prepare the following solutions in six 100-mL volumetric flasks:

1 mL of 10% hydroxylamine hydrochloride

5 mL of 0.1% 1,10-phenanthroline

1 mL of 10% sodium acetate

4. Dilute contents of one of the six flasks to 100 mL with DI water and label this as the "Blank".

5. For the other five flasks, calculate the amount of stock solution to use to have an evenly distributed range of concentration of Fe2+ from 20-100 uM. Add the needed volume of each stock solution to each of the remaining five flasks.

1.2 0.8 0.6 B 0.4 0.2 -0.2 Absorbance at 508 nm Amount of Stock Solution in Beaker y 0.2093x 0.2376 R2 0.99582

Explanation / Answer

Let us calculate the concentrations at different dilutions

The initial concentration = 2mM and volume 50mL

diluted to 1000mL so the new concentration = 2X10^-3 X 50 /1000 = 0.1mM

b) the next concentrations required are :

100uM , 80uM, 60uM, 40uM , 20uM [final volume = 100mL]

(i) For 100uM we will take the solution as such

(ii) for 80uM

100 X Volume = 80 x 100

We will take 80mL of stock solution

(iii) For 60uM

100 X Volume = 60 X 100

We will take 60mL of stock

Similarly for 40 and 20 uM we will take 40 and 20mL respectively.

The equation from Beer's law is

y = 0.2093x - 0.2376

So here y = absrobance

x = concentration

If we know the absrobance values we can calculate the concentration

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