2. To make the least concentrated sample, use a pipet to accurately transfer 1.0

ID: 1052479 • Letter: 2

Question

2. To make the least concentrated sample, use a pipet to accurately transfer 1.00 mL of the standard

iron solution into the 100 mL volumetric flask provided.

3. Dilute to about 50 mL with distilled water.

4. Add 1.0 mL of the hydroxylamine hydrochloride solution to the volumetric flask.

5. Add 5.0 mL of the 1,10-phenanthroline solution to the volumetric flask.

6. Buffer the solution by adding 8.0 mL of the sodium acetate solution.

7. Using pH test paper, make sure that the solution pH is between 3 and 5.

8. If the pH is above 5, add HCl solution to the volumetric flask.

9. Dilute to the mark with distilled water. Transfer the solution to a clean container and wait at least

15 minutes for full color development. After 15 minutes the sample can be placed in the

spectrophotometer.

10. Clean the volumetric flask thoroughly with distilled water. Repeat the above procedure with 2.00,

4.00, 5.00, and 10.00 mL aliquots of the standard iron solution. Use other beakers from your

drawer to hold the solutions while they develop, but make sure to label them.

11. To make the blank solution, repeat the above procedure, omitting step 2

Fill the other cuvette with the standard of highest concentration.

3. Set the spectrophotometer to 600 nm.

4. Zero the spectrophotometer with the blank solution as described in .

5. Take a reading using the standard solution. Repeat steps 4, 5, and 6 as you change

the wavelength by 20 nm increments and zero with the blank between each wavelength change.

6. Stop at 400 nm.

NOTE: At this point you have completed a "scan" by recording the absorption spectrum of

find the wavelength of maximum absorbance (lambdamax) reported in the

literature for the Fe-Phenanthroline complex.

From literature, you should use max = 508 nm for the absorbtion.

Note that this is unique for Fe-Phenanthroline, and should not be used with other complexes.

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