Spectroscopic Determination of Iron with Phenanthroline

Experiment A Spectroscopic determination of Iron with Phenanthroline unfamiliar 2 Mass of Mohrs Salt 0. 2040 1. 5mL of 6M acetic acid was measured and transferred into a 100mL volumetric flaskful with a pipette and diluted to the mark. denseness= 0. 2040(0. 0001)g/100(0. 08)mL*(1mol/392. 16g)/(1L/1000mL) = 0. 005202(0. 09382%) = 0. 005202(0. 000005)mol/L 2. 10mL of the above air solution was transferred to a 250 mL volumetric flask and diluted to the mark. Concentration= 0. 005202(0. 9382%)mol/L*10(0. 02)mL/250(0. 12mL) = 0. 00020808(0. 22607%) = 0. 00020808(0. 0000005)mol/L 3. Standard error of burette is 0. 02mL in every reading. firmness of purpose Desired Volume Absorption 1 Absorption 2 norm Absorption Standard 1 30 0. 662 0. 664 0. 662 Standard 2 25 0. 544 0. 546 0. 545 Standard 3 20 0. 43 0. 434 0. 432 Standard 4 15 0. 317 0. 309 0. 313 Standard 5 10 0. 222 0. 217 0. 2195 Standard 6 5 0. 113 0. 112 0. 1125 Unknown 1 0. 096 Unknown 2 4.Sample exemplar concentratio n calculation with standard 1, Concentration= 30(0. 02)mL/100(0. 08)mL*0. 00020808(0. 0000005)mol/L = 0. 000062424(0. 2807%) = 0. 000062424(0. 0000002) 5. From the Calibration curve of Absorbance Vs Concentration, we know the equation of the graph is y = 10553. 63(190. 5558)x 0. 00363(0. 007721) Where, y is the absorbance and x is the concentration. We know the absorbance of the unknown is 0. 096. Therefore, 0. 096 = 10553. 63(190. 5558)x 0. 00363(0. 007721) x= 0. 096+0. 00363(0. 07721)/ 10553. 63(190. 5558) = 0. 00000944(7. 957%) = 0. 0000094(0. 0000008) 6. Standard Concentrations Uncertainties bonnie Absorbencies 0. 000062424 0. 0000002 0. 662 0. 00005202 0. 00000013 0. 545 0. 000041616 0. 000000108 0. 432 0. 000031212 0. 00000007 0. 313 0. 000020808 0. 00000006 0. 2195 0. 000010404 0. 00000005 0. 1125 SUMMARY OUTPUT Column1 Regression Statistics Multiple R 0. 999348603 R hearty 0. 99869763 Adjusted R Square 0. 998372037 Standard Error 0. 008293572 Observations 6analysis of v ariance Column1 Column2 Column3 Column4 Column5 df SS MS F Significance F Regression 1 0. 2109807 0. 2109807 3067. 32299 6. 3634E-07 residue 4 0. 000275133 6. 8783E-05 Total 5 0. 211255833 Column1 Coefficients Standard Error t Stat P-value dismantle 95% Upper 95% Lower 95. 0% Upper 95. 0% Intercept -0. 003633333 0. 007720895 -0. 4705845 0. 66245106 -0. 025069975 0. 017803308 -0. 025069975 0. 017803308 X Variable 1 10553. 63322 190. 5558304 55. 3834181 6. 3634E-07 10024. 56542 11082. 0102 10024. 56542 11082. 70102 7. Isobestic point is a limited wavelength at which two chemical species have the same molar absorptivity. A pair of substances can have several isobestic points in their spectra. In a 1-to-1 chemical reaction that involves a pair of substances with an isobestic point, as long as the sum of the concentrations of the two molecular entities in the solution is held constant on that point will be no change in absorbance at this wavelength as the ratio of the concentra tions of the two entities are varied.This is because the two substances absorb light of that limited wavelength to the same extent. We do non observe any isobestic point in this experiment because we did not scan by dint of the entire spectrum but earlier chose a wavelength at which the species have different molar absorptivity. Besides, if we were working with an isobestic point, we would not be able to obtain changes in absorption with changing ratios of concentrations. 8. transmittance is the ratio of the radiation f everying upon a material, to the radiation transmitted through a material.Absorbance is negative logarithm of transmittance. Molar absorptivity is a mensuration of how strongly a chemical species absorbs light at a give wavelength. From Beers law we know that, A=? bc. Therefore the absorbance is proportional to the concentration. 9. A solution of Fe34- would show a violet-blue color at an absorbance maximal of 562. And if the absorbance maximum were 414, a gr een-yellow color would be observed. The spectra for absorbance maximum 562 are sketched in the sideline The spectra for absorbance maximum 414 are sketched in the following 10.There could be instrument link up sources of error. Stray light could be a problem since the detector responds to all the light that reaches it. In liquids, the extinction coefficient usually changes slowly with wavelength, which could add to the manageable errors. There could be errors from the measurement uncertainty of the results. There could also be errors while preparations of the standards, due to presence of impurities in the apparatus which may carry to discrepancy in the calculation of the concentration. 11. Van De Water, Leon G. A Jaap A. Bergwerff, T.Alexander Nijhuis. UV-Vis Microspectroscopy Probing the sign Stages of Supported Metal Oxide Catalyst Preparation. J. Am. Chem Soc. 2005, 127(14), pp 5-24-2025. academician Search Premier. EBSCO host. University of Minnesota Lib. correspond Citi es. Minneapolis. MN. 05/02/12. In this article UV-Vis microscopy is used to monitor macro distribution and speciation of the particle accelerator precursor species. Through this experiment more detailed information on the structure-function correlation of the catalytic material is obtained. Koeppet, Benjamin Tolstoy, Peter M Limbach, Hans-Heinrich.Reaction Pathways of Proton reassign in Hydrogen-Bonded Phenol Carboxylate Complexes Explored by Combined UV-Vis and NMR spectroscopy. J. Am. Chem. Soc. 2011, 113(20), pp7897-7908. Academic Search Premier. EBSCO host. University of Minnesota Lib. Twin Cities. Minneapolis. MN. 05/02/12. In this article better cleverness about the tautomeric states of the H bonded anions, and the solvent configurations were obtained from UV-vis time scale. The UV-vis absorptions were broadened inhomogeneously because of distribution of the H-bond geometries from the different solvents.