Methods Bases on the Absorption of Radiation

Methods Bases on the Absorption of Radiation - Methods...

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Methods Bases on the Absorption of Radiation Chemistry 210 3/30/2011 Kimberly Hargraves
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Hargraves 2 Abstract: The Fe(III) concentration level in natural water was determined in this experiment by the red orange complex between Fe(III) and 1,10-phenanthroline (orthophenanthroline). Based on the results from this experiment the iron concentration in an unknown solution can be determined when compared with the concentration of known solutions. In order to due this a calibration curve needs to calculated, simply comparing the colors of the solutions will not work. Once the calibration curve is complete, excel was used to determine the concentration of the unknown. The three unknown samples had a concentration of 9.37 x 10^ -7 , 6.94 x10^ -7 , 6.54 x 10^ -7 respectively. Introduction: Determining the Fe (III) concentration level in natural well water is the purpose of this experiment. The red-orange complex that forms between Fe (III) and 1, 10-phenanthroline (orthophenanthroline) is useful in determining iron in water supplies. The reagent is a weak base that reacts to form phenanthrolinium ion, phenH+, in acidic media. Complex formation with iron is thus best described by the equation, Fe3 + 3phenH+ Fe(phen)32+ 3H+. Iron(II) is quantitatively complexed in the pH range between 3 and 9. A pH of about 3.5 is ordinarily recommended to prevent precipitation of iron salts, such as phosphates. An excess of a reducing reagent, such as hydroxylamine or hydroquinone, is needed to maintain iron in the +2 oxidation state. The complex, once formed, is very stable. The accuracy of spectrophotometric measurements is critically dependent on the availability of good-quality matched cells. These should be calibrated against one another at regular intervals to detect differences resulting from
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Methods Bases on the Absorption of Radiation - Methods...

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