Spectrophotometric Analysis of Kmno4 Solution

1686 WordsMar 4, 20137 Pages
Experiment # 9: Optical Method of Analysis Use of Beer’s Law on a KMn04 Gregorio, Justin Edrik A. March 2013 Department of Chemical Engineering, Faculty of Engineering University of Santo Tomas España, Manila Abstract The purpose of this analytical laboratory experiment is to determine the unknown concentration of potassium permanganate (KMnO4) solution by finding its absorbance through the use of spectrophotometer. The preparation of four known concentration of KMnO4 was done namely, 2.00×10-4M, 1.50×10-4M, 1.00×10-4M, 5.00×10-5M, respectively and is to be place on the spectrophotometer with the unknown and distilled water for the determination of each concentration’s absorbance. As the concentration is proportional with the absorbance…show more content…
IV. Results and Discussion The molarity of KMnO4 is dependent on the volume of the KMnO4 used and the volume of the distilled water added. In this table, it can be observed that the lower the amount of H2O and the higher the amount of the KMnO4 is, the higher the molarity is and the lower the amount of KMnO4 and the higher the amount of the H2O added, the lower the concentration is. The computation of the molarity can be seen on the appendix. Table 1: Data | V of KMnO4 (2.00×10-4M)(mL) | V of H2o(mL) | VT(mL) | [M]f | Absorbance | B1 | 10 | 0 | 10 | 2.00×10-4 | 0.168 | B2 | 30 | 10 | 40 | 1.50×10-4 | 0.121 | B3 | 10 | 10 | 20 | 1.00×10-4 | 0.084 | B4 | 10 | 30 | 40 | 5.00×10-5 | 0.047 | unknown | | | | 2.50×10-4 | 0.204 | The absorbance of each solution is determined by the use of spectrophotometer. While the molarity of the unknown is acquired through the use of graph and is reflected at Absorbance Graph. The computation of the concentration of the unknown is presented at the appendix. V. Conclusion and Recommendation From this experiment, we have determined the concentration of the unknown with the help of spectrophotometer and Beer’s Law. The experiment and familiarization with the spectrophotometer has been successfully done. In the preparation of the known concentration, it is best advised to have an accurate measurement because it can directly affect its absorbance. Be sure to rinse
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