Lab Report for Stoichiometry of a Metal Complex (Lab Report Sample)

Name Tutor Course Date Lab Report for Stoichiometry of a Metal Complex Introduction Fe (II) ions combine with ortho-phenanthroline to form Fe (II) metal complex. Its absorbance was determined using the stoichiometry methods. Fe 2+ (aq) + "n" (ortho-phenanthroline) (aq) = Fe (o-phenanthroline) n2+ The experiment follows the premise that the metal complex produced absorbs visible light strongly, with a maximum absorbance of 510 nm. It is also known that the aqueous ferrous ion absorbs an insignificant amount of light at the wavelength, as well as the ortho-phenanthroline molecule. From Beer’s law, A= εbC, light absorption by a complex metal A is directly proportional to the molar concentration, C, of the respective complex with the path length, b, and the molar absorptivity ε being constant. Colour appearance accompanies the formation of a complex compound. To determine the amount of complex ion in the solution, measurement of the absorbance of the solution is conducted. As the number of metal complex ions increase in the solution, the absorption increases proportionally. If the number of Fe2+ ions was maintained constant, the increase in the number of moles of the ortho-phenanthroline leads to an increase in the number of the Fe (II) complex in the solution and, therefore, the absorbance increases until all the ions are utilised. Procedure The Fe (II) solution was prepared in a clean volumetric flask using ferrous ammonium sulphate salt in distilled water, hydroxylamine sulphate and sodium sulphate. 0.26 grams of the salt was dissolved in 20 millilitres of distilled water, the solution was labelled as stock A. the molarity of the solution was measured. 5 grams of hydroxylamine sulphate and sodium sulphate each were slowly added to a volumetric flask and shaken to dissolve with 25 millilitres of the stock A, transferred to the flask using a pipet. The solution was comprised of Fe (II) solution. A 10 ml volume of the Fe (II) solution was transferred to a 100 ml volumetric flask and diluted with distilled water. The spectrophotometer was calibrated in readiness for the experiment using this solution. A 10 ml solution of the Fe (II) solution was then placed into a volumetric flask, and ortho-phenanthroline added. The initial and final volumes in the flask were noted. The flask was then filled with distilled water to the mark and the contents poured into a clean dry beaker. The cuvette was rinsed with a small portion of the solution. It was filled and inserted into the spectrometer. The absorbance values were recorded. Data Grams of sodium sulfate: 5.1293g Grams f hydroxylaminesulfate: 4.9595 Molarity of ortho-phenothroline: 0.00242 Sample number ML Fe(II) mL a-phenilflos K I F O-phen used abs 1 10.0 0 0 0 0.00 0 2 10.00 22 2.63 4.74 2.11 0.171 3 10.00 24 4.74 8.62 3.88 0.337 4 10.00 26 8.62 14.91 6.29 0.554 5 10.00 28 14.91 22.82 7.91 0.719 6 10.00 12 22.82 33.66 10.84 0.804 7 10.00 15 33.66 48.18 14.52 0.808 8 10.00 ...