The purpose of the coordination complex lab is to determine the absorbance spectra of complexes based on their color. Every complex has its own color which results from the wavelengths of white light it reflects. The complexes will be compared by the color each reflects and by the energy of the waves each absorbs. The purity of the synthesized complex will also be found. Procedure
Part I: Preparation of the Complex
A sample of copper sulfate pentahydrate (6.285g) was weighed out. The copper sulfate pentahydrate was dissolved in water (11.99mL) in a 250mL beaker. The solution was heated on a hot plate to 90 degrees Celsius. A sample of potassium oxalate monohydrate (10.006g) was dissolved in water (50.0mL). The heated copper sulfate solution was added to the potassium oxalate solution and rapidly stirred. A blue substance formed in the mixture. The mixture was cooled in an ice bath for 20 minutes. The blue crystals were collected by vacuum filtration and were washed once with cold water (12mL), once with 95% ethanol (10mL), and once with acetone (10mL). The crystals were allowed to dry before weighing the product. Part II: Absorption Spectrum
A sample of the complex (0.256g) was weighed out and dissolved in deionized water (9.99mL). Some of the solution was removed and more deionized water (1.50mL) was added to the solution. A cuvette was filled with deionized water and another with the solution. Each cuvette was filled to the same level. The transmittance of the solution was found at 400nm and then consecutively recorded at intervals of 25nm. Absorbance was calculated from percent transmittance and then plotted on a graph as a function of wavelength. Part III: Analysis of the Complex
A buret was filled with a potassium permanganate solution (0.02015M). Two samples of the complex were weighed out (0.157g and 0.155g). A solution of sulfuric acid (1.0M) was added to each sample of complex (12.5mL and 12.6mL...
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