The purpose of Experiment 4 was to determine the effects of concentration on the amount of light transmitted through aqueous solutions.
The general procedure used in this experiment was to first prepare an undiluted sample of copper sulfate by obtaining two clean cuvettes. One of the cuvettes was used as a blank sample filled with deionized water which served as a solvent, and on the other cuvette, it was rinsed out with 0.5 mL of the copper sulfate solution and filled up with about 80% of the same solution. The second cuvette served as our undiluted solution. Next, 3 diluted solutions of copper sulfate are prepared. The first diluted solution was equal to 50% of the stock copper sulfate solution, the second 25%, and the third 12.5% of concentration from the stock solution. For each of the diluted solutions, a cuvette with solution is rinsed, and filled with about 80% of the solution. A cap is placed on the cuvettes and is wiped with kimwipe to avoid any mishaps. After preparing the diluted solutions, a solution of copper sulfate from solid was prepared. This was done by using an analytical balance and a weigh boat. 0.0750 to 0.4000 grams of copper sulfate pentahydrate was weighed out and added into a clean 25 mL volumetric flask. Then, 10 mL of deionized water is added and swirled to dissolve the solid. Next, a cuvette was rinsed with the solution then was filled about 80% of the cuvette with the same solution. A cap is placed is wiped with kimwipe. Lastly, the spectrophotometer is used to measure the absorbance and transmittance of the solutions. The blank cuvette is placed first to calibrate the spectrophotometer. then , the undiluted copper sulfate sample solution is placed and data is collected. Then, the data for the 3 diluted solution is collected and recorded. After all data is recorded and collected. All equipment is cleaned and put away for next use. The major results of this experiment is that dilution 1 of 50 % of the solution proved to be most concentrated at 0.05 nm, although the stock solution had the most absorbance at lambda max of 1.331.
For experiment 5, the purpose of this experiment is to get acquainted with the concept of nanomaterials, spectrophotometry, and Beer’s law by preparing solutions of silver nanoprisms that are used to obtain absorption spectra. Dilutions for one of the nanoprism vials are used to test Beer’s law to obtain the molar absorptivity
The general procedure of this experiment is to carefully prepare four different solutions of silver nanoparticles. After cleaning out all glassware with distilled water followed by Millipore grade water, the vials are labeled 1-4, and 3 solutions were put into each vial which was: 2 mL of 1.25 x 10^-2 M sodium citrate, 5 mL of 3.75 x 10^-4 M silver nitrate, and 5 mL of 5 x 10^-2 M hydrogen peroxide. After all the solutions are added to each vial, each solution is given different amounts of sodium bromide to differentiate each vial to create different colors. Vial...