Spec 20 Lab Results

To begin the experiment, the Spec 20 was turned on to warm up for 15 minutes and set to maximum absorbance wavelength. Ten test tubes were then prepared. The Spec 20 was set to 0% and a test tube of blank solution (water) was wiped off and placed into the Spec 20. Transmittance was then set to 100% to calibrate the machine. Next, five test tubes were prepared and labeled with one of the standard solutions of 0.05 M, 0.1 M, 0.2 M, and 0.5 M CuSO4 in them. The Spec 20 was set to 600 nm and % transmittance was measured of the standard solutions. Absorbance was calculated and recorded. Then, 2 g of solid CuSO4∙5H2O was measured out and placed in a 100 mL beaker. Water was added (about 15 mL) to make a 20 mL of 0.5 M solution from CuSO4∙5H2O by. Solution …show more content…
Next, the solution was transferred back into the 100 mL cylinder and water was added to the solution in the cylinder to reach 20 mL. The amount of water needed was determined. A 20 mL of 0.2 M CuSO4 solution was created. Afterwards percent transmittance was measured and recorded. The process was repeated to create and measure transmittance of 20 mL of 0.1 M CuSO4 solution and 20 mL of 0.05 M CuSO4 solution. Next, a test tube was filled with CuSO4 solution of unknown concentrate and percent transmittance was measured. For analysis, the procedure to make 0.5 M CuSO4 solution from the solid was written out and discussed. Next, the percent transmittance that was recorded for the standard solutions were converted to absorbance. A plot was then made on excel of concentration values (x-axis) versus the absorbance values (y-axis). A line of best fit was included on the graph as well. After making the graph, absorbance was calculated from the percent transmittance of the made solutions. Actual concentration of the made solutions were later calculated by using the equation of the line of best fit from the excel chart