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Project 13- Analysis of Colas

Plotting the absorbance and molarity of that given

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Unformatted text preview: ntration (molarity) of the compound (supported by Beer’s law in the literature). This objective will most likely match up with Beer’s Law as stated earlier (Cooper, 2009). By using the information and knowledge gathered in these experiments we were to accurately predict the phosphate content of three different types of cola beverages and determine the molarity (concentration) of each. Plotting the absorbance and molarity of that given solution and taking the unknown concentration’s absorbance and finding the value on the plotted data will find the phosphate content of the specific cola beverage. We will use the analytical wavelength when doing so to find the wavelength of most absorbance and using that as a reference for the remainder of our figures. We expect to see our results match up with Beer’s Law and the data associated with it. We also expect that the phosphate contents are different from one another and that the molarity of phosphate can be determined by creating a calibration curve and finding the absorbance of the phosphate and then finding the corresponding molarity. 3 Results In the first part of the lab absorbance was measured for four different solutions from wavelengths 350 to 650(nm), three with food coloring and the fourth being potassium permanganate. The first solution was water with a drop of food coloring and the analytical wavelength was found around 490 nanometers. The second solution’s (blue) analytical wavelength was determined to be approximately 625 nanometers. The third analytical wavelength for purple was determined to be about 510 nanometers. Lastly the fourth solution (potassium permanganate) was analyzed and its analytical wavelength was determined to be 530 nanometers. These results can be seen in the table and figure located below. Each solution had its own distinct curve. Figure 1: Wavelength vs. Absorbence of Various Solutions 2.0 1.8 Absorbence (AU) 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0 350 370 390 410 430 450 470 490 510 530 550 570 590 610 630 650 Wavelength (nm) water + red dye water + blue dye water + Mix KMNO4 The second part of the lab was used to determine the difference between absorbance and concentration at a given wavelength. The smallest concentration was diluted to 0.00002M and the absorbance was 0.0655. The second solution was 0.00005M and its absorbance was 0.1811. The third solution was 0.0001M and absorbance came out to 0.3516. The last solution was 0.00015M and that ended up being 0.5272 absorbance units. The results listed can be viewed on figure 2 below. 4 Figure 2: Molarity vs. Absorbance of KMnO4 at Analytical Wavelenght 530nm 0.6000 Absorbance 0.5000 0.4000 0.3000 0.2000 0.1000 0.0000 0 0.00002 0.00004 0.00006 0.00008 0.0001 0.00012 0.00014 0.00016 Molarity (concentration)...
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