Lab Report Project 13 - Project 13 Analysis of Colas...

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Project 13: Analysis of Colas Beckilyn Dorsey Course: Chemistry 1011, Section 002 Instructor: Tatiana Estrada November 13, 2016 My signature indicates that this document represents my own work. Outside of shared data, the information, thoughts and ideas are my own except as indicated in the references. I have submitted an electronic copy through Blackboard to be scanned by TurnItIn.com. In addition, I have not given aid to another student on this assignment.”
Discussion and Scientific Explanation The goals of this lab was to learn how to use a spec 20, and to use this machine to find the concentration of phosphate in different colas, so that a cola company could decide how much phosphate to put into their cola. They wanted to find this out since people drink cola because they think that the phosphate will settle their stomachs, so if this company has more phosphate content then more people will buy their cola. The first week was mainly for accomplishing the first goal and figuring out how to use the spec 20. This was done by using different samples of food coloring and Potassium Permanganate, 2 drops per 100 mL were added for each solution, and finding the percent transmittance of these different samples at different wavelengths ranging from 350 nm to 650 nm. Before calculating the percent transmittance, a blank had to be used, the blank for this week was water. So after this percent transmittance was able to be found and it was found that it ranged from 6 percent to 92.8 percent for the red food coloring, it ranged from 1.9 percent to 69.8 percent with the green food coloring, the green and red ranged from 15.1 percent to 50.1 percent, and the potassium permanganate ranged from .4 percent to 60.3 percent. By finding the percent transmittance, the absorbance could then be calculated by using the equation A=2-log(%T). Calculating the absorbance helps to find what wavelength to use when finding the percent transmittance and absorbance of dilutions of potassium permanganate. The wavelength that is used is decided from the largest absorbance. This is used because this is where the absorbance curve is most precise and accurate because it somewhat plateaus at this point 2 . The analytical wavelength found was 530 nm where the absorbance was 2.4. So then this is used to measure the dilution’s percent transmittance, it needed to measure between fifteen and eighty-five percent, which they were each of the four times it was measured. These numbers were 83.9 percent at a concentration of . 00001 M, 71.4 percent at .00005 M, 52.2 percent at .0001 M, and 28.8 percent at .0002 M. The concentration and volumes for each of these dilutions was decided by using the formula V stock *C stock =V dilution *C dilution, a concentration was plugged in for each dilution so then the volume of

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