Beverage-density-lab-1.docx.docx



Kylie SalcidoPeriod 710/7/13Beverage Density Lab ReportBackgroundDensity is figured out by measuring the mass and volume of a substance and then dividing the two. Mass can be measured with a balance, where as volume can be measured with a graduated cylinder. The density of a solution depends on the concentration of solute. The higher the solute value, the more the density, the lower the solute value, the lower the density. To express concentration, scientists use units that have to do with weight.In this lab, we will be calculating and measuring the mass and volume of different beverages to figure out its percent sugar and it’s over all density.HypothesisIf we color code different beverages and separate them by known amounts of sugar, then we will be able to determine the percent sugar content of each beverage.Experiment OverviewThe purpose of this experiment is to determine the percent sugar content inbeverages. The density of five sugar “reference” solutions will be measured in Part A. The reference solutions contain known amounts of sugar (0-20%) and have been dyed with food coloring to make it easier to tell them apart. Theirdensities will be plotted on a graph to obtain a calibration curve of density versuspercent sugar concentration. In Part B, the densities of four beverages and an unknown will also be determined and the calibration curve used to find how much sugar they contain.The results will be compared again the information provided on the nutritionlabels for these beverages.Purpose:To construct a graph of sugar content versus density for 5 sugar solutions.To determine the sugar content of 4 beverages and an unknown using graphical analysis.Materials:balance small beaker, 5 sugar solutions graduated cylinder, 4 beverages plus unknownSafety: goggles, glass breakage, spillsData Table A: Density of Reference SolutionsSolutionMass, gSample Volume, mLDensity, g/mL0% Sugar9.46 g10.000.946 g/mL5% Sugar9.71 g10.000.971 g/mL10% Sugar9.97 g10.000.997 g/mL15% Sugar10.43 g10.001.043 g/mL20% Sugar10.64 g10.001.064 g/mLData Table B: Beverage DensitiesBeverageMass, gSample Volume, mLDensity, g/mL Pepsi10.14 g10.001.014 g/mLDiet Pepsi9.85 g10.00.985 g/mLApple Juice10.07 g10.001.007 g/mLLemonade9.95 g10.00.995 g/mLPowerade10.19 g10.001.019 g/mL Unknown _____10.16 g10.001.016Results Table:BeverageExperimental % sugarPowerade9.5%Diet Pepsi5%Pepsi8.5%Apple Juice7%Lemonade5.5%Post-Lab: Results TableBeverageMeasured density, g/mLPercent sugar (experimental)Amount of sugar(Nutrition label)Percent sugar(calculated from Nutrition label)Percent error Powerade1.019 g/mL9.5%21 g/350 mL5.7%66.67%pepsi 1.014 g/mL8.5%41 g/355 mL11.4%25.4%Apple Juice 1.007 g/mL7%27 g/240 mL11.2%37.5%Diet pepsi.985 g/mL5%0 g/355 mL0%0%Lemonade .995 g/mL5.5%31 g/240 mL13%57.7%Post-Lab Calculations and AnalysisPlot density versus concentration for the five reference solutions on a graph. The concentration is the independent variable (x-axis) and the density is the dependent variable (y-axis). Use a ruler to draw the “best-fit” straight line through the data points.Use the graph to estimate the unknown sugar concentrations in the first beverage. To do this, locate the point on the y-axis that corresponds to the density value of the beverage. Follow the point on the y-axis across horizontally to where it meets the “best fit” straight line through the data. Now read down vertically from this point on the “best fit” line to the x-axis. The point where this vertical “line” meets the x-axis equals the percent concentration of sugar in the beverage solution. Construct a Results Table and record the density of the beverage and the estimated percent sugar concentration.Repeat step 2 to determine the percent sugar concentration of the second beverage. Record all information in your Results Table.Calculate the actual or accepted value of the sugar concentration in weight percent for each beverage, using the nutrition label information and the measured density value. Hint: See Pre-Lab Question #3 for how to do this calculation. Record both the nutrition label information and the actual percent sugar concentration in your Results Table.Use the following equation to calculate the percent error in our experimental determination of the sugar content in each beverage. Enter the percent error in the Results Table.What was your measured density for pure water (0% sugar solution)? The density of water is usually quoted as 1.0 g/mL, but the precise value is for 4oC. Comment on why your measured density might be higher or lower than 1.00 g/mL.This lab looks at the relationship between the density of a beverage and its sugar content. What assumption is made concerning the other ingredients in the beverage and their effect on the density of the solution? Do you think this is a valid assumption? ExplainThe assumption of the other ingredients of the beverage is that it does not affect the percent sugar. I am not sure if this is a valid assumption.When plotting data such as that obtained in this experiment, why is it not appropriate to “connect the dots?” If you were to repeat the lab, do you think you would get exactly the same results? Comment on the sources of error in this experiment and their likely effect on the results.It is important not to connect the dots because the line must be straight in order to get the experimental percent. The line will not be straight if you connect the dots, so it is important to draw the line between the dots if the line is not going to be straight. If the lab was repeated, I do not think all of the results would be the same. Liquid substances can get caught onto cups an other materials, causing the measurements to be slightly off each time.ConclusionAfter completing the lab, I was able to conclude my hypothesis correct. We were able to calculate the percent sugar of each beverage by separating them by their known amounts of sugar and measuring the mass and volume of each. By measuring the correct amount of liquids in each measurement, my lab group and I were able to calculate the percent sugar by graphs we created on our own, and exact calculations using the nutrition label. The percentages were different of course, so we also calculated the percent error of the sugar calculations. Overall, through careful direction and technique, the lab was successful. ................
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