Lab: Sugar Content in Beverages - Honors Chemistry Coursework

Lab: Sugar Content in BeveragesA Solution Density Analysis________________________________________________________________Introduction and Background: Nutritionists have recently raised concerns about the increasing popularity of sodas, fruitdrinks, and other beverages due to their high sugar content. Do you know how much sugar is in yourfavorite beverage. The density of a solution depends upon its concentration, that is, how much solute is dissolved in the solvent. Ifthe density of a solution is plotted on a graph against the concentration of the solute, a regular pattern is evident - densityis proportional to concentration. The resulting graph, called a calibration curve, shows a straight-line relationship betweenthe density of a solution and the concentration of solute. A calibration curve can also be used to determine theconcentration of solute in an unknown solution whose density has been measured. The purpose of this lab is to measure the densities of popular beverages and determine their sugar contents usinga calibration curve obtained by plotting the densities for a series of reference solutions versus percent sugar. Theexperimentally determined percent sugar for the beverages will be compared against the information provided on theirnutritional labels to evaluate the accuracy of this method.Hypothesis:How well does the sweet taste of beverage correlate with the amount of sugar it contains?Based on your memory of their taste, predict the relative sugar content in the following beverages: cola, grape juice,and sports drink/energy drink. Rank the beverages from 1, highest sugar content, to 3, lowest sugar content.Materials: beverage samples balance beakers graduated cylinder thermometersSafety:Although the materials are considered nonhazardous, follow all normal lab safety procedures.Any food-grade items that have been brought into this lab setting are considered labchemicals and are for lab use only. Do not taste or ingest any materials in the lab and do notremove any food items from the lab. Wear safety goggles at all times. After you havefinished with all materials, wash hands thoroughly before leaving the lab.Procedure:Place a 25-mL graduated cylinder on the balance and hit the “tare” or “zero” button.Fill the cylinder with 10mL of a selected beverage. Measure and record the mass of the beverage in the graduatedcylinder. Also record the exact volume of the liquid sample to the correct number of significant figures.Measure and record the temperature of the beverage sample.Re-zero the balance with the graduated cylinder containing the beverage sample. Fill the graduated cylinder with anadditional 10mL of the beverage. Measure and record the mass of the beverage in the second sample. Also recordthe exact volume of the liquid sample to the correct umber of significant figures.Calculate and record the value of the density of each beverage sample and calculate the average beverage density.Repeat the above procedure for the other two beverage samples.Data Analysis:Answer the questions and solve the problems in the Data Analysis section on the lab sheets.Disposal:The beverage solutions may be rinsed down the drain with excess water. Wash the graduated cylinders and beakers andleave the clean glassware on the drying racks in the rear of the classroom. Return the balances and thermometers to theirdesignated location.page 1 of 3

Lab: Sugar Content in Beverages! ! Lab Heading:A Solution Density Analysis______________________________________________________________________________Hypothesis:Based on your memory of their taste, predict the relative sugar content in the following beverages: cola, grape juice,and sports drink/energy drink. Rank the beverages from 1, highest sugar content, to 3, lowest sugar content.(1) _________________________ (2) _________________________ (3) _________________________Data and Calculations:SamplenameTrialno.Initialvolume(mL)Finalvolume(mL)Samplevolume(mL)Samplemass(g)Density(g/mL)Temp.( o C)Cola 12Grape Juice 12Red Bull 12Average DensityColaGrape JuiceRed BullData Analysis:1. The following data represents percent and density values from known sugar solutions. Use this data to create acalibration curve by creating a Density versus Percent Sugar graph of the reference solutions. Use a ruler to draw a“best-fit” straight line through the data points. Be sure to include all correct labels and units and (of course) beneat.Percent sugarDensity at 20 o C1% 5% 10% 15% 20%1.002 g/mL 1.018 g/mL 1.038 g/mL 1.059 g/mL 1.081 g/mLpage 2 of 3

2. Use the calibration curve you have just created to estimate the sugar concentration of your beverage samples basedon your calculated densities. Record the estimated percent sugar for each different beverage type. Mark and labelthe points for each beverage on your calibration curve.Est. Percent SugarColaGrape JuiceRed Bull3. Consult the nutritional label for the beverage and record the sugar content in grams of sugar per serving and recordthe serving size in milliliters. Then convert this information to percent sugar in the beverage. (Divide the grams ofsugar by the serving size, then divide by the measured density of the beverage, and fina%y multiply by 100 to make it a percent.)Show a sample of this calculations, including all units.ColaGrape JuiceRed BullSugar Content (g) Serving Size (mL) Calculated % SugarSample Calculation:4. Calculate the percent error in the experimental determination of the sugar content. Assume the calculated valuebased on the nutritional label to be the most accurate piece of information and therefore your accepted. Show asample of this calculation.Percent ErrorColaGrape JuiceRed Bull Sample Calculation:5. This lab examines the relationship between the density of a beverage and its sugar content. What assumption ismade concerning the other ingredients in the beverage and their effect on its density? Is this a valid assumption?why or why not?page 3 of 3