Beverage Density Lab

Transcription

1 Name: date: Beverage Density Lab Introduction: It is known that popular beverages often contain large amounts of. Nutritionists have raised concern in recent years as to the high levels of in these drinks and it s detrimental effects such as tooth decay, hyperactivity and obesity. Do you know how much is in your favorite beverage? In this lab we will determine the amounts of in various soda, juice, and sports drink. Background: The density of a solution depends on its concentration, that is, how much solid (solute) is dissolved in the liquid (solvent). If you graph of density versus concentration, you will get a straight line. Therefore, density is directly proportional to concentration. In this lab we will make a graph of density vs. concentration using solutions of known concentrations. This graph will be used as our calibration curve. The calibration curve can then be used to determine the concentration of in an unknown solution (soda, etc.) whose density has been measured. The determined percent of for the beverages will then be compared against the information provided on their nutritional labels to evaluate the accuracy of this method. Hypothesis: Based on your memory of their taste, predict the relative content in the following beverages. Rank them from #1 to #3, with #1 being the sweetest in taste. Coca-cola (Coke) white grape juice Powerade Procedure: To make standard solutions: 0% solution (mass/mass): Put ml deionized water into a beaker and label 5% solution: Add 2.50 g to 47.5 ml DI water. Stir well and label. 10% solution: Add 5.00 g to 45.0 ml DI water. Stir well and label. 15% solution: Add 7.50 g to 42.5 ml DI water. Stir well and label. 20% solution: Add g to 40.0 ml DI water. Stir well and label.

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3 To determine density of standard solutions: 1. Place a 100 ml beaker on a balance and tare the balance. 2. Measure exactly ml of the 0% solution in a graduated cylinder. 3. Add the solution to the beaker and record the mass in the table below. 4. Repeat steps 1-3 using 5%, 10%, 15% and 20% solutions. Be sure to clean and dry your beaker between samples. 5. Repeat steps 1-3 using Coke, white grape juice and Powerade. 6. Calculate the density (g/ml) of each beverage sample using the following equation: Density= mass volume 0% 5% 10% 15% 20% Coke Grape Juice Powerade Mass of 10.00mL (g) Density (g/ml)

4 Data Analysis: 1. Create a graph with density on the y-axis and % on the x-axis. BE SURE TO USE AS MUCH OF THE GRAPH PAPER AS POSSIBLE! 2. Plot the data points for your standard solutions. Use a ruler to draw a best fit straight line through the data points. 3. Use the density you determined for Coke, grape juice, and Powerade to determine the % in the three drinks. Record your data on the table below. 4. Record the grams of per serving from the nutritional label for each beverage on the table below. Grams per serving can be converted to % (theoretical). A sample calculation has been provided. 5. Compare the actual percent measurement you obtained in lab to the theoretical percent from the nutritional label and calculate your percent error. Coke Grape Juice Powerade % (actual) Nutritional label info g / ml g / ml g / ml % (theoretical) Percent error (%) Ex. Sample Calculation: Measured density = g/ml Nutrition label info = 42 g / 355 ml 42 g X 1mL beverage = g per gram of beverage 355 ml beverage g beverage Percent (theoretical) = g / gram of beverage x 100 = 11.4 % Percent (actual) = what you determined from the graph Percent error = I actual -theoretical I X 100 theoretical

5 Questions: 1. This lab examines the relationship between the density of a beverage and its content. Name two other factors that may contribute to the density of a beverage: a) b) 2. Look back at your hypothesis as to which beverage you expected to have the highest content. Do you results from this lab support your hypothesis? Explain your above answer.

6 3. Look at the nutrition label on each of the beverages. Notice that there is often more than one serving in the container. If the nutrition label says 22 g per 8 oz serving and you drink the entire 20 oz container, you will consume 55 g. (fyi: a 55 g sample of has about the same volume as a golf ball!) Calculate how many grams of you would be consuming if you drank a typical 20 oz (591 ml) glass full of each beverage. SHOW YOUR WORK IN THE TABLE BELOW Coke grape juice Powerade TOTAL SUGAR CONSUMED (remember units) Final Answer