9. Make sure you see a graph of your data. Select the area on the graph (and the corresponding data) where the temperature remained constant ( see Figure 1 ). Use the collection device to analyze this area and provide statistics (mean, max, min, etc.). Record the mean as your melting temperature for lauric acid. Save and print out a graph and data table. Time Figure 1 Part II Freezing Temperature of a Solution of Benzoic Acid and Lauric Acid 10. Measure ~0.6 g of benzoic acid and ~5 g of lauric acid into separate weigh boats. Record the precise masses of benzoic acid and lauric acid in your data table. Put both solids into your test tube, and place the test tube in a hot water bath to melt them into a solution. Repeat Steps 3-8 to determine the freezing point of this mixture. When you are finished, dispose of your test tube as directed by your instructor. 11. At the completion of the 10 minutes, make sure the graph is displayed. To determine the freezing point of the benzoic acid-lauric acid solution, you need to determine the temperature at which the mixture first started to freeze. Unlike pure lauric acid, cooling a mixture of benzoic acid and lauric acid results in a slow gradual drop in temperature during the time period when freezing takes place. Scroll through the data points to locate the freezing point of the solution, as shown in Figure 2. Record the freezing point (y- value) in the Data and Calculations table.
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- Fall '16
- Algebra, Freezing-point depression, Lauric acid