agents the sides or bottom of the test tub just gently swirl or move up and down. 10. Stop data collection after 10 minutes, or when the temperature is no longer changing. Use the hot water bath provided by your teacher to melt the probe out of the solid lauric acid. Do not attempt to pull the probe out (if the solution is completely solid)—this might damage it. Leave the test tube and lauric acid in the hot water for part 2. Do not disposed of the lauric acid sample until the end of the lab. 12. To determine the freezing temperature of pure lauric acid, you’ll need to graph your temperature vs. time data and identify the average temperature over the straightest and most horizontal portion of the line, or when the temperature stops decreasing. Part II Freezing Temperature of a Solution of Benzoic Acid and Lauric Acid 14. Weigh out 1.0g of benzoic acid and dissolve it into your ~10 g sample of lauric acid that is warming up in the hot water bath from part 1. Leave it to dissolve for 5 minutes in the hot water bath then vigorously swirl the hot test tub to insure all of benzoic acid has dissolved. ( DANGER : Solid benzoic acid, C 6 H 5 COOH: Do not eat or drink when using this product— harmful if swallowed. Causes serious eye irritation. May cause respiratory irritation ). 15. Clamp the test tub back onto the stand and insert the temperature probe. After the 30 seconds have elapsed, start data collection. Record the temperature every 30 seconds for 15 minutes. 16. Use the hot water bath provided by your teacher to melt the probe out of the solid lauric acid and benzoic acid mixture. Then dump the liquid lauric acid in to the waste liquid container, rinse the test tub is acetone and dumb that in to the liquid waste container, then wash with soap and water. The temperature probe should be wiped down with a kin wipe and acetone before being put away.
- Spring '19
- Freezing-point depression, Lauric acid