DRAFT: This module has unpublished changes.

Procedure:

1. Start a new experiment on the data collection system.

2. Connect the stainless steel temperature sensor to the data collection system.

3. Display data on the graph to show Temperature versus Time.

4. Measure about 8 g of lauric acid and record the mass of this solvent to the nearest 0.01 g in Table 1.

5. Place a 400-mL beaker ¾ full of water on a hotplate.

6. Place a stirring bar into the beaker.

7. Use a clamp to connect the test tube to the ring stand so it is immersed in the water as far as possible.  If necessary, add more water to the beaker.

8. Wrap the copper wire coil around the stainless steel sensor.  Clamp it to the ring stand and insert it into the test tube as shown in the illustration.

 

Collect Data:

9. Carefully transfer the solvent into the test tube.

10. Turn on the hotplate and the stirring bar.

11. When the crystals melt, place the stainless steel sensor with the copper coil wrapped around it into the melted crystals.

12. Once the test tube is clear (the crystals are melted), remove the test tube from the water bath, with the sensor and coil still in it, and clamp it in the empty Erlenmeyer flask.

13. Start data recording and start stirring the contents of the test tube by moving the copper coil up and down.

14. Adjust the scale of the graph.

15. Once the contents of the test tube are completely solidified, stop data recording.

16. Mount the test tube into the water bath again and allow the contents of the test tube to melt.

17. Measure about 0.5 g of the unknown sample to the nearest 0.01 g and record the mass in Table 1.

18. Carefully transfer the solute into the test tube.

19. Once the test tube is clear (the crystals are melted), remove the test tube from the water bath, with the sensor and coil still in it, and clamp it in the empty Erlenmeyer flask.

20. Start the data recording and start stirring the contents of the test tube by moving the copper coil up and down.

21. Once the contents of the test tube are completely solidified, stop data recording.

22. Display both data runs in the graph.

23. From the curves, locate the freezing points of the pure solvent and the solution. Record these in Table 1.

24. Print the graph.

25. Melt the contents of the test tube again and dispose of the chemicals into the designated waste container.

26. Save your experiment and clean up according to your teacher’s instructions.

DRAFT: This module has unpublished changes.