1. COOLING CURVE OF PALMITIC ACID LAB

2. No Food or Drink in the Laboratory

3. Purpose:
To study the effects of cooling a pure substance through a change of phase.
To construct a cooling curve of a pure substance using experimental data.
To determine the freezing point temperature of the pure substance.

4. Equipment:
Sample test tube containing Palmitic Acid
Hot Plate
Beaker
Goggles
Thermometer
Test tube rack
Stop watch/timer with second hand
Materials:
Palmitic acid
Water

5. Procedure
Remove test tube sample from the hot water bath and place in into a test tube rack.
This is time = 0. Record initial temperature in appropriate place on data table.
Continuously stir the sample with the thermometer and make temperature readings every 30 seconds. Record your temperature readings on your data table.
At some point the thermometer will cease to move. The substance is now frozen. Continue to record the temperature for another 5 minutes.

6. Data Table and Graph

7. Results and Analysis:
At what temperature did you notice solid forming?
At what temperature did you notice all liquid had changed to solid?
What is the freezing point of palmitic acid based on your results?