For the class, we did Experiment 2B, "Heating and Cooling Curves of a Pure Substance". The experiment is to find out how long it takes pre substances to get to their melting point and freezing point. The pure substance we used during this class was dodecanoic acid.
The Cooling Process:
We first submerged the heated dodecanoic acid into the room temperature water. In 30 second intervals, we observed and recorded the temperature and solidity of the substance. We continued this for about 9 minutes until the temperature of the dodecanoic acid lowered to 25º C , whiten and solidify.
The Heating Process:
Now that we have cooled the dodecanoic acid, it is time to heat it up! We replaced the room temperature water with hot water that is around 60º C. The beaker is placed on a hot plate to ensure the temperature does not drop. Next, the test tube is submerged into the hot water. The temperature of the dodecanoic acid rose steadily, slowly melting into a yellow liquid. The temperature of the dodecanoic acid reached around 59º C to turn into liquid completely.
Lastly, we made a graph out of the results.