Heating & Cooling Curves of a Pure Substance
(Temperature Changes during Phase Changes)
(Temperature Changes during Phase Changes)
Overview:
Here is a sample data of another similar lab:
Lab Notes:
A substance should be selected that will has a freezing/melting point that is well under the boiling point of water. Possible candidates - lauric acid (m.p. 44°C), acetamide (m.p. approx. 80°C), p-dichlorobenze (mothballs; m.p. 53°C).
This lab is relatively easy to set up and carry out, and may be completed in a one-hour lab period. Minimal lab equipment is required. The actual lab set-up varies with the reference used but are all similar and can be easily modified to suite the lab situation. Either the heating or cooling data may be recorded first - to record the melting phase first, either a crystallized form of the solid should be used, or the thermometer should already by "frozen" into the sample.
Questions are included in the student version, but a formal lab report may be prepared instead. An evaluation rubric for marking formal reports can be found by following the "Evaluation" link at the top of this page.
Here is a video found on YouTuBe:
After a review of atoms, ions, molecules, and states of matter, this module presents a discussion of changes of state, phase diagrams, and heating curves. The module also addresses mixtures, with a focus on separation of mixtures.
