Bongo, Sayre, J1
1Student, Organic Chemistry 1 Laboratory / B11, School of Chemical Engineering, Chemistry and Biotechnology, Mapúa Institute of Technology
ABSTRACT
The melting point of a substance is the temperature at which the material changes from a solid to a liquid state while the boiling point is the temperature at which it changes from liquid to solid. In this experiment, the main objectives were to determine the effects of the following either on the melting or boiling point of organic compounds: 1) intermolecular forces of attraction and geometric isomerism on melting point, 2) purity on melting point range, and 3) intermolecular forces of attraction and branching on boiling point. The experiment was composed of two parts: determination of melting points and determination of boiling points. The Thomas-Hoover melting point apparatus was used for the first part of the experiment, while the micro method for boiling point determination was performed for the second. Both the melting and boiling point of compounds are affected by intermolecular forces. The three kinds of intermolecular forces that can operate on covalent molecules listed by increasing strength are van der Waals forces, dipole-dipole attractions, and hydrogen bonds. Also, purity and isomerism also affect melting point and branching for boiling point.
Keywords: melting point, boiling point, intermolecular forces, chemical structure, Structural Theory
INTRODUCTION
The structural theory states that properties of organic compounds, both chemical and physical, are largely influenced by their chemical structures. Two of these physical properties studied in the experiment were boiling point and melting point.
The melting point of a compound can simply be defined as the temperature at which a substance undergoes a phase change from solid to liquid. More specifically however, we define melting point as the temperature at a specific pressure at
References: 1. Baluyot, J.Y. G., De Castro, K. A., Organic Chemistry Laboratory Manual for Chemistry Students, Part1 2. Ophardt, C. (2003) Virtual Chembook, Elmhurst College or from www.elmhurst.edu 3. “Micro Method Determination of Boiling Point of Hydrocarbons”. Dr. Pahlavan. <http://swc2.hccs.cc.tx.us/pahlavan/2423L3.pdf>. January 12, 2007