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Melting Point Abstract Finding the melting point of an organic substance is a practical and efficient way for scientists to identify an unknown substance or determine
Melting Point Determination OBJECTIVES 1. To determine the identity of an unknown by its melting point. 2. To confirm the identity of an unknown by using the mixed
Identification of an unknown solid by melting point ?. Summary of Results A. Melting point of Benzoic Acid Temperature (?C) Observation Unmelted White salt First
Aspirin and Tylenol were synthesized by means of crystallization, recrystallization, and melting point determination. Synthesis produced significantly high percent
Isolation of the active ingredient in an Analgesic Drug from extraction, filtration and melting point. Chm237 Abstract: Acetaminaphen was crushed then extracted for
Submitted by crawford769 on February 27, 2008
Category: Science
Words: 1353 | Pages: 6
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Abstract
Finding the melting point of an organic substance is a practical and efficient way for scientists to identify an unknown substance or determine a known substance's level of purity. When organic substances are mixed together in varying degrees they take on a melting characteristic that is lower and broader than in its pure form. This property was manipulated in the lab to observe the various melting points of Naphthalene and Biphenyl when the percentage of composition was altered. A eutectic point of 45 °C at 52% Naphthalene was determined from the class data. An unknown crystalline substance was identified to be Benzophenone by mixing and finding its melting point with known substances.
Introduction
Organic compounds are categorized by their physical properties and/or chemical reactions. Naphthalene is classified as an aromatic hydrocarbon that consists of two benzene rings that are fused together. Its physical appearance is that of white crystal flakes. Solid crystalline materials consist of a three dimensional structure that is called the crystal lattice. Organic crystalline solids are held in fixed positions by cohesive forces that are fairly weak which gives them a low to moderate melting point (mp). When an organic crystalline solid is heated it absorbs the energy and the molecules begin to vibrate, eventually overcoming the cohesive forces. Once the molecules begin to move past one another, the structure starts to collapse and there is an appearance of fluid (lower end of melting range) which continues until the substance is entirely liquid (upper end of melting range) ¹.
Melting points are used in identifying unknown substances and assessing the purity of a compound. Pure substances like 100% Biphenyl will have a sharp melting temperature (68.93 °C). A compound that is mixed or has even a small amount of impurity will have a lower melting point and broader melting range. This...
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