Lab 1 - Ankur Patel Chem-233 Tuesday 2:00-5:50 TA Mark...

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Ankur Patel Chem-233 Tuesday- 2:00-5:50 TA: Mark Kinch Lab One Partners: Lauren and Joe Characterization of Organic Solids and Liquids by Elemental Analysis, Mass Spectrometry, Melting Point, Boiling Point and Infrared Spectroscopy.
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Introduction: The purpose of the experiment is to determine the structures of an unknown organic solid and liquid using the techniques of elemental analysis. These include mass spectrometry, melting point and boiling point determination, IHD calculation, and infrared spectroscopy. Theory: Elemental analysis, also known as molecular formula determination, is used to determine the empirical formula of a compound. The given relative abundances (in percents) are converted to grams, by assuming that the compound is 100 grams. After converting to moles, the empirical formula is determined through simple ratios, followed by mass calculation and comparison the given to give the final molecular formula. To reach the ultimate goal of identifying the structure, the index of hydrogen deficiency then is calculated. Also known as the degrees of unsaturation, the IHD is equal to the number of double bonds and rings in a molecule. It is calculated by the equation {[( 2 x # of C) + 2] – ( H + N)} / 2; where C is the number of carbon atoms, H is the number of hydrogen atoms, and N is the number of nitrogen atoms in the compound. To further construct the structure, the IR of the compounds is determined using the spectrometer. The readings on the IR scale give a spectrum be comparing percent transmittance and wavenumber. Then the determined data can be compared to known spectrums to give the appropriate functional groups. For example, the alcohol functional groups is located between 3000- 2600 and is broad. From the concepts and equations above, the structure(s) can be determined. However, the hypothetical structures must be narrowed to reach the actual structure. When the melting points and boiling points are determined, the data is then compared to the Merck index (versus hypothetical structures) to reveal the final structure. Procedure: The first step in this lab is to perform an elemental analysis to determine the molecular formula of the unknown compound, which then can be used to calculate the index of hydrogen deficiency. Then to determine the Fourier Transform Infrared Spectroscopy, 3 spatula scoops KBr and the unknown solid are ground in a mortar and pestle and placed into the spectrometer on the appropriate films. The melting point of the solid is then determined by placing the unknown into the heating device (shown on next page) and waiting for the melting temperature to be reached (when the solid melts). The final step in the procedure is to set up the boiling point
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Lab 1 - Ankur Patel Chem-233 Tuesday 2:00-5:50 TA Mark...

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