Working on a vacuum manifold: See LLP chapter 9.2 for an excellent discussion on working with air-sensitive reagents, including how to use a two-way manifold. De-gassing solvents: The best way to remove water and oxygen from a solvent is to distill it over an appropriate drying agent (such as sodium). This can sometimes be a lengthy (and dangerous)task. Since we

1高分子化合物与低分子化合物有何区别? 答案: 高分子化合物与你分子化合物的最根本的区别在于两者的相对而言分子质量 的大小不同,通常低分子化合物的相对分子质量在1000以下,而高分子的相对 分子质量在5000以上,高分子化合物具有相对密度小,强度大,高弹性和可塑 性特殊性质

Thin Layer Chromatography (TlC) is an extremely useful technique for monitorin reactions. It is also used to determine the proper solvent system for performing separations using column chromatography. tLC uses a stationary phase, usually alumina or silica, that is highly polar(standard) or non-polar(reverse phase). The mobile phase is a solvent whose polarity you will choose. In 5.301, and in most lab

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X-Ray diffraction is an important and powerful tool for determining the solid state structure of compounds. Modern advances have made data collection and structure solution almost routine for many small molecules To use this technique, however, good quality single crystals are still needed. In this exercise you will experiment with the art of growing single crystals

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6.1 确定分子量和元素组成式 6.1.1 由EI谱确定分子量 6.1.2 由ESI谱多电荷离子峰簇求分子量 6.1.3 解析软电离的谱图得到分子量 6.1.5 峰匹配法（peak matching） 6.1.6 用低分辨质谱数据推测未知物元素组成

Chemists use spectroscopy (Ir, UV-Vis, NMR) to determine molecular structure. spectroscopy: technique that measures the amount of radiation a substance absorbs at various wavelengths(based on the quantization of molecular energy levels Molecules exist in quantized energy states (rotational, vibrational, and electronic quantum states) Molecules absorb discrete amounts of energy(ae)and are excited to higher

described in these materials are potentially hazardous and require a high lcvel ofsafity training special facilitics and equipment, and supavision by approprinte duals. You bear the sol responsiblity, liability, and risk for the impkemcntation of such safety procedures and measures. MiT shall have no responsibility, liability, ar risk for the content ar implem of ay of the matcrial presented. Legal Notices

This is two-day- experiment. Do not start this experiment unless you have two free lab days to complete it.*** Techniques Checklist: Picking the correct eluent Adsorbtion of a crude mixture onto silica gel Separating complex mixtures using gradient elution Pre-lab Discussion: Suggest limited list of eluent solvent systems Discuss sample adsorption and gradient elution strategies