dscnibed in these materials are potentially hazardous and require a high level ofsafcty training special facilitics and equ by approp lividuak You bear the sole responsibility, liability, and risk for the in plementation of such safety procedures and measures. MIT shall have no responsibility, liability, or risk for the content or implementation of amy of the matcrial presented. Legal Notices

应用绝对反应速度理论和统计力学到化学气相沉积(CVD)钽上,建立了反应速度模型。实验表明,测定值与计算值间吻合较好。证实了用绝对反应速度理论建立的速度模型的正确性,而且证实了化学气相沉积钽的速度控制环节为表面化学反应

described in these matorials arc potentinlly hazandous and require a high levd ofsafety training spccial facilitics and equip mant, and supervision by approp iate individuals. You bea the sole responsibility, lisbility, and risk for the implamnentation of such safcty procedures and mcasures. MIT shall have no respongibility, liability, or risk for the content or implementationc any of the material presanted. Legal Notices

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

对包头底吹转炉含铌渣用硫酸—过氧化氧法进行了提取铌化学精矿的实验室研究。原渣含Nb2O55～8%。经破碎、球磨及除铁后加浓硫酸及硫酸铵在200～250℃进行硫酸化焙烧。焙烧渣在固∶液=1∶3,硫酸酸度为4N及低于25℃的条件下用过氧化氢浸出。滤液经煑沸分解过氧化氢络合物以沉淀铌酸。铌由渣中浸出率为81～85%,由液中沉淀率为95～99%,总回收率为79～82%。铌化学精矿含Nb2O5>65%

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

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

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

For a two-solvent recrystallization, you should have one solvent (solvent #1) in which your desired compound is soluble at the boiling point. The second solvent(solvent #)should induce crystallization when added to a saturated solution of your compound in the primary solvent. Reference:

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