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对高中化学竞赛试题中有关立体化学试题进行归类解读, 帮助参加化学竞赛的指导教师和同学形成解答此类试题的一般方法, 并对今后的该类化学竞赛试题进行展望。 相似文献
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以第29-31届全国高中化学(奥林匹克)竞赛中晶体结构试题为例,从基础知识角度出发,对试题内容进行探讨,对命题思路及解题策略进行了分析,拓展了晶体结构类试题的研究背景和相关知识,引导读者了解试题背后的科学思想,感受化学学习的乐趣,并对今后化学奥赛中该类试题进行了展望,供参赛老师和学生参考。 相似文献
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详细分析并解答了第33届中国化学奥林匹克(初赛)试题。本届初赛试题对知识储备的要求有所降低,但对思维能力与解题准确度的要求略有提高。每一道题目都附有详尽的分析、讨论与解答过程,引导读者综合运用所学的化学知识,通过推理、演算、论证等方法顺利解题。对于部分题目,还给出了科学背景介绍、知识拓展与思考题,鼓励读者了解题目背后的科学思想,举一反三。 相似文献
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化学实验在2007年高考试题中的体现形式以及解答方式均出现了新的变化;纵观2007年高考化学试卷(含理科综合卷)发现,化学实验试题及分值占的比例较大,全国卷与各省自主命题的试卷各有特点,研究新课改背景下的化学实验教学和实验高考复习无疑是一个新的课题,认真分析高考试题的新特点无疑也是备考复习过程中的重要一环,本文拟结合2007年全国高考试题中化学实验试题来解读化学实验考查的特点及对化学实验备考复习的启示。1试题设计突破常规模式,注重基本实验设计能力的考查例题1(全国Ⅰ)28(15分)水蒸气通过灼热的焦炭后,流出气体的主要成分是C… 相似文献
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选择部分高考理综化学试卷选择题进行案例分析,认为试题情境背景材料的选择与改造应作为试题命制技术的一项重要内容。基于具体试题的分析与讨论,提出试题情境的背景材料选择及控制应依据考生现有的知识基础、应考量考生已有的知识经验、应满足考生认知的"最近发展区"。试题情境"新""特"背景材料的认知要求如果没有得到合理控制,对试题的测量效度和试题分数的信度都会产生较大影响。 相似文献
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Under the background of "double first-class" construction, we embrace the teaching philosophy of "student-centered and goal-oriented" in the physical chemistry teaching process. Through the heuristic teaching model guided by questions, the concepts and laws are elaborated based on the history of scientific development. The frontiers of the discipline and application cases are introduced into teaching, aiming at cultivating students' innovative consciousness and scientific thinking. Through flipped classroom and group discussion, students' self-educated ability and team spirit are developed. 相似文献
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Toussaint B Schimmel H Klein CL Wiergowski M Emons H 《Journal of chromatography. A》2007,1156(1-2):236-248
The certification of the purity of CRMs intended for calibration, where no other certified material already exists for comparison, raises principle questions on how to determine the purity of a "first" calibrant in the calibration hierarchy. We developed and certified two calibration CRMs for their purity in thyroid hormones taking into consideration inorganic residues, residual solvents and organic impurities detectable by HPLC-UV and HPLC-MS. IRMM-468 was certified for a thyroxine (T(4)) mass fraction of 98.6+/-0.7% and IRMM-469 was certified for a 3,3',5-triiodothyronine (T(3)) mass fraction of 97.1+/-0.7%. The approach we used aims to determine the purity of these two CRMs to the best of our knowledge and taking all scientific aspects properly into account for the estimation of an uncertainty related to the stated purity. 相似文献
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The fundamental parameters and limitations that determine the signal strength in tip-enhanced Raman scattering (TERS) are discussed. A semiquantitative analysis of the Raman signal expected in different experimental geometries and with different sample systems is presented, taking into account experimental parameters including Fresnel factor, numerical aperture of the illumination and collection optics, detection efficiency, and the Raman scattering cross section of the material. A top/side-on illumination geometry is essential for the study of nontransparent samples. It can yield the highest signal levels when strong tip–sample coupling using a metallic substrate provides large field enhancement. In contrast, axial/through-sample illumination is limited to transparent sample materials. Although conceptually simpler in experimental implementation and despite high numerical aperture signal collection efficiency, signals are generally weaker due to limited field enhancement. Crystalline solids with small Raman cross sections and dense molecular/biological systems with unavoidable far-field background provide the biggest challenge for TERS analysis yet at the same time hold the most exciting outstanding scientific questions TERS has the potential to answer. Figure 3
Excitation and emission sequence in tip-enhanced Raman scattering. The signal intensity can be estimated for a given experimental layout considering numerical aperture, Raman scattering cross-section, and plasmonic field enhancement. 相似文献
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Electrochemistry of the silicon oxide dielectric layer, a notable insulator often used as a gate oxide, is counterintuitive, but addresses fundamental questions to yield novel scientific discoveries. In this minireview, the fundamental electron transfer mechanism of silicon oxide in the electrolyte solution is elucidated. The possible electrochemical reactions to date are discussed in detail, providing numerous potential areas of application which are elaborated and justified. This minireview not only provides background but also guides future research. 相似文献
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What kind of "war" did Japanese chemists fight during World War I, and what impact did their experiences have on Japanese chemistry in its aftermath? By focusing on the role of Jōji Sakurai (1858-1939), this paper attempts to answer these questions by looking at the drastic changes in the international relationships of the Japanese chemical community caused by the war. It examines how the Japanese National Research Council was established in 1920 as part of the International Research Council, a product of the reconfiguration of international scientific powers triggered by World War I. This paper argues that Sakurai advocated the establishment of the National Research Council after the American model of wartime mobilisation of science, coordinated fractured Japanese chemical communities for international functions, and facilitated Japan's participation and increased influence in international scientific associations such as the International Union of Pure and Applied Chemistry, established in 1919. 相似文献
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Jaime Wisniak 《The Chemical Educator》2001,6(1):41-49
The academic and research career of Raoult is an example of success against the odds. He was born into a family of modest means and made his academic career far from Paris, the center of scientific power and means. He did his research on the behavior of solutions in general, and electrolytes in particular, before the concepts of molecular association, salt dissociation, and molecular structure had been established. In spite of this, by precise experimental work and brilliant intuition he made fundamental and everlasting contributions to thermodynamics. Raoults results are discussed against the scientific background of his time and then reanalyzed using current thermodynamic ideas. 相似文献
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基于高中化学新课程教学理念和评价促进教学的观点,反思传统试题的不足和评价弊端,结合新课程高考试题样例,提出了新课程背景下高中化学试题命制的6条原则。 相似文献
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