Selenium (Se) as an element of Group ⅥA has the properties of non-metallic, as well as some metallic characters. Se is widely spread but unevenly distributed in the natural environment, and the content of Se in earth's crust ranges 0.05~0.09 mg/kg. As an essential trace element for animals and human beings, Se has important physiological and biochemical functions. However, excess Se and its compounds are highly toxic, and the range between toxicity and essentiality is quite narrow. This paper briefly introduces the natural existence of Se in the environment, the biological effect of Se as well as its molecular basis with the aim of commemorating the 150^th anniversary of the discovery of periodic law of elements.

This paper briefly introduces the overall characteristics of The General High School Chemistry Textbooks edited by WANG Lei and CHEN Guang-Ju of Beijing Normal University (published by Shandong Science and Technology Press).From the aspects of the organization and arrangement of textbook structure and contents, the appearance of subject recognition models and methods, the setting of problem tasks and series of micro-projects, the arrangement of students' necessary experiments and chemical science practice activities, the design of performance evaluation of discipline core competencies, the selection of subject education materials, etc., the strategies for compilation to carry out the curriculum standards and interpretations of subject core competencies and moral education are introduced.

This paper analyzed 22 chemical syllabus and curriculum standards promulgated by China after the founding of New China, combed the core competence of chemical syllabus and curriculum standard in different periods from three value levels and four perspectives, and found that the expression of chemical core competence varied from abstract to concrete, and the connotation of chemical core competence varied from junior high school to senior high school, the methods of characterizing chemical core competence were gradually improving and tending to be stable.

This paper analyzes the type, content distribution, presentation form, content difficulty, subject competence, core literacy level and proposition characteristics of chemical experiment questions in the College Entrance Examination 2018 paper Ⅰ, Ⅱ, Ⅲ, and puts forward several suggestions for high school chemistry experiment teaching.

Based on the SEC consistency analysis model, this paper makes a coding analysis of the consistency between the chemistry experimental questions in Fuzhou, Xiamen and Quanzhou senior high school entrance examination and the content topics and cognitive level requirements of the experiment contents in the Chemistry Curriculum Standards for Compulsory Education (2011 edition), summarizes the proposition requirements of the experimental questions, and puts forward that emphasis should be laid on experimental teaching, and the system of experimental proposition should be closely linked to the requirements of curriculum standards.

Combining with the overall study and sample research, it has been discovered that the changes of exercises in Chinese senior high school chemistry textbooks published since the late Qing Dynasty followed these features:the textbook exercises gradually become necessary; the position of exercises has gradually shifted from being concentrated in the end of the book to being dispersed in the content; the types of exercises are gradually varied. The content of exercises pays more attention to the experimental process and situational application, and gradually pays attention to value orientation. All these changes reflect the reform of educational ideas and provide new thought for the compilation and use of textbook exercises in the future.

With the idea of cultivating students' dialectical power of thought, around "talk about what you know about burning and extinguishing" "reflections on experimental devices exploring burning conditions of combustibles" "reflections on burning conditions and phenomena" a series of related experiments were designed and successfully implemented to develop students' dialectical thinking ability while correcting their existing precognitive biases.

Based on the present practical teaching situation integrated chemistry history into high school chemistry, after referencing other teaching modes integrated the history of science into other disciplines teaching and practicing a lot of teaching examples, this paper constructed a "four-lines" teaching mode for the history of chemistry integrated into high school chemistry, including "line of history" "line of inquiry" "line of knowledge" and "line of application". This mode can run through the whole teaching process to cultivate students' chemistry key competencies.

Industrial production is an important embodiment of the contribution of chemistry to society and an important source of material for chemistry teaching. When developing teaching materials for industrial production, chemical knowledge in the production process can be analyzed from the perspectives of material transformation and reaction regulation based on chemical reaction principle, and the influence of scientific progress and technological renewal on chemical reaction selection and principle regulation in industrial production can be realized with the help of historical development clues. According to the requirements of the curriculum standards, the analysis results of industry material were screened and reorganized to confirm the teaching objectives. Then, the key issues of teaching were extracted, and the ability activity design was carried out. The result of teaching practice proved the validity of the idea of developing teaching materials for industrial production.

This paper made an interpretation of key concepts such as chemical culture and observation, and further explained the individual's understanding of the cultivation of core literacy under the chemical culture. This paper proposed the use of "three-line" parallel methods such as task line, logic line and emotion line (educational line) to stereoscopically structure classroom chemistry culture. These three lines included bright and dark lines, they cooperated and supported each other. This paper took the teaching of "precipitation-dissolution equilibrium" as a carrier to fully try and apply this proposition, and moderately integrated the STEAM education concept, analyzed its specific role in cultivating students' chemical core literacy. Finally, teaching reflection was carried out.

Based on 286 pre-service and post-service high school chemistry teachers, this paper explores the psychological structure of high school chemistry teachers' inquiry teaching efficiency and its possible influencing factors by means of investigation, interview and statistics. It found that high school chemistry teachers' inquiry teaching efficiency really had a certain psychological structure, which included four aspects:the understanding of inquiry, the understanding of inquiry teaching, the ability of inquiry and inquiry teaching, and the expectation of inquiry teaching results. The teaching age had a significant influence on the sense of inquiry teaching efficiency of high school chemistry teachers. The sense of inquiry teaching efficiency showed an upward trend with the increase of teaching age. Gender, teaching stage, administrative division of the school, economic development level of the school area and school type had no significant influence on the sense of inquiry teaching efficiency of high school chemistry teachers.

The unique micro structure and reaction details of Crocodile Chemistry 605 can promote developing discipline key literacy "macro-identification and micro-analysis" and "the ideas of changes and balance". Took specific cases as examples, this paper presented how this Crocodile Chemistry 605 software apply to the quantitative experiment, in order to provide for chemistry teachers a novel, practical, scientific and quantitative simulation teaching software.

This paper used infrared thermography to measure the change in temperature, compare the differences in temperatures, and present the distribution of temperatures. The advantages of the infrared thermography were remote sensing measurement (no touching), visibility (visual presentation), real-time measurement (presentation of dynamic changes), and etc. It was suitable for micro or untouchable experiments or for the requirement of observation of temperature distribution and dynamic change. Simultaneously, this technique could reduce the risks of experiments.

The experiment of determination of acetic acid in vinegar has been arranged in some university and high school textbooks. But because of the deep color of the aged vinegar, the decolorization efficiency of activated carbon is low, which seriously affects the progress of the experiment. The decolorization efficiency of commercial activated carbon, self-made sawdust activated carbon, bamboo activated carbon, peanut shell activated carbon, cooked bone activated carbon and walnut shell activated carbon for aged vinegar were studied systematically. The results showed that:when decolorizing aged vinegar, the activated commercial activated carbon had the highest efficiency, and the self-made bamboo activated carbon was slightly inferior to the former; in decolorization, oscillation was better than non-oscillation; the decolorization efficiency was the highest when the volume of the decolorized liquid was in proper proportional to the decoloring agent; the colorless clear liquid could be obtained quickly by centrifugation.

This paper summarized the examination points of organic chemistry in 32nd National Chemistry Olympiad (Preliminary) by the knowledge frameworks, and analyzed the test questions in detail. Hope this can help candidates who are committed to participate in the high school chemistry competition to achieve excellent results.