Students' understanding degree of disciplinary core concepts directly impacts the achievement of the learning targets. The national science education standards in China and other countries pay great attention on cultivating students' ability of conceptual understanding to improve the civic scientific literacy. For exploring and identifying students' conceptual understanding, content-specific concept in a certain level of learning progression needs to be concerned. Compared with other types of diagnostic tools, two-tier diagnostic instrument is more precisely and concretely. Furthermore, Rasch modeling theory is better than classical testing theory in validating the quality of measurement instrument. Thus, this paper took an example of the concepts of "ionic equilibrium in solution" to illustrate how to develop two-tier diagnostic instrument for measuring students' conceptual understanding, and to present how to use Rasch modeling to validate and revise the measurement instrument.

This paper analyzed Singapore's junior high school chemistry textbook G.C.E.‘O’ Level Science Discover Chemistry mainly from the columns and the specific cases,and concluded that the textbook had the following characteristics:information prompting column was showing unique features,experimental research program was emphasizing on practical application,extracurricular information program was highlighting to keep pace with the time,summarize program was strengthening macro-micro combined and thought exercise program was focusing on individualism,and also put forward some suggestions on the columns setting of junior high school chemistry textbook of China.

Flow Map's quantitative statistics of the content difficulty of "redox reaction" in Chinese and American textbooks showed that significant differences existed in the integration extent and the representation depth of Chinese and American textbooks, which indicated that higher degree of the latter, namely the relative difficulty of American textbooks was smaller; while the qualitative evaluation manifests that American textbooks which took the "electron in chemical changes" as the understanding core constructed a cognitive context "gain and loss of oxygen-electronegativity of oxygen and gain or loss of electron-oxidation number and electron gain or loss", which applied the "electronegativity" as the advance organizer and integrates a large number of application knowledge (oxidation) by using information processing strategies, such as comparison and contrast, context reasoning and interpretation.

In teaching practice,teachers lacked proper teaching strategies to present green chemistry,students had a shallow understanding of the connotation of green chemistry. This paper made many heterogeneous forms for the same subject,comparison and analysis,and found that teachers should pay more attention to the latest achievements in the forefront of science and technology,and present real problem situations to students in a systematic and integrated way,and should stimulate students' inner motivation to look at green chemistry in many dimensions,so that green chemistry could be the background of students' scientific scroll.

In order to improve the pertinence and effectiveness of each stage of teaching, this paper analyzed the learning progressions of ionic reaction, discussed the cross section design of teaching sequence, and hoped to provide reference for teachers to carry out the teaching of ion reaction.

This paper analyzed two excellent chemistry teachers' (called A,B) classroom teaching of "from bauxite to aluminum alloy",used 3C-FIAS method to encode the classroom teaching language,summarized the language features and possible deficiencies in the teaching of elemental compounds,and provided effective suggestions for the construction of efficient chemistry classroom.

Through two examples of competing reaction and salt drying in the sea,this paper expounded that:in the course of teaching the principles of chemistry,using modeling ideas could make complex processes concise and clarify abstract principles and laws behind the phenomenon.

Taking the properties of ammonium salt as the main line,this paper reorganized and integrated "ammonium and ammonium salt",combined "properties inquiry of ammonia" with "properties inquiry of ammonium salts",combined "physical property inquiry" with "chemical property inquiry",combined "preparation of ammonia" with "application to upgrade",and had achieved ideal teaching effect in practice.

Based on the FLOWMAP,this paper measured senior two students' cognitive structure,discipline core competencies and learning difficulties with "halogenated hydrocarbon" as an example. Research showed that the advantage of excellent students cognitive structure was reflected in the higher degree of "integration" and accuracy,the disadvantage of students with learning difficulties was reflected in the low efficiency of information retrieval,and excellent students were better at using information processing strategies such as description and situational reasoning. Students differed greatly in their academic requirements for achieving different levels of literacy in halogenated hydrocarbon knowledge system. Learning difficulties mainly included:did not know the classification,physical properties and use of halogenated hydrocarbon,did not understand or confuse characteristics and conditions of substitution reaction and elimination reaction.

Taking the representative senior high schools in seven cities of Henan province as the object of investigation,this paper investigated the basic facilities of chemical laboratory,students' interests in chemistry learning and the empathy of teachers and students,and made a statistical analysis of the survey data. Through the investigation,it was found that the basic facilities were well equipped,but lacked laboratory staff. Through the comparison,it was found that the opening of chemical experiments did not significantly improve the students' interests in chemistry and their achievements. In view of the investigation results,this paper put forward the countermeasure of bringing the experimental examination into the college entrance examination.

This paper discussed the main problems in the teaching of the amount of substance,used the independent interaction teaching software to innovate the traditional "amount of substance" teaching. In order to cultivate students' scientific research methods and logical reasoning ability,started from students' existing knowledge and experience,through specific understanding and operational problems,formed tasks and realized students' independent inquiry under task driven,got the conclusion,established the concept and derived the formula. The practice showed that this method could effectively help students establish the concept and calculation formula of molar,eliminate the confusion of concepts,and played a role in the cultivation of quantitative scientific research methods.

From the perspective of "deep learning",the chemical experiment could promote students to construct knowledge,cultivate students' thinking of chemistry based on experiment and improve students' scientific inquiry ability. However,many students still stayed in the surface learning level in the current senior high school chemistry experiment teaching. Through access to literature and analysis of teaching case found the reasons for students' shallow learning. According to these reasons,the corresponding teaching strategies were proposed and demonstrated through the case,so as to promote students' deep learning. These strategies included the following aspects:establishing the experimental teaching goal of higher order thinking development,choosing the challenging experimental questions,constructing the real critical experiment situation,integrating the experimental content of the meaningful join,using flow chart,mind mapping and other tools to show the thinking process,establishing the continuous attention feedback evaluation method.

This paper used instruments such as homemade wooden fixer, syringe to design experiment device, used pressure sensor to show the effect of pressure on chemical equilibrium "2NO₂?N₂O₄". This experiment was easy to operate, and the equilibrium movement process was displayed intuitively, it was very helpful for students to learn the chemical equilibrium, especially the understanding of Le Chatelier's principle.

In order to facilitate students to understand the chemical equilibrium in depth. On the basis of the teaching materials,this paper used hand-held technology to quantitatively inquire the effect of multiple concentrations on the chemical equilibrium; the effect of the addition of crystals on the chemical equilibrium was also explored. By analyzing the experimental phenomena and graphs,it was concluded that the degree of chemical equilibrium was increasing in the direction of positive reaction with the increase of the concentration and mass of KSCN.

This paper used control variable method to explain how to adjust a eudiometer. Firstly controlled the height of liquid level through clipped a stop clip on the rubber tube,and reduced variables. When the adjustment of the right tube was completed,fixed the right tube and opened the stop clip,so that the liquid level automatically adjusted to the same height through the pressure difference.

In view of the use of a large quantity of liquid,low utilization rate of reaction liquid,and poor safety of the Kipp's apparatus,this paper designed a new gas generator,which was composed of a liquid storage cup,a flow regulator,an exhaust pipe and a reaction vessel. Liquid reactants were added into the reaction vessel by the flow regulator and reacted completely with solid reagents,and discharge liquids contained very few liquid reactants. Therefore,the amount of liquid reactants required was greatly reduced. The experimental results showed that the new device had the advantages of little dosage of liquid reactants,high efficiency,good safety performance,and convenient operation. Meanwhile,it had the characteristic of the immediate use just like Kipp's apparatus. It could be effectively applied in chemical experiment teaching.

This paper used crystallization alcohol formed by calcium chloride and ethanol as ethanol stream donor in experiment of ethanol oxidation into acetaldehyde,in which crystallization alcohol could provide ethanol stream under heating condition. The crystallization alcohol enhanced conveniences in experimental operation and saved the amount of alcohol. And the generation and test experiments of acetaldehyde were carried out concurrently,which saved the time and increased the reliability of acetaldehyde test.

This paper briefly introduced the activities of American national chemistry week in 2017,then got some enlightenments on high school chemistry teaching in China:(1)creating a relaxing atmosphere with education in amusement; (2)highlighting evidential reasoning and enhancing the ability of identification; (3) striving for green education and blowing safety alarm; (4) encouraging to question and developing exploration spirit; (5)broadening chemistry reading and widening field of vision; (6)developing colorful experiments and enjoying the beauty of chemistry.