Sourness is one of the five flavors. The sourness of foods is caused by the acidic compounds contained in them. The structures of the acidic compounds in different sour foods are different. Starting from the principle of sour flavor, the structure and properties of the acidic compounds contained in common sour foods were introduced.

This paper introduced the changes of the IUPAC atomic weights of elements 2007―2017 and the contributions made by Chinese scientists in the determination of atomic weights. It also pointed out the problems existing in the periodic table of elements and the atomic weights of elements in the chemical textbooks, in order to attract the attention of the compilers and publishers.

Taking Chemistry 1 and Chemistry 2 as the objects of study, chemistry textbooks are divided into three categories:“subtext” in text, “subtext” in table, “subtext” in illustration. The roles and functions of “subtext” in textbooks, the types of “subtext” and the way of presenting knowledge are explained and analyzed in this paper.

Focusing on the training of students’ core literacy and the “situational” characteristics of knowledge, this paper elaborates the development of quality-oriented school-based Chemistry textbooks, the construction of evaluation systems and implementation strategies. This study will provide important references for teachers to develop school-based curriculum and textbooks.

“Knowledge of washing” is a topic closely related to students’ daily life and chemistry. A series of learning tasks which are closely related to the chemistry curriculum standards of junior and senior high schools are developed. The project helps students understand the cleaning principle, constructing the chemistry idea and expanding the vision of washing. The project will enhance students’ ability to analyze and deal with things around them.

In this paper, organic reactions are classified by the way of breaking chemical bonds. Chemical reactions are divided into non-polar reactions and polar reactions. Students are guided to construct models of polar reactions caused by hetero-cracking of chemical bonds through the uneven distribution of electronic clouds and the difference of electronegativity. Substitution reactions in polar reactions and additive reaction models of polar π bonds represented by aldehydes and ketones are summarized. In the form of group discussion, students are guided to reanalyze the existing reactions in textbooks based on models; based on polar reaction models, students construct the formation reaction of carbon-carbon bonds independently, which is a part of the migration from known to unknown; finally, based on polar reaction models and the formation of carbon-carbon bonds, comprehensive application of organic synthesis is carried out to enable students to form a pathway for organic synthesis.

This paper introducd the problem situation into the classroom, and summarized the basic methods of substance content determination in solving specific problems, let the students choose the experimental principle and reagents independently in the form of group cooperation, built the corresponding experimental device, and guided the students to make error analysis and improvement on their own experimental designs. Open experimental design was an effective way to improve students’ chemical core literacy.

This paper aims at the problems existing in the current chemistry class, such as the fragmentation of teaching contents and the failure of the evaluation process to implement the development of students’ high-order thinking ability. Based on the SOLO classification theory, through the existing research, the concept of teaching content is optimized and integrated, thus constructing the learning progression model of “metals and their compounds” unit, and designing the teaching activity of “sodium and its compounds”. Then, according to the concept of integration of teaching, learning and evaluation emphasized in the new curriculum standard of high school chemistry revised in 2017, the corresponding evaluation framework of teaching, learning and evaluation is designed. This research has certain theoretical and practical guiding significance for effectively implementing the cultivation and evaluation of core literacy advocated by the new curriculum standards.

Focusing on students’ experience and perception in learning process and cultivating students’ scientific inquiry ability is the focus of the new round of chemistry curriculum reform. With the aid of digital experiments, classroom teaching creates problem situations and conduct metric titration is used to study the rule of double decomposition ion reaction among acid, alkali and salt. Based on the digital experimental results, the experimental results are analyzed and explained from the perspective of four representations of macro-micro-symbol-curve, so that students can experience and perceive the real occurrence of ion reaction in the demonstration, and reflect on teaching.

Focus on the core literacy from the research object, problem situation, subject knowledge, subject ability and other four aspects, establish the goal of chemical homework design, and prepare the basic, situational, open, layered and practical chemical homework. Now, taking the extracurricular assignment design of “hydrocarbon derivatives” as an example, it is designed according to five horizontal dimensions, such as “perception of life, analogy structure, migration application, experimental exploration, situational practice”, highlighting the quality cultivation function of the assignment. From the perspective of focusing on the core literacy, this paper considers four aspects: research object, problem situation, subject knowledge and subject ability, establishes the goal of chemical homework, and sets the basic, situational, open, layered and practical chemical homework. Taking the homework design of “hydrocarbon derivatives” as an example, it is designed according to five levels of “perception of life, analogy structure, migration application, experimental exploration and situational practice”, highlighting the quality cultivation function of the homework.

The composition of solute and filter residue in “one metal reacts with a variety of salts in solution” and “one salt reacts with a variety of metals in solution” were dialyzed by the aid of number axis. It intuitively showed the reaction process and results, established a thinking model, and made it easy. It was good for students to master and apply.

Based on Flanders interactive analysis system, a double-coding analysis model of classroom interaction with the characteristics of chemistry was constructed. Taking the classroom of an excellent novice teacher and an expert teacher who won the first prize in Anhui Senior High School Chemistry Quality Course Competition as an example, this paper comprehensively introduced the application of the double coding model in classroom analysis by comparing and analyzing the four aspects of classroom interaction matrix, dynamic polygraph, classroom interaction variables and teacher representation conversion level.

The purpose of this study is to develop a three-tier diagnostic test to assess students’ conceptual understanding of chemical equilibrium. The participants come from a secondary key middle school in Zhejiang Province, and all of them select chemistry subject in the college entrance examination. The three-tier diagnostic test are consisted of three dimensions: judgment of chemical equilibrium state; equilibrium constant and reaction conversion rate; influencing factors of equilibrium movement. The results indicate that students’ understandings of chemical equilibrium are good in general. But there are lots of alternative conceptions when students use reaction rate to judge the equilibrium state. Students’ calculation ability and self-confidence in conversion rate are slightly inadequate. There are also cognitive deficiencies in the influencing factors of equilibrium movement, such as catalyst and pressure. Especially the latter, students have not really understood the mechanism of pressure affecting equilibrium movement.

China’s education research field vigorously advocates empirical research, but faces the problems of lack of operational guidelines and unclear quality standards, resulting in few high-quality empirical research cases. The number of research samples and their representativeness or intention are important factors to ensure the quality of empirical research. This paper discusses the principle of selecting research samples in quantitative research and qualitative research, clarifies the quality indicators and content requirements of research samples in the writing of empirical research papers, and analyzes four cases of educational empirical research papers by using the quality indicators and content requirements. It is found that the task of improving the quality of educational empirical research in China is still relatively arduous.

On the basis of the improved micro-experiment of chemical reaction rate determination and the principle of situational similarity, the experimental data were developed into a simulation experimental software. It helps to determine the simulated chemical reaction rate, record, analyze and integrate data and draw images in classroom teaching. In the context of similar situation, students are allowed to experience the process of scientific research, explore the teaching value of chemical experiment data analysis, understand and establish the relation of v=Δc/Δt and understand the source of various change curves.

In view of the fading reaction between potassium permanganate and oxalic acid, a method for quantitative determination of potassium permanganate concentration in the system was established by RGB analytical means, and the effects of concentration, temperature and catalyst on the reaction were investigated by this method. The standard colorimetric card and standard curve obtained by this method could provide other teachers with quantitative research tools and help them to carry out experimental research quickly in class.

Graphite electrode is a kind of inert electrode commonly used in middle school electrochemical experiment, but the cause of small oxygen volume and the loss of graphite anode is unclear. The experiment uses hand-held technology to explore the phenomenon of graphite electrode electrolysis of water, and further study of the cause of deviation experiment results. The experiment shows that the graphite electrode for hydrogen adsorption capacity is better, and graphite anode electrolysis produce free radicals reaction is the main cause of deviation and anode loss.

With the aid of innovative experimental device, the parallel experiment of acid potassium permanganate solution absorbing sulfur dioxide gas produced by matchhead gunpowder combustion and partially fading was carried out; the standard curve of absorbance and concentration of gradient concentration acidic potassium permanganate solution was established by means of color sensor, and the concentration difference of certain volume acidic potassium permanganate solution before and after fading was obtained in parallel experiment, according to reaction correlation, the mass of sulfur dioxide gas produced by gunpowder combustion was calculated separately, and the average sulfur content in the matchhead was 6.03%.

Based on the analysis of many research results, three methods of experimental control for acetylene preparation were summarized: external control, internal control and bidirectional control. In addition, according to the principle of bidirectional control, an integrated experimental device for acetylene preparation, purification and property test was designed, which completely solved the problems existing in traditional experiments. The device was simple, easy to operate and had obvious experimental phenomena, which ensured the safety and effect of the demonstration experiment.

This paper analyzed 8 difficult problems in middle school chemistry experiments, addressing practical problems in teaching and improving the professionalism of teachers, could help students remove learning disabilities and open up knowledge horizons.