Food is the people's priority. As a Sichuan cuisine with a history of more than 100 years, Mapo Tofu is popular all over the world and is deeply loved by people. Based on the production steps of Mapo Tofu, this paper introduced the chemical changes and disappeared or newly produced flavor chemicals in four important cooking stages: fried meat, fried base material, braised color mixing, and thickened sauce, so that students could further feel the close relationship between chemistry and life, and enhanced their interest in learning chemistry.

Chemical experiment is a basic method to explore and learn substances and their changes, and an important way to develop students' chemical discipline core literacy. The Senior High School Chemistry Curriculum Standards (2017 Edition) clearly stipulates 18 students' compulsory experiments. The corresponding teaching suggestions are put forward based on the several analysis, namely, the status, content, distribution of the required experiments in the new curriculum standards and the relevant suggestions, the contents and characteristics of 18 students' compulsory experiments in the chemistry textbooks of senior high school published by Shandong Science and Technology Press.

Based on Gagne's study result classification theory, this paper compared chemistry compulsory textbooks of People's Education Press, Shandong Science and Technology Press and Jiangsu Education Press in topic 3 “material structure basis and chemical reaction law” exercises from verbal information, intellectual skills, cognitive strategies, motor skills, attitude change dimensions, the results showed that the distribution trend of the study results dimension was the same, proportion in intellectual skill dimension was the largest, the second was information dimension, the remaining three dimensions were small; In addition, this paper divided textbook exercises which belong to the intellectual skill dimension into discrimination, specific concepts, definition concept, rule, and senior rule, this was a from low to high series, then made a statistics on the distribution of three versions of exercises in five levels, the results showed that the largest proportion in both the textbooks of People's Education Press and Jiangsu Education Press was specific concepts level, that in the textbook published by Shandong Science and Technology Press was rule level. What's more, the wisdom skill level of textbook published by Shandong Science and Technology Press was highest, the level of textbook of Jiangsu Education Press was little higher than the textbook published by People's Education Press. Finally, some enlightenment on compiling and using textbook exercises were obtained.

In the “refined salt: from the micro perspective of the removal of soluble impurities in coarse salt”of unit teaching, through the initial knowledge of the impurity in the coarse salt,from the microscopic perspective of sodium chloride,coarse salt solution,and the removal of impurities,and designing scheme and implementation of activities in removing impurity promote students' understanding and application of core concepts, such as ionization, ionic reaction, leading the students to solve real problems, to form the basic train of thought to solve the problem of removing impurity experiment, realize the ability of literacy development. After many rounds of teaching improvement, combined with teaching practice and the teaching effect to put forward “focus on the core concepts and students will be doing the experiment, and realizes the cognition of the advanced and practical problem solving process fusion”“through practice and experiments to explore, to establish a link between macro and micro, symbols, and highlight the evidential reasoning and build a model of thinking”“ through continual evaluation activity, explicit concept before students, promote the concept of change, be chemical science thinking mode” and other teaching strategies.

The current teaching of “Sodium Carbonate and Sodium Bicarbonate” focuses on the analysis and comparison of the properties of the two, and lacks the attention to the application of the two in life and hands-on practice. Students cannot personally experience the practical value of sodium carbonate and sodium bicarbonate. It is believed that from the perspective of core literacy, chemistry teaching should be deeply integrated with life. Set up project-based learning and practice before class, report the results of practice in class, and conduct experimental exploration to solve real situation problems, deeply integrate chemistry with life, and help students deeply understand “the properties and applications of sodium carbonate and sodium bicarbonate”, develop students' core literacy of subjects and implement the requirements for consistency in teaching, learning and evaluation.

This article takes the teaching of “determining the content of sodium carbonate in sodium chloride mixed with sodium carbonate” as an example to build a thinking model for quantitative experiment analysis in junior high schools. Driven by the “general problem” and “sub-problems”, junior high school students are guided to gradually establish general methods to solve quantitative experimental problems, enhance the ability to design, evaluate and improve quantitative experiments, and form key capabilities with migration value.

Based on understanding chemistry subject, we condensed the subject origin of the topic of chemical balance,extracted the cognitive perspective and constructed the hierarchical structure of the concept. The research process of “attainment-oriented” classroom teaching based on understanding chemistry subject is systematically presented from the aspects of teaching objective and teaching idea design, teaching implementation process, student harvest, teacher reflection and expert evaluation.

It is an important foundation for teachers to grasp the subject knowledge system, improve the station of teaching design and realize “quality-based” teaching. The overall preparation of teaching materials unit in the perspective of chemistry understanding is mainly to comb the system of the logical order and understanding idea of the content of the teaching material, to determine the overall teaching objectives of the unit and the time of class, to excavate the core quality of the subject and the value of education and teaching hidden in the content of the teaching material unit, and to reconstruct and design the teaching content and strategy. It is an effective way to improve the overall preparation quality of the module to interpret and understand the curriculum standards and compare and integrate the relevant contents of different textbook versions.

Based on the connotation of model cognitive ability, core knowledge content of galvanic cell and Bloom's taxonomy of educational objectives, the research framework of model cognitive ability of galvanic cell was constructed and evaluation tools were designed and developed. The final evaluation tools were determined after trial testing, modification, re-testing and quality demonstration. Selecting 419 students from two county-level high schools in S city as the research objects, based on the obtained effective data, analyzed the cognitive ability level of galvanic cell model of high school students, and focused on the comparison of the cognitive ability of galvanic cell model between senior two and senior three students, according to the research results, some suggestions were put forward to develop the cognitive ability of galvanic cell model of high school students.

The teaching dilemma and resolution strategy of chemistry knowledge from the perspective of core literacy education is entering the era of core literacy. The knowledge teaching of core literacy text has caused many teachers' discomfort. It is necessary to understand the relationship between classroom teaching and knowledge teaching, core literacy and knowledge teaching. Combined with the content of metal sodium and its compounds, the dilemma of knowledge point selection, situation selection including knowledge and training feedback practice selection in chemistry teaching was expounded. The strategies to solve the teaching dilemma are as follows: select the core knowledge which can cultivate the students' key ability and essential character; create the teaching situation which is conducive to knowledge learning; and give full play to the leading role and construction of knowledge learning process to promote students' significance and enlightenment of knowledge teaching.

Starting from the elemental compound recognition model, taking “iron and its compounds” as an example, the unit teaching design ideas are explained based on the construction and application of the elemental compound recognition model, and unit teaching objectives are determined from the unit theme, and unit teaching is clarified. Starting point, design unit teaching advancement, create activities in real situations, and implement unit teaching design practice research in the aspects of “teaching evaluation” integrated design.

The redox reaction tests were selected as the materials, eye tracking technology was used to conduct a 3 (academic level) *3 (test difficulty) two factor mixed experiment on 12 senior one students. After the experiment, a follow-up oral report was carried on. The results show that premium students' information processing speed is fast, the depth is shallow, and the difficulty is small, the combination strategy of forward processing and reverse elimination can be used, and can be well combined with the stems and options in the process of solving the problem of redox reaction. Medium students' information processing speed is slow, the depth is deep, and the difficulty is great, the forward processing strategy can be adapted; and the attention is paid more to the problem stem. Students with learning difficulties' information processing is ineffective, easy to give up, and the attention is paid more to the problem options. With the increase of problem difficulty, the information processing speed becomes slower, the depth becomes deeper and the difficulty becomes larger.

Strengthening teachers' teaching reflection is not only the requirement of The Times, but also an important way for teachers' professional development. Through nearly a decade of science teachers' teaching reflection combing and analysis of the empirical research, the pulse current research progress both at home and abroad, set science teachers' teaching reflection empirical research direction in our country, the science teacher teaching reflection the paradigm of research, based on the perspective of students of teaching reflection, science teachers' teaching reflection of follow up study, pre-service science teachers' teaching reflection culture research, in order to provide references for the study of the current science teacher teaching reflection.

Combined with hand-held techniques, the method to determine the equilibrium constant of Fe³⁺+SCN^-FeSCN²⁺ was improved, and became more miniaturized and facilitated. An experimental scheme for the determination of equilibrium constants was provided for high school teaching. The value obtained was K=1.6×10² (experimental conditions: T=(26.5±0.5) ℃,I=0.7,[H⁺]=0.15 mol/L).

In this study, the catalytic effect of halides on metal replacement reaction was studied qualitatively and quantitatively. The experimental results show that all halogen elements have catalytic effect, and Cl^- has the most obvious catalytic effect; compared with alkaline earth metal ions, the copper tree crystal shape is more regular under alkali metal conditions, and the ornamental effect is better; at the same time, the reaction rate is positively correlated with Cl^- concentration. Through the exploration of reaction conditions, the so-called “copper tree” reaction of aluminum replacement of copper is transformed into a classroom demonstration experiment which can produce obvious phenomena in 20 minutes. It can create a situation for the teaching of metal replacement reaction and electrochemical corrosion kinetics, and cultivate students' chemical core literacy of evidence reasoning and model cognition.

The temperature of Fe combustion in Cl₂ was measured by high temperature sensor. Based on the actual reaction temperature, pressure and the state of matter, the thermodynamic analysis of the related reactions between Fe and Cl₂ was carried out. It was found that FeCl₃ (Fe₂Cl₆) was the thermodynamic stable product in most cases of the reaction process of Fe and Cl₂, but the reaction conditions of Fe and Cl₂ to produce FeCl₂ were more stringent. Through the kinetic analysis of the reaction and the structure analysis of FeCl₂ and FeCl₃, it is also concluded that the reaction of Fe and Cl₂ to form FeCl₃ is more favorable.

In basic chemistry teaching for high school chemistry and university general chemistry,the introduction of empirical equilibrium constant based on the chemical reaction rate and the introduction of standard equilibrium constant based on the chemical thermodynamics are two common approaches. These two kinds of equilibrium constants are essentially the same though the former is usually specific and vivid, and the latter is a bit abstract to the students. However, the empirical equilibrium constant is relatively complicated because of its various forms and different dimensions. The standard equilibrium constant is strict, regular and unique, and it reflects that great truths are always simple. It is suggested to understand and summarize chemical equilibrium and equilibrium constant more from the chemical thermodynamics in teaching, and to use standard equilibrium constant as uniformly as possible in quantitative calculations.

The concept of pH and its test method were first introduced by the Danish biochemist, Soren Peter Lauritz Sorensen, in 1909. This scale for measuring acidity and alkalinity ensured the unity of product quality and flavor in the beer manufacturing industry then. Due to its obscure origin in chemistry, there are certain misunderstandings about the idea of pH in domestic and international chemistry teaching, which leads to the problematic use of unclear chemical knowledge and the pH test paper. By reviewing this history, we can restore its original connotation and promote the development of chemical teaching norms.