Among the variety of bakery items in China, steamed bread is one of the most preferred staple food items in China. The secret behind making a delicious steamed bread is to generate bubbles and to trap them. Herein, we studied the change of sulfydryl and disulphide bonds on gluten index in the process of dough mixing. Moreover, the relationship of toughness of steamed bread with kneading time of dough is also studied. In the stage of fermentation, we analyzed the effect of temperature and different leavening agent types on the fluffiness of bread. By tracking the pH and sugar content evolution with steaming time, we analyzed the influence of steaming time on the sweetness of bread. This paper represents a fascinating chemical phenomenon in daily life. Such study not only provides a better understanding in how to make delicious steamed bread, but also stimulate students’ interest in chemistry.

The periodic table, as the incarnation of the periodic trends, has an instructive role in the development of modern chemistry and its relevant disciplines, such as the studies into the in vivo distribution and mechanism of long-period, nonmetal trace elements. This manuscript specifically focuses on one period 5 element, iodine, by systemically analyzing the biosynthesis and degradation of iodine-containing amino acid-derived hormones to explore the mechanism of iodine by combining methodologies from different disciplines. Through analyzing the transformation of different oxidation states and the intrinsic property of iodine as a chemical element, we reveal both the irreplaceable role of iodine in vivo, and the meticulous regulation upon the synthesis and degradation of biomolecules in nature. The combination and integration of many interdisciplinary subjects such as inorganic chemistry, element organic chemistry, coordination chemistry, enzymology, molecular biology, bioorganic chemistry, biophysics and chemical biology are intended to not only impel students to learn the intrinsic rules of biological sciences, but also to train their ability of analogy and critical thinking in order to arouse their enthusiasm towards learning and scientific research.

With the upgrading of people’s consumption concept, food packaging materials have received much attention. From the perspective of chemical elements, this paper introduces the composition, characteristics and development trends of new food packaging materials as well as food surface coating materials. Nanomaterials and bio-based materials in food packaging materials are popular among consumers due to their good mechanical properties and environmental protection. The food indicates that the edible film material has won the favor of the public because of the simple operation, low investment and high safety in the rise of “instant consumption”.From the perspective of the research and development process of new food packaging materials, its innovative development is closely related to the nature of chemical elements. In the future, the improvement of the performance of food packaging materials must also rely on the combination and utilization of characteristic chemical elements.

It is difficult to give a clear and accurate criterion for ignoring the second dissociation process during the hydrogen ion concentration estimation for a weak diprotic acid, because the analytical concentration c, the dissociation constants of K_a1 and K_a2 will influenced this criterion in a very sophisticated manner. In order to solve this tough but important problem, an imaginary acid A, acid B and a special diprotic acid were designed and their properties were investigated. The results of this paper are as follows: 1) The larger of $\frac{[H^{+}]_{AV}}{2K_{a2}}$,the better of the approximate result, where the approximate value of $[H^{+}]_{AV}$ is given by $[H^{+}]_{AV}$=$\frac{-K_{a1}+\sqrt{K^{2}_{a1}+4cK_{a1}}}{2}$. 2) The smaller of $\frac{K_{a1}}{K_{a2}}$ is, the more stringent criterion needs. 3) The criterion for the special diprotic acid $\lgroup{\frac{K_{a1}}{K_{a2}}=1}\rgroup$ is $\frac{2K_{a2}}{[H^{+}]_{AV}}$≤0.01,this rule can apply to all diprotic acids. 4) The criterion of $\frac{2K_{a2}}{[H^{+}]_{AV}}$≤0.01 is powerful and robust, it can be widely used to make a right decision whether we ignore the second dissociation process or not.

Guided by the constructivism, we applied the teaching design which combine a knowledge presentation method of ‘from concrete to abstract’ with realistic situations in our lives to further enlarge the applications of the basic concepts about the degression of saturated vapor pressure in chemistry course, while building the connections between the new concepts and the knowledge learnt before. Not only did this pedagogical practice help the students to consolidate the concepts and knowledge of degression of saturated vapor pressure, but also it inspired the students’ learning interests and cultivated their abilities of analyzing problems and agilely dealing with realistic problems by using learnt theoretical knowledge.

In this paper, we present a comprehensive organic chemistry experiment about the synthesis of the sulfonamide intermediate, 5-methylisoxazole-3-formamide, from acetone and ethyl oxalate by Claisen condensation, oximation cyclization and ammoniation. The structure was characterized by IR, NMR and melted point. This experiment is suitable for students to learn comprehensively not only the operation units of organic synthesis, product separation and structure determination but also analytical techniques such as IR, NMR in laboratory.

Combined with the scientific research projects and teaching practice of chemistry experiment, an creative experiment has been designed named “determination of naphthols in environmental water samples by molecular-complex based dispersive liquid microextraction(MC-DLLME) followed by high performance liquid chromatography(HPLC)”. Begin with the complex sample pretreatment, a MC-DLLME method was established and applied in the analysis of naphthols in water. The factors affecting the extraction were investigated and optimized, and the appropriate extraction device, operation mode and HPLC conditions were determined. The design combined with new scientific research, which can lead the students to participate in the experiment design actively and explore the unknown knowledge independently, is beneficial to improve the students’ innovative ability and comprehensive quality.

The amino acid-catalyzed asymmetric Aldol reaction is a research hotspot in the field of asymmetric catalysis, which is transformed into a design innovative experiment and offered to third-year students in the college of chemistry. Through the exploration of different reaction conditions such as substrates, catalysts and solvents, students’ understanding of concepts and mechanisms such as chirality and enamine catalysis is deepened, and students’ scientific research ability and innovative ability are trained.

The level of chemistry teachers’ chemical modeling ability directly impacts the strength of students’ modeling ability. Based on the Rasch model, the article develops a four-level questionnaire on the chemical modeling ability of the pre-service chemistry teachers. This questionnaire evaluates the chemical modeling ability of 83 pre-service chemistry teachers from three dimensions: model representation ability, model construction ability and model application ability. Studies show that pre-service chemistry teachers surveyed have weak chemical modeling capability overall. In the light of the high school chemistry curriculum standard (version 2017),the specific requirements of chemical modeling capability, the study demonstrates that the percentage of 88 surveyed pre-service chemistry teachers have the qualified model representation ability, however, qualified ability of model construction and application only in 42 percent and 54 percent respectively. Therefore, recommendation is put up to optimize the development of pre-service chemistry teachers modeling abilities in normal colleges.

This paper uses the View About Scientific Inquiry (VASI) questionnaire prepared by Norman G. Lederman and Judith S. Lederman for 38 pre-servicechemistry teachers in order to investigate their scientific inquiry concept. The results show that pre-service chemistry teachers have a different level of understanding of scientific inquiry. The best level of understanding is dimension 3 (D3), 74% of pre-service chemistry teachers hold an “informed” view on this dimension. The middle level is dimension 2 (D2), 66% of pre-service chemistry teachers hold a “mixed” view on this dimension. The worst level of understanding is dimension 7 (D7), 61% of pre-service chemistry teachers hold the “naive” view, and no one has a “informed” view on this dimension. In response to this situation, three improvement strategies are proposed. The first is “ explicithess”. The “explicithess” approach presents contents related to scientific inquiry and understanding in curriculum standards and textbooks.The second is “activization”. Teachers design and implement various practical activities based on understanding and inquiry in teaching. The third is “reflective”, guiding students to actively reflect on scientific inquiry activities to gain an in-depth understanding of scientific inquiry.

Combined with the teaching situation of the chemistry teaching theory experiment, this paper integrates the concepts of the cloud teaching and flipping classroom to reconstruct the curriculum, designing and implementing this mode with the “Moso Teach” cloud platform which is as the teacher-student interactive bridge. Taking the secondary school chemistry digital experiment teaching as an example, let the chemistry normal students experience the learning process of the mode with the dual roles of “learners” and “future teachers”, and use SERVQUAL model evaluation method to analyze and improve the cloud teaching. Through further questionnaire analysis, it is learned that students not only master the knowledge content, but also have a deeper understanding of the flipped classroom mode and practice details. Finally, some suggestions are put forward for the this teaching mode and normal students’ teaching.

Aiming to explore a new lab-teaching case about copper-based metal-organic framework (Cu-MOF), the synthesis condition was optimized to meet the requirements of material chemistry experimental course. 5-aminoisophthalic acid was applied to act as the ligand and reacted with different kinds of copper salts, such as copper(Ⅱ) nitrate, copper(Ⅱ) trifluoromethanesulphonate, copper(Ⅱ) chloride and copper(Ⅱ) sulfate. In order to reduce the experimental cost, decrease the energy consumption, and improve the yield, the ratio of start materials, reaction temperature, and reaction time were further investigated to obtain the best condition. Powder X-ray diffractometry (PXRD) was carried out to characterize the phase purity of product. The students showed high motivation to learn lab skill and characterization method for crystalline material.

In this paper, taking the knowledge point of multi-layer cylindrical wall heat conduction as an example, the specific application of student-centered teaching mode combined with intelligent teaching tools and method was discussed, andBOPPPS structure design was adopted. The practical results showed that this teaching mode stimulate students’ learning interests and improve their learning outcome.

In order to improve students’ exploration spirit, train their scientific innovative thinking, and cultivate more pharmaceutical professionals for society need, the comprehensive design experiment was introduced to the course of pharmaceutical analysis experiment. The contents of quercetin and luteolin in Cayratia japonica (Thunb.) Gagnep.were determined simultaneously by HPLC and the system suitability of methodology was carried out. Through guiding students to consult documents, design the experimental program, complete the experiment scheme, analyze and discuss results, students’ understanding of basic theoretical knowledge was deepened and their abilities to investigate literature, extend knowledge, study by themselves and innovate were all improved, which would serve as bases for their employment and further studies.

The cultivating mode of “successive program of bachelor and doctoral academic dissertation” could not only consolidate the theoretical foundation, but also gradually change the thought patterns of mere learning curriculums to innovative research during the bachelor thesis stage period. And in the short-term postgraduate stage, the theoretical knowledge could be further sublimated. Besides, students could master the research status and development direction of the subject, improving the ability of discovering, analyzing and solving problems. At last, the doctoral phase mainly aims at the frontiers of the discipline, inspires them to explore “new methods” and “new ideas”, effectively implementing the successive program of bachelor and doctoral academic dissertation.

This paper introduces the application of MestReNova software in the course of spectra analysis of organic compounds, which taking the NMR spectra of 6-methoxyl-7-hydroxy coumarin as the example.Students candeeply understand the parameters involved in the nuclear magnetic spectra, such as the origin of the chemical shift, coupling constant, andthe relationship between theproportion integral pointsand proton number through familiar and application of the software. In this case, students’ learning interests and enthusiasm will be stimulated and improved, and identification the structures based on the analysis of spectra independent. They could apply theoretical knowledge to analytic examples better. It is beneficial to cultivate students’ ability to explore and solve practical problems by combination of theoretical knowledge and practical application, and cultivate thinking ability and independent thinking ability for future research.

This paper organically combines the Materials Studio of computer simulation software with organic chemistry teaching. First of all, the teacher taught the software knowledge, the principle and the cases to solve scientific problems using the software. Then, the students were familiar with the software, found the difficulties and puzzles in the course of organic chemistry by themselves. Finally, using the software, the students could solve some problems with the help of the teacher and the team. This teaching method not only enhances the vitality of classroom teaching, enriches classroom teaching content, but also improves students’ cognitive ability of three-dimensional structures and deepens students’ understanding of reaction mechanism. More importantly, the ability of students’ exploratory thinking of is also greatly cultivated.

There are hundreds of formulas involved in physical chemistry, and students have great difficulty in memorizing them. To solve this problem, this paper introduces several different methods of formula understanding and memory, including deductive derivation method, comparative memory method, dimensional verification method, understanding error correction method and interactive verification method. Several examples are illustrated to describe the application of these methods in detail.

The vapor pressure of two immiscible liquids system was studied experimentally and theoretically. At equilibrium, the vapor pressure of the system approaches to, but is always less than, the sum of the saturated vapor pressures of the two pure components as their mutual solubilities decrease. When two immiscible liquids were placed together in static state, the upper layer could effectively but not completely prevent the volatilization of the lower layer. It was pointed out that this prevention effect was caused by the slow kinetic processes of dissolution, diffusion, and volatilization. A method was proposed to prevent the volatilization of the lower layer, that is, using an immiscible liquid with lower density to cover the lower layer, fulfill the container and sealed.

From ancient speculative atomism to modern scientific atom-molecule theory, the determination of atomic weight is the key to its development from qualitative to quantitative. The atomic weight paradigm provides a new way for chemists to study matter. The relative definition of atomic weight determines the importance of the base value of atomic weight. Eventually, atomic weight took over from equivalent weight measure and spread before it, and went global. This process not only makes us realize the twists and turns of scientific development, but also makes people understand the importance of scientific communication.