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2016 Volume 31 Issue 9
2016, 31(9): 1-6
doi: 10.3866/PKU.DXHX201606015
Abstract:
The important reforms and progresses of chemistry laboratory teaching in China during the past 20 years are summarized. The main problems and challenges for the present chemistry laboratory teaching are analyzed. Using the objective-orientated strategy, the reform tendency and main approaches for defining the teaching objective, teaching contents, teaching pedagogies, and administration regime are discussed. It is of theoretical significance for future reform in laboratory teaching for chemistry majors.
The important reforms and progresses of chemistry laboratory teaching in China during the past 20 years are summarized. The main problems and challenges for the present chemistry laboratory teaching are analyzed. Using the objective-orientated strategy, the reform tendency and main approaches for defining the teaching objective, teaching contents, teaching pedagogies, and administration regime are discussed. It is of theoretical significance for future reform in laboratory teaching for chemistry majors.
2016, 31(9): 7-9
doi: 10.3866/PKU.DXHX201601014
Abstract:
In this paper, the authors demonstrated that laboratory skill examination could be a main approach to choose talented students by illustrating the fundamental reasons for using laboratory skill examination, the structure and content of the exam, how the exam was organized and conducted as well as the characteristics and results of the exam. The authors believe that the combination of interview and the laboratory skill examination is the best approach.
In this paper, the authors demonstrated that laboratory skill examination could be a main approach to choose talented students by illustrating the fundamental reasons for using laboratory skill examination, the structure and content of the exam, how the exam was organized and conducted as well as the characteristics and results of the exam. The authors believe that the combination of interview and the laboratory skill examination is the best approach.
2016, 31(9): 10-14
doi: 10.3866/PKU.DXHX201602019
Abstract:
To improve normal university students' comprehensive quality has become a tendency in current innovation of teacher education. Combining with the teaching practice and obtained achievements of students studying in College of Chemistry and Pharmaceutical Science of Guangxi Normal University, this paper discusses the functions of chemistry competitions in cultivating excellent quality, knowledges and skills of normal students, and emphatically introduces principles and implementation strategies.
To improve normal university students' comprehensive quality has become a tendency in current innovation of teacher education. Combining with the teaching practice and obtained achievements of students studying in College of Chemistry and Pharmaceutical Science of Guangxi Normal University, this paper discusses the functions of chemistry competitions in cultivating excellent quality, knowledges and skills of normal students, and emphatically introduces principles and implementation strategies.
2016, 31(9): 15-19
doi: 10.3866/PKU.DXHX201512002
Abstract:
The current training of pre-service teachers suffers from the low percentage (20%) of PCK from students themselves, low teacher- to- student ratio, short schooling terms, less teacher- student interactions, less practice courses offered, and little practice time. In this regard, our work begins with improving normal university students' PCK (ontological knowledge, conditional knowledge, practical knowledge). The practice uses the double guide system (mentoring and peer-leading) as the main tool to explore effective culture model for chemistry-majoring normal university students. In the innovation, three practice modes, teaching design- based simulation, observing the activities of teaching, and trainee teaching under real-life situation, have been adopted to enhance the training.
The current training of pre-service teachers suffers from the low percentage (20%) of PCK from students themselves, low teacher- to- student ratio, short schooling terms, less teacher- student interactions, less practice courses offered, and little practice time. In this regard, our work begins with improving normal university students' PCK (ontological knowledge, conditional knowledge, practical knowledge). The practice uses the double guide system (mentoring and peer-leading) as the main tool to explore effective culture model for chemistry-majoring normal university students. In the innovation, three practice modes, teaching design- based simulation, observing the activities of teaching, and trainee teaching under real-life situation, have been adopted to enhance the training.
2016, 31(9): 20-23
doi: 10.3866/PKU.DXHX201601002
Abstract:
Students of non-chemistry & chemical engineering majors often think that organic chemistry is useless, dull and troublesome, causing inefficiency in organic chemistry teaching. With an attempt to solve the problem, this paper makes some reform of organic chemistry teaching, including the introduction setting, the lead-in, the arrangement of teaching contents, the teaching methods and assessment of the course. We hope that the reform practice in the organic chemistry course could provide us corresponding research ideas and methods in the organic chemistry teaching for the non-chemistry & chemical engineering specialties, and as a result, improve the students' learning efficiency.
Students of non-chemistry & chemical engineering majors often think that organic chemistry is useless, dull and troublesome, causing inefficiency in organic chemistry teaching. With an attempt to solve the problem, this paper makes some reform of organic chemistry teaching, including the introduction setting, the lead-in, the arrangement of teaching contents, the teaching methods and assessment of the course. We hope that the reform practice in the organic chemistry course could provide us corresponding research ideas and methods in the organic chemistry teaching for the non-chemistry & chemical engineering specialties, and as a result, improve the students' learning efficiency.
2016, 31(9): 24-28
doi: 10.3866/PKU.DXHX201512025
Abstract:
After extensive investigations on the valence bond theory in the curriculum of structural chemistry, it was found that the limitation or even failure of the valence bond theory especially for the double bond electronic structure of oxygen molecule does not exist. Valence theory is capable of not only rationalizing or predicting the molecular structures but also revealing the chemical nature for many properties such as aromaticity and ferromagneticity in comparison with molecular orbital theory.
After extensive investigations on the valence bond theory in the curriculum of structural chemistry, it was found that the limitation or even failure of the valence bond theory especially for the double bond electronic structure of oxygen molecule does not exist. Valence theory is capable of not only rationalizing or predicting the molecular structures but also revealing the chemical nature for many properties such as aromaticity and ferromagneticity in comparison with molecular orbital theory.
2016, 31(9): 29-32
doi: 10.3866/PKU.DXHX201601021
Abstract:
In this paper, according to the knowledge characteristics of the copper group elements, the reform of the teaching contents and teaching methodology has been analyzed in detail in order to enhance students' interest in learning chemistry, make students master the chemical knowledge, and improve the teaching quality.
In this paper, according to the knowledge characteristics of the copper group elements, the reform of the teaching contents and teaching methodology has been analyzed in detail in order to enhance students' interest in learning chemistry, make students master the chemical knowledge, and improve the teaching quality.
2016, 31(9): 33-37
doi: 10.3866/PKU.DXHX201601016
Abstract:
The comprehensive chemical experiments are introduced. After summarizing the advantages and drawbacks in the operation, cost, and impact on the environment based on the literature reading, students can make chemical products with a variety of methods and experimental designs starting with the raw materials provided by teachers. In such a way, the ability to bring forth new ideas is enhanced.
The comprehensive chemical experiments are introduced. After summarizing the advantages and drawbacks in the operation, cost, and impact on the environment based on the literature reading, students can make chemical products with a variety of methods and experimental designs starting with the raw materials provided by teachers. In such a way, the ability to bring forth new ideas is enhanced.
2016, 31(9): 38-42
doi: 10.3866/PKU.DXHX201601022
Abstract:
With the development of information communication technology, the development of higher education has witnessed an unprecedented shock of big data. In this paper, based on the teaching reform practice of chemistry of fine chemicals course for undergraduates in applied chemistry major of Nanjing University of Information Science & Technology, some approaches have been adopted in order to enhance the construction of curriculum system, increase the quality of teachers, improve the frontier and interestingness of the curriculum content and diversify teaching form from a big data perspective, which have achieved the excellent results and progresses.
With the development of information communication technology, the development of higher education has witnessed an unprecedented shock of big data. In this paper, based on the teaching reform practice of chemistry of fine chemicals course for undergraduates in applied chemistry major of Nanjing University of Information Science & Technology, some approaches have been adopted in order to enhance the construction of curriculum system, increase the quality of teachers, improve the frontier and interestingness of the curriculum content and diversify teaching form from a big data perspective, which have achieved the excellent results and progresses.
2016, 31(9): 43-50
doi: 10.3866/PKU.DXHX201601018
Abstract:
The four volumetric analyses were summarized and compared in the feasibility of titration, the formula of end point error, the allochroic principle of indicators, and the influencing factors for jump ranges. The computational formula for jump ranges were deduced.
The four volumetric analyses were summarized and compared in the feasibility of titration, the formula of end point error, the allochroic principle of indicators, and the influencing factors for jump ranges. The computational formula for jump ranges were deduced.
2016, 31(9): 51-55
doi: 10.3866/PKU.DXHX201601017
Abstract:
We re-organized the layout of the laboratory and formulated detailed regulations and instructions for all lab class participants (teachers, students and technicians). Then, a set of complete, detailed and implementable regulation, conforming to features of basic organic chemistry experiments teaching, was formed to achieve the meticulous management as well as safe and smooth operation of basic organic chemistry laboratory, which effectively guaranteed the teaching quality.
We re-organized the layout of the laboratory and formulated detailed regulations and instructions for all lab class participants (teachers, students and technicians). Then, a set of complete, detailed and implementable regulation, conforming to features of basic organic chemistry experiments teaching, was formed to achieve the meticulous management as well as safe and smooth operation of basic organic chemistry laboratory, which effectively guaranteed the teaching quality.
2016, 31(9): 56-61
doi: 10.3866/PKU.DXHX201602015
Abstract:
The gas chromatography method using internal standard and area normalization calibration and the NMR method using internal standard calibration are adopted for the determination of product purity in the synthesis of ethyl acetate. The purity of ethyl acetate detected by the GC internal standard method was the lowest. In contrast, the purity detected by the NMR internal standard method was the highest. The NMR internal standard method has more advantages, for this method can be used to complete the quantitative analysis and structural identification simultaneously, without the need to measure the correction factor.
The gas chromatography method using internal standard and area normalization calibration and the NMR method using internal standard calibration are adopted for the determination of product purity in the synthesis of ethyl acetate. The purity of ethyl acetate detected by the GC internal standard method was the lowest. In contrast, the purity detected by the NMR internal standard method was the highest. The NMR internal standard method has more advantages, for this method can be used to complete the quantitative analysis and structural identification simultaneously, without the need to measure the correction factor.
2016, 31(9): 62-67
doi: 10.3866/PKU.DXHX201601020
Abstract:
The experiment of visible-light-driven water splitting for hydrogen was set up as a comprehensive physicochemical experiment. The preparation, characterization and photocatalytic test of photocatalyst were systematically reported. g-C3N4 was used as a photocatalyst in the experiment because it can be easily prepared and has nontoxicity, as well as visible- light-response properties. The effects of preparation temperature of g-C3N4 on its structure and photocatalytic performance were investigated.
The experiment of visible-light-driven water splitting for hydrogen was set up as a comprehensive physicochemical experiment. The preparation, characterization and photocatalytic test of photocatalyst were systematically reported. g-C3N4 was used as a photocatalyst in the experiment because it can be easily prepared and has nontoxicity, as well as visible- light-response properties. The effects of preparation temperature of g-C3N4 on its structure and photocatalytic performance were investigated.
2016, 31(9): 68-76
doi: 10.3866/PKU.DXHX201512016
Abstract:
The drawbacks in interpreting the chemical equilibrium in current general chemistry textbooks were discussed. An easy-understood introduction of chemical isothermoequation of several types of reactions was proposed. Reversible and irreversible reactions, reversible and irreversible processes, and complete and incomplete reactions were distinguished, respectively.
The drawbacks in interpreting the chemical equilibrium in current general chemistry textbooks were discussed. An easy-understood introduction of chemical isothermoequation of several types of reactions was proposed. Reversible and irreversible reactions, reversible and irreversible processes, and complete and incomplete reactions were distinguished, respectively.
2016, 31(9): 77-82
doi: 10.3866/PKU.DXHX201512011
Abstract:
We reviewed briefly the developing history of two basic concepts, surface tension and surface Gibbs free energy, in physical chemistry of surfaces, and gave a detailed discussion about the formation mechanisms of surface tension and surface free energy and the relationship between the bond energy and the surface tension. Finally, we addressed that while a surface phase could be simplified to a geometric surface, it is an actual phase which is always a metastable state owing to the surface free energy.
We reviewed briefly the developing history of two basic concepts, surface tension and surface Gibbs free energy, in physical chemistry of surfaces, and gave a detailed discussion about the formation mechanisms of surface tension and surface free energy and the relationship between the bond energy and the surface tension. Finally, we addressed that while a surface phase could be simplified to a geometric surface, it is an actual phase which is always a metastable state owing to the surface free energy.
2016, 31(9): 83-86
doi: 10.3866/PKU.DXHX201601012
Abstract:
In the course of frontier orbital theory, the teacher and students discussed the conditions for the nitric oxide formation reaction, by using this theory. In an extracurricular practice, students testified the reaction mechanism obtained from the course by molecular orbital calculations. The course practice improved students' understanding of these theories and their abilities to apply them to exploration of chemical problems.
In the course of frontier orbital theory, the teacher and students discussed the conditions for the nitric oxide formation reaction, by using this theory. In an extracurricular practice, students testified the reaction mechanism obtained from the course by molecular orbital calculations. The course practice improved students' understanding of these theories and their abilities to apply them to exploration of chemical problems.
2016, 31(9): 87-90
doi: 10.3866/PKU.DXHX201601011
Abstract:
We report here the relativistic effects on molecular configuration. The most stable states of group IIAmetal hydride were calculated by density functional calculation and we discussed the relationship between the AH2 molecule structure and the NBO data of A―H bond. The application of the relativistic effects in hybrid orbital was concluded and some advice was given about chemical education in college.
We report here the relativistic effects on molecular configuration. The most stable states of group IIAmetal hydride were calculated by density functional calculation and we discussed the relationship between the AH2 molecule structure and the NBO data of A―H bond. The application of the relativistic effects in hybrid orbital was concluded and some advice was given about chemical education in college.
2016, 31(9): 91-97
doi: 10.3866/PKU.DXHX201601009
Abstract:
The basic functions and working procedures of Tenua, a software for chemical kinetics simulation, are introduced in this paper. Three examples of using this software in teaching college chemistry are presented. The first example deals with the common kinetic curves of zero, first and second order of reactions respectively. The second one is about single-substrate enzyme-catalyzed reaction, and the third one is about reversible reaction in gas phase. On the one hand, Tenua can enhance the teaching effect of reaction rates and their formulations among the theory for chemical kinetics. On the other hand, Tenua can diversify the form of the class teaching, raise perceptual knowledge to rational knowledge, and inspire students' interests in learning chemical kinetics.
The basic functions and working procedures of Tenua, a software for chemical kinetics simulation, are introduced in this paper. Three examples of using this software in teaching college chemistry are presented. The first example deals with the common kinetic curves of zero, first and second order of reactions respectively. The second one is about single-substrate enzyme-catalyzed reaction, and the third one is about reversible reaction in gas phase. On the one hand, Tenua can enhance the teaching effect of reaction rates and their formulations among the theory for chemical kinetics. On the other hand, Tenua can diversify the form of the class teaching, raise perceptual knowledge to rational knowledge, and inspire students' interests in learning chemical kinetics.
2016, 31(9): 98-102
doi: 10.3866/PKU.DXHX201510017
Abstract:
Using the Ringbom equation for titration of dibasic acids, the first and second titration jumps were derived. As followed, the accurate conditions for sequential titration of dibasic weak acids were derived with the first and second titration jumps. And the deduction is also applied to titration of polyprotic acids.
Using the Ringbom equation for titration of dibasic acids, the first and second titration jumps were derived. As followed, the accurate conditions for sequential titration of dibasic weak acids were derived with the first and second titration jumps. And the deduction is also applied to titration of polyprotic acids.
2016, 31(9): 103-107
doi: 10.3866/PKU.DXHX201601019
Abstract:
The Fe(PDP) catalytic system which processes high efficiency and selectivity is introduced in this paper. Its selectivity rules have been clarified and applied to complicated organic molecule system. Based on the selectivity features of Fe(PDP) and current research advances on activation of C―H bonds by metal catalysis, a hypothetical mechanism is proposed.
The Fe(PDP) catalytic system which processes high efficiency and selectivity is introduced in this paper. Its selectivity rules have been clarified and applied to complicated organic molecule system. Based on the selectivity features of Fe(PDP) and current research advances on activation of C―H bonds by metal catalysis, a hypothetical mechanism is proposed.
2016, 31(9): 108-113
doi: 10.3866/PKU.DXHX201608023
Abstract:
2016, 31(9): 114-118
doi: 10.3866/PKU.DXHX201601024
Abstract:
In this paper, the question about distribution of NiO and CuO on the surface of γ-Al2O3 involved in the National Chemistry Competition (finals) was investigated and discussed. The test questions were redesigned and recombined.
In this paper, the question about distribution of NiO and CuO on the surface of γ-Al2O3 involved in the National Chemistry Competition (finals) was investigated and discussed. The test questions were redesigned and recombined.
