Improvement Research On Three Experiments Of "Chemical Reaction Principle"

ABSTRACT Since the new curriculum reforming,the status of chemistry experiments in chemistry teaching of high school has ever increasing.Experimental teaching is regarded as the first core element in cultivating students' chemical accomplishment.Through a survey of the current situation of chemistry experiment teaching in three high schools in a certain district of Chengdu,the author found that a variety of reasons leading to the phenomenon of experimental teaching weakening is very common.The reasons include:'"Classroom teaching time of chemical subject is not adequate","Time spent in classroom experiments takes up too much classroom teaching time"," The requirements of experimental precisions are too high to succeed","The experimental effect is not obvious","The teacher's experimental teaching awareness is weak"' etc.The 'Principles of Chemical Reactions' of elective PEP 4 is generally considered by teachers and students to be the most difficult teaching and learning part of the entire high school chemistry curriculum module.Therefore,each chapter of the textbook is of chemical experiments,aiming to transform abstract concepts into visual images and microscopic into macroscopic.And through the chemical experiment,which is a very practical and intellective inquiry activity,students can understand and be acquainted with the general principles of chemical reactions better.Many teachers neglect the development of chemical experiments when conducting the "Chemical Reaction Principles”teaching.They just pay too much attention to the theoretical analysis and simply demonstrate the experiments with verbal description or video.This manner cannot exhibit the superiority of experimentation based chemistry.To enhance the experimental consciousness of the teachers and students,making them actively participate in the experiment,and playing the teaching function of the chemical experiment better,this study optimized three chemical experiments in the"Chemical Reaction Principles" module from the perspectives of environmental protection,time-consuming reduction,obvious phenomena and knowledge point correlations,etc.For the experiment of measuring the rate of reaction between zinc and dilute sulfuric acid,syringe is used for multi-purpose,integrating gas generation,collection and measurement,which reduces the amount of reagent used and solves the problem of collected gas volume error,and completes the reaction facilely.In the improvement research of "comparing the reaction rate of H2O2 in the presence or absence of MnO2 catalysis",the use of self-made MnO2/clay ceramic or MnO2/red brick as a catalyst avoids the waste of MnO2,reduces the concentration and amount of H2O2 solution,thus reagents are economized.The using of a Y-shaped tube as a reaction vessel make the reaction be comparable and controllable to occur and stop.In the improvement study of the "oxygen absorption corrosion test of iron ",the number of nails was increased,and a glass adhesive was used to bond a straight single-ball drying tube and a glass capillary as a reaction device,and an obvious experimental phenomenon was observed in 1 minute,A micro-experiment for oxygen absorption corrosion of iron was designed using a Y-shaped glass tube,which verified that the oxygen absorption corrosion of iron is the product of the primary battery reaction and its positive and negative reactions.The study aims to emphasize the important role of experimental teaching,especially the improved experiment of the textbook,in the teaching of chemical reaction principle,and to improve the teachers' attention to the experiments of principle of chemical reaction.I hope that the experimental facts collected by the author in the improvement experiment can provide some research materials with reference value for related research.