Research On Students’ Problem Representation Of Chemical Calculation Problem Solving In Senior School

Solve the practical problems from industrial production and daily life, is the ultimate goal of chemical calculation problem solving. Problem representation is the key link in the process of problem solving. The right or wrong of problem representation affects the success or failure of the problem solving directly. The research on problem representation in the process of chemical calculation problem solving of senior students, which can help teachers to understand students’ thinking and students’ ability of solving problem in the process of solving chemical calculation problems, and it is beneficial to carry the teaching activities, and also conducive to cultivate students’ ability of solving problem.At the beginning of this study, I have read a lot of papers on the topic of "research on problem solving in chemical problem". I analysis the results of those researchers, find the weak link in their study, and decide the research subject:research on students’ problem representation of chemical calculation problem solving in senior school. With the direction of the constructivism learning theory and intentional learning theory, I researched problem representation ways and the problem representation strategies in the process of chemical calculation problem solving respectively. And all kinds of strategies of problem representation are described in detail in my study with some concrete examples.This paper mainly includes five parts. Part one is the psychological mechanisms of chemical calculation problem solving. The psychological mechanisms have four stages:the identification of problem, the representation of problem, to seek answers and try to answer the question, and the evaluation and reflection. Part two is the basic chemical knowledge to solve chemical calculation problems you must know. All chemical calculation problems have relations to the conversion between the macro-composition of material and the micro-composition of particles. Part three is the forms of problem representation in the process of chemical calculation problem solving, including the representation of words, chemical symbol representation, abstract representation, visualized representation and mathematical representation. Part four is the strategies of problem representation in the process of chemical calculation problem solving. I will illustrate how to use the strategies to characterize the problem in the process of problem solving. Part five is the practical application of problem representation strategies in the process of solving chemical calculation problems. I will illustrate different problem representation strategies in detail with concrete examples. In the study, I advise them choose different strategies to characterize the problem, according to the actual situation of the students. When they meet some strange chemical calculation problems, for the students with good cognitive structure in chemistry, I will suggest them to represent problem by using principle command strategy; For the students with the second chemistry cognitive structure, I will suggest them adopt the context reasoning strategy to characterize the problem; For some students with poor chemistry cognitive structure, I will help them representing problem by using blind search strategy.The results of the research show that context reasoning strategy and the principle of command strategy are two effectively strategies in solving chemical calculation problem.In the process of solving chemical calculation problem, to characterize the problem comprehensively, problem solver often chose two or three representation strategies at the same time. Between context reasoning strategy and the principle of command strategy, there is no absolutely borderline, students usually used this two strategies in the process of problem solving at the same time. The problem solver must have a good foundation of mathematical knowledge, when choose the mathematical model strategy. Because that they should use mathematical model to solve chemical problems. Not all of the chemical calculation problems can be successfully converted to pure mathematics problems, so this strategy only can be used to some chemical calculation problems.