Pay attention to the application of chemical knowledge in life

From the analysis of this year's urban survey examination, the examination questions advocate the innovation of questions and pay attention to the setting of situations. Among the 25 questions in the city test, there are 22 questions that combine chemical knowledge with practice, accounting for 88% of the total questions. In the creation of these situations, we not only pay attention to drawing materials from daily life, the output of products in industrial production and social hotspots in news reports, but also pay attention to the characteristics of combining basic knowledge with basic skills and combining process methods with emotions and values.

Curriculum standards advocate that the proposition of senior high school entrance examination should face all students, be close to their real life, pay attention to social hotspots, and pay attention to their survival ability, lifestyle and learning ability. This year's chemistry test materials for senior high school entrance examination may be extracted from real life, social hotspots in news reports and other issues, so as to design familiar, true and novel scenarios for candidates and ask questions with knowledge in textbooks, with a high starting point and low knowledge. Therefore, candidates must pay attention to the application of chemical knowledge in production, life and science and technology when reviewing. Pay attention to explain the changes around us and nature with macro and micro ideas.

Read the concepts and principles repeatedly and combine reading with thinking.

Reading should start with the most basic content, such as the meaning of all the illustrations in the textbook, the composition of all the important substances listed, and some data related to the properties of substances. Candidates should memorize and understand it to ensure that the basic knowledge part does not lose points. Taking the questions in the city mock exam as an example, this paper explains the importance of reading and understanding textbooks.

The suggested answer is divided into three steps: examination, analysis and answer.

It is suggested that candidates must divide the answering process into three steps, namely, examining questions, analyzing questions and solving problems. "Examining the topic" means reading the original topic and understanding the meaning of the topic, so as to prevent the whole topic from being taken out of context and careless. "Analysis" is to analyze the original problem, find out the meaning of key words on the basis of investigation, analyze and synthesize many facts or complex phenomena, dig out hidden conditions and internal relations, find out the breakthrough, and thus establish the ideas and methods of solving problems. This is the most critical step to solve the problem. "Solving problems" is carried out on the basis of analyzing problems, using known information and paying attention to conciseness of language, but it must be accurate and rigorous.

The topics of chemical experiments include design, separation and impurity removal.

The chemical experiment in the textbook is mainly divided into two parts, the basic operation and the design of the experiment. The second round of special review, the topics of scientific inquiry, physical and chemical synthesis, information, emotional evaluation and comprehensive calculation almost all include the design, separation and impurity removal of the experiment. It is worth reminding students that in the operation of impurity removal and mixture separation, both the "quality" relationship and the "quantity" relationship between reactants should be considered. In the experimental design of preparation, verification and purification of some gases, the connection sequence of devices must be considered.

Set the standard time for self-test.

At present, it has entered the third round of review sprint stage. Candidates should have a compilation of examination questions from various provinces and cities, set standard time, conduct self-simulation tests and self-evaluation, and be aware of it. Note that your own grading should be carried out in strict accordance with the grading standards, not only depending on the answers, but also focusing on the multiple-choice points. So that I can answer questions succinctly and rigorously. Through constant experience, grasp your weaknesses, find out the existing problems and solve them in time.

How to improve the ability of solving problems in chemistry

First, the college entrance examination should pay attention to the problem:

The adjustment of the first volume of questions, the focus and hot spots are still maintained, and the scoring rate of traditional questions should be guaranteed. The second volume should be more difficult than last year, highlighting the innovation, application and inquiry of the test questions.

Experiment: The first question in the experiment part is the basic experiment, including basic operation and instrument selection. We should attach importance to some basic experiments in textbooks. The second question mainly examines the experimental thinking ability, such as the design, evaluation and analysis of the experimental scheme, and helps students form the basic problem-solving methods and ideas of this kind of questions.

Inorganic: pay attention to the way of thinking from structure to essence. The block diagram problem can be property inference or analytical inference of industrial or purification process. There are many breakthroughs in the block diagram and it won't get stuck in one place. It is necessary to help students learn the basic methods of perceiving test questions as a whole.

Organic: Write a simple formula of material structure by calculation (or drawing) and inference, and help students master the common methods to determine the molecular formula of organic matter by calculation. Organic inference questions are usually information questions. Pay attention to information extraction, understanding, induction and knowledge integration. Pay attention to the standardized expression of answering questions and improve the correct rate of answering questions.

Calculation: The first question is usually basic chemical calculation, so you should make sure to score. The calculation of the second question is often divided into several small questions, which are difficult and easy, and the difficulty does not necessarily increase in turn. It is necessary to remind students to read as a whole, which is easy before difficult, and it is not necessary to answer the questions in turn.

Second, the play of chemistry level in the college entrance examination

On the existing level and basis, the key to the success of college entrance examination is to establish self-confidence, which is a good medicine to relieve stress. Some suggestions are put forward for chemistry review.

First, we must first master the basic knowledge. In the last few days, don't blindly do difficult problems, digressions and strange questions, but seriously review the most important backbone knowledge in the basic knowledge.

Second, carefully analyze and feedback the simulated test questions done in various places in the recent stage, especially the wrong places and places where the thinking method is not agile enough. Think carefully and write while thinking.

Third, spend some time reading books, especially the chemical properties that need to be memorized in textbooks, the laboratory preparation methods of important substances, and the most important laws in basic theories. Don't do more new questions in the final stage, you must digest the questions you have done before, and there are still some questions that need to be done seriously one by one, that is, the sample questions and sample papers in the exam outline. Finally, approaching the college entrance examination, we should talk more about our inner feelings with teachers, classmates or family members, relieve stress and build confidence. I'm sure you will get good grades in the college entrance examination.

Third, about the arrangement of chemistry review.

I suggest that in the last few days, don't do more simulation sets, and do special training first. For example, in chemistry, I suggest you do five special trainings: 1, chemical reasoning training. 2. Training of chemical experiment questions. 3. Training in organic chemistry. 4. Chemical calculation training. 5. Basic theoretical problem training.

First, organize the important and good topics done in the last two months into four subjects, and then review them specially. For example, it takes special time to review the chemical experiment questions of each test paper, and then it takes special time to review the chemical inference questions of each test paper, and so on. You can improve your ability to solve all kinds of problems.

Second, before the exam, use part of the time to review the whole set of questions. Be sure to choose the best one or two sets of questions and do them again from beginning to end to find the feeling of doing that set of questions. Do not spend too much time, not more than one third. Be sure to focus on special review. In addition, if you feel that some basic knowledge is not solid enough, you can also look back at the textbooks, especially the knowledge of typical elements and compounds and students' experiments.

Fourth, the key direction of review

1, the embodiment of chemical knowledge in college entrance examination mainly includes the following points:

One is the synthesis of redox reaction and acid-base neutralization reaction in ion reaction, and the synthesis between chemical reaction and basic theory.

The second is the synthesis between important elements and their compounds in inorganic chemistry and typical representatives in organic chemistry.

Thirdly, the synthesis between chemical experiment and chemical calculation means to infer the nature of matter by using the relationship between data and phenomena.

Four, the synthesis of chemical calculation and basic theory has a feature this year, that is, the application of mathematical thinking methods to solve chemical calculation problems. There are three main types of thinking methods in applied mathematics:

① The idea of classified discussion. ② The idea of combining numbers with shapes. ③ the idea of equivalent transformation

2, chemical inference questions should pay attention to the following two points:

1. The substances examined in the inference questions must be the most important typical substances in the high school textbooks. There are four nonmetals: chlorine, sulfur, nitrogen and carbon, and three metals: sodium, aluminum and iron.

Secondly, the typical chemical properties of important compounds of seven important elements were emphatically investigated. You can directly substitute the answer you think is possible into the question for verification. If all the reaction points can be explained clearly, then your answer is correct.

The relations, differences and connections between elements and their compounds and other elements and their compounds are reviewed. Re-examine the mistakes made before and summarize the methods and skills. For example, when solving chemical information problems, you will not panic when you encounter new situations, find problems, find prototypes, expand associations and solve problems. Textbooks are not only a tool for us to study at ordinary times, but also the basis for the proposer of college entrance examination questions. They can't go beyond the knowledge level of textbooks to write exercises that no one can do. To put it another way, no matter how novel the scene of the test questions is, the "selection points" of the answers are basically from textbooks. Therefore, we must read through the textbook, think carefully, implement it bit by bit according to the requirements of the college entrance examination, and try our best to find out the loopholes in our understanding of basic concepts and basic theories. Returning to textbooks is not extensive reading, but "thinking about the past and thinking about the future", supplementing the knowledge related to the knowledge points in this chapter as much as possible, spreading the ideas and rebuilding your own knowledge network.

3. How to do organic chemistry well?

Organic chemistry is a compulsory subject in the college entrance examination, and the examination mainly has three directions:

Firstly, the molecular formula of organic compounds containing nitrogen or sulfur is deduced by simple calculation according to the data, and then the structure is simplified and inferred according to the properties of substances.

Secondly, according to the synthesis roadmap provided by the title, typical organic compounds are synthesized, involving the types of chemical reactions, isomers of typical substances and reactions between important substances.

Third, master the mutual transformation of multifunctional compounds. Important multifunctional compounds include halogen acids, hydroxyl acids, amino acids and carbonyl acids.

In the study of organic chemistry, we have studied hydrocarbons → (halogenated hydrocarbons) → alcohols (phenols) → aldehydes → carboxylic acids → esters, sugars, amino acids and protein, and we should focus on their mutual transformation and reaction types. Did you notice the structural characteristics when the reaction took place? Do you know the reaction from the perspective of chemical bonds (that is, consider the position of molecular structure fracture and bonding in the reaction)? For example, the reaction at C-H can be halogenation reaction (such as CH4+Cl2), catalytic oxidation reaction (such as α-H under the influence of alcohol hydroxyl), elimination reaction (such as β-H under the influence of alcohol hydroxyl), oxidation reaction under the influence of carbonyl group (such as silver mirror reaction of -CHO) and decomposition reaction (such as CH4). Information questions are questions that examine students' ability to obtain information, choose information and organize information processing. The knowledge content in the exercises compiled by the college entrance examination over the years has never appeared in the teaching materials. But if you look closely, you will find that information questions often have a high starting point and a low landing point. The topic has created a new situation, paying attention to combining with practice, transforming the latest scientific and technological achievements into acceptable knowledge for middle school students, making social hot issues scientific and clarifying some vague understandings of people. Therefore, the most basic requirement to solve the information transmission problem is to be confident, not to be intimidated by seemingly profound knowledge, but to read the problem carefully, pay attention to the structural characteristics of molecules, identify keywords, see clearly the relationship between data, connect with what you have learned, and find the information and methods needed to solve the problem. The knowledge used to solve this kind of exercises is usually learned, but rote learning is never effective. It requires us to pay attention to social hot spots, scientific and technological trends and improve our own quality in an all-round way.

4. How to do the chemical experiment?

The review of chemical experiment questions is divided into two parts:

First, do a good job in student experiments and typical teacher demonstration experiments in textbooks, and read each experiment carefully, which requires four aspects: ① understand the principle and purpose of the experiment; (2) master experimental instruments; ③ Understand the experimental phenomena and their causes; ④ The experimental phenomena can be correctly explained.

Secondly, to learn to design important chemical experiments, there are four main steps in designing chemical experiments: ① to clarify the purpose and principle of experiments; (2) Identify the instruments and supplies needed for the experiment; ③ Clarify the steps and methods of the experiment; ④ Correctly handle the experimental data.

In the college entrance examination, chemical experiment questions are basically two questions, one is the basic operation and knowledge of the experiment; The second is comprehensive experiment, which mainly examines students' comprehensive ability and ability to design experimental schemes. The experimental problem is the difficulty of most students, and its intervention point is the basic knowledge and skills of the experiment, including the separation and purification of substances, the identification of substances and ions, the preservation of reagents, and the assembly of basic instruments. It is indeed difficult for candidates to design experimental schemes, but in fact, it is necessary to examine students' innovative ability and overall awareness. When answering these questions, you should make clear what the purpose of the experiment is. Candidates should analyze the principles to be applied to achieve this goal and which principles you have learned can achieve this goal. It is also possible that these principles are given to you in the title. At the same time, pay attention to the information given to you in the title, including text information, some equations given in the title and some information prompted. What needs special attention is that when the device diagram is given in the test questions, it is very important for you to analyze what information the device diagram gives and eliminate some interference factors in the experiment.

5. How to do chemical calculation?

It is not how many skills are important to solve chemical calculation problems, but how to apply mathematical thinking methods to chemical calculation. The most commonly used mathematical ideas are:

First, the idea of equivalent transformation. We also call it "conservation method" in chemistry, including element conservation, mass conservation, charge conservation and electron gain and loss conservation.

Second, the idea of classified discussion, which we call "number axis method" in chemistry, is mainly applied to the calculation of different relative quantities and different reactions between two substances.

Third, the idea of combining numbers with shapes. This year, there may be a problem of inferring the chemical reaction equation according to the diagram or drawing in the coordinate system according to the chemical reaction equation. The key is to find three or more points, starting point, ending point and exact reaction point. If you master these three kinds of chemical calculation problems, you will master the basic methods of chemical calculation problems. What matters is the way of thinking, not the skills.

5. How to answer the college entrance examination questions?

1. How to "review the questions"? How to extract the information in the topic? Taking the topic of experiment as an example to illustrate how to examine questions in chemistry, we should first distinguish what kind of experiments the topic requires us to carry out, that is, what is the purpose of the experiment, and then figure out what steps the experiment needs to carry out, what are the possible experimental phenomena and what causes this phenomenon. When we understand all these problems, we can actually check them. At the same time, pay attention to the corresponding problem-solving methods, pay attention to the teacher's usual explanations, and pay attention to his own induction and summary. The score of the experiment can be very high.

The extraction of information in chemistry is mainly the examination of organic chemistry. The organic chemistry exam is relatively large every year, and the relevant knowledge of freshmen or sophomores may be put into the college entrance examination. Take it easy. Combine the information with what the high school teacher teaches, and you will understand the topic and apply it to the new situation or new background in time. This kind of topic often starts at a high level and ends at a low level. The content of the topic is university knowledge, but the content of the answer is that the key is to build confidence, which seems to be a difficult problem, but it is not difficult.

2, chemical inference questions should pay attention to the following two points:

1. The substances examined in the inference questions must be the most important typical substances in the high school textbooks. There are four nonmetals: chlorine, sulfur, nitrogen and carbon, and three metals: sodium, aluminum and iron.

Secondly, the typical chemical properties of important compounds of seven important elements were emphatically investigated. You can directly substitute the answer you think is possible into the question for verification. If all the reaction points can be explained clearly, then your answer is correct.