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How to learn chemistry well;

"Chemistry Curriculum Standard" points out: let every student know the colorful chemistry closely related to human beings with a relaxed and happy mood, actively explore the mysteries of chemistry, form a sustained interest in chemistry learning, and enhance self-confidence in learning chemistry well. So, how to learn chemistry well? Through these years of teaching, the author thinks that we should pay attention to the following aspects in learning chemistry well:

First, read the chemistry textbook carefully.

Chemistry textbook is a teaching book that systematically expounds the contents of the textbook according to the syllabus. Grasping textbooks will also grasp basic knowledge. We should focus on the main principles, laws and important conclusions and laws in textbooks and remember them. At the same time, we should also pay attention to the methods of studying problems in chemistry. Mastering scientific learning methods is more important than mastering knowledge. Because it can improve the thinking ability of learning.

The process of reading chemistry books is generally divided into three steps.

1. Read a textbook comprehensively, grasp the overall content of a book, form a preliminary overall impression in your mind, and outline the key, difficult, key and essential issues in the textbook.

2. Grasp the key. On the basis of comprehensive reading, focus on the key points, difficulties and key terms in the textbook, and ponder carefully.

3. Think positively when reading, master key knowledge and gradually break through difficult knowledge.

In short, the reading procedure can be summarized as "whole jujube is a part of whole jujube", that is, overall perception, partial exploration and overall understanding.

Second, pay attention to the learning methods of chemistry.

Learning method is the way and strategy for students to acquire knowledge, master knowledge, develop intelligence and cultivate ability.

First, the learning methods of chemical experiments

(A) Experiment-means of learning chemistry

Chemistry is a natural science based on experiments. Experiment is a scientific method and an important means to learn chemistry.

(2) observation experiments should be combined with thinking.

The observation of chemical experiments is generally carried out in the order of "before reaction → during reaction → after reaction". Observe and think positively at the same time. For example, observing the phenomenon that copper and zinc are put into dilute sulfuric acid respectively, why can we see that zinc will produce gas when put into dilute sulfuric acid, but copper will not produce gas when put into dilute sulfuric acid? Through thinking and sublimation of perceptual knowledge, we will more deeply realize that zinc is more active than hydrogen and can replace hydrogen in acid, while copper is not as active as hydrogen, so it cannot replace hydrogen in acid.

(3) "One, Two, Three" in chemical experiment operation

1. When taking solid powder in the laboratory, it should be "one inclined, two delivered and three vertical". Even if the test tube is tilted, carefully send the medicine spoon containing medicine to the bottom of the test tube, then erect the test tube and let all the medicine fall to the bottom of the test tube.

2. When using bulk solid or metal particles in the laboratory, it should be "one horizontal, two horizontal and three vertical". That is, put the container horizontally, put the medicine or metal particles into the mouth of the container, and then slowly erect the container, so that the medicine or metal particles can slowly slide to the bottom of the container to avoid the container from breaking.

3. In the liquid filtration operation, attention should be paid to "one viscosity, two low and three poor". That is, the filter paper clings to the inner wall of the funnel, the edge of the filter paper should be lower than the funnel mouth, the liquid level in the funnel should be lower than the edge of the filter paper, the beaker should be close to the glass rod, the end of the glass rod should gently lean against one side of the three-layer filter paper, and the nozzle at the lower end of the funnel should be close to the inner wall of the beaker.

B, the study of chemical terms

(1) Chemical terminology is a tool for learning chemistry.

Chemical terminology is unique to chemistry, a tool for studying chemistry and an international language of science and technology. If you don't know chemical terms, you can't start learning chemistry. Therefore, it is very important to master it.

(2) Write a good way to remember chemical formulas.

1. Master the writing of simple chemical formulas

2. Master the writing of chemical formula of compounds

(3) Master the writing and memory methods of chemical equations.

1. master the reaction law

2. Write and remember the chemical equations related to the experimental phenomena.

Third, grasp the law, learn to associate and simplify memory.

Chemistry, compared with mathematics and physics, places more emphasis on memorizing things, is more "abnormal" knowledge, and its regularity is not very strong. How to systematize seemingly messy knowledge and simplify memory is a problem that must be solved to learn chemistry well.

The first thing to emphasize is that learning any knowledge requires memory. Without memory, there is no knowledge.

The ancients said that "you can recite poems by reading 300 Tang poems" and "you can see the meaning of a book by reading it a hundred times". Its main purpose is to emphasize memory and experience, deepen and sublimate in memory. This is what we still need to learn today. It is wrong to emphasize the improvement of ability and ignore the memory of basic knowledge. "Ability" is based on knowledge. But how to simplify memory, in general, is: summarize, try to be organized and grasp the regular knowledge.

For example, the chemical properties of substances are different, but if you look closely, you can find that the chemical properties of a substance are actually a reaction with simple materials and compounds (within the scope of middle school), as shown in the following figure:

Elemental metal: sodium (lithium) magnesium aluminum iron copper.

simple substance

Non-metallic elements: H2, carbon, silicon, nitrogen, phosphorus, oxygen, sulfur and Cl2 (X2).

alkali

A substance+acid

Compound salt

oxide

organic matter

As long as this substance is analyzed a little, its chemical properties can be recorded completely and accurately.

Another example is electrolysis, because the electrolyte is different, the products are also different. When the inert electrode is used for electrolysis, it will be found that the solution of oxyacid salt, oxyacid and strong alkali of electrolytic active metal is actually electrolytic water; Electrolysis of non-oxygen acid (except HF), non-oxygen acid salt solution of inactive metal, in the electrolysis of solute; When electrolyzing the solution of non-oxyacid salt of active metal or oxyacid salt of inert metal, solute and solvent participate in electrolysis at the same time.

By analogy, as long as you learn with your heart and keep summing up, you will sort out the complicated knowledge in order. Pay attention to association in the process of combing, and it is difficult for students who can't associate to "live" their knowledge. There is an advertisement: "What will the world be like if human beings lose their association?" Similarly, if we are not good at association in our study, your knowledge will be in a state of fragmentation, and you may perform well in one chapter and one section alone; If you take the comprehensive exam, you will do well. In the process of learning, we must link the knowledge before and after.

For example, there is no separate oxygen section in high school chemistry, but the nature of oxygen runs through the whole middle school chemistry. This requires you to learn to associate when learning the nature of oxygen, and to drive your chemical knowledge from point to surface. Please refer to the following table:

Metal lithium sodium magnesium aluminum iron copper

simple substance

Non-metallic H2 carbon silicon N2 phosphorus oxygen

Basic ferric hydroxide

Inorganic acid H2S trisulfate

Na2SO3 FeSO4 salt

Oxide carbon monoxide sulfur dioxide iron oxide

Combustion reaction of hydrocarbons: alkanes, alkenes and alkynes.

Combustion reaction of organic aromatic hydrocarbons

Catalytic oxidation of alcohols and aldehydes

Oxygen absorption corrosion of galvanic cell reaction.

The pathway of producing oxygen also extends from the decomposition of KMnO4 and KClO3 to:

Salt decomposition: KCIO3, KMnO4 AgNO3 NaNO3 Cu(NO3)2.

Decomposition of acid: HCIO. nitric acid

Peroxide: H2O2 decomposes Na2O2+ H2O and CO2.

Electrolysis: CuSO4 AgNO3 and other solutions.

Photosynthesis: CO2 +H2O

In this way, through O2, you will review the knowledge in three middle school chemistry books. If you think of H2. X2.HNO3.H2SO4 and other substances, over time, your knowledge is no longer scattered, but networked and three-dimensional, forming your own knowledge network, which will be handy to use.

Fourth, pay attention everywhere and sum up from time to time.

Generally speaking, we should follow the route of reading in class → thinking → practice → thinking (induction, summary and deepening knowledge). Listening to classes and reading textbooks are influenced by knowledge, and mastering knowledge through thinking only stays in the "rational" stage (eye to eye, heart to heart). Test your understanding and application of knowledge through practice. Think, classify and summarize knowledge in practice, avoid analogy and jump out of the sea of questions. For example, whether there can be a large number of ionic groups in the solution and whether the combination mode of ions can be changed at will, but when insoluble matter, gas and weak electrolyte are generated between ions, redox reaction occurs, and double hydrolysis reaction is adopted in the complex reaction, a large number of ions cannot exist at the same time. Mastering this principle, although this kind of topic constantly changes its "face", the treatment method is the same.

Among the related problems that can react with both H+ and OH-, it is only necessary to summarize that amphoteric substances [Al, Al2O3, Al (OH) 3], acid salts of weak acids, weak acid base salts, amino acids and protein can meet the above requirements, but none of them can meet them, which greatly simplifies memory.

In the calculation of material composition, the mixture of FeSO4 _ 4 _ 4 and Fe _ 2 (SO _ 4) _ 3 contains A% sulfur, so the percentage content of Fe can be determined. Note that the amount is naturally 1-3a%. There are many similar topics, such as: Na2S, Na2SO3, Na2SO4 mixture, knowing the percentage of sulfur and finding the oxygen content; In the mixture of CH3COOH and CH3COOCH2CH3, knowing the mass percentage of oxygen is the same as finding the mass percentage of carbon. As long as you understand with your heart and sum up the rules in the process of solving problems, practice can play a role.

With regard to some calculations of PH value, hydrocarbon combustion has laws to follow. The key is to be good at summing up, pay attention everywhere, and do academic research.

Five, eyes, hands and heart, taste the fruit.

Chemistry is a subject based on experiments. Experiment is the basis of the formation and development of chemistry. Experiment is a necessary means to stimulate the senses, remember deeply and arouse thinking in the teaching process. Have you learned to observe and think in your study? What happens when excessive chlorine drops into Kl solution? Can you explain it? If not, are you interested in asking questions?

In the experiment of preparing ethylene and testing the chemical properties of ethylene in the laboratory, when ethylene is introduced into Br2 water, Br2 water quickly fades. Do you realize that this is contrary to the characteristics (slow speed) of organic reactions we have learned? Do you think ethylene may be mixed with other inorganic reducing agents? Notice that the mixture of ethanol and concentrated H2SO4 turns brown or even black when making ethylene? Have you thought about the possible chemical reaction here? If so, can you get more pure ethylene? And so on. As long as you put your heart into it, the problem will come.

It's not enough to think about it. If you want to know the taste of pears, you must taste them yourself. Do it yourself "Nothing is impossible." You can't understand the difficulty from theory to practice without doing it yourself. "All one's wishes come true" is just people's good wishes. What you think is often out of step with what you do. How to explain some abnormal phenomena and how to prepare for experiments are the best opportunities to improve their learning ability.

"Poetry with flavor is bitter and sweet". After your imagination, experiment and summary, you will find that learning chemistry is so interesting and it is easy to learn chemistry well.

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