I want to teach myself junior high school chemistry, which teacher to ask for help and advice,

Wang Houxiong, who went to the bookstore to buy a junior high school chemistry textbook, bought a junior high school chemistry textbook, as long as you work hard, you will definitely be able to learn well, and I also taught myself.

Be self-taught. Just buy your own reference books.

Chemistry is the main note.

Summary. 2) 1, CH4 2, no pollution because the product is water 3, Si+O2=SiO2 No exhaust emissions.

Middle school chemistry questions need to be answered by a professional chemistry teacher.

Hello, send the question, I'll try.

20. (1) The red phosphorus heated by N2 does not burn, but the red phosphorus heated by oxygen will burn; Water isolates oxygen.

2) 1, CH4 2, no pollution because the product is water 3, Si+O2=SiO2 No exhaust emissions.

It is the foundation of learning chemistry well to pay attention to basic learning, take textbooks as the main line, carefully read textbooks, fully grasp the basic knowledge, and not leave obvious knowledge and skill defects and loopholes. In the process of learning, many students can not be down-to-earth, so ambitious, thinking that they will not be able to test the content of the textbook or the content of the textbook is too simple, so in the case of the basic knowledge of junior high school chemistry textbooks has not been able to really understand and understand thoroughly, blindly pursue deviations, difficult problems, and engage in tactics of the sea of questions, in fact, this is more than worth the loss.

Among them, junior high school chemistry terms are the foundation of learning chemistry well, so when we learn, we must make efforts to master common element symbols, chemical formulas, chemical equations and other chemical terms through memorization, intensive training and other methods, only in this way can we lay a good foundation for continuing to learn chemical knowledge.

In addition, it is necessary to master the basic steps of chemical experiments in books and the role of each step, and master the use and prescription methods of chemical instruments.

1. Be diligent in previewing, good at listening to lectures and taking notes.

If you want to learn chemistry well, you must first understand this course. For this reason, students can use the summer vacation to read through the chemistry textbook first, maybe the interesting and lush chemistry textbook will deeply attract you. In addition to reading the content of the new lesson carefully, you should also mark the areas you do not understand, and try to do the exercises in the textbook.

In this way, with questions and difficulties, the efficiency of listening to the class will be greatly improved.

2. Thoroughly understand the textbook and connect with reality.

Students must be good at reading textbooks, so that they can read before class, read carefully after class, and often choose to read, etc., not only pay attention to the main content, but also do not ignore the small print part and some charts and optional content, because these contents help to deepen the understanding of the main content and broaden the scope of knowledge. When reading carefully after class, you should read and remember while thinking, and strive to solve all the unsolved problems in the preview and listening to the class.

3. Pay attention to experiments and cultivate interest.

Chemistry is an experiment-based discipline, we should pay attention to the review of experiments, find some good teaching aids on the Internet to do, practice more experimental content in textbooks, and understand and memorize the instruments, drugs, devices, experimental principles, steps, phenomena and precautions used in experiments.

Do more, especially if it's similar to the 14 and 15 question types.

It seems that we are in the same boat!

My DU a little feeling: 1. Not every question has to be explained in detail.

DAO solution, it is more important to explain it in a targeted manner.

The main thing is interaction, junior high school students have just come into contact with chemistry, and they are still full of curiosity about it, as long as they are curious, learning is not a problem, the beginning is very simple knowledge, there is interest, and then it is good.

First of all, pay attention to the teacher copy

Interaction between students, according to the topic to ask some small questions, ask students to answer, so that students do not feel drowsy, secondly, pay attention to the extension of the topic at the same time, give examples of some questions that use the same method as this question, and ask students to do it themselves. There is a lot of content in junior high school chemistry memory, especially some key knowledge points, so it is also good to intersperse some knowledge points with the consolidation of some knowledge points while lecturing the topic.

Pay attention to the interaction between teachers and students, ask some small questions according to the topic, and ask students to answer, so as not to let students feel drowsy. Middle School Chemical Memory.

In a chemical change, molecules are divided into atoms and recombined into molecules.

So since you think that atoms can be divided, what are atoms that can be divided into?

Electrons, sorry, this cannot be understood as atomically divisible.

Protons and neutrons, sorry, such a change is neither a chemical nor a physical change. This is nuclear fission or nuclear fusion.

The physical change is the impact of high-velocity particles, such as with particle accelerators.

Hello, the definition of physical change is the change that does not generate new matter, that is to say, the physical change only occurs on the surface of the substance, such as the three-state change of water, and there can be no matter in the physical change that is divided into atoms. Still have any questions?

Atoms are the smallest particles of chemical reactions and can no longer be divided, such as 2NaOH + CO2 = Na2CO3 + H2O

Chemical change is the process of recombination of atoms, and the smallest unit is the atom, so the atom is indivisible.

The number of electrons outside the nucleus of an atom = the number of protons.

But when an atom becomes an ion, it loses or gains electrons, and the number of electrons outside the nucleus ≠ the number of protons.

That is, the relative atomic mass = the number of protons + the number of neutrons, not the number of electrons outside the nucleus + the number of neutrons.

1. The electronic mass is too small and negligible.

2. The electrons gained and lost by the atom become ions, and their relative atomic masses are almost unchanged, while the electrons have changed.

So the relative atomic mass = number of protons + number of neutrons, not the number of electrons outside the nucleus + the number of neutrons.

The mass of electrons outside the nucleus and the comparison of protons and neutrons can fluctuate.

The number of electrons outside the nucleus of an atom is equal to the number of protons, while that of an ion is not equal to.

CO32- +H2O=reversible=HCO3- +OH-

There will be a small amount of OH- produced, so it cannot be proven.

After answering, I wish you a happy study.

There is a blue precipitate (indicating that there is hydroxide), and wrong, copper carbonate is also a blue precipitate.

The key is to identify rather than test the pro.

I don't know if your teacher has summarized for you which are soluble, slightly soluble, and insoluble. Copper carbonate is also precipitated.

Potassium hydroxide can also precipitate with copper chloride. Sodium bicarbonate and hydrochloric acid can also produce bubbles. Your experimental design is not rigorous.

The general property of alkaline solutions is that they all contain hydroxide ions, and copper chloride contains copper ions, and as long as the alkaline solution reacts with it, it will form a blue precipitate.

Copper carbonate is hydrolyzed to produce copper hydroxide and water.

I'm also a junior high school student

I feel more miserable than you, just a month after the start of school, when I didn't learn equations in chemistry, the teacher went to the countryside, and the teacher was also super fast, and I didn't understand anything after a class. The whole class was in a bad mood at the time. There was no interaction in the class, and there was no time for note-taking, and she also said that we should find the key points by ourselves.

Later, I learned the chemical formula and memorized the valence, but I also had a headache. Trimming of chemical equations is also a headache.

However, don't give up your confidence in chemistry, the reason why we can't keep up with the teacher in class is because we don't grasp the simple knowledge and the new content is not pre-trained.

Now I am very familiar with chemical formulas and chemical equations every day, and I am very familiar with them, and I can apply them quickly.

Preview before class, review in time after class, other students think that the teacher is fast, I don't think so. Because I've been getting used to it.

You also have to learn to adapt to it. Chemistry is really simple

Chemistry: First, the knowledge of chemistry is very fragmented, and there are too many knowledge points; Second, there are too many things to memorize, especially chemical equations, which are particularly difficult to memorize. In fact, there is a deviation in this understanding, there are indeed many chemical knowledge points, which seem to be broken, but these knowledge points are not isolated, but have a structure and system, so we should learn to make a summary, if we don't know how to communicate with teachers and classmates at the beginning, even if we imitate it at the beginning or do it step by step under the guidance of the teacher, it doesn't matter, but we have to learn to do it, and it is much easier to learn and understand the knowledge points in a system.

As for memorizing and memorizing, we must be clear about the logical relationship between them, "knowledge must be memorized but must not be memorized", the memory of understanding and the memory of mastering the law are correct, and they can be remembered for a long time, and they can also be used in solving practical problems.

Chemistry is a discipline that is a bit mixed with liberal arts, and there is no way to do chemical equations, but to memorize them on the basis of understanding. Chemistry is actually quite simple, but the knowledge points are a bit scattered, and there is a lot of knowledge that needs to be memorized. Everyone has their own experience to talk about, but it may not be suitable for you, or you need to explore it slowly.

In fact, any subject has its rules, as far as chemistry is concerned, first of all, you must know how to write chemical formulas, as long as you usually write more and practice more, and secondly, like you are just in the third year of junior high school, before you are contacted, you have to memorize the valency of the elements, this is a formula, I think it should be difficult for you, and finally to understand the properties of chemicals, which is inevitably related to whether chemical reactions can occur. Just look at the sediment at the back of your book, and remember the substances that can precipitate. The valency is prepared for the trim equation.

Molecules, atoms and elements, on the other hand, are just conceptual issues. Just take a look and think about it.

As long as you know that. Chemistry in junior high school is very simple. You have to have faith in yourself! Good luck and hope it helps.

Chemistry is an experiment-based discipline.

If you can, you can do more experiments.

Take good notes in class + review hard after class + do more practice questions + don't know how to ask more questions + do more experiments will make you memorize deeply = good grades.

The chemical elements are completely backrested, and they are easy to memorize, so find some skills to memorize.

Then when learning, first of all, the common element symbols on the periodic table are proficiently silent, and then practice writing the chemical formula, because the chemical formula is a formula composed of element symbols and numbers, and the writing method is to write from back to front, in addition, the valency of various commonly used elements should be memorized, and the quantitative relationship between the elements can be determined according to the valence, and then the chemical formula is written with the algebraic sum of the positive and negative valency of each element of the substance is zero, and the correct or false is judged to be true or false, then the chemical equation is written by combining various chemical formulas with the quantitative relationship, and practice submitting answers.

Find some exercises on the Internet to do, and if you make a mistake in your homework, it is best to find the same type of questions on the Internet to practice, or you can buy a "Knowledge List" and use it as a textbook to fully solve. I believe you will be able to learn well.

Chemical equations must first master the method of trimming, and then based on experiments, comprehensible memorization.

I've been through this too, and I've been helpless, but I should preview the textbook every day, and then take notes on what I don't understand and listen carefully to the lesson, especially if I don't understand. You can also ask the teacher, the key is not to rush and take your time, and believe that you can do it.

Listen carefully in class, don't know how to ask the teacher after class, and do more questions.

Chemistry! If I want to find feelings to understand, I am looking for problems to do, and I can integrate formulas by doing problems.

As long as you understand all the contents of the book, and then do a few corresponding questions, if you don't understand, ask questions, and learn to "guess" in learning", because guessing expands your thinking skills, such as those inference questions... In this way, the correct answer rate of chemistry can be kept within 90%, which is how I learned chemistry at that time.

In fact, the most rare part of the third year of junior high school is the part of acid and alkali salts. I don't know if you're a solid learner? The basics are important.