I ve been taking the exam for a month, and I don t know how to do it

The focus is on Chapter 8 of the second volume of the eighth grade, and I think you should be fine with the calculation questions. It mainly depends on the chemical formula. Next is the reaction class of acid-base salts.

For example, the reaction between salt and alkali is a metathesis reaction, the reactants are soluble in water, and the products must have water, precipitation, and gas, which you can find in the reference book, which is the point. Then we can figure out a few special sediments. (Take a look at the properties of sodium hydroxide) and then figure out several identification methods.

The properties of acid-base salts, their physical and chemical properties. You can find all of these in the tutorial book.

There are some common colored solutions that are familiar with precipitation.

In Chapter 7, you can take a general look at the properties of solubility.

Also, I wish you a good grade.

Read a lot of books,,, there is everything in junior high school books.

In chemistry, as long as you memorize everything, you're fine.

Rote memorization is one way to do it.

My advice is to do more questions, not just turn the book right away, so that after a lot of it, you will gradually get used to it, and then you can do it.

Temporary cramming.

The first is the equation.

The second is elemental properties.

The third is experimental principles and phenomena.

Of course, the elements themselves must also be remembered, and this is the basic.

There are no shortcuts to learning, but there are methods. The method teacher should teach you! Learning cannot be rote memorization, but must find patterns.

Acid and alkali salts are specially marked, and there should be one at the back of the book.

Actually, I think that the special place in chemistry is to find insoluble substances (precipitates) and remember.

The teacher should have written.,Look for notes.,Or look at the notes of classmates.,Just remember the special.。。。

1. Write the reactants first, and use them if there are multiple reactants in between"+"Connect 2, write an equal sign, and indicate the reaction conditions on the equal sign (if not, you can not write it) 3, and then write the product, and also use it if there are multiple things generated"+"Connect 4, final trim. That is, the number of the various elements that make up the reactants before the equal sign should be the same as the number after the equal sign (this is the only difficulty in the equation).

5. It should be noted that if there is no gas in the reactant, but there is in the product, one must be added after the chemical formula of the gas generated"If there is no insoluble precipitate in the reactant and there is one in the product, one must be added to the chemical formula of the precipitate generated"↓".(If there is gas or precipitation in the reactant, there is no need to add an arrow).

For example: Na2CO3+2(HNO3)==2(Nano3)+CO2+H2O

As a senior in high school, let me come to you.

I am a representative of a chemistry class in the third year of Xinhai High School in Jiangsu Province.

I haven't had a perfect score since high school, but it's basically between 130 and 147. He has won the third prize of the Municipal Chemistry Competition and the second prize of the province. Here I would like to send you a piece of advice, which is to read more books, especially when dealing with elemental compounds and organic.

When I first taught myself how to do organic covering, I was stunned to look at hydrocarbons and hydrocarbon derivatives no less than ten times in a week. There are many organic reactions, the principles are complex, and it is difficult to remember, so I can only move forward 1 or 2 verses every time, and then I continue to look at why the following reactions occur and what type they belong to, I can't figure it out, but I still try to remember the reactions. The method may be a bit stupid, but when you read all the reactions 10 times and understand the chest, and then compare them, why the reactions occur, and what type they belong to, you can easily understand.

As long as you persevere, how can you not learn chemistry well? In addition, you can also take a look at the two paragraphs of "Periodic Law" and "Organic Compounds" in the Book of Olympiad (Elementary Edition) to open your eyes. If you read too many things, you won't be afraid of information problems.

Chemistry is actually not difficult, it is more miscellaneous, I recommend a method, that is, you must have a relatively complete notebook, the basic knowledge can be seen if you are fine, but don't force it, usually do the questions will not be able to flip through the look, so that it is easier to remember, not necessarily have to follow the teacher's ideas, find a set of learning methods by yourself The most important.

Memorize all the knowledge points in the book, and then write the chemical equations in the book. It is best to memorize the mantras summarized by the teacher in class, etc.

Such as salt hydrolysis: only if there is weakness, there is no weakness without hydrolysis; The weaker it is, the more hydrolyzed, and whoever is stronger shows who is sexual (remember ammonium acetate is neutral).

Chemistry needs to bring more practice questions, and if you do more, you will naturally do it.

Learn the four key points of chemistry well.

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. Be sure to preview before class, in addition to reading the content of the new lesson carefully, you should also mark the areas you don't 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.

There is a lot of chemistry content in junior high school, and the knowledge is relatively scattered, so teachers focus on the key content when lecturing. Therefore, everyone should listen carefully to the lecture and take notes carefully, which is not only conducive to reviewing after class and mastering the key points, but also can effectively prevent "distraction" during class. However, when taking notes, on the basis of listening to what the teacher says, you should remember the key points, difficult points, doubts, and things that are not in the textbook.

2. Review often and memorize more.

After class, you should review in time and do your homework carefully, which is an important part of learning chemistry well. Revision can be done after class, after week, unit, chapter, and comprehensive. Methods of revision include retelling, dictation, and making connections.

Knowledge can only be firmly grasped through multiple revisions. There are many basic concepts and principles in the current junior high school chemistry textbooks, more than 20 element symbols that require mastery, as well as many chemical formulas, chemical equations and other knowledge. Most of these contents need to be memorized on the basis of understanding, and most of them are the basis for learning chemistry, and if you can't memorize them, you will find it difficult to walk in the "kingdom of chemistry".

It is necessary to keep in mind the various terms and definitions of chemistry, and to distinguish them carefully, such as compounds, pure substances, elemental substances, and mixtures, and their definitions should not only be remembered, but also distinguished and compared. Once you really figure it out, then I ask you which substance milk is above and you won't have to think about it for a long time. Common chemical reactions must be kept in mind, to be able to write silently, conditions (heating, light, catalyst, arrow reversible, irreversible need to be paid attention to, the phenomenon of the reaction process is needless to say, important must be remembered.

Formulas in chemistry, understand them like memorizing mathematical formulas, remember to integrate and use them flexibly, pay attention to flexibility Don't be a nerd, I don't like nerds either.

3. Thoroughly understand the textbook and connect it with reality.

Taking the textbook as the main line and carefully reading the textbook is the foundation of learning chemistry well. To this end, students must be good at reading textbooks, pre-reading before class, careful reading after class, and frequent reading. It not only pays attention to the main content, but also does not ignore the small print part, some charts, information and optional content.

The content of chemistry in middle school is closely related to life and production. This requires us to learn chemistry at the same time, we should try to connect with the reality of production and life, discover chemistry from the life around us, and taste chemistry, so that the more we learn, the more we want to learn, the more we love to learn.

How to tell if the substance is added to the water, and the resulting solution is colorless and transparent?

A: Remember the colorless ions (most cations, anions); It is also possible to keep in mind the colored ions (small amounts of cations, anions; For example: 3-valent iron ions, permanganate ions), to remember all the colored ions, in addition, to obtain a colorless and transparent solution.

Which ions can coexist in aqueous solution?

A: Ions that cannot undergo chemical reactions can coexist.

Oxide + water alkali, how to write a chemical equation? Is it a metathesis reaction?

Answer: Oxide + water base, e.g. CA + H2O = Ca(OH)2 is not a metathesis reaction.

The color of the solution is generally to see whether the particles obtained by the substance after dissolving in water have a color, for example, ferrous ions are green, copper ions are blue... The need to summarize and memorize is rote memorization.

It seems that there are several conditions 1 that cannot react with ions, such as hydrogen ions and hydroxide ions, cannot coexist; 2. Insoluble and insoluble substances cannot be produced, such as copper ions and hydroxide ions cannot coexist, and intolerant copper hydroxide will be generated, and I have forgotten other conditions.

There are not many oxides and water reactions to form alkali, this oxide must be a metal oxide, sodium peroxide can react with water to form alkali and oxygen, which does not belong to the metathesis reaction, this process can be divided into two, but at the beginning, the teacher also talked about the reaction of sodium peroxide and water separately into hydrogen peroxide and sodium hydroxide, which belongs to the metathesis reaction, hydrogen peroxide is decomposing reaction.

Metathesis reaction is defined as the reaction of two compounds to form two new compounds, both of which are compounds.

How to tell if the substance is added to the water, and the resulting solution is colorless and transparent?

At the end of this chemistry book there is a table that says ...

Which ions can coexist in aqueous solution?

See if the ions react with each other.

Oxide + water alkali, how to write a chemical equation? Is it a metathesis reaction?

The reaction in which two compounds exchange components with each other to form two other compounds is called metathesis. Its essence is: the two substances that undergo metathesis reaction exchange ions with each other in the aqueous solution, and combine into substances that are difficult to ionize--- precipitation, gas, and water, so that the ion concentration in the solution is reduced, and the chemical reaction is carried out in the direction of the reduction of ion concentration.

It can be abbreviated as ab+cd=ad+cb. (It can be abbreviated as: alkali salt, salt brine dissolved, precipitated gas water generated.)

In order to correctly write the chemical equation of the metathesis reaction, it is necessary to memorize the solubility tables of common acids, bases, and salts, and use the solubility of substances correctly.

The alkaline oxide is added with water to form the corresponding base.

For example: cao+h2o=ca(oh)2

Na2O+H2O=2NaOH chemical reaction.

Chemistry is actually not difficult, as long as you put your mind to it, you can learn it well.

First of all, it's a very comprehensive subject and it's a lot of fun.

Chemical formulas, chemical equations, concepts, experimental phenomena can be solved in the form of memorization in the liberal arts - this is dead knowledge, you must work hard to memorize these, memorize these well, and you will have a foundation in the future.

You can use the divergent thinking of science to solve experimental problems, as well as comprehensive problems. It is closely related to mathematics and physics, but it is simpler than mathematical physics. For example, experiments, experiments are particularly fun, as long as you watch the class carefully, even if you don't memorize the experiment, you will remember it during the exam.

And so on, and so on.

In fact, the most important thing is interest, as a new subject in the third year of junior high school, as long as you are serious, it is impossible to learn badly. If you are interested in this subject, you will naturally learn it well

The most important thing is the most basic, the substance name, form, properties, transformation (reaction equation, this is the most important test) after memorizing it, there is basically no big problem.

That's it at the beginning, just come into contact with things that you weren't familiar with before, it's a little uncomfortable, it's okay, it's good to adapt, it's important to read more books.

The early stage of chemistry is to clarify various concepts, it will not be difficult, read the book well, the difference between chemical changes and physical changes, and some simple chemical expressions to remember, if you learn the air, look at the content of various gases, and the test to verify the volume fraction of oxygen in the air, refueling.

It's not difficult, learn chemistry with the method that suits you best, and you will definitely learn it well.

Actually, it's okay, you can write down some concepts in the book, especially the properties of some substances, what are the phenomena of chemical reactions, and so on,。。 The most important thing is to work hard.

Liberal arts in chemical formula science, so you should memorize more basic knowledge.

Well, just memorize all the chemical equations you've learned. Simple theories are also remembered. In this way, you will definitely be able to pass.

I just came from the third year of junior high school, in fact, chemistry is very simple at the beginning, as long as you memorize the steps of the experiment, the precautions and something, the focus is still on the acid-base salt, it doesn't matter, in fact, everyone is similar later, write more questions, read more books, you must work hard, come on.

Looking at the textbook first, it is actually a distortion of textbook knowledge.

Preview before class, and make up for it if you can't do it.

I was more miserable in high school chemistry because the chemistry teacher was beautiful, otherwise I wouldn't have studied, hehe. If it really doesn't interest you, I think you can change the way, such as studying a few topics with your classmates or teachers, and don't deliberately memorize them every day. You won't feel the pain anymore.

In addition, I think you can focus on your strengths, such as physics or biology, and I don't think it will affect your overall score in the gaokao.