Is the concept of chemistry used in the second year of junior high school? What to memorize?

There are many chemical concepts, and I am afraid that I can't memorize them. It's better to understand and memorize, do more exercises, and consolidate your understanding of concepts.

Chemistry! How to say, I personally like chemistry, junior high school and high school chemistry have better grades, for chemistry, I want to say that memorization is necessary to remember, but also to memorize some things to be ripe, but this can not be rote memorization, rote memorization, will not get good results, only use English methods to memorize the key points of knowledge, with physical thinking to solve chemical problems, the main thing is to be able to apply what you have learned (to be able to use knowledge flexibly). I can say that I am a person who has come over, and I hope mine is of some help to you!

Study hard, I wish you success in your studies!

To memorize: periodic table, chemical formulas, equations, physicochemical properties of some substances, etc.

If you have a shallow junior high school education, it is good to memorize some common exams and classics.

What is the concept.

However, what I know clearly is that you must know all the textbooks, at least all the knowledge points, otherwise the high school entrance examination will definitely be a cup.

And you don't need to learn chemistry in advance. Chemistry is super simple at the beginning, and it is difficult at the end of the second half of the semester.

According to your own understanding, it is enough to understand and read both textbooks every day, the key is to understand! Hope that helps....

Books on the basics such as various definitions, theorems, properties of matter, and more.

Those who are not allowed to study chemistry in the second year of junior high school.

Summary. Hello, junior high school chemistry physics needs to memorize 1Balance Measurement Quality [Experimental Purpose] Measure quality with a tray balance.

Experimental equipment] balance (tray balance). 【Experimental Procedure】1Place the balance on a level table and remove the rubber gaskets from both ends.

2.The code is moved to the leftmost zero tick of the ruler (the code is zeroed and the leftmost end of the code is aligned with the zero tick mark). 3.

Adjust the balance nuts at both ends (if the left disc is higher, the balance nut is screwed to the left; The same goes for the right disc) until the hand points to the dial** and the balance is levelly balanced. 4.Left and right until the balance is rebalanced.

Addition and subtraction of weights or mobile travel codes) 5When reading, the mass of the measured object = weight mass + the number of the code (m object = m weight + m swim) [experimental record] The mass of this object is shown in the figure: 62 g2

Spring dynamometer force measurement [Experimental purpose] Use spring force gauge to measure force [Experimental equipment] fine wire, spring dynamometer, hook code, wooden block.

Hello, junior high school chemistry physics needs to memorize 1Balance Measurement Quality [Experimental Purpose] Measure quality with a tray balance. Experimental equipment] balance (tray balance).

【Experimental Procedure】1Place the balance on a level table and remove the rubber gaskets from both ends. 2.

The code is moved to the leftmost zero tick of the ruler (the code is zeroed and the leftmost end of the code is aligned with the zero tick mark). 3.Adjust the balance nuts at both ends (if the left disc is higher, the balance nut is screwed to the left; The same goes for the right disc) until the hand points to the dial** and the balance is levelly balanced.

4.Left and right until the balance is rebalanced. Addition and subtraction of weights or mobile travel codes) 5

When reading, the mass of the measured object = weight mass + the number of the code (m object = m weight + m swim) [experimental record] The mass of this object is shown in the figure: 62 g2Spring dynamometer force measurement [Experimental purpose] Use spring force gauge to measure force [Experimental equipment] fine wire, spring dynamometer, hook code, wooden block.

I'm about to take the high school entrance exam, and I need to memorize these two subjects to quickly improve my score.

Hello, physical formulas and chemical equations.

After two months, can the child still improve?

Hello, yes, junior high school knowledge can be improved by memorizing more.

The content to be memorized in the third year of junior high school chemistry is as follows:

1. Changes and properties of matter:

1. Changes in matter: Physical change: no change in the formation of new matter.

Chemical change: There is a change in the formation of new substance.

2. Properties of substances: Properties of substances that do not need to be manifested through chemical changes are called physical properties, mainly including color, state, smell, hard sleep, density, melting point, boiling point, etc.

Substances must undergo chemical changes to manifest their properties, which are called chemical properties. Such as flammability, oxidation, reduction, toxicity, etc.

2. Basic experimental operations:

1. Access to medicines:

Dosage: The dosage is not stated, the solid only needs to cover the bottom of the test tube, and the liquid is 1-2ml.

Precautions: "three nos": do not smell, do not taste, do not gesture to touch.

Take a small amount of liquid medicine with a rubber tip dropper, take a certain amount of liquid medicine with a graduated cylinder, when reading, the graduated cylinder must be flat, and the line of sight and the lowest part of the liquid heart level are kept horizontal. When taking a large amount of liquid, use the pouring guessing method, the bottle stopper is upside down, the label is in the palm of the hand, and the bottle mouth should be close to the container.

The meaning of chemistry

1. Ensure the survival of human beings and continuously improve the quality of human life. As a basic discipline of natural science, chemistry is closely related to human daily life. Chemicals can be used to produce fertilizers and pesticides to increase food production.

the use of chemistry to develop new energy and new materials to improve the living conditions of human beings; The use of chemistry to comprehensively apply natural resources and protect the environment to make human life better.

2. The core knowledge of chemistry has been applied to all areas of natural science, and chemistry is an important pillar of the powerful force of transforming nature. Chemists use the perspective of chemistry to observe and think about social problems, and use the knowledge of chemistry to analyze and solve social problems, such as energy problems, food problems, environmental problems, health problems, resources and sustainable development problems.

How to memorize chemistry equations in junior high school to memorize as follows:

1. Master the essentials of writing chemical equations.

Write the reactant on the left, write the generation on the right, write the chemical formula, the coefficient to balance, the middle with an equal sign, the condition should be clear, the precipitate gas is generated, and the arrow is indicated.

2. Categorize memory.

According to the knowledge series or reaction type or substance category memory, the scattered knowledge is summarized into a knowledge network with rules to follow and key substances as the center.

3. Linking the memory of experimental phenomena.

Chemical equations are boring and difficult to remember, how to make the learning of chemical terms sound and interesting, and can be linked to the memory of experimental phenomena. For example, sulfur burns in oxygen, memory associations: burning sulfur into oxygen, burning becomes vigorous, the flame is blue and purple, beautiful and beautiful, and produces gas, which is really enough to "choke".

Phosphorus burns in oxygen, memory associations: red phosphorus burns, it can be really lively, thick smoke billows, bright like a "light bulb".

Chemistry is the basic natural science that studies the composition, structure, properties, transformation and application of matter at the atomic and molecular levels. It originates from life and production practices, and continues to evolve with the progress of human society.

Different from particle physics and nuclear physics, which study the smaller scale, the material structure of atoms, molecules, ions (groups), chemical bonds, intermolecular forces and other interactions are studied in chemistry, and the scale in which they are located is the closest to the macroscopic in the microscopic world, so their natural laws are also most closely related to the physical and chemical properties of matter and materials in the macrocosm of human existence.

The way to memorize chemical equations in junior high school is to consolidate the foundation of writing chemical formulas using valency, memorize chemical equations according to experimental phenomena, and memorize them according to common characteristics.

1. Consolidate the foundation of using valency to write chemical formulas.

Chemical formula is an important basis for writing chemical equations, if there is no solid foundation in the teaching process of writing chemical equations using valency, then the more difficult it is for students to learn to write chemical equations in the future, so that the writing of chemical equations for metathesis reactions in the later stage is always difficult to overcome, and it becomes a sandwich meal. Because, using the valency formula, it is particularly important to write the chemical formula correctly with the root valence formula.

2. Memorize chemical equations based on experimental phenomena.

Phosphorus and oxygen reaction, the phenomenon of this experiment is to produce a large amount of white smoke, white smoke is phosphorus pentoxide, students can know that the product of phosphorus and oxygen reaction is a kind of white smoke, and white smoke is phosphorus pentoxide, so that the reactants and products are remembered, in the balancing.

3. Memorize according to common characteristics.

There are three chemical equations for producing oxygen in the laboratory: first remember the chemical formula of the reactants, hydrogen peroxide (H2O2), potassium permanganate (KMNO4), potassium chlorate (KCLO3), the common special of these three chemical equations, are decomposition reactions, reactants are matched with 2, and oxygen is produced.

So from the first one, the catalyst manganese dioxide is added to H2O2 to start the reaction, then H2O2 and H2O look similar, then the first product is water, what does this reaction want to make? O2 is made, so the products are all written, and the reactants have been matched with 2, decomposition reaction, and the back is well balanced.