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Anonymous users2024-02-12Basically, since it is written in a book, it is required to be mastered, and there are a large number of equations for acids, alkalis, metals, and carbon.
Personally, I think that if the teacher tries to listen and follow the teacher in class, it will be very good to achieve at least 75% of the class absorption rate, if not 100%, but it is absolutely not wrong to memorize the equation in advance. An equation in the college entrance examination will account for a lot of points, some calculations involving equations, if you don't know the equation, then it's blind, no matter how familiar you are with it, it won't hurt, so it's okay to memorize the equation if you preview something.
Memorize according to chapter classification, special key points, such as what needs to be ignited, what needs to be heated, what needs catalyst, and there is a very simple, through experiments, remembering that an experiment is often relatively simple and the amount of information obtained is much greater than simply memorizing the formula. If you have the conditions to do your own experiments, if you don't have the conditions, you can search on the Internet, or you can ask your own teachers, there are some teachers who have this aspect, so you don't have to find them yourself.
There are also some similar ones to memorize together, and those magic mantras are to be memorized and very useful.
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Anonymous users2024-02-11In order of importance: Unit 6 Unit 8 Unit 9 Unit 10 Unit 11 Salt.
It is advisable to read through the entire book first.
Key points (important knowledge): element symbols, molecular formulas (chemical formulas), equations, molecular weight calculations, valency, these can be copied several times.
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Anonymous users2024-02-10To understand the concepts of molecular atoms and element valency to memorize, grasp the preparation of oxygen in the previous volume, and the property device diagram is more than half.
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Anonymous users2024-02-09Back equations and elements, symbols, masses, etc.
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Anonymous users2024-02-08The first volume is very simple, mainly in the following aspects: the composition of air (the concept of mixtures and pure substances), oxygen, carbon dioxide, water, inclusion (composition, use and preparation method), the mystery of the composition of matter (molecules, atoms, ions and the transformation relationship between them), the conditions of combustion, the method of extinguishing fires. and principle.
The nature of the metal, the use of limestone (Yu Qian's lime moan can be summarized).
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Anonymous users2024-02-07The water is evaporated into water vapor, and the magenta molecules are in a never-ending irregular movement (1) mass and volume.
2) Open the cap of the vinegar or alcohol bottle and smell the smell later. A drop of red ink is dropped into the water, the ink spreads, and the whole glass of water turns red.
3) There is a gap between fast molecules.
They are small in size and mass; Both molecules and atoms are in constant motion; There are gaps between molecules and atoms.
Elite Education Teacher He.
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Anonymous users2024-02-06（1）1 (2) (3)2 (4)4 (5)5
The cations that can be ionized by acid are all hydrogen ions.
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Anonymous users2024-02-05It should be clear that the root cause is that acids contain hydrogen ions.
You have to endorse the precipitation after the first.
Acid-base salts Properties of acids: >>>More
It's not difficult, as long as you read more books, use your brain more, and do more exercises. There are not many chemical equations involved in the ninth grade chemistry book, and the exams mainly focus on oxygen, hydrogen, carbon dioxide, acids, alkalis, and salts. If you are willing to work hard, your foundation will be strengthened here, and you will be able to understand it by yourself in high school. >>>More
1. Common elemental substances.
Hydrogen, H2, Nitrogen, N2, Chlorine, Cl2, Oxygen, O2, Ozone, O3, Helium, He >>>More
According to "take the filter residue gram in step 1, add a sufficient amount of dilute sulfuric acid to fully react with the filter residue, filter, wash and dry to obtain solid grams", it can be seen that the solid gram is activated carbon that does not react with dilute sulfuric acid, then: (1) the total mass of iron and ferric oxide in the gram of filter residue is; >>>More
Answer: This title is a block diagram material inference problem, the key to complete this kind of problem is to find the breakthrough point of the solution, according to the key to the narrative, as well as the nature of the substance and the reaction between the substance, make a judgment, A is the main component of magnetite, then A is ferric oxide, B and D are gases, then B may be carbon monoxide, D may be carbon dioxide, the generated C is iron, J is a green powdery solid, then J may be basic copper carbonate, and the heat energy decomposes to produce water, copper oxide and carbon dioxide, F is a red solid element, heating can generate I, then F may be copper, I may be copper oxide, H may be water, E can generate water by ignition, then E may be hydrochloric acid, reagent A may be hydrochloric acid, iron can react with reagent B to form copper, then B may be copper sulfate, G is a white solid insoluble in water, then G may be calcium carbonate, carbon dioxide can react with C to form calcium carbonate, then C may be calcium hydroxide, substitute into the block diagram, reasonable inference Answer: Solution: >>>More