Shanghai science edition chemistry ninth grade first volume outline
1. Changes and properties of substances
(1) Physical change: there is no change of new substance.
(1) There is no new substance produced macroscopically and no new molecule produced microscopically.
(2) often refers to the change of material state, shape and position.
For example: three-state change of water, volatilization of gasoline, sublimation of dry ice, tables and chairs made of wood, broken glass and so on.
(2) Chemical changes: changes in the formation of new substances, also known as chemical reactions.
(1) Macroscopically produces new substances and microscopically produces new molecules.
② Chemical changes are often accompanied by some reaction phenomena, such as luminescence, fever, gas production, discoloration and precipitation. Sometimes we can judge whether there is a chemical change or what the product is by the reaction phenomenon.
(3) Physical properties: the properties that a substance can exhibit without chemical changes.
(1) Physical properties are not only physical changes of matter; For example, wood has the property of density and does not need to change its shape to express it.
② Physical attributes of sensory perception mainly include color, state and smell.
(3) Physical properties to be measured by instruments include: melting point, boiling point, density, hardness, solubility, conductivity, etc.
(4) Chemical properties: the properties that substances can only show in chemical changes.
For example: metal, nonmetal, oxidation, reduction, acid and alkali, thermal stability, etc.
2. Composition of matter
Atomic group: In many chemical reactions, the atomic group that participates as a whole as if it were an atom.
Ion: charged atom or radical.
Element: A general term for a class of atoms with the same nuclear charge number (i.e. proton number).
3. Classification of substances
(1) mixture and purity
Mixture: There are two or more substances in the composition. Common mixtures are: air, seawater, tap water, soil, coal, oil, natural gas, explosive gas and various solutions.
Purity: There is only one substance in the composition.
(1) there is a composition on the macro level and only one molecule on the micro level;
(2) Pure substances have fixed components and unique chemical properties, which can be expressed by chemical formula;
(3) Purity can be composed of one element (simple substance) or multiple elements (compounds).
(2) Simple substance and compound
Elemental substance: A pure substance consisting of only one element. It can be divided into metallic elements, nonmetallic elements and rare gases.
Compound: A pure substance consisting of two or more elements.
(3) Oxides, acids, bases and salts
Oxide: A compound consisting of two elements, one of which is oxygen.
Oxides can be divided into metal oxides and non-metal oxides; It can also be divided into acid oxides, basic oxides and amphoteric oxides;
Acid: A compound in which all cations ionized in a solution are hydrogen ions. Acids can be divided into strong acids and weak acids; Monobasic acids and polybasic acids; Oxy-acid and anaerobic acid, etc.
Alkali: A compound in which all cations ionized in a solution are hydroxide ions. Alkali can be divided into soluble alkali and insoluble alkali.
Salt: A compound that can ionize metal cations and acidic anions when ionized. Salt can be divided into normal salt, acidic salt and alkaline salt.
4. Chemical terminology
(1) relative atomic mass and molecular mass, molecular-atomic motion theory, arrangement of extranuclear electrons.
(2) the meaning of element symbols
(1) some kind of element.
(2) Atoms of this element.
If a substance is directly composed of atoms, then the elements that make up the substance can also represent this simple substance, such as:, S, P, etc.
(3) Valence: The number of atoms combined with each other of an element determines the valence of this element.
The valence is closely related to the number of electrons in the outermost layer of atoms; In the compound, the algebraic sum of the positive and negative valence of elements is zero; The valence of elements in a simple substance is defined as zero.
(4) Chemical formula: a formula for expressing the composition of matter with element symbols.
(5) Chemical equation: chemical reaction is expressed by chemical formula. Pay attention to writing principle, steps, balance, reaction conditions, and use arrows correctly.
(6) Types of chemical reactions
(7) Law of Conservation of Mass
solution
(1) Definition: A uniform and stable mixture formed by dispersing one or more substances into another.
(2) Composition of solution: solute and solvent. In solution, solution mass = solute mass+solvent mass.
(3) Characteristics: The solution is uniform and stable.
(4) saturated solution and unsaturated solution and their mutual transformation
General rule: saturated solution unsaturated solution
(5) Solubility, factors affecting the solubility of solids, and the application of solubility curve.
Solubility: at a certain temperature, the mass of a solid substance dissolved in 100g solvent is called the solubility of the substance in the solvent.
Factors affecting solid solubility: ① Properties of solute and solvent. Different solutes and solvents have different solubility at the same temperature. ② temperature. The solubility of most solid substances increases with the increase of temperature; The solubility of a few substances (such as sodium chloride) is little affected by temperature; The solubility of a few substances (such as hydrated lime) decreases with the increase of temperature.
Factors affecting gas solubility: ① Temperature: The higher the temperature, the smaller the gas solubility; ② Pressure: The greater the pressure, the greater the gas solubility.
6. Four basic types of chemical reactions: (See the summary at the end of the article for details)
(1) Combination reaction: A reaction in which two or more substances form one substance.
Such as: A+B = AB
(2) Decomposition reaction: a reaction in which one substance generates two or more other substances.
For example: AB = A+B
③ Displacement reaction: a reaction between a simple substance and a compound to produce another simple substance and another compound.
Such as: a+BC = AC+B.
(4) Double decomposition reaction: a reaction in which two compounds exchange components with each other to form two other compounds.
For example: AB+CD = AD+CB.
7. Reduction reaction: the reaction in which the oxygen of oxygen-containing compounds is taken away (not the basic reaction type of chemistry).
Oxidation reaction: chemical reaction between substance and oxygen (not the basic reaction type of chemistry).
Slow oxidation: the oxidation reaction is very slow and even difficult to detect.
Spontaneous combustion: spontaneous combustion caused by slow oxidation.
8. Catalyst: a substance that can change the chemical reaction rate of other substances in the process of chemical change, but its own quality and chemical properties have not changed (one change and two changes) before and after chemical change.
9. Law of Conservation of Mass: The total mass of substances participating in chemical reactions is equal to the total mass of substances generated after the reaction.
Before and after the reaction, the number, species and quality of atoms remain unchanged; Elements are of the same type)
10. solution: one or more substances are dispersed into another substance to form a uniform and stable mixture.
Composition of solution: solvent and solute. (Solute can be solid, liquid or gas; When solids and gases are dissolved in liquids, they are solutes and liquids are solvents. When two liquids are mutually soluble, the solvent is one with more quantity and the solute is one with less quantity; When there is water in the solution, no matter how much water there is, we are used to using water as a solvent and others as solutes. )
1 1. Solid solubility: at a certain temperature, the mass of a solid substance dissolved in 100g solvent is called the solubility of the substance in the solvent.
12. Acid: All cations produced during ionization are hydrogen ions.
For example: HCl==H++Cl-
Nitric acid ==H++nitric acid-
H2SO4==2H+ + SO42-
Alkali: A compound in which all anions produced during ionization are hydroxyl ions.
For example: KOH==K++OH-
NaOH==Na+ + OH-
Ba(OH)2==Ba2+ + 2OH-
Salt: A compound that produces metal ions (ammonium ions) and acid ions when ionized.
For example, KNO3==K++NO3-
Na2SO4==2Na+ + SO42-
BaCl2==Ba2+ + 2Cl-
13. acidic oxide (not necessarily nonmetallic oxide, such as manganese oxide): any oxide that can react with alkali to form salt and water.
Basic oxide (metal oxide): Any oxide that can react with acid to form salt and water.
14. Crystal water: a substance containing crystal water, such as Na2CO3? 10H2O、CuSO4？ 5H2O FeSO4？ 7H2O
27. deliquescence: the phenomenon that substances can absorb moisture in the air and become damp.
Weathering: The phenomenon that crystal hydrate can gradually lose crystal water and become powder when placed in dry air at normal temperature.
15. Combustion: the violent oxidation reaction between combustible substances and oxygen gives off light and heat.
Combustion conditions: ① combustible; ② Oxygen (or air); (3) The temperature of combustible materials should reach the ignition point.
Chemistry learning method
1, except for students' own inquiry experiments, you don't have to preview, but you must review after class every day to remember the knowledge points you learned that day clearly; Review once a week to summarize and review the concepts, theories, experimental methods and requirements, phenomena and matters needing attention learned this week. Because there are many things in chemistry, we hardly have this concept in our daily life, and even if there is, there is a great deviation in understanding. Therefore, only through continuous review can these concepts be deeply imprinted in our minds.
2. Memorizing chemical formulas and chemical equations requires chemical methods. Some of our classmates have been learning English since kindergarten, at least from scratch. They have formed the habit of spelling English words since childhood. However, when exposed to chemical formulas and chemical equations, some students can't help remembering English words, which leads to memory difficulties. Chemical formulas and chemical equations should be remembered by chemical methods, that is, chemical formulas and chemical equations should be remembered by names. For example, remembering ammonium bicarbonate (NH4HCO3) seems a bit complicated, but it is not difficult to remember it chemically. Read from the back to the front, and write from the front to the back: ammonium (+1 valence) hydrogen (+1 valence) carbonate (-2 valence), and judge that the algebraic sum of positive and negative valence is 0, so as long as you remember the symbols of elements, atomic groups and their valence in the compound, you can write its chemical formula according to the name of the substance. The same is true of chemical equations. On the basis of chemical formula, we should understand the characteristics of reaction and master the reactants, products and reaction conditions, so that we can write them out according to the names of substances and then balance them. For example, dropping sodium hydroxide solution into the chemical equation of copper sulfate solution, as long as you remember that copper sulfate reacts with sodium hydroxide to generate sodium sulfate and copper hydroxide precipitate, and then write the chemical formula according to the name of the substance, the final balance will be much simpler.
3, the basic operation method of chemical experiment should be mastered, and the main points and precautions should be clearly remembered; We should understand the method and principle of gas distribution in the laboratory, the selection of instruments, the acquisition method and the consequences caused by misoperation; Inquiry experiments should be designed with instruments, drugs and operating procedures, not as experimental principles. Due to the limitation of experimental conditions, it is impossible for us to repeat all the experiments. Therefore, the experimental reports that have been made should be reviewed as review materials before the exam.
What should we pay attention to when studying chemistry?
Review frequently and remember more.
After class, you should review in time and do your homework carefully, which is an important link to learn chemistry well. Review can be done after class, after week, unit review, chapter review and comprehensive review. Review methods include retelling, dictation, contact, etc. Only by reviewing many times can we firmly grasp the knowledge. There are many basic concepts and principles in the current junior high school chemistry textbooks, which require more than 20 element symbols, as well as a lot of knowledge such as chemical formulas and equations. These contents need to be memorized on the basis of understanding. Most of them are the basis of learning chemistry. If you can't remember them, it will be difficult for you to walk in the "chemical kingdom".
We should keep in mind all kinds of terms and definitions of chemistry and distinguish them carefully, such as compounds, pure substances, simple substances, mixtures and so on. We should not only remember their definitions, but also distinguish and compare them. We should deduce the words in the definition and find out who includes who. Once you really find out, then I ask you what milk is on it, and you don't have to think about it for a long time. Common chemical reactions must be kept in mind, conditions (heating, light, catalyst, arrows? Both reversible and irreversible need to be paid attention to, needless to say, the phenomenon of the reaction process, and important things should be remembered. Formulas in chemistry should be understood as mathematical formulas. Remember to be comprehensive and flexible, pay attention to flexibility? Don't be a nerd. I don't like nerds either, okay? .
Read through the textbook and connect with reality.
Taking textbooks as the main line, carefully understanding textbooks is the basis of learning chemistry well. To this end, students must be good at reading textbooks, so as to preview before class, read carefully after class, read diligently and so on. Pay attention to the main content, ignore the small print, some charts, materials and selected content. The content of middle school chemistry is closely related to life and production. This requires us to learn chemistry, at the same time, we should try our best to contact with the reality of production and life, discover chemistry from the life around us, and appreciate chemistry, so that the more we learn, the more interested we are, and the more we want to learn, the more we love learning.
Attach importance to experiments and cultivate interest.
Chemistry is a subject based on experiments. We should carefully observe the teacher's demonstration experiments and do well in each group experiment. Be sure to make clear and memorize the instruments, drugs, devices, experimental principles, steps, phenomena and precautions used in the experiment.
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