Chemistry chapter 1 opens the door to chemistry
What does chemistry bring us? 〗
4. Understanding: Explore the experimental principle of oxygen consumption of rust.
5. Understanding: To verify the experimental method of generating sulfur dioxide by burning sulfur-containing matches.
[What is chemistry in the second quarter? 〗
7. Know that the object of chemical research is the nature, change, composition, structure, use and preparation of substances.
9. Understanding: the decisive relationship between nature, change, composition, structure, use and preparation method.
10. research institute: analyze the physical and chemical changes during candle burning.
1 1. research institute: experimental method to explore whether flour and other organic substances contain carbon (combustion)
12. Learn to judge the properties of common changes.
13. research institute: describe the common physical and chemical properties of substances.
15. research institute: can give examples to illustrate the absorption or release of energy in the process of chemical change.
[How to study and study chemistry in the third quarter? 〗
16. Understanding: physical properties, constituent elements, and two chemical properties of patina and zinc (can be integrated).
17. Understanding: Physical and chemical properties of magnesium tape.
18. research institute: general methods and steps to explore the essence of matter.
Chapter 2 Things around us
[Section 1 Air composed of various substances]
25. Learning: the experimental method of capturing air.
26. Remember: the volume fractions of nitrogen, oxygen and carbon dioxide in the air.
27. Understanding: Explore the experimental principle of oxygen content in the air.
28. Learn to distinguish between mixtures and pure substances (ordinary substances).
3 1. Research Institute: Have a comprehensive understanding of air self-purification ability, air pollution status and air pollution prevention measures, and can make simple comments.
[Active Oxygen in the Second Section]
32. Remember: the existence, natural significance and common physical properties of oxygen (specific data do not need to be memorized).
33. Understand the phenomena and products of common substances burning in air and oxygen. . Learn to check the existence and collection of oxygen.
34. Understand the basic meaning of oxidation reaction and slow oxidation, and distinguish combustible and combustion-supporting concepts.
35. Understand: The main purpose of oxygen.
37. Master: the experimental principle, process and matters needing attention of making oxygen with potassium permanganate, hydrogen peroxide and manganese dioxide. Understand the role of catalysts (don't discriminate and explore this concept).
[wonderful carbon dioxide in the third season]
4 1. Master the concepts of combination reaction and decomposition reaction, and skillfully use them.
42. Understanding: the principle of carbon dioxide fire fighting.
43. Master: the principle and specific experimental methods of preparing carbon dioxide in the laboratory.
[Section 4 Water in Nature]
48. Research Institute: Test methods of hydrogen combustion products.
49. Learning: Learn two basic operations: evaporation and filtration.
50. Know: the concept of hard water and its harm.
5 1. Understanding: Identification methods of natural water and pure water, soft water and hard water.
52. Understanding: social issues such as water resources protection, comprehensive utilization and development of water resources, and water conservation. And can be briefly described.
Chapter 3 The Mystery of Material Composition
[The first part looks at matter from the perspective of particles]
53. Understanding: Establish basic viewpoints such as "matter is composed of particles", "particles are constantly moving", "there are gaps between particles" and "in gas, the distance between particles is greater than the distance between solid and liquid".
54. Learn to explore the experimental methods of the above viewpoints.
[Section 2: Basic Particles Constituting Matter]
55. Understanding: Molecules, atoms and ions are three important particles that make up matter. Can distinguish the constituent particles of common substances (for ions, only need to know that NaCl, CaCl2 and CaCO3 are composed of ions; For atoms, it is only necessary to know that simple metals, diamond, silicon dioxide and silicon are all directly composed of atoms. Will use the concepts of molecules, atoms and ions to describe the composition of matter.
56. It is understood that different substances have different properties, because the particles that make up different substances are different.
57. Understand the changing process of substances composed of molecules in chemical changes, and then understand the basic principle that atoms are the smallest particles in chemical changes, atoms are inseparable in chemical changes, and molecules are composed of atoms.
58. Understanding: Basic particles such as molecules, atoms and ions actually exist and are very tiny.
59. Understanding: the process of exploring the internal structure of atoms. Know two scientists who have made important contributions and their famous experiments.
60. Understanding: the composition of atoms (only the energy levels of nuclei and electrons, but no protons and neutrons), the charging situation and the mass distribution.
6 1. Understand the definitions of relative atomic mass and relative molecular mass, and master relevant calculations.
62. Know that ions and atoms are transformed into each other through gain and loss electrons, and pay attention to the relationship between the number of charges and the number of gain and loss electrons.
63. Learn how to write ion symbols.
[Section III Chemical Elements of Substances]
64. Understanding: the concept of elements.
65. Learn to write element symbols of common elements. Will use the concept of elements to describe the composition of matter. Understand the two representative meanings of element symbols.
66. Understanding: We can understand the concepts of mixture, pure substance, simple substance, compound and oxide from the level of molecular atomic elements. And can distinguish common substances.
67. Remember that the top five elements in the earth's crust are O, Si, Al, Fe and Ca. The first two elements in the ocean, the human body and the sun: O and H. The most abundant element in the core is iron.
Understanding: A large number of "essential elements" in human body: O, C, H, N, Ca, P, S, K and "trace elements": Fe, Cu, Mn, Zn, Co, i. And understanding the lack of calcium, Zn, I and Se and the excess of Ga and Se.
[Section 4 Representation of Material Composition]
70. Master: Write the chemical formulas of common substances.
7 1. Institute: Through chemical formula, judge the category of substances, calculate the mass ratio of constituent elements, judge the molecular composition, and calculate the valence and relative atomic mass of unknown elements.
72. Remember: the valence of common elements and atomic groups.
73. Learning: Simple methods, skills and principles of writing chemical formulas according to valence and calculating valence according to chemical formulas. There is no requirement for the calculation of chemical formulas containing letters instead of element symbols and unknowns.
75. Learn to solve the calculation problem of simple mixture composition analysis according to chemical formula. And can comprehensively use basic calculation skills such as intermediate quantity to make simple calculations and judgments. There is no need for chemical formula calculation of unknown letters, calculation of more than two impurities and pure technical calculation. Focus on the ability to solve practical problems.
Chapter 4 Burning Fuel
[Section 1 Burning and extinguishing]
76. Understanding: Fire is a phenomenon. Combustion is a violent chemical reaction that gives off light and heat. Know that combustion must emit light and heat, and oxygen is not necessary. However, the junior high school stage did not deliberately examine whether there was oxygen participation.
77. Understanding: Three conditions of combustion. And it will be used to explain some related phenomena in life.
78. Understanding: Understand the conditions under which hydrocarbons will burn completely or incompletely, and know the differences in combustion products, combustion speed and heat release under the two conditions. Understand the negative effects of incomplete combustion.
79. Understanding: The mechanism of carbon monoxide poisoning on human body. Understand the main production methods of carbon monoxide, and have the awareness of preventing air pollution.
80. Understand: the conditions of explosion formation and the influencing factors of combustible combustion intensity. Understand the precautions for storage, transportation and use of common inflammable and explosive articles, and be familiar with relevant signs.
8 1. Understanding: conditions for explosion of combustible gas or dust. Understand the concept of explosion limit. Understand the common factors of detonation (open flame, electric spark, high temperature, impact, etc.). ).
82. Understanding: Basic principles and common methods of fire fighting.
83. Learn how to deal with common fires. When trapped in a fire zone, you can know how to distinguish different situations.
84. Understanding: Common fire extinguishing equipment, its usage and application scope (mainly referring to the application scope of foam extinguisher and liquid carbon dioxide fire extinguishers).
[Section 2 Quantitative Understanding of Chemical Changes]
85. Understand the connotation of the law of conservation of mass, and know how to explain the reasons of conservation from the microscopic point of view of particles. Understand the basic principle of determining the composition of material elements through experiments (such as electrolytic water and organic matter combustion). ).
86. Understand the basic principle of writing chemical equations and learn how to calculate the chemical formula of unknown objects according to the principle of conservation of mass.
87. Learn to skillfully write chemical equations of common chemical changes.
The whole book should master the equation * * *:
I. Reaction of substances with oxygen:
(1) the reaction of simple substance with oxygen;
1. Magnesium burns in air: 2Mg+O2 ignites 2MgO.
2. Iron burns in oxygen: 3Fe+2O2 ignites Fe3O4.
3. Aluminum burns in air: 4Al+3O2 ignites 2Al2O3.
4. Copper heating in air: 2Cu+O2 heating 2CuO.
5. Combustion in hydrogen and air: 2H2+O2 ignites 2H2O.
6. Red phosphorus burns in air: 4P+5O2 ignites 2P2O5.
7. Sulfur powder burns in air: S+O2 ignites SO2.
8. Complete combustion of carbon in oxygen: C+O2 ignites CO2.
9. Incomplete combustion of carbon in oxygen: 2C+O2 ignites 2CO.
(2) the reaction of compounds with oxygen:
10. Carbon monoxide burns in oxygen: 2CO+O2 ignites 2CO2.
1 1. Methane burns in air: CH4+2O2 ignites CO2+2H2O.
12. The reaction between sulfur dioxide and oxygen: 2SO2+O2 dust 2SO3.
2. Several decomposition reactions:
13. Decomposition of water under direct current: 2H2O charged 2H2 =+O2 =
14. Heating ammonium bicarbonate: NH4CO3 = = = = NH3 =+H2O+CO2 =
15. heating potassium permanganate: 2KMnO4 heating k2mno4+MnO2+O2 =
16. Hydrogen peroxide and manganese dioxide generate oxygen: 2h2o 2mno22h2o+O2 =
17. Carbonic acid is unstable and decomposed: H2CO3 === H2O+CO2↑ =
18. high temperature calcined limestone: CaCO3, high temperature CaO+CO2↑ =
3. Breathing and photosynthesis:
19. respiration: c6h12o6+6o2 = = 6co2+6o2.
20. Photosynthesis: 6CO2+6H2O Photochlorophyll C6H 12O6+6O2.
Four. redox
2 1. Carbon monoxide reduces iron oxide: 3CO+ Fe2O3 heats 2Fe+3CO2.
5. Relationship among simple substance, oxide, acid, alkali and salt
(1) elemental metal+acid salt+hydrogen (displacement reaction)
22. Reaction of zinc with dilute sulfuric acid: Zn+Zn+H2SO4 === ZnSO4+H2↑ =
23. Reaction of iron with dilute sulfuric acid: Fe+Fe+H2SO4 === FeSO4+H2↑ =
24. Reaction of magnesium with dilute sulfuric acid: mg+Mg+H2SO4 === MgSO4+H2↑ =
25. Reaction of aluminum with dilute sulfuric acid: 2al+3H2SO4 = = Al2 (SO4) 3+3H2 =
26. the reaction of zinc with dilute hydrochloric acid: Zn+Zn+2HCl === ZnCl2+H2↑ =
27. Reaction of iron with dilute hydrochloric acid: Fe+2 HCl = = FeCl 2+H2 =
28. the reaction of magnesium with dilute hydrochloric acid: mg Mg+ 2HCl === MgCl2+H2↑ =
29. the reaction of aluminum with dilute hydrochloric acid: 2al+6hcl = = 2alcl3+3h2 =
(and this reaction has the same law as ordinary matter. )
(2) Simple metal+salt (solution)-another metal+another salt
30. The reaction between iron and copper sulfate solution: Fe+CuSO4 = = FeSO4+Cu.
3 1. The reaction between zinc and copper sulfate solution: Zn+CuSO4 = = ZnSO4+Cu.
(and this reaction has the same law as ordinary matter. )
(3) metal oxide+acid salt+water
32. The reaction of iron oxide with dilute hydrochloric acid: Fe2O3+6HCl === 2FeCl3+3H2O+3H2O.
33. Reaction of iron oxide with dilute sulfuric acid: Fe2O3+3H2SO4 = = Fe2 (SO4) 3+3H2O+3H2O.
(and this reaction has the same law as ordinary matter. )
(4) nonmetallic oxide+alkali salt+water
34. Caustic sodium will deteriorate when exposed to air: 2NaOH+CO2 ==== Na2CO3+H2O.
35. The slaked lime deteriorates in the air: Ca (OH) 2+CO2 = = = CaCO3 ↓+H2O+H2O.
(5) acid+alkali-salt+water
36. Reaction of hydrochloric acid with caustic soda: HCl+NaOH = = = NaCl+H2O.
37. Reaction of hydrochloric acid and potassium hydroxide: HCl+KOH = = = KCl+H2O.
38. The reaction between hydrochloric acid and copper hydroxide: 2hcl+Cu (OH) 2 = = cucl2+2h2o.
39. The reaction between hydrochloric acid and calcium hydroxide: 2 HCl+Ca (OH) 2 = = CaCl2+2H2O.
40. Aluminum hydroxide for the treatment of hyperacidity: 3HCl+Al (OH) 3 = = = AlCl3+3H2O.
4 1. Reaction of sulfuric acid and caustic soda: H2SO4+2NaOH = = = Na2SO4+2H2O.
42. The reaction between sulfuric acid and potassium hydroxide: H2SO4+2koh = = = K2SO4+2h2o.
43. The reaction between sulfuric acid and copper hydroxide: H2SO4+Cu (OH) 2 = = CuSO4+2H2O.
44. The reaction between nitric acid and caustic soda: nitric acid+sodium hydroxide = = = sodium nitrite+H2O H2O.
45. Ammonia and sulfuric acid: 2NH3? H2O+H2SO4 = = = = (NH4) 2SO4+2H2O
(and this reaction has the same law as ordinary matter. )
(6) acid+salt-another acid+another salt
46. marble reacts with dilute hydrochloric acid: CaCO3+2hcl = = CaCl2+H2O+CO2 =
47. Sodium carbonate reacts with dilute hydrochloric acid: Na2CO3+2HCl = = 2NaCl+H2O+CO2 =
48. The reaction of sulfuric acid and sodium carbonate: Na2CO3+H2SO4 = = Na2SO4+H2O+CO2 =
(and other similar reactions of acids with carbonates. )
(7) alkali+salt-another alkali+another salt
49. Sodium hydroxide and copper sulfate: 2 NaOH+CuSO4 = = Cu (OH) 2 ↓+Na2SO4.
50. Calcium hydroxide and copper sulfate: Ca (OH) Ca (OH) 2+CuSO4 = = = Cu (OH) 2 ↓+CaSO4.
Verb (short for verb) Other reactions:
5 1. Carbon dioxide is soluble in water: CO2+H2O === H2CO3.
52. Sulfur dioxide is soluble in water: SO2+H2O = = = H2SO4.
53. Sulfur trioxide is soluble in water: SO3+H2O = = = H2SO4.
54. Quicklime is soluble in water: CaO+H2O === Ca(OH)2.
88. Mastery: Mastering the basic methods and skills of writing chemical equations. Will write the equation of strange reaction based on the information provided.
89. Understanding: Basic principles of calculation based on chemical equations. Knowing is essentially the same as chemical formula calculation.
90. Mastery: Calculate the particle number ratio and mass ratio of each substance according to the chemical equation. And master the calculation according to a chemical equation. Pay attention to the specification of calculation format. The calculation difficulty is controlled within the range of moderate difficulty, and the skills are not overemphasized, but the application is emphasized.
[Section III Utilization of Fossil Fuel]
9 1. You know, coal, oil and natural gas are the three most important fossil fuels in the world today. Among them, coal is called "industrial food" and oil is called "industrial blood".
92. It is understood that China was the first country to use coal and exploit oil and gas, but China's fossil fuel resources are unevenly distributed. Understand the significance of "West-East Gas Transmission".
93. Know: the main components and elements of coal, oil and natural gas.
94. Understanding: Pollution caused by burning fossil fuels: greenhouse effect, thermal pollution and air pollution. It is known that fossil fuels generally contain sulfur, which will produce SO2, CO and dust after combustion.
95. Understanding: Basic principles of coal and oil processing and refining. Understand the non-renewable nature of fossil fuels and the significance of comprehensive utilization of fossil fuels.
Chapter V Metals and Minerals
[Section 1 Metals and Metal Minerals]
96. Understand: Some physical properties that metals usually have. Can distinguish between ordinary metals and nonmetals; Understand the important role of metal materials in production and life. Understand the use of metals, the relationship between their existing forms and their properties.
97. Know: the common reaction of metal with oxygen and acid solution, the reaction of iron with copper sulfate and the concept of displacement reaction.
Understand:
ironstone
Copper mine
Aluminium ore
[Section II Ferroalloy Smelting]
100. Remember: ironmaking equipment and raw materials; Carbon content of pig iron and steel.
10 1。 Know: the main elements of bronze, stainless steel and Wude alloy, and the relationship between the composition and physical and chemical properties of the alloy.
103. Know: Calculation of chemical equations containing impurities. The change in one step is mainly based on the calculation of actual production.
[Section III Protection and Recovery of Metals]
104. Understand the principle of metal corrosion, especially the principle and influencing factors of iron products corrosion, and learn to explore the conditions of metal corrosion by using the control variable method.
105. Know: the main component of rust (Fe2O3), the method of rust removal and the general method of preventing metal rust.
106. Know the pollution of scrap metal to the environment, know the importance of recycling metal, and improve the awareness of resources and environmental protection.
[Section 4 Utilization of Limestone]
107. Understanding: Main uses of limestone. Know the common substances containing calcium carbonate.
108. research institute: carbonate inspection. Know the composition of "plant ash" and "ammonium bicarbonate".
109. Understand the mutual transformation among CaCO3, CaO and Ca(OH)2, and master the relevant chemical equations. And can be associated with production and life. As we all know, quicklime can be used as a desiccant, which releases heat after dissolution.
the second part
Chapter VI Dissolution Phenomenon
[Section 1 Dissolution of Substances]
1 10. Understanding: Understand the dissolution phenomenon and the common suspensions and emulsions.
1 1 1. Understanding: The solution is a homogeneous and stable mixture. Understand the important role of solution in production, life and scientific research experiments.
1 12. Learn about emulsifying phenomenon.
1 13. Understanding: Energy changes accompanying the dissolution process. Familiar with the phenomenon of ammonium nitrate absorbing heat and sodium hydroxide releasing heat, and understand its application in the laboratory.
1 14. Understanding: Understand the changes of freezing point, boiling point and conductivity of common substances after they are dissolved in water, and know their applications in life. Understand the reason why the solution conducts electricity (ionization produces free-moving ions).
[Expression of Solution Composition in Part 2]
1 15. Learn to distinguish between "solute" and "solvent" in common solutions.
1 16. Understanding: Understand the definition of solute mass fraction and the mass relationship among solution, solvent and solute.
1 17. research institute: learn the preparation method and related calculation of a solute mass fraction solution (only one solute), and be familiar with experimental steps, instruments, precautions, conversion of mass and volume, and strict writing format. Can read the literal meaning of reagent bottle label. Distinguish different preparation methods when solute is liquid or solid.
[Section III Solubility of Substances]
1 18. I know that medical physiological saline is 0.9% sodium chloride solution; Learn to explore the factors affecting the solubility of substances by controlling variables.
1 19. Yes, alcohol, gasoline, chloroform, benzene and banana oil are commonly used organic solvents.
120. Understanding: the concepts of saturated solution and unsaturated solution. Familiar with the mutual transformation methods of saturated and unsaturated solutions of common solutes.
12 1. Understand the meaning of solubility. Learn to check the solubility or solubility of related substances with solubility table or solubility curve; Draw a solubility curve according to the given data.
122. Understand the relationship between gas solubility and temperature and pressure (it is not required to master the concept of gas solubility).
123. Understand the concept of crystallization.
124. research institute: common methods of solute crystallization (evaporation, cooling, etc. ). It will be used flexibly in solving the problems of separation and purification.
Chapter VII Widely Used Acids, Alkalis and Salts
[Section 1 Acidity and Alkalinity of Solution]
125. Know: What is an acidic solution and what is an alkaline solution; Can tell the acidity and alkalinity of common substances in life (soda ash, soapy water, lime water, ammonia water, salt water, sucrose water, vinegar, gastric juice, etc.). ); Acid-base indicator, litmus test paper and pH test paper will be used to test the pH of the solution.
126. Understanding: the expression method of solution pH value. Learn the correct use of pH test paper. Understand the commonly used materials or instruments for measuring pH value (pH test paper, precision pH test paper, pH meter).
127. Know: the influence of pH on life activities and crop growth. As we all know, most crops are suitable for growing in neutral soil. If the rain is slightly acidic and too acidic, acid rain will do great harm to the environment. (No need to memorize specific data).
[Common Acids and Bases in the Second Section]
128. Understanding: the connection and difference between "acid" and "acid", and the connection and difference between "alkali" and "alkali".
129. Learn how to smell chemical reagents.
130. Understanding: Chemical properties of common acids: react with active metals to generate salts and hydrogen; React with metal oxide to generate salt and water; React with carbonate to form salt, water and carbon dioxide. And can understand other similar reactions.
13 1. It is known that H+ contained in acidic solutions makes them have the above commonalities.
132. Remember: two common names of calcium hydroxide, color, state and solubility; The smell of ammonia (ammonia solution); Type of ammonia water (also alkaline solution); Three common names of sodium hydroxide: color, state, water absorption (deliquescence), exothermic solubility and solubility.
133. understanding: sodium hydroxide, calcium hydroxide, potassium hydroxide aqueous solution and ammonia water have the following properties: they react with acid-base indicators; React with CO2; React with copper sulfate to form alkali and salt. And you can learn about other similar reactions you may have and make a simple migration.
134. Know: OH contained in alkaline solution makes them have the above commonalities.
135. Understanding: the definition of metathesis reaction. Can distinguish the basic types of common chemical reactions, and know the constant valence of various elements before and after the double decomposition reaction.
[Section III Reaction of Acid and Alkali]
136. Understanding: the definition of neutralization reaction.
137. Understand the changes of solution temperature and acidity during acid-base neutralization reaction and the role of acid-base indicator in the experiment. Some phenomena in production and life can be explained by the principle of acid-base neutralization.
139. Remember: the solubility of some acid and alkali salts: potassium salt, sodium salt, ammonium salt and nitrate are all soluble; Carbonate and phosphate are mostly insoluble; Calcium carbonate, barium carbonate (white), barium sulfate (white), silver chloride (white) and copper hydroxide (blue) are insoluble; Calcium hydroxide and calcium sulfate are slightly soluble; The colors of copper ion, iron ion and ferrous ion solutions are blue, yellow and light green respectively, and potassium permanganate solution is purplish red.
14 1. Understanding: the metal activity sequence of common metal elements. Based on this, we can judge whether there is a displacement reaction between metal and acid, and whether there is a displacement reaction between metal and salt, understand the relationship between reaction speed and metal activity, analyze the relationship between quality change in such problems, and read the function images of related problems. (The reaction of potassium, calcium and sodium with water, and the strong oxidation of nitric acid and concentrated sulfuric acid are not included in the investigation. )
142. research institute: design a simple experiment to judge the activity sequence of three metal elements.
[Section 4 Application of Acid, Alkali and Salt]
143. I know that "three acids and two alkalis" in industry refer to sulfuric acid, hydrochloric acid, nitric acid, caustic soda and soda ash. I know that Hou has made great contributions to the manufacture of pure alkali.
144. Understanding: Main and typical uses of common acid and alkali salts (see Table 7-6 in the textbook)
145. Yes, seawater is rich in salt and can be used to make salt.
146. understanding: common fertilizers are divided into nitrogen fertilizer, phosphorus fertilizer, potassium fertilizer and compound fertilizer, which can be classified according to chemical formula by examples respectively.
148. Learn the inspection method of ammonia and master the inspection method of ammonium nitrogen fertilizer.
149. learning: the method of concentrated sulfuric acid dilution, knowing the characteristics of concentrated sulfuric acid, such as heat release after dissolution, higher density than water, strong corrosiveness, and knowing the consequences of illegal operation.
15 1. Institute: I can use what I have learned to make general identification, separation, qualitative determination (SO _ 4- and Cl- as the necessary knowledge for students) and simple experimental treatment such as quantitative determination.
Summary of junior high school chemistry practice experience
1. Names, shapes and main uses of commonly used instruments.
2. The basic operation of chemical experiment
(1) Access and weighing of drugs
(2) heating the substance
(3) Basic operations such as dissolution, filtration and evaporation.
(4) Instrument connection and device air tightness inspection
(5) Cleaning of instruments
(6) preparing a solution with a certain mass fraction
3. Laboratory preparation and collection of common gases
(1) Preparation of Three Gases (H2, Oxygen and Carbon Dioxide)
(2) Collection methods of three gases
4. Inspection and identification of substances
(1) Inspection and identification of common gases
(2) Identification of two acids, two bases and salts.
5. Basic chemistry experiment synthesis
The key to mastering these knowledge points is to do the following aspects well.
(1) Chemistry experiment is about hands-on, entering the chemistry laboratory and participating in all activities of chemistry practice. In the laboratory, we should observe all kinds of experimental instruments, experimental supplies, experimental drug reagents, various drugs and their status, smell, color, name and precautions. We should also observe various complete sets of experimental devices. Under the guidance of teachers, we should also do various required experiments, and observe and remember them purposefully during the experiment. For example: ① name, shape, characteristics, main uses, how to use it correctly and matters needing attention when using it. (2) No matter what the content of the experiment is, it is inseparable from the basic operation of the chemical experiment. Therefore, it is necessary to master the basic operation of various chemical experiments, clarify the operation methods and matters needing attention, and achieve proficiency. ③ Attention should also be paid to observing various experimental phenomena, which is the first step to cultivate the ability of observing, thinking and analyzing problems. This will be explained in further detail below. (4) Start taking notes, because there is a lot of perceptual knowledge in the experimental activities, and if you don't take notes, you may be forgotten or omitted. This is not conducive to the analysis and judgment of experiments.
(2) How to observe well
Observation ability is one of the abilities that students should have, and observation is the most direct means to obtain perceptual knowledge. Learning to observe things is a basic quality, which will benefit both now and in the future. Especially for the phenomena in chemical experiments, it is required to learn to observe, and to observe comprehensively, accurately, with emphasis and thought.
① Comprehensive observation of experimental phenomena. Generally, it should include the color and state of reactants, the color and state of products, the changes of light, flame, sound, color, heat release, precipitation, odor and the severity of the reaction during the reaction. For example, when copper wire is inserted into mercury nitrate solution, the observed phenomenon should include two aspects. One is that the surface of copper wire gradually changes from red to silvery white, and the other is that the solution gradually changes from colorless to blue. However, many students only observed that the copper wire turned silvery white and ignored the color change of the solution, which was not comprehensive. The further analysis of the reaction properties is not profound, and it does not mean that there is a blue solution of copper nitrate in the product.
② Accurately describe the observed phenomenon. Pay attention to the difference between "light" and "flame" and the difference between "smoke" and "fog". Generally speaking, gaseous substances burn with flame, while solid substances burn without flame and glow. For example, the combustion of hydrogen, methane and carbon monoxide is light blue flame and blue flame respectively. Although sulfur is solid, it melts first and then volatilizes into sulfur vapor when burning, so its combustion flame is faint light blue in air and bright blue-purple in oxygen. Solid substances, such as charcoal, iron wire, magnesium tape, etc. , burning respectively, emitting white light, sparks and dazzling light.
When water droplets are scattered in the air, fog is formed. For example, hydrogen chloride gas volatilized from concentrated hydrochloric acid combines with water vapor to form hydrochloric acid droplets, which form acid mist in the air. "Smoke" refers to small solid particles dispersed in the air. For example, red phosphorus burns in the air to form a large number of thick "white smoke", which is made up of small white solid particles of phosphorus pentoxide.
③ The observation of experimental phenomena should be comprehensive and focused. The phenomena of chemical experiments are rich and varied, some are very prominent and obvious, some are fleeting, and some are hidden and difficult to detect. Pay attention to the phenomenon that the nature of the reaction changes when observing. How can we grasp the phenomenon of reaction essence? Therefore, before the experiment, we should carefully study the purpose and process of the experiment and determine the focus of observing the phenomenon. For example, when verifying the essential difference between chemical change and physical change by experiments, it is important to observe whether the substance has changed and whether there is a new substance different from the original substance. If the magnesium strip is cut short, it means that it is only a physical change and no new substance is generated. Still maintains a silver metallic luster and is elastic. When the magnesium strip is ignited on the flame of alcohol lamp, it will produce dazzling white light, smoke, react violently and heat, and turn into white powder after being extinguished. The focus of this series of experimental phenomena is to generate a white solid substance different from the original magnesium strip, which is a new substance, and this is the focus of observation. The white solid material is different from the original magnesium strip in luster, state and elasticity, which indicates that chemical changes have taken place, while the white light and heat release during the reaction are the phenomena accompanying chemical changes, not the essential phenomena to judge the material changes.
④ Observe the phenomenon deeply, think deeply, and strive to change from perceptual knowledge to rational knowledge. After each experiment, we should make a comprehensive analysis of the observed phenomena, think carefully about the reasons, compare, reason and judge, and then draw a conclusion, so as to have a deeper understanding and understanding of things. Only by unremitting efforts can we firmly grasp the concepts, principles, laws and knowledge of elemental compounds that appear in chemistry learning.
⑤ Correctly record and describe the experimental phenomena. For example, zinc reacts with dilute sulfuric acid, and the correct experimental phenomenon is described as follows: there are a lot of bubbles in the test tube, and the zinc particles gradually become smaller, so it feels a little hot to hold the test tube with your hand. The wrong description says, "hydrogen is produced in a test tube." Eyes can only see bubbles, but they can't tell what bubbles are. Another example is to drop purple litmus test solution into hydrochloric acid solution. The correct description should be "solution turns red" or "purple litmus test solution turns red", not "hydrochloric acid turns red".