The first part: Selected design of chemistry teaching plans for senior one in ordinary high schools.
1. Physical knowledge requirements:
(1) Know and remember what Brownian motion is, know the factors that affect the intensity of Brownian motion, and know the causes of Brownian motion.
(2) Know that Brownian motion is a reflection of irregular molecular motion.
(3) Know what molecular thermal motion is and the relationship between the intensity of molecular thermal motion and temperature.
2. Through the observation of Brownian motion, the characteristics are found, and the reasons of Brownian motion are analyzed and summarized; Cultivate students' ability of generalization, analysis and reasoning.
By analyzing the causes of irregular movement of suspended particles, students are exposed to the inevitable results of analyzing a large number of accidental events from the perspective of probability and statistics.
Second, analysis of key points and difficulties
1. Through students' observation of Brownian motion, students are guided to think and analyze that Brownian motion is not caused by external influence, but by the imbalance of liquid molecules hitting particles. Brownian motion is an endless random motion, which reflects the endless random motion of liquid molecules. The conclusion of this series of conclusions is the teaching focus of this class.
2. Brownian motion observed by students is not molecular motion, but indirectly reflects the characteristics of irregular motion of liquid molecules. This is a difficult point in class. This difficulty starts with the problem that molecular motion can't be seen under the analytical microscope, and gradually disperses to solve the problem.
Third, teaching AIDS
1. Diffusion experiment of gas and liquid: glass cylinder and glass sheet filled with nitric oxide and air respectively; The 250ml water cup contains clear water and red ink.
2. Water prepared with Garcinia suspension particles, microscope slides, miniature cameras and large-screen projection televisions.
Fourth, the main teaching process
(A) the introduction of new courses
Let students observe two demonstration experiments:
1. Put the glass bottle filled with nitrogen dioxide in vertical contact with another glass bottle, and see the nitrogen dioxide gas gradually expanding from the lower bottle to the upper bottle.
2. After dropping one or two drops of red ink in a beaker filled with clear water, the red ink gradually diffuses in the water.
Question: What are the physical phenomena of the above two experiments? What does this phenomenon mean?
On the basis of students' answers, the above experiment is the diffusion phenomenon of gas and liquid, and the diffusion phenomenon is a thermal phenomenon. It shows that molecules are doing endless random motion. Moreover, the speed of diffusion phenomenon is directly related to temperature, and high temperature accelerates the diffusion phenomenon. These contents have been learned in junior high school physics.
(B) the new teaching process
1. Introduce Brownian motion phenomenon.
From 65438 to 0827, British botanist Brown observed pollen suspended in water with a microscope and found that pollen particles kept moving irregularly in the water. Later, this irregular motion of particles was called Brownian motion. Not only pollen, but also other substances, such as gamboge and charcoal particles in ink, all of which have Brownian motion when suspended in water.
This paper introduces how to observe Brownian motion under microscope. Drop a few drops of Garcinia Garcinia into the groove on the glass, cover the glass and put it on the microscope stage. Then you can see many particles, large and small, in your field of vision through a microscope. If you carefully observe one of the very small particles, you will find that it is constantly moving, much like the movement of small fish and insects in the water. Put a microscope on the platform, then let miniature camera shoot Brownian motion, and display the projected image on the big screen by computer for all students to observe. The teacher points the pointer to the position of a particle on the screen, and then lets the students see the movement of the particle for a period of time.
Ask the students to look at the pictures in the textbook and point out that this is not the trajectory of Brownian particles, but just some connecting lines of the positions observed every 30 seconds. In fact, in this short period of 30 seconds, the motion of particles is also extremely irregular, not linear.
2. Introduce several characteristics of Brownian motion.
(1) Through continuous observation of Brownian motion, it is found that this motion will not stop for many days or even months as long as the liquid does not dry up. This Brownian motion is always in motion day and night, summer and winter (as long as it is suspended and not frozen). Therefore, this Brownian motion is endless.
(2) Brownian motion exists in different kinds of suspended particles, such as pollen, gamboge and carbon particles in ink, indicating that Brownian motion does not depend on the particles themselves. When different kinds of liquids are replaced, there is no Brownian motion.
(3) The smaller the suspended particles, the more obvious Brownian motion. When the particle is large, Brownian motion is not obvious, or even no motion can be observed.
(4) With the increase of temperature, Brownian motion becomes more and more intense.
3. Analyze and explain the causes of Brownian motion.
(1) Brownian motion is not caused by external factors. The so-called external factors refer to the existence of temperature difference, pressure difference and liquid vibration.
Ask students in different levels: If there is a temperature difference between the two ends of the liquid, how can the liquid transfer heat? Will the suspended particles in the liquid move directionally or irregularly? Can external factors such as temperature difference produce Brownian motion?
Induce students to answer that when there is a temperature difference between liquids, the liquids transfer heat by convection, so the floating particles will move directionally with the liquids. But Brownian motion is different for different particles, so it is impossible for the temperature difference of liquid to produce Brownian motion. Another example is that the pressure difference or vibration of the liquid can only make the liquid produce impact motion, and the directional motion of small particles suspended in the liquid is not Brownian motion. Therefore, it is concluded that the influence of external factors is not the cause of Brownian motion, but the influence of liquid interior.
(2) Brownian motion is caused by the unbalanced impact of liquid molecules on tiny particles suspended in liquid.
What you see under the microscope are tiny solid suspended particles, but liquid molecules are invisible because they are too small. However, many molecules that move irregularly in liquid keep hitting tiny suspended particles. When the tiny particles are small enough, it is unbalanced to be hit by liquid molecules from all directions. As shown in the illustrations in the textbook.
At a certain moment, a tiny particle is strongly impacted in a certain direction, and it moves in this direction. The next moment, the tiny particle is strongly impacted in another direction, and it moves in another direction. The impact of tiny particles at any moment is only accidental in a certain direction, resulting in the irregular Brownian motion of particles.
The smaller the particles suspended in the liquid, the less the number of molecules colliding with them at a certain moment. When the particle size of Damblanc motion is in the order of 10-'m and the molecular size of liquid is in the order of 10-'m, the imbalance of impact action is more obvious, so Brownian motion is more obvious. The larger the particles suspended in the liquid, the more molecules collide with them at a certain moment, and the less obvious the collision imbalance is, so that it can be considered that the collisions are balanced with each other, so Brownian motion is not obvious or even observed.
The second part: The molar volume of selected gas in the design of high school chemistry teaching plan.
I. teaching material analysis
The molar volume of gas is learned on the basis of learning the amount of substance, and the volume of gas is linked with the amount of substance of gas, which lays the foundation for learning the calculation of gas participating in the reaction in the future.
Second, the teaching objectives
(1) Knowledge and skills:
1, to understand the factors that determine the volume of matter;
2. Understand the concept of molar volume of gas;
3. Master the conversion relationship between gas volume and substance quantity.
(2) Process and method:
Starting with analyzing the factors that determine the size of matter, we can cultivate students' awareness of finding problems, stimulate students' desire for knowledge by setting questions, guide students to sum up, and understand the influence of the main and secondary aspects of contradiction on the conclusion.
(3) Emotional attitudes and values:
By studying the factors that determine the volume of matter and the molar volume of gas, we can cultivate students' ability to analyze problems and the spirit of unity and cooperation, and feel the charm of science.
Third, teaching focuses on difficulties.
Teaching emphasis: molar volume of gas.
Teaching difficulties: the factors that determine the volume of matter and the molar volume of gas.
Fourth, the teaching process
Gas is often used in scientific research and practical production, and it is often more convenient to measure the volume of gas than to weigh the mass. So what is the relationship between the volume of a gas and the amount of its substance? Today we are going to learn the bridge between the volume of gas and the amount of matter-the molar volume of gas.
Molar volume of gas
Teacher's activity shows electrolytic water experiment video.
Students observe, discuss, think and answer questions.
1. Read the textbook P 13 —P 14 and fill in the blanks.
(1) Phenomenon in the experiment: Both poles produce gas, one of which is hydrogen and the other is oxygen, and the volume ratio of the two is about.
(2)
Mass (g) The amount of substance (mol) The ratio of the amount of substance between hydrogen and oxygen, and between hydrogen and oxygen, from which it can be concluded that at the same temperature and pressure, the volumes are 1molO2 and H2.
2. The following table lists the densities of O2 and H2 at 0℃, 10 1 kPa (standard conditions). Please calculate the volumes of oxygen and H2 at 1 mol. What conclusion will you draw from it?
Quantity (mol) mass (g) density (g L- 1) volume (l) o 211.429h210.0899 conclusion: under standard conditions, the volume of any gas 1mol is about.
At the same temperature and pressure, the volume of any gas is almost the same. 1mol Are solids and liquids similar? The following table lists the densities of several solids and liquids at 20℃. Please calculate the volume of 1 mole of these substances.
Density/g cm -3 mass/g volume/cubic cm 3 iron 7.86 aluminum 2.70 water 0.998 sulfuric acid 4 1.83
Conclusion: Under the same conditions, the volume of solid or liquid is 65438±0mol.
Part III: Selected design of chemistry teaching plans for senior one in ordinary senior high schools 1. Common dangerous chemicals
Explosives: KClO3KMnO4KNO3 combustible gas: H2CH4CO combustible liquid: alcohol _ benzene gasoline and other spontaneous combustion articles: white phosphorus P4 inflammable articles when wet: NaNa2O2 oxidant: KMnO4KClO3.
Dramatic drugs: KCN arsenic compound corrosion products: concentrated H2SO4, concentrated NaOH, HNO3.
2. The dispersion of the substance is a colloidal turbid solution.
Dispersion size
3. The essential difference between colloid and other dispersion systems lies in the diameter of dispersoid particles.
Distinguishing solution from colloid: Tindal effect (there is a bright road)
Separate the suspension from colloid and solution: filter paper (only the suspension can't penetrate the filter paper)
Separation of colloid and solution: semipermeable membrane (colloid cannot penetrate semipermeable membrane)
4. electrolyte: a compound that can conduct electricity in aqueous solution or molten state, such as KClHCl.
Non-electrolyte: a compound that cannot conduct electricity in aqueous solution or molten state, such as sucrose alcohol so _ 2 co _ 2 NH _ 3.
Strong electrolyte: strong electrolyte acid HClH2SO4HNO3 which can be completely ionized in aqueous solution.
Strong alkali sodium hydroxide
Most salt
Weak electrolyte: weak electrolyte acid HClOH2SO3 3 which can be partially ionized in aqueous solution.
Weak base NH3 H2O
5. Material separation and water purification
Filtration method: it is suitable for separating a solid mixture in which one component is soluble and the other component is insoluble, such as the purification of crude salt.
Evaporative crystallization: the difference of solubility of each component in solvent.
Filtration and evaporation (e.g. purification of crude salt)
The order of removing reagents such as CaCl2, MgCl2 and Na2SO4 contained in NaCl is NaOH→BaCl2→Na2CO3→ filtration →HCl. It can also be changed to: BaCl2→Na2CO3→NaOH→ filtration →HCl. It can also be changed to: BaCl2→NaOH→Na2CO3→ filtration →HCl.
However, it should be noted that BaCl2 solution must be added before Na2CO3 solution, and hydrochloric acid must be put at the end.
Distillation: The impurities that are volatile, difficult to volatilize or nonvolatile are removed by using the different boiling points of the components in the mixture. It is suitable for separating mutually soluble liquid mixtures with different boiling points. Such as the separation of alcohol from water, distilled water from tap water, gasoline from kerosene, etc.
Instruments needed for distillation: alcohol lamp, distillation bottle, condenser tube, trumpet tube, conical bottle, thermometer.
Matters needing attention in distillation operation: 1. The mercury ball of the thermometer is located on the branch pipe of the distillation bottle; 2. Add zeolite or broken porcelain to the distillation bottle to prevent boiling; 3. The lower inlet of the condensing tube is a water inlet, and the upper outlet is a water outlet; 4. Water is introduced before distillation and then heated; After distillation, turn off the lights first and then the water.
Separation: Separation of two immiscible liquids. The lower liquid is discharged from the lower piston, and then the upper liquid is poured out from the upper opening of the separation funnel.
Why do you have to open the glass stopper before dispensing?
Opening the glass stopper makes the pressure in the separating funnel equal to the external atmospheric pressure, which is beneficial to the outflow of the lower liquid.
Extraction: The difference of solubility of a substance in two immiscible solvents is used to separate a liquid mixture.
Instruments: separating funnel, beaker
To separate bromine from bromine water, benzene or carbon tetrachloride can be used. The upper water/carbon tetrachloride layer is colorless and the lower layer is orange-red. Alcohol-free extraction (note that carbon tetrachloride is denser than water and benzene is smaller than water)
To separate iodine from iodine water, carbon tetrachloride can be used to separate layers, the upper layer is colorless, and the lower layer is purplish red, so it cannot be extracted with alcohol.
Key points of flame reaction operation platinum wire was washed with hydrochloric acid, then burned in alcohol lamp until colorless, and then immersed in the solution to be tested.
Flame color of sodium: _; Flame color of potassium: purple (through blue cobalt glass) flame reaction is the nature of elements.
6. Ion inspection
Cl- test: the white precipitate produced by adding silver is insoluble in dilute solution (Ag2CO3 is also a white precipitate, but it is dissolved by adding dilute solution).
SO42-Test: White precipitate produced by adding BaCl2 solution and HCl is insoluble in dilute hydrochloric acid Na2SO4+BaCl2=BaSO4↓+2NaCl.
NH4+ test: NaOH is added and heated to generate gas, so that the wet red litmus paper turns blue.
Fe3+ test: Blood red solution Fe3++3SCN-==Fe(SCN)3 appeared after adding KSCN.
Al3+ test: White precipitate appears at first when NaOH is added, and disappears after dripping.
7. About the volumetric flask: the flask is marked with temperature, volume and scale line.
(1) Check the cork for water leakage before use.
(2) Put the accurately weighed solid solute in a beaker and dissolve it with a small amount of solvent. Then transfer the solution to a volumetric flask. In order to ensure that all solutes can be transferred to the volumetric flask, the beaker should be cleaned with solvent for many times, and all cleaning solutions should be transferred to the volumetric flask. Drain with a glass rod when transferring. The method is to lean one end of the glass rod against the inner wall of the capacity bottleneck, and be careful not to let other parts of the glass rod touch the capacity bottleneck below the graduation line to prevent the liquid from flowing to the outer wall of the volumetric flask.
(3) When the liquid level added to the volumetric flask is about 65438±0cm away from the marking line, carefully drop it with a dropper, and finally make the concave liquid level tangent to the marking line. If the water exceeds the scale line, it needs to be rehydrated, and the excess solution cannot be absorbed.
(4) Cover the bottle stopper tightly, and mix the liquid in the bottle evenly by reversing and shaking. If it is found that the liquid level is lower than the scale line after standing, it is because a very small amount of solution in the volumetric flask is wetted at the bottleneck and lost, so it does not affect the concentration of the prepared solution.
Experimental instruments: balance, medicine spoon, volumetric flask, beaker, measuring cylinder, rubber dropper, glass rod.
The steps of preparing a substance into a solution with a certain concentration are: weighing → dissolving → transferring → washing → constant volume → shaking → bottling. If concentrated sulfuric acid is prepared, it should be left to cool after dissolution.
Common error analysis:
When the low concentration solution (1) is stirred and dissolved, a small amount of liquid overflows. (2) The beaker and glass rod were not cleaned during the transfer. (3) When the solution is transferred to the volumetric flask, a small amount of liquid flows out. (4) When the volume is constant, add too much water. Suck it out with a dropper. (5) After constant volume, shake, shake, let stand, and add water after the liquid level drops. (6) When the volume is constant, check the scale number.
If the concentration is too high (1), inject it into the volumetric flask before cooling to room temperature. (2) When the volume is constant, look down and read the scale number.
No influence (1) After constant volume, the liquid level drops after shaking, shaking and standing. (2) There is a small amount of distilled water in the volumetric flask.
8. Properties of metallic sodium: soft, silvery white, less dense than water and more dense than kerosene, stored in kerosene. Put out the fire with dry sand.
Experimental phenomenon of sodium metal igniting in air: melting into small balls, burning violently, producing _ flame and light _ solid.
The phenomenon and explanation of the reaction between sodium and water: ① Float: indicating that the density of sodium is less than that of water; ② Melting: It means that the melting point of sodium is low; Reaction exotherm; Swimming; Explain that there is gas. ④ Ringing: Explain that there is gas. ⑤ Red: Phenolphthalein drops into the solution in red; The resulting solution is alkaline. (3) The chemical equation of the reaction between sodium and water is 2na+2h2o = 2n NaOH+H2 = 2na+2h2o = 2na+2oh-+H2 = ionic equation.
Uses of sodium: ① Preparation of important compounds of sodium; (2) as a thermal conductor of an atomic reactor; (3) smelting titanium, niobium, zirconium and vanadium; ④ Sodium light source.
Sodium peroxide is a strong oxidant, which can be used to bleach fabrics, wheat stalks, feathers and so on. 2na2o2+2h2o = = 4 NaOH+O2 = (when phenolphthalein is added, it turns red first and then fades).
It can also be used as a source of oxygen for breathing masks and submarines. 2Na2O2+2CO2==2Na2CO3+O2
Sodium carbonate (Na2CO3), commonly known as soda ash or soda, is a white powder. The chemical formula of sodium carbonate crystal is Na2CO3 10H2O. Sodium carbonate is widely used in glass, soap making, paper making, textile and other industries, and can also be used to make other sodium compounds.
Sodium bicarbonate is one of the main components of baking powder. Medically, it is a medicine for treating hyperacidity.
Impurity removal: Na2CO3 solid (NaHCO3) is heated to 2nahco3 = = Na2CO3+CO2 =+H2O.
Na2CO3 solution (NaHCO3) plus nahnahnahco3+NaOH = = Na2CO3+H2O.
The method of distinguishing sodium carbonate from sodium bicarbonate. The gas produced by heating is sodium bicarbonate, or the gas produced by adding acid first is sodium bicarbonate, and the gas produced after no gas is sodium carbonate.
Compare sodium carbonate and sodium bicarbonate: solubility (sodium carbonate dissolves more), alkalinity (sodium carbonate is more alkaline) and stability (sodium carbonate is stable).
Aluminum is the most abundant metal element in the earth's crust, which mainly exists in the combined state. The main component of bauxite is Al2O3.
9. Properties of aluminum: silvery white metal solid with good ductility. Conductive aluminum is a relatively active metal with strong reducibility.
React with oxygen: react with oxygen in the air at room temperature to form a firm oxide film (red when heated, but not dripping), 4al+3o2 = = = 2al2o3.
React with non-oxidizing acid 2al+6HCl = = 2alcl3+3H2 ↑ 2al+3H2SO4 = = Al2 (SO4) 3+3H2 ↑.
Concentration and passivation of aluminum and concentrated sulfuric acid at room temperature
React with alkali 2al+2NaOH+2H2O = = 2NALO2+3H2 =
Alumina oxide
Al2O3+3H2SO4==Al2(SO4)3+3H2O
Al2O3+2NaOH = = 2NALO2+H2O ionic equation Al2O3+2OH-==2AlO2-+H2O.
aluminum hydroxide
( 1)Al(OH)3+3 HCl = = 3 ALCL 3+3 H2 oal(OH)3+NaOH = = NAA lo 2+2H2O
Ionic equation: Al (OH) 3+OH-= AlO2-+2H2O is decomposed by heating 2Al(OH)3==Al2O3+3H2O.
(2) NaOH was added into AlCl3 solution until it was excessive: white precipitate appeared first, and then disappeared.
Al3 ++ 3OH—= = Al(OH)3↓Al3 ++ 4OH—= = alo 2-+2H2O
Al(OH)3 is prepared by aluminum salt and enough ammonia water in the laboratory.
Al2(SO4)3+6nh 3·H2O = 2Al(OH)3↓+3(NH4)2so 4
Ionic equation: Al3++3NH3 H2O = Al (OH) 3 ↓+3NH4+
(3) Alum: Potassium aluminum sulfate dodecahydrate [kal (SO4) 2. 12h2o] is easily soluble in water, and when dissolved in water, it generates flocculent aluminum hydroxide, which has adsorption and sinks by adsorbing suspended substances in water, so alum is often used as a water purifier.
10. Transformation between Fe3+and Fe2+
Fe2+Fe3+Fe3+Fe2+
Oxidant reducing agent
2 FeCl 2+Cl2 = = 2 FeCl 32 FeCl 3+Fe = = 3 FeCl 2 Cu+2 FeCl 3 = = cuc L2+2 FeCl 2
Chlorine reacts with metallic iron: 2Fe+3Cl2 ignites 2FeCl3.
Iron reacts with water vapor at high temperature: Fe+H2O(g)=Fe3O4+H2.
Preparation of iron hydroxide: FeCl _ 3+3 NaOH = = Fe (OH) _ 3 ↓+3 NaCl heating decomposition; 2 Fe (OH) _ 3 = = Fe2O3+3H2O。
4Fe(OH)2+2H2O+O2==4Fe(OH)3 Phenomenon: At room temperature, the gray-white precipitate quickly turns to gray-green and finally to reddish brown.
Iron oxide: red-brown solid
Alloy: Metallic materials with metallic properties are made by heating and melting some metals or nonmetals in metals. Steel is the most widely used alloy. It can be divided into carbon steel and alloy steel by composition)
Compared with pure metal, the alloy has the advantages of low melting point and high hardness.
1 1. silicon: a gray-black solid with metallic luster, high melting point, high hardness, high brittleness and inert chemical properties at room temperature. Silicon exists in nature in the form of silica and silicate. Crystalline silicon is a good semiconductor material, which can be used to manufacture solar cells, silicon integrated circuits, transistors, silicon rectifiers and other semiconductor devices. The main component of optical fiber is silicon dioxide.
Silicon dioxide is an acid oxide insoluble in water, which is chemically inactive, resistant to high temperature and corrosion.
(1) does not react with water and acid (except HF). SiO _ 2+4hf = = SiF4 =+2H2O HF acid is not packed in glass bottles, but in plastic bottles.
② SiO _ 2+Cao = = casio _ 3 reacts with basic oxides.
(3) The reaction of SiO _ 2+2 NaOH with alkali = = Na2SiO3+H2O rubber stopper is used for the reagent bottle containing NaOH in the laboratory.
Silicate: sodium silicate na 2 SiO 3(NaO SiO 2 2 2) (use: adhesive, refractory)
Kaolinite Al _ 2 (Si _ 2O _ 5) (OH) _ 4 (Al _ 2O _ 3.2 SiO _ 2.2 H2O)
Clay and limestone are the main raw materials for making cement. The raw materials for making ordinary glass are soda ash, limestone and timely. The main reaction is Na2CO3+SiO2 2na2sio3+CO2 = CaCO3+SiO2 casio3+CO2 = Artificial molecular sieve is an aluminosilicate with uniform micropore structure, which is mainly used as adsorbent and catalyst.
12. Laboratory preparation of chlorine:
Reaction principle: MnO2+4HCl (concentration) = = mncl2+Cl2 ↑+2h2o; Generator: round bottom flask, separating funnel, etc.
Impurity removal: HCl gas is absorbed by saturated salt solution; Absorb water with concentrated H2SO4; Collecting: collecting by upward ventilation;
concentrated hydrochloric acid
Inspection: turn the wet starch potassium iodide test paper blue; Tail gas treatment: absorb tail gas with sodium hydroxide solution.
manganese dioxide
Dry cloth strip
Wet cloth strip
Sodium hydroxide solution
concentrated sulfuric acid
collect
Saturated salt solution
Part IV: Design of Selected Chemistry Teaching Plan for Senior One in Ordinary Senior High School I. teaching material analysis:
1. The position and function of this course in the textbook
Two kinds of organic compounds are common in "Organic Compounds" in the third section of Chapter 3 of the compulsory course of Ethanol People's Education Edition 2. Learning this section well can help students master the structure and properties of functional groups in the study of hydrocarbon derivatives, and confirm the general law of structure determining properties, which not only consolidates the properties of alkanes, alkenes, alkynes and aromatics, but also lays a solid foundation for later learning phenols, aldehydes, carboxylic acids, esters and sugars, so that students can learn to use them.
2. Teaching objectives
According to the requirements of the syllabus, combined with the characteristics of this course and the requirements of quality education, the following teaching objectives are determined:
(1) Cognitive goal:
Master the structure, physical properties and chemical properties of ethanol.
(2) Ability objectives:
① Cultivate students' scientific thinking ability.
② Cultivate students' ability to observe and analyze experimental phenomena.
(3) Moral education goal: to cultivate students' spirit of seeking truth and being pragmatic.
3. Teaching emphases and difficulties
(1) ethanol is the representative of alcohol substances, so the structure and properties of ethanol are the key and difficult points in this section.
(2) Breakthrough of key and difficult points, two breakthrough points can be designed:
① The characteristics of ethanol structure can be deduced by methods such as question inquiry, chemical calculation and molecular model, and confirmed by computer display, which can fully arouse students' enthusiasm for attending classes and participating in classroom activities, so that students can learn the rigor of logical reasoning while mastering the ethanol structure;
② Understand and master the chemical properties of ethanol through experimental exploration and computer multimedia animation demonstration.
Second, the flexible use of teaching methods
Teaching activity is a bilateral activity between teaching and learning, so we must give full play to the main role of students and the leading role of teachers, promote each other and develop harmoniously. According to this basic principle, I adopted the following teaching methods:
1. Situational learning method creates the artistic conception of problems, stimulates learning interest, mobilizes students' intrinsic learning motivation, and urges students to actively explore the mysteries of science in artistic conception.
2. Experiment to promote learning: Through the teacher's demonstration, let students operate, observe and analyze the experimental phenomena, and master the chemical properties of ethanol.
3. Computer-aided teaching method: advanced teaching methods are adopted, and the microscopic phenomena are macroscopic and the instantaneous changes are fixed to help students master the essence of ethanol chemical reaction.
4. Induction: Through students' induction and logical deduction, the molecular structure of ethanol is finally determined.
Third, teaching AIDS
1 indicates the experiment:
① The reaction between ethanol and sodium can be used as a comparative experiment of the reaction between metallic sodium and water, and the size of metallic sodium used is the same as much as possible, with little difference in surface area.
(2) Ethanol oxidation, in which one end of the copper wire is coiled into a spiral shape, so as to increase the surface area of the catalyst and speed up the reaction.
2. Modern teaching methods: The main chemical properties of ethanol can be expressed by the following two equations:
( 1)2Na+2ch 3 ch 2 oh→2ch 3 ch 2 ona+H2↑
(2)2CH3CH2OH+O2→2CH3CHO+2H2O
The process of the above two reactions can be simulated by computer animation, so that students can deeply understand and master the essence of each reaction and the position of bond breaking, and make the micro-reaction macroscopic.
Chapter five: The teaching objectives of selective design of chemistry teaching plans for senior one in ordinary senior high schools.
Knowledge and skills:
Understand the molecular structure, physical and chemical properties of nitrogen; Understand the purpose of nitrogen.
Process and method:
Learn to think and analyze the corresponding structure of atoms from their structural characteristics.
Emotional attitudes and values:
Have the consciousness of applying chemical knowledge to production and life practice, and be able to make reasonable judgments on social and life problems related to chemistry.
Important and difficult
Key points: molecular structure and chemical properties of nitrogen.
Difficulties: chemical properties of nitrogen.
Teaching process design
Say: This lesson is about learning about nitrogen. We know that free nitrogen mainly exists in air, so what is the structure, physical properties and chemical properties of nitrogen? Let's take a look at its structure first.
The teacher asked the students to write the atomic structure diagram of nitrogen atom on the blackboard. )
Teacher: We see that there are five electrons in the outermost layer of nitrogen atoms, so if the two outermost nitrogen atoms in a nitrogen molecule reach a stable 8-electron structure, they need to share several pairs of electrons.
Student: Three pairs.
Teacher: Yes, let's look at its electronic structure and structural formula.
So what are the physical properties of nitrogen?
Student: Pure nitrogen is a colorless and odorless gas. Insoluble in water, slightly less dense than air. Teacher: We know the physical properties of nitrogen, so what are its chemical properties?
Let the students write the chemical equations of nitrogen and hydrogen, nitrogen and oxygen, nitrogen and magnesium on the blackboard.
People often say that thunderstorms can produce crops, so what do you know to explain this phenomenon?
(Students think for a moment) Speech: We know that nitrogen in the air generates nitric oxide under the condition of lightning, nitric oxide reacts with oxygen to generate nitrogen dioxide, and nitrogen dioxide reacts with water to generate nitric acid, which is then absorbed by plants. This is the reason why thunderstorms produce crops.
As mentioned earlier, as long as there is free nitrogen in the air, we can make nitrogen from liquefied air. We see this is a picture of nitrogen liquefaction. So what is the purpose of nitrogen?
Say: Nitrogen is relatively stable and can be used as a protective gas. Nitrogen-hydrogen reaction can be used in industrial synthetic ammonia, nitric acid production and nitrogen fertilizer production. In science and technology, nitrogen provides a low temperature environment for superconductors. Liquid gasification absorbs heat, and liquid nitrogen can be used as refrigerant. We also talked about that nitrogen can be used to transport crops in thunderstorms.
End: Well, that's all for today. Thank you.