Senior high school chemistry composition 1
On the Creation of Chemistry Teaching Situation in Senior High School
Learning is an interactive activity between teachers and students. The traditional chemistry classroom teaching mode focuses on teachers' explanation, supplemented by students' passive acceptance and mechanical practice, which increases students' academic burden and makes it difficult to develop students' personality and specialty to a greater extent. An important feature of the new curriculum reform is the change of students' learning style, which requires students to change from the original? Learn? Become? Inquiry learning? In order to stimulate students' learning interest and motivation. Creating problem situations in teaching is to organically combine chemical knowledge with students' actual feelings, and present students with a tangible teaching background, which can be real production and living materials, problems in this discipline, or related contents in other disciplines. This can not only stimulate students' interest in learning, arouse students' desire and pursuit for knowledge, but also provide positive emotional experience for further learning and make them actively participate in learning. Therefore, the teaching situation we create should be based on students' familiar life experience and knowledge, fully tap various situational resources, and create a lively learning situation for classroom teaching. Enhance the interest, novelty, vividness, visualization and effectiveness of classroom teaching, so as to stimulate students to enter the learning state quickly, promote the active construction of knowledge and the harmonious development of knowledge, skills, emotional attitudes and values, and improve the efficiency of classroom teaching.
First, the basic requirements of creating chemistry teaching situation
The real situation not only has cognitive value, but also is closest to students' life experience, which can mobilize all students' sensibility and past life experience. The real situation is conducive to cultivating students' observation ability, thinking ability and application ability, and to cultivating students' true skills, feelings, attitudes and values. Therefore, to ensure the effectiveness of chemistry teaching, we must first ensure the effectiveness of chemistry teaching situation.
1, requirements for teachers
Teachers are the creators of situations. First of all, teachers themselves must accumulate (preferably stored in their brains so that they can call at any time) a large number of situational materials such as chemical historical materials, life events and social hotspots. Therefore, teachers should read chemical historical materials in many ways, pay more attention to chemistry-related events in their lives, and pay more attention to news reports and "exploration". The contents related to chemistry in the discovery. Secondly, teachers should fully tap the deep-seated things in the textbook, think repeatedly and create a situation consistent with the content of the textbook. Finally, teachers should pay full attention to students' direct experience, knowledge level and other information, which in turn can guide teachers to create situations that students can easily accept; Being familiar with students' knowledge level can determine their knowledge level? The nearest development zone? Create students? You can pick peaches in one jump? Progressive problem situations are oriented to all students, so that students with poor foundation can enter, students with average foundation can leave, and students with good foundation can leave.
Teachers are situational? A tour guide? In the implementation of situational teaching, teachers should be full of passion, and only with passion can students be infected. In the teaching process, teachers should be real, tell the truth, tell the truth and be a real person; It is necessary to closely connect with students' ideological reality, convince people with reason and move people with emotion.
2. Requirements for students
Students in the situation? Tourists? Is the main body in chemistry teaching, so if you want to fully appreciate the chemistry class? Infinite scenery? First of all, students should preview the textbooks before class, so that students can understand the difficulty and depth of knowledge in the new lesson and know fairly well. Secondly, students should try their best to participate in the experience in the inquiry situation and think positively in the problem situation. Because students' participation is not only a form, but also a state of excitement and excitement. In this state, students either concentrate on thinking, debate actively, or make bold statements. Through various channels, students have developed their own knowledge and skills, gained experience in the process, and been stimulated in emotional attitudes and values.
3, the requirements of the classroom
Is the classroom created by the teaching situation? Location? Say it, right? Location? Is it because the classroom is a place where teachers and students communicate and interact, and it is a spark of wisdom? Cradle? . Of course, if teachers and students want to promote the interactive thinking contest, the premise is that teachers create a scientific, reasonable and effective teaching situation, with which students can take the initiative? Break in? Situation, progress? Treasure hunt? The exploration of. Secondly, teachers and students should establish equal dialogue and speak freely. Through these, our classroom will be full of vitality.
Second, the method of creating chemistry teaching situation
1, create situations with life to arouse students' love for life and chemistry.
Chemistry comes from life, and life contains chemistry everywhere. Creating situations with life can not only make students feel that chemistry learning is close to life and enhance their sense of closeness, but also make students feel that chemistry learning ultimately serves life and enhance their practical consciousness.
[Case 1]: Teaching fragment about nitrogen oxides in the compulsory course of chemistry 1 published by People's Education Press.
Teacher: Our times are impetuous, so we urgently need a calm heart. Now, let's calm down and listen carefully to the voice of nature.
Student: Sit there quietly with expectant eyes.
Teacher: Play the sound "Thunder"
Thunder: from far to near, from light to loud, suddenly there was a loud noise, which was deafening. Suddenly a picture of lightning, thunder and downpour appeared on the slide, which was naturally drawn? Devil valley, Xinjiang? And then what? Thunderstorms send crops? Two situations. Through such use? Thunder? Does it play a role to create a situational guidance classroom so that students can quickly enter the learning situation and be there, thus touching the scene? Take the lead? The guiding role.
Life contains a lot of chemical knowledge and situations. Starting from students' familiar life experience, creating situations that students are familiar with, interested in and conform to the teaching content can stimulate students' desire for knowledge, enhance students' awareness of paying more attention to various chemical problems in life, and trigger students' thinking about chemical phenomena in life.
2. Create situations through experiments, so that students can experience the process and feel the endless fun brought by scientific exploration.
Chemistry is a natural science based on experiments, and experiments are the soul of chemistry learning. In teaching, experiments can be carefully designed for a certain problem and a certain link to change the boring atmosphere, activate students' thinking and make the class lively and interesting.
[Case 2]: Add a few zinc particles into the test tube and pour a few milliliters of dilute sulfuric acid to let the students observe the phenomenon; Dip another copper wire bent into a spiral into sulfuric acid and contact with zinc particles, so that students can observe the phenomenon. When the students observed that bubbles appeared after the copper wire was inserted, the experimental phenomenon collided with the students' original knowledge, and the students' learning enthusiasm was mobilized.
3. Create teaching situations through chemical historical facts to stimulate students' interest in learning.
The history of chemical development is the history of human material civilization and progress, and it is also a high-quality material for creating teaching situations. Inserting some chemists' stories and short stories about material discovery in teaching will arouse students' strong interest in learning.
[Case 3] Faraday made a long-term study on an oily liquid (long neglected) produced in the process of producing lighting gas, and found benzene as a result. French chemist Jural and others determined that the relative molecular weight of benzene was 78 and the molecular formula was C6H6. Scientists are surprised at the high carbon content in benzene. How to determine its structural formula? student
Our enthusiasm for learning will be better mobilized.
4. Create teaching situations through popular science stories to stimulate students' curiosity.
Affected by physiology and psychology, middle school students always have a strong curiosity about new things. In our wonderful world, many stories related to chemistry are even more attractive to middle school students.
[Case 4] Primary battery teaching situation design:
Mrs. Green has neat teeth, but there are two dentures embedded in them: one is gold, which is a symbol of Green's wealth; One is made of stainless steel, which is the trace left by a car accident. It is puzzling that since the car accident, Mrs. Green has often had headaches, insomnia and irritability at night. Although some internationally renowned experts and professors have racked their brains, Mrs. Green's condition has not been alleviated at all, but has become more and more serious. Is her illness really incurable? Later, a chemist uncovered the cause for Mrs. Green. What did the chemist find?
5. Create teaching situations through social hotspots to arouse students' attention to the relationship between chemistry and society.
Chemistry is closely related to society, and has extensive and close ties with social production, life and environment. Such as energy, materials, food, the role and protection of ozone layer, the work and excess of carbon dioxide, the utilization of new energy sources such as alcohol fuel, hydrogen and solar energy, the development and production application of new composite materials, etc. We can use social hot issues to extract materials and create teaching situations.
[Case 5] The identification of high-quality plastic wrap and inferior plastic wrap in life introduces the study of polyethylene and polyvinyl chloride.
Third, the problems that should be paid attention to in the creation of chemistry teaching situation
? Learning begins with thinking, and thinking begins with doubt? . Students' thinking process of exploring knowledge always begins with questions, and a good question can stimulate students' strong thirst for knowledge and curiosity. Therefore, teachers should strive to create problem situations suitable for students to explore, discover and construct new knowledge, so as to awaken students' desire and wisdom of inquiry learning and promote students' active learning and inquiry.
1. The design of problem situations should be combined with the actual situation of students, which is conducive to the transfer and formation of knowledge. Students should not only experience success through thinking, but also have a certain goal orientation, such as some problems that can form cognitive conflicts and cause controversy, turn abstraction into images, turn difficulties into ease, lead cognition to in-depth problems step by step, and guide students to think and explore.
2. The design of problem situations should be hierarchical. If the question is too simple, no? Bite your head? Students can't afford to learn; On the other hand, if the problem is too difficult, students' thinking can't be gradual. Even if they are full of confidence in solving the problem, they will eventually be forced to give up and it is difficult to achieve the expected results. So the gradient and difficulty of the question should be moderate. The nearest development zone? Is it okay for students? what can I do? Properly solve it in order to facilitate the reproduction and positive migration of knowledge.
3. The design of problem situations should be conducive to cultivating students' thinking ability. The cultivation of thinking ability is the basis of teaching, and the design of problems should focus on guiding students to think from different angles and explore from different ways and methods; Or inspire students to break away from convention and analyze and solve with new ideas and methods; Or provide sufficient perceptual materials to induce students to analyze the appearance of things to understand their essence and create a relaxed, harmonious and democratic atmosphere for students. Only in this way can students dare to ask questions. In addition, teachers should encourage students to ask questions, and never dare to ask questions boldly. From simple questions to questions with certain quality, students' thinking is bound to develop in the process of asking questions. Let questions enter students' minds and train students to ask questions consciously and pertinently, which will strengthen students' awareness of questions and train students' thinking. Teachers' questions should be open to some extent, and knowledge design of other disciplines can also be interspersed from different angles and in different ways. Like what? How to design an experimental scheme with refined salt and water as reactants to prepare household disinfectants under family conditions? What are the particles with 10 electrons? What are the schemes for preparing CuO from Cu, which scheme is the best, and so on. Open-ended questions are exploratory, enlightening, and can inspire students' thinking.
4. The creation of problem situations should be combined with the actual production and life, and cultivate students' application awareness and ability to analyze and solve practical problems. ? The questions explored not only come from books, but also from the social life practice that students come into contact with? . Many common life and production practices contain rich chemical knowledge, but students are often not good at contact. Teachers should dig more materials related to production, life practice and even the frontier of science and technology, and create problem situations. Let students construct cognitive activities in a specific background? The combination of learning and application can cultivate students' application consciousness, strengthen science and technology and social education, and promote students' ability to internalize what they have learned into analyzing and solving practical problems.
5. The creation of problem situations should focus on encouraging students to question and ask difficult questions, and guiding scientific inquiry methods, so as to cultivate students' problem consciousness, innovative spirit and scientific inquiry ability. To create problem situations, on the one hand, we should start with guiding students to discover, ask, analyze and solve problems themselves, and pay attention to the inspiration and guidance of inquiry learning methods, so that students can learn to learn and explore and develop their lifelong learning ability; On the other hand, it is necessary to create a relaxed atmosphere for students to put forward different opinions or even wrong opinions, so that students can dare to question and be good at questioning, thus cultivating students' problem consciousness, innovative spirit and scientific inquiry ability.
Senior one chemistry composition 2
On Green Chemistry
introduce
There are 70,000 kinds of chemical products in the world, with a total chemical output value of about 1 trillion US dollars (about 500 billion RMB in China). Chemical substances have greatly enriched the material life of human beings, improved the quality of life, and played an important role in controlling diseases, prolonging life, increasing crop varieties and yields, and in grain storage and preservation. However, in the process of producing and using these chemical products, a large amount of waste is also produced, which pollutes the environment. At present, the world produces 300-400 million tons of hazardous waste every year (wastewater, waste gas and solid waste discharged by China Chemical Industry account for 22.5%, 7.82% and 5.93% of the total industrial discharge respectively), which brings disasters to mankind. So, in today's society, it is necessary to mention? Chemistry? Many people have to frown. It's all because of it, right? Chemistry? A misunderstanding caused by the lack of comprehensive understanding of this science, as long as you carefully observe and think, the progress of chemical technology has brought great benefits to mankind in our food, clothing, housing and transportation and in overcoming diseases. The development of drugs helps to treat many diseases and prolong human life. Polymer technology has created new clothing and building materials; The development of pesticides and fertilizers has controlled pests and increased production. Everything is inseparable from the help of chemists. It is no exaggeration to say that human life is inseparable from the development of chemistry. Solving this contradiction has become a scientific challenge to human environmental problems in the 2 1 century.
main body
I. Concept
The production, use and treatment of chemicals have caused more and more serious pollution to the environment. At first, people tried to solve the pollution problem by reducing the emissions of waste gas, waste water and solid waste, and then managed the waste through laws and regulations. Now, people have fully realized that the best way to protect the environment is to prevent pollution at the source, rather than to deal with it after it is produced. 199 1 year, proposed by American Chemical Society? Green chemistry? As an important and strategic means to prevent environmental pollution from the source, the concept of pollution control has attracted more and more attention. Green chemistry is a basic chemical problem of sustainable development, a chemistry to prevent pollution from the source, and a hot research field to be solved urgently.
Second, the definition of green chemistry
Green chemistry is the latest scientific and technological achievement in designing and producing chemical products with the goal of protecting the environment, and it is the chemistry to prevent pollution from the source. Once the concept of green chemistry was put forward, its modern connotation was made clear. It is a reaction way to study and find non-toxic raw materials that can be fully utilized, save energy to the maximum extent, and realize purification and pollution-free in all links.
1) Main characteristics of green chemistry:
1. Make full use of resources and energy, and adopt non-toxic and harmless raw materials;
2. React under non-toxic and harmless conditions to reduce the discharge of waste to the environment;
3. Improve the utilization rate of atoms, and try to make all atoms as raw materials absorbed by products, so as to realize? Zero emissions? ;
4. Produce environmentally friendly products that are beneficial to environmental protection, community safety and human health.
2) The meaning of green chemistry:
1. restore. Save resources and reduce? Three wastes? Discharge.
2. reuse. This is not only the need to reduce costs, but also the need to reduce waste, such as
Catalysts, carriers, etc. In the chemical process.
3. Recycling. Can it be effectively realized? Save resources, reduce pollution and reduce costs? ask
Requirements, such as recovery of unreacted raw materials, recovery of by-products, recovery of cosolvent and catalyst, and stabilization.
Non-reactive reagents, such as reagents.
4. regeneration. Turning waste into treasure, saving resources and energy, reducing pollution,
Such as ion exchange resin, sulfonated coal, etc.
5. refuse. Refers to irreplaceable, non-recyclable, non-renewable and non-repeatable things.
Raw materials that are used, have toxic side effects and pollution effects, and refuse to be used in the chemical process.
Third, the basic principles of green chemistry
Third, the basic principles of green chemistry
Principles of green chemistry:
1. Atomic economy.
2. As long as it is feasible, try to adopt a low-toxic chemical synthesis route.
3. Safer chemicals should be designed to maintain their efficacy, but reduce their toxicity.
4. Auxiliary substances (such as solvent separating agent, etc.). ) should be avoided as far as possible, and should be non-toxic when used.
5. Preventing pollution is better than controlling pollution.
6. We should consider the impact of energy consumption on the environment and economy and use as little energy as possible.
7. Raw materials should be renewable, not exhausted.
8. Try to avoid unnecessary derivative steps.
9. The catalytic reagent (with the best selectivity) is superior to the equivalent reagent.
10. After completing its mission, chemical products should not remain in the environment, but can be degraded to be harmless.
Things.
1 1. In the process of chemical transformation, the selected substances and substance forms should be as low as possible.
Possibility of chemical accidents.
12. In the process of chemical transformation, the selected substances and substance forms should be as low as possible.
Possibility of chemical accidents.
2) Understanding of this principle:
1. Use non-toxic and harmless raw materials. Toxic and harmful raw materials, such as highly toxic phosgene, hydrocyanic acid, benzene, aldehydes and other raw materials and intermediates, are often used in chemical research and chemical production, seriously polluting the environment and endangering human health. For human health and social security, it is an important task of green chemistry to replace them with non-toxic and harmless raw materials to produce the required chemical products.
2. Use non-toxic and harmless catalysts. Adopting a new, efficient, environmentally friendly and recyclable catalyst can improve the selectivity of the reaction, avoid the formation of by-products, improve the utilization rate of atoms and reduce the emission of harmful substances to the environment.
3. Use non-toxic and harmless solvents. A large number of pollution problems related to chemical manufacturing not only come from raw materials and products, but also from substances used in their manufacturing process. The most common are reaction media, solvents used in separation and preparation. At present, some widely used solvents will cause the formation of ground ozone during use. Some will cause water pollution. Therefore. It is necessary to limit the use of these solvents.
Fourthly, green chemistry and sustainable development.
The strategy of realizing sustainable development has become the overall strategy of many countries in the world to guide economic and social development, that is, economic development must be considered as a whole with population, environment and resources. 1987 the world commission on environment and development put forward the general principle of sustainable development: Today's human beings should not meet their own needs at the expense of the happiness of future generations. ? The core idea of sustainable development is to pay attention to protecting resources and improving the environment while developing the economy, and to protect and improve the environment reasonably to provide a material basis for sustainable development. The restriction of environment on development is caused by unreasonable development destroying the environment, and reasonable development provides more technology and funds for environmental governance. Green chemistry is an effective way for sustainable development. Green chemistry puts forward a new technology and driving mechanism to produce green chemistry, thus improving the ability of human beings to engage in material production. First of all, it has a positive impact on human society and natural environment, controls the extension of pollution in time and space, and promotes sustainable development; Secondly, it provides a protective function of regulation and restriction for the sustainable development of mankind. It can constantly adjust and balance the orderly development and comprehensive utilization of resources, limit the speed and scale of resource utilization, foster strengths and avoid weaknesses, turn harm into benefit, reduce and overcome the negative impact on nature in the process of human social development, protect endangered species, and continuously reduce the use of resources, thus coordinating human social development and economic growth. Thirdly, green chemistry provides the planning function of observing and monitoring for sustainable development, such as global warming, ozone layer destruction and other environmental problems, which require the joint efforts of all countries in the world. The function of green chemistry can continuously observe and monitor the performance and trend of global development, provide intellectual support for the decision-making and action of human social, economic and ecological environment development, and thus form an effective planning blueprint. It can be seen that green chemistry provides a complete system and approach for the sustainable development of human beings, and it is the only way for sustainable development.
To sum up, green chemistry has been completely abandoned? Develop first, then manage? Developing the economy at the expense of the environment, and then adopting a green development model to stop pollution at the source and fundamentally reduce or eliminate pollution, conforms to the requirements of sustainable development of modern society and is the only way for coordinated development of population growth, economic development, social progress, environmental governance and resource conservation.
Five, the development direction of green chemistry
From the goal of green chemistry, we must pay attention to two aspects: first, to develop? Atomic economy? The new chemical reaction process is the basic principle, and the other is to improve the existing chemical industry and reduce and eliminate pollution.
The development direction is as follows:
Study on the new chemical reaction technology of 1.
2. Green chemical transformation of traditional chemical process.
3. Green chemical problems in energy and clean coal chemical technology.
4. Research on resource regeneration and recycling technology.
5. Comprehensive utilization of green biochemical engineering. Such as coal desulfurization and microbial production of modern biotechnology.
Research on papermaking and biomass energy.
Concluding remarks
Looking forward to 2 1 century, the industrialization and urbanization of China will continue to develop, the population will increase, and the demand for chemical industry will also increase. Although the traditional chemical industry has made great contributions to pesticides, polymers, materials science, detergents, petroleum additives, water treatment and waste treatment, on the other hand, it has also brought negative effects of environmental pollution and increased environmental pressure. People's demands for improving the environment and quality of life are getting stronger and stronger. The CPC central Committee and the State Council have repeatedly stressed that environmental protection is a basic national policy of our country and an important part of the sustainable development strategy, which is directly related to the success or failure of modernization and the rejuvenation of the Chinese nation? ,? To speed up economic construction, we must never destroy the environment, never oppose or separate environmental protection from economic construction, and never take the old road of pollution before treatment, which is too costly? ,? Construction projects must implement environmental pollution prevention facilities and main projects? Three at once? (synchronous design, synchronous construction and synchronous operation). Vigorously promote cleaner production? ,? Prevent waste of resources? . Green chemistry and its? Atomic economy? As a basic principle, on the one hand, make full use of resources to prevent waste, on the other hand, realize? Zero emissions? Thereby achieving the effect of not polluting the environment. Therefore, it is of inestimable significance to the modernization of China and the future life of mankind. As long as we improve the level of science and technology, make good use of green chemical technology, do a good job in invigorating the economy, make the water of the motherland clearer, the sky bluer and the mountains and rivers more beautiful, and build a beautiful home for mankind.
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