Several common salt classes

Textbook version used: compulsory education curriculum standard experimental textbook-Chemistry (People's Education Press).

First, teaching design ideas

(A) Basic concepts

Let students know the colorful chemical world closely related to human beings with a relaxed and happy mood. Actively explore the mysteries of chemistry and form an interest in continuing to learn chemistry.

② Starting from students' existing experience, let them feel the importance of chemistry in familiar life scenes and understand the close relationship between chemistry and daily life. Gradually learn to analyze and solve some simple practical problems related to chemistry.

(3) Let students actively experience the inquiry process and gradually form the awareness and ability of lifelong learning.

(2) Design concept

This topic is closely related to human production and life, and also to the development of society. In teaching design, we should pay attention to connecting with social reality, arouse students' enthusiasm and initiative, let students explore new knowledge in a strong desire for knowledge, turn boring into vivid, and regard learning as a kind of enjoyment; On the other hand, the curriculum design should be as close as possible to students' real life, so that students can feel, experience and compare through a large number of objects, videos and pictures, and deepen their understanding and application of what they have learned. The design of this topic is divided into two categories. The first lesson introduces the composition of sodium chloride, calcium carbonate, sodium carbonate and sodium bicarbonate and their main uses in life, and grasps the inspection method of carbonate ions. The second lesson introduces the purification and displacement reaction of raw salt.

Second, the teaching background analysis

(A) the role and status of classroom teaching content

This lesson introduces several common salts in life: sodium chloride, sodium carbonate, sodium bicarbonate, calcium carbonate and the inspection of carbonate and bicarbonate ions. This course uses multimedia teaching to introduce the preparation process of sodium chloride, the formation process of stalagmites and stalactites that students are familiar with, to ensure the audio-visual combination of students with rich forms of expression, to mobilize students' various senses to participate in classroom activities, to show their chemical charm, and to stimulate students' interest in learning and desire to explore. Discuss with students and show some properties and uses of sodium chloride, calcium carbonate, sodium carbonate and sodium bicarbonate. Provide every student with equal learning opportunities, so that they have the necessary chemical knowledge and skills to adapt to modern life and future society, and enhance their confidence in learning chemistry well. Let students understand that chemistry is closely related to human production and life, and truly embody "from life to chemistry" and "from chemistry to society". Through students' inquiry experiments, we should pay attention to cultivating students' inquiry consciousness, enhancing students' inquiry ability, and let students increase their knowledge in practice and feel the close connection between chemistry and social production and life reality. Cultivate students' cooperative spirit and sense of participation in the activities, and embody the teaching methods of cooperative learning and teacher-student interaction. So as to achieve the three-dimensional goals of knowledge and skills, process and method, emotion, attitude and values. Finally, let the students look up the deeds of Mr. Hou who has made great contributions to China soda industry online with a relaxed and happy mood.

This lesson is the last part of the knowledge of elemental compounds. Based on the familiar substances around students, we can learn more about salt systematically by understanding the properties and uses of common salt around us. Furthermore, we have a systematic understanding of the properties, applications, transformation rules and chemical reactions of acids, bases and salts, and we can also comprehensively summarize the classification and universality of inorganic compounds, which will play a summary role in the study of chemistry knowledge in junior high school and lay a good foundation for the future study of chemistry.

(B) Analysis of students' situation

Existing knowledge and life experience: I know that salt, sodium carbonate, sodium bicarbonate and calcium carbonate are common salts in life, salt is the most common condiment in life, and sodium carbonate and sodium bicarbonate are the main components of common baking powder, which are used to steam steamed buns; Calcium carbonate is a common building material; Understand the properties and uses of common acids and bases (for example, the reaction of sodium carbonate and calcium carbonate with hydrochloric acid can produce CO2); There is also a wrong concept: "salt", which is often used in life, is often equivalent to salt in the material classification of chemical concepts.

Basic ability: After nearly a year's study, students have gained certain ability in chemistry. Able to solve some practical problems by chemical methods, with basic experimental skills and simple experimental design ability.

Learning methods and skills: organizing discussion and carrying out inquiry activities are important ways to learn this topic well. It is more challenging to make full use of students' thirst for knowledge and existing knowledge to set up inquiry activities, which is conducive to students mastering the scientific methods of analyzing and solving problems.

Third, the teaching objectives

Knowledge and skills

1. Remember the components of common salts such as sodium chloride, sodium carbonate, sodium bicarbonate, calcium carbonate, etc., and tell their main uses in life;

2. Learn the inspection method of carbonate ion; ;

(2) Process and method

1. Explore the reaction between carbonate and acid through experiments, learn the inspection method of carbonate ions, and further understand and experience the process of scientific inquiry;

2. Through the analysis, comparison and induction of experiments, we can understand the relationship between knowledge and form a reasonable cognitive structure.

Emotions, attitudes and values

1. Experience the fun of success in the process of scientific experiment inquiry and stimulate the interest in learning chemistry;

2. Understand that chemical knowledge comes from life and serves life, and there is chemistry everywhere in life;

Feel the importance of chemistry in the process of human development, understand the close relationship between chemistry and daily life, and believe that chemistry will continue to play an important role in realizing the bright future of mankind.

Fourth, the focus of teaching

The relationship between chemistry and life and production.

3. Test method of carbonate ion.

Five, the teaching difficulties of carbonate ion testing method.

Six, teaching supplies, teaching means and main teaching methods

realia

Instruments: test tubes, alcohol lamps, matches, etc.

Drugs: salt, sodium carbonate, sodium bicarbonate, calcium carbonate, dilute hydrochloric acid, limewater, etc.

Teaching methods: computer and experiment.

The main teaching method is experimental inquiry (creating situation-experimental inquiry-induction-knowledge application).

Seven. teaching process

Teacher-led activity, student-led activity design intention

[Introduction] Sodium ion combustion experiment

Careful students may find that natural gas sometimes has a yellow flame when cooking. We know that burning natural gas will produce a blue flame. Do you want to know who is burning? Please see the experiment:

(Sprinkle salt on the flame of alcohol lamp)

[Explanation] Salt is the salt we are most familiar with. Today, we are going to learn about common salt in life. Listen-because of thinking.

Watch the experiment

Uncover the mystery: the yellow flame you see when cooking is caused by salt.

Starting with the familiar life scenes of students, this paper explains the common phenomena in life through experiments and realizes the close relationship between chemistry and life.

I. Sodium chloride

According to what the students talk about the use of salt, guide the students to summarize the use of sodium chloride in medicine, agriculture, food, industry and transportation.

The use of sodium chloride projection: the use of sodium chloride.

Introduce the wonderful use of salt in life;

(1) When taking a bath, adding a small amount of salt to the water can make the skin firm.

⑵ Flowers planted in light salt water will not fade for several days.

(3) Newly bought glassware should be rubbed with salt and should not be fragile.

(4) When washing colored clothes, soak them in 5% salt solution for 10 minute, and then wash them, so that the color will not fade.

5] Bronze rust or black spots can be wiped off with salt.

[6] Eating by mistake is toxic, and drinking some salt water can detoxify.

..... sort out and summarize:

1. Medically: prepare physiological saline (100g water contains 0.9g medical sodium chloride), disinfect with physiological saline, and rinse your mouth.

1. In agriculture: 10%- 16% sodium chloride solution is used for seed selection.

3. Food industry: pickled vegetables, fish, meat, eggs, etc. Adding salt makes these foods unique in flavor and prolongs the shelf life.

4. Industry: important chemical raw materials.

5. Traffic: Spraying sodium chloride on snow can melt the snow on the road and reduce accidents.

Students look at the pictures.

Understand some wonderful uses of salt in daily life. Let students learn the methods of induction and arrangement.

Salt is a substance that students are very familiar with, so that students can learn chemistry in their familiar life situations and understand the close relationship between chemistry and daily life. Solving practical problems in life can stimulate students' enthusiasm for learning chemistry, arouse their thirst for knowledge and make them feel that learning is useful.

Physiological functions of sodium chloride:

Description: Salt is an important condiment. Most edible sodium chloride exists in body fluids in the form of ions. Sodium ion: maintain normal water distribution inside and outside the cell and promote material exchange inside and outside the cell. Chloride ion is the main component in gastric juice, which can promote the production of hydrochloric acid, help digestion and stimulate appetite. Salt supplementation can supplement sodium chloride discharged by sweating and urination. It should be noted that you can't eat too much salt for a long time. Too little sodium ion intake will make potassium ions enter the blood, thicken the blood and yellow the skin. Listen and let the students know the important physiological functions of sodium chloride.

3. Introduce the distribution of sodium chloride:

Ask questions:

Do the students know that there is a lot of sodium chloride in those places?

4. Preparation of salt:

Do you want to know how to extract salt from seawater?

Play video:

(1) seawater drying salt:

Natural extraction of sodium chloride: the water in seawater, salt lakes and salt wells evaporates until it is saturated, and then the salt will be precipitated. The salt made in this way contains many impurities, also called crude salt.

Projection: Yantian

Do you want to know how to make salt in industry?

② Play video: the process of industrial salt production. Students read, think and answer:

There are a lot of sodium chloride in seawater, salt lakes, salt wells and salt mines in nature.

Watch videos and pictures to gain new knowledge.

Watch the video to understand the general process of industrial salt production. Develop the study habit of reading and thinking, and enhance students' understanding and inductive ability.

Make students realize the close relationship between chemistry and production through multimedia demonstration.

Stimulate students' desire to explore and understand several salt-making methods.

5. Salt and table salt

Have you ever heard of salt poisoning?

Play video:

(1) Information on poisoning caused by cooking food with industrial salt.

(2) Information about illegal traders curing food with industrial salt.

Guide the students to put forward the difference between salt and table salt.

Introduction: Several kinds of poisonous salts.

Sodium nitrite and copper sulfate

Discuss and exchange information.

Watch the video and think:

Why is salt edible and some salt inedible?

Students answer after discussion:

The difference between salt and table salt: table salt is not equal to salt, table salt is a substance, table salt is a substance, table salt is a salt. Create a problem scenario.

Let students perceive, experience and compare through concrete objects, deepen their impression of correct knowledge, correct wrong ideas and complete their understanding and application of new knowledge.

Second, the use of calcium carbonate.

Ask questions:

1. Have you ever seen or touched limestone in your life?

What substances containing calcium carbonate did the students collect?

Show me a piece of limestone and a toothpaste.

3. What is the connection between limestone and toothpaste?

Description: One ingredient in toothpaste is made of limestone, just like limestone. This ingredient is calcium carbonate (CaCO3).

(4) What is the purpose of calcium carbonate?

Summary:

Calcium carbonate is widely used in the construction industry. The main component of natural limestone and marble is calcium carbonate. It can also be used as calcium supplement.

Ask questions:

Have you visited this cave? Projected picture:

Do you know how these stalagmites and stalactites are formed?

The formation process of stalagmites and stalactites is introduced.

Description: Karst caves are mostly distributed in limestone mountains. The main component of limestone is calcium carbonate, which will react with water dissolved with carbon dioxide to produce more soluble calcium bicarbonate. When the water in which calcium bicarbonate is dissolved is heated or the pressure drops suddenly, the calcium bicarbonate dissolved in the water will decompose, so that calcium carbonate can be regenerated and deposited, and carbon dioxide will be released at the same time. When the water at the top of the cave slowly leaks downward, the calcium bicarbonate in the water will react as mentioned above, answering questions and communicating.

Show the physical objects containing calcium carbonate collected in life, and introduce the purpose of the physical objects. (limestone, marble, white marble)

Think boldly, associate, guess.

Draw a conclusion:

There is no connection between limestone and toothpaste.

② The main components in limestone and toothpaste are the same.

The use of calcium carbonate collected by reading newspapers, books and periodicals or through the Internet before students exchange classes.

look at the picture

Listen and explain.

Combine students' existing knowledge and experience, and gain new knowledge through * * * learning.

Guide students to guess, provoke students' thinking contradictions, and stimulate students' desire to explore.

Cultivate students' cooperative learning ability.

Combine practical and geographical knowledge to show the charm of chemistry and stimulate students' interest. Cultivate students' feelings of loving the great rivers and mountains of the motherland.

activity

Explore the reaction between carbonate and acid

[Explanation] Calcium carbonate can react with dilute hydrochloric acid to generate CO2, so can sodium carbonate and sodium bicarbonate have similar reactions?

[Projection] Exploration of experiment;

Reaction of carbonate with acid

Thinking and discussing

Viewing projection

Group experiment and comparative analysis.

complete the table

Learn the inspection method of carbonate. Learn to analyze the experimental conclusions and summarize the rules through comparative analysis.

Homework: P75, question 65438 +0, question 2. Students finish and consolidate what they have learned after class.

Eight, the characteristics of instructional design

1. Introduce a new lesson-"Yellow Flame in Cooking" experiment from the familiar life scene of students, stimulate students' interest in learning, experience the close relationship between chemistry and life, realize the reasonable transfer of knowledge, correct students' misconceptions, and clearly realize that the yellow flame in the burning of alcohol and natural gas is caused by salt, which will lay a foundation for studying color reaction in the future.

2. Strengthen experimental inquiry teaching. Scientific inquiry is an important learning method and practical activity for students to actively acquire chemical knowledge, understand and solve chemical problems. This class creates inquiry activities, and through personal experience and understanding of the scientific inquiry process, it stimulates the interest in learning chemistry and enhances self-confidence in learning chemistry well.

Nine, teaching reflection

1. Attention should be paid to stimulating students' thinking and cultivating their innovative spirit and practical ability.

2. Be good at discovering the bright spots of students' thinking, give encouragement and praise in time, further stimulate students' creativity, and let students want to learn, learn and learn.

X. Blackboard Design

Common salt in life

Sodium chloride. Inspection of carbonate ion and bicarbonate ion

1. Use of sodium chloride

2. Physiological function of sodium chloride

3. Distribution of sodium chloride

4. Preparation of salt

5. Salt and table salt

Two. The use of calcium carbonate. Use of sodium carbonate and sodium bicarbonate

1. Widely used in the construction industry.

2. Formation of stalagmites and stalactites

enclose herewith