Открытый урок химии на английском языке

Content: Types of chemical reactions

Teaching aims: To explain the difference between four different types of chemical reactions: composition, synthesis, single replacement, and double replacement. To study the classification of chemical reactions, to teach students to apply the knowledge about the types of chemical reactions in practice - to determine the types of chemical reactions and to characterize chemical reactions based on their classification

Students should be able to identify the type of reaction and predict the products of these types of reactions.

Learning outcomes Know: Classification of substances, how to distinguish types of chemical reactions Be able to: continue the formation of skills to observe, write down the equations of the reaction and arrange the coefficients, anticipate the products of chemical reactions Be aware: Replacement reactions can be completed only when there is residue of gases and poorly soluble substances (water formation). Replacement reactions can be completed with soluble substances only.

Assessment Assess the students’ ability to describe the types of reactions in their own words. If students are able to describe the reactions in terms of "boys" and "girls" then they have a basic understanding of the concept, but if they are able to explain the reactions in terms of metals and nonmetals then they have a deeper understanding. Also, the students' understanding can be further determined by their ability to identify the types of reactions on their own. Can the learners distinguish the reactions, arrange the coefficients, write down the equations of the reaction

Communication Vocabulary Revisited: Аtoms, molecules, simple and complex compounds; New vocabulary: Decomposition synthesis/combustion single/double replacement Structures: Passive voice, conditional, present/past simple Function: describing processes , comparing types of reaction, reading formulas

Examples of communication: Simple substances contain similar atoms whereas complex substances contain different atoms One complex substance decomposes into several simple or complex substances. This reaction is called decomposition reaction. For example: Fe+S FeS (1) SO2+O2 SO3 (2) H2 O+ SO3  H2 SO4(3) 2KClO32KCl +3O2(4)

Cognition: 1. Remembering 2. Understanding 3. Applying 4. Evaluating	Examples of cognition: Activating prior knowledge, i.e. “What is an atom?” Understanding videos, teacher’s speech, teacher’s instructions, worksheets content Applying given knowledge to complete worksheet tasks and activities Evaluating the work of other groups/providing feedback
Citizenship The sulfuric acid is produced by synthesis reaction in two stages	Examples of Citizenship Ust-Kamenogorsk Lead-Zinc plant
Resourсes and materials: video, Types of Chemical Reaction flowchart (picture), Worksheets 1,2,3, 4 5 a beaker, a vial, test tube stand, different kinds of reagents (hydrochloric acid, sodium carbonate)

I. Activating prior knowledge

Teacher asks following questions:

What is an atom? What is a molecule? What is a simple substance? Give examples. What is a complex substance? Give examples.

II. Lead-in

Students watch a short video clip then discuss what they have seen and guess what the topic is today. Ss may use L1 https://youtu.be/L2Q2q20KaEk

Questions

What is the video about? What did you see/understand? What do you think is the topic today?

III. Presenting new information

Gallery walk

Teacher cuts Worksheets 1 and 2 as indicated and hangs Worksheet 1 all over the classroom. Each strip of paper contains different chemical reactions definitions. Students in pairs use strips from Worksheet 2 to guess which chemical reaction is depicted on their worksheets.

T then provides an OCFB to elicit write answers, shows students Types of Chemical Reaction flowchart slide and gives uncut Worksheet 1.

Worksheet 2. What do you see? Describe each substance. Determine the type of reaction

Types of Chemical Reaction flowchart slide

Worksheet 1.

A synthesis reaction occurs when two or more substances combine to form one substance.

Most synthesis reactions involve two elements combining to form a compound.

A decomposition reaction occurs when one substance breaks down into two or more substances.

Most decomposition reactions involve one compound breaking down into two elements

A single replacement reaction occurs when a more active element replaces a less active ion in a compound.

Metals replace less active metals, nonmetals replace less active nonmetals.

A double replacement reaction occurs when two metallic ions switch places and one of the products is insoluble in water and forms a solid.

IV. Controlled practice

1. Teacher hands out Worksheet 3 where students working individually have to match the reactions with their equations. Then Ss compare their ideas in pairs. T provides OCFB

2. T hands out Worksheet 4 where Ss working in pairs have to balance the equation and indicate the type of chemical reaction. Then Ss work in groups of 4 to compare their ideas. At the end T provides OCFB

Worksheet 3

Match reactions with their name and place the coefficients

__ Al2(SO4) 3 + 3 Ca(OH) 2  3 CaSO4 + __Al(OH)3	1	combustion	A
Fe(OH)3  Fe2O3+ H2O	2	double replacement	C
___Al + __ Fe2O3  __ Fe + ___ Al2O3	3	decomposition	B
___Mg +___ Cl2  ___MgCl2	4	single replacement	D
__ C3H8 + ­­­­___ O2 ___ CO2 + ___ H2O	5	synthesis	E

Worksheet 4 For each of the reactions below, balance the equation and indicate which type of reaction it is.

1 group Type of reaction:

1. __ Na +__ O2  __ Na20 ________________________

2. __ SF6  __ S + __ F2 ________________________

3. __ Al + __ CuSO4  __ Cu + __ Al2 (SO4)3 ________________________

4. __ Pb(NO3)2 + NH4Cl  __ PbCl2 + NH4NO3 _______________________­­­­­­_

5. __ C6H14 + __ O2  __ CO2 + __ H2O ________________________

Worksheet 4 For each of the reactions below, balance the equation and indicate which type of reaction it is.

2 group Type of reaction:

6. __ Al2O3 + H2O  Al(OH)3 __________________________

7. __ Fe2O3  __ Fe +__ O2 __________________________

8. __ Zn + __ SnCl2 __ Sn + __ ZnCl2 __________________________

9. __ Cu(NO3)2 + __ Na2S  __ CuS + __ NaNO3 __________________________

10. __ Al(OH)3 + __ H2SO4 __Al2(SO4)3 + __ H2O __________________________

Worksheet 4 For each of the reactions below, balance the equation and indicate which type of reaction it is.

3 group Type of reaction:

11. __ C2H4 + __ O2  __ CO2 + __ H2O ___________________________

12. __ Ag + __ S  __ Ag2S ___________________________

13. __Al + __ Fe2O3  __ Fe + __ Al2O3 ____________________________

14. __ HgO  __ Hg + __ O2 ____________________________

15. __ KCl + __ AgNO3  __ AgCl + __ KNO3 ____________________________

Key to Worksheet 4

1 group Type of reaction:

1. __ Na + O2  Na20 synthesis/combustion

2. __ SF6  __ S + F2 decomposition

3. __ Al + __ CuSO4  __ Cu + __ Al2 (SO4)3 single replacement

4. __ Pb(NO3)2 + NH4Cl  __ PbCl2 + NH4NO3 double replacement

5. __ C6H14 + __ O2  __ CO2 + __ H2O combustion

2 group

6. __ Al2O3 + H2O  Al(OH)3 synthesis

7. __ Fe2O3  __ Fe +__ O2 decomposition

8. __ Zn + __ SnCl2 __ Sn + __ ZnCl2 single replacement

9. __ Cu(NO3)2 + __ Na2S  __ CuS + __ NaNO3 double replacement

10. __ Al(OH)3 + __ H2SO4 __Al2(SO4)3 + __ H2O double replacement3

3 group

11. __ C2H4 + __ O2  __ CO2 + __ H2O combustion

12. __ Ag + __ S  __ Ag2S synthesis

13. __Al + __ Fe2O3 __ Fe + __ Al2O3 single replacement

14. __ HgO  __ Hg + __ O2 decomposition

15. __ KCl + __ AgNO3  __ AgCl + __ KNO3 double replacement

V. Freer practice

T hands out Worksheet 5 where Ss working in groups of 5 or more people have to conduct a chemical experiment on different types of reactions. Instructions are given on the worksheet. At the end of the experiment they have to write down reaction equations, their observations and draw conclusions

Worksheet 5 (Group 1)

Task: conduct chemical reactions and decide which type is it

Equipment: chemical beaker, test tube.

Substances: zinc, hydrochloric acid, sodium carbonate, hydrochloric acid.

Procedure:

1. Place 2 zinc granules on the bottom of the tube and add 2 ml of hydrochloric acid solution. What do you see?

2. Pour 2 ml of sodium carbonate solution into the tube and add 2 ml of hydrochloric acid solution.

What do you see?

3. Make a report on the work done:

- write down the reaction equations;

- observations;

- draw conclusions (classify reactions according to a given characteristic).

Worksheet 5 (Group 2)

Task: conduct chemical reactions and decide which type is it

Equipment: a tripod for test tubes, test tubes

Substances: calcium carbonate decomposes on heating to calcium oxide and carbon dioxde.

Procedure:

1. Pour 1 ml of copper sulphate solution and the same solution of sodium hydroxide into the tube.

What do you see?

2. Pour 2 ml calcium carbonate of solution into the tube. The solution is mounted on a

3. Make a report on the work done:

- write down the reaction equations;

- observations;

- draw conclusions (classify reactions according to a given characteristic).

Worksheet 5 (Group 3)

Task: conduct chemical reactions conduct chemical reactions and decide which type is it

Equipment: a tripod with test tubes

Substances: sulfuric acid solution, potassium iodide solution, 3% hydrogen peroxide solution, manganese oxide (IV).

Procedure:

1. Pour a little potassium iodide solution into the tube and acidify it with sulfuric acid. Add 3% hydrogen peroxide solution. Pour the resulting solution into a tube with starch.

What do you see?

2. Equipment:

Substances: Sulfur. A few pieces of sulfur put on an iron spoon and heated. Sulfur will burn forming smoke in the form of sulfur dioxide gas.

What do you observe?

3. Make a report on the work done:

- write down the reaction equations;

- observations;

- draw conclusions (arrange the degree of oxidation of atoms, classify reactions according to a given characteristic).

VI. Feedback

T answers questions, provides feedback.

Ss discuss

What they have learned _____________

How they can apply it ______________

What was difficult _________________

Сan you write down your wishes and remarks “Two stars, One wish”.

Thank you for active participation.Now give me your thoughts and feedback. Lesson is over.

Good bye!