Topic: Analysis reactions

Target group

Elementary school student (grades 7. and 8.)

Core curriculum

Elementary school. Chemistry.

III. Chemical reactions. Pupil:

2. gives examples of different types of reactions (synthesis reaction, analysis reaction, exchange reaction); indicates substrates and products.

General aim of education

The student explains the essence of the reaction of the analysis

Key competences

• communication in the mother tongue;

• communication in foreign languages;

• mathematical competence and basic competences in science and technology;

• digital competence;

• learning to learn.

Criteria for success
The student will learn:

• to write the analysis reaction equations along with the selection of reagemts, indication of substrates and products;

• to present on the models the analysis reaction;

• to draw the models of analysis reaction;

• to read and write the course of the chemical reaction verbally;

• to follow the safety rules when performing chemical experiments;

• to describe a chemical experiment, including glass and laboratory equipment, chemicals, schema, observations and conclusions.

Methods/techniques

• expository

  • talk.

• activating

  • discussion.

• exposing

  • film.

• programmed

  • with computer;

  • with e‑textbook.

• practical

  • exercices concerned.

Forms of work

• individual activity;

• activity in pairs;

• activity in groups;

• collective activity.

Teaching aids

• computers with internet access, or tablets;

• e‑textbook;

• interactive whiteboard, tablets/computers;

• methodician or green, yellow and red cards;

• equipment, laboratory glass and reagents;

• ball‑and‑ball models.

Lesson plan overview

Introduction

1. The teacher hands out Methodology Guide or green, yellow and red sheets of paper to the students to be used during the work based on a traffic light technique. He presents the aims of the lesson in the student's language on a multimedia presentation and discusses the criteria of success (aims of the lesson and success criteria can be send to students via e‑mail or posted on Facebook, so that students will be able to manage their portfolio).

2. The teacher together with the students determines the topic – based on the previously presented lesson aims – and then writes it on the interactive whiteboard/blackboard. Students write the topic in the notebook.

3. Health and safety – before starting the experiments, students familiarise themselves with the safety data sheets of the substances that will be used during the lesson. The teacher points out the need to be careful when working with them.

Realization

1. The teacher asks the students the message from the previous lesson asks: „What is the linking reaction and how can it be saved using symbols?”. Eager responders - the lecturer informs that this lesson will present the reverse reaction to the synthesis reaction.

2. The lecturer asks students how they would define the reaction of the distribution (analysis) - there is a discussion, after which the teacher displays the explanation of the concept on the multimedia presentation and presents the record of this equation with symbols.

3. The teacher asks you for a blackboard. He instructs him to record the course of chemical transformation (decomposition of mercury(II) oxide), including substrates and products and verbal recording, and then write down the chemical reaction equation using the symbols of elements and the formula of the chemical compound and balance the equation. The others write this information in the work sheets.

4. The teacher again divides the students into groups, distributes the ball‑and‑ball models and asks for the distribution of mercury(II) oxide decomposition. Controls the work of students, gives advice and checks the correctness of the task.

5. The volunteer writes on the table the distribution of hydrogen oxide (water), including substrates and products as well as the verbal notation, and then the equation of the chemical reaction with the symbols of elements and the chemical formula. He balances the equation - the other students write them in the work sheets.

6. The students, working in groups, arrange the equation of water distribution reaction with ball‑rod models. The teacher checks the correctness of the task.

7. The lecturer recommends students willing to write down the equations of decomposition of barium oxide, magnesium chloride and zinc sulphide on the board.

8. At the end of the lesson, the teacher asks students to do an interactive exercise - individual work.

Summary

1. The teacher asks the students to finish the following sentences:

   • Today I learned ...

   • I understood that …

   • It surprised me …

   • I found out ...

   The teacher can use the interactive whiteboard in the abstract or instruct students to work with it

Homework

1. Listen to the abstract recording at home. Pay attention to pronunciation, accent and intonation. Learn to pronounce the words learned during the lesson.

2. Make at home a note from the lesson using the sketchnoting method.

The following terms and recordings will be used during this lesson

Terms

Texts and recordings

Analysis reactions

Under appropriate conditions, water undergoes a reaction, which produces the elements it consists of. The course of this reaction is described by the equation:

$\text{water → oxygen + hydrogen}$

Note that in this reaction, two substances (oxygen and hydrogen) are formed from one substance (water).
Chemical transformation, during which at least two products are formed from one substrate, is called decomposition reaction or analysis reaction. It can be described using the scheme:

$\text{substrate → }{\text{product}}_{\text{1}}\text{ +}{\text{ product}}_{\text{2}}\text{ + …}$

The analysis reactions take place in our environment. They are also used in the industry to obtain useful elements and chemical compounds.

Process of obtaining of calcium oxide via the decomposition of the calcium carbonate takes place at high temperature. It can be described by the following reaction equations:

$\text{calcium carbonate }\stackrel{\mathrm{ temperature }}{\to }\text{ calcium oxide + carbon dioxide}$

${\text{CaCO}}_{\text{3}}\stackrel{\text{temperature}}{\to }{\text{ CaO + CO}}_{\text{2}}$

• The analysis (decomposition) reaction is a type of chemical reaction that results in at least two products from one substrate.

analysis reaction