Topic: Oxoacids – how to obtain them and their structure

Target group

Elementary school student (grades 7. and 8.)

Core curriculum:

Elementary school. Chemistry.

VI. Oxoacids. Student:

1) recognizes acid formulas; writes the sum formula of acids: HNOIndeks dolny 3₃, HIndeks dolny 2₂SOIndeks dolny 3₃, HIndeks dolny 2₂SOIndeks dolny 4₄, HIndeks dolny 2₂COIndeks dolny 3₃, HIndeks dolny 3₃POIndeks dolny 4₄ and give their names;

2) designs and ponducts an experiment, which results in the production of the oxygen acid HIndeks dolny 3₃POIndeks dolny 4₄; writes the corresponding reaction equations in the molecular form;

3) describes the properties and resulting applications of some acids (eg. HIndeks dolny 2₂SOIndeks dolny 4₄).

General aim of education

The student acquires knowledge and skills about the topics discussed in the classes

Key competences

• communication in foreign languages;

• digital competence;

• learning to learn;

• mathematical competence and basic competences in science and technology.

Criteria for success
The student will learn:

• define the concept of oxoacid;

• design methods for the production of oxoacids;

• describe the construction of oxoacids;

• to describe the structure of the indicated acid and construct a model of its molecule;

• to write verbally the reaction equation for the production of oxoacids;

• to design and perform an experiment to obtain an oxoacids, e.g. HIndeks dolny 2₂SOIndeks dolny 3₃ or HIndeks dolny 3₃POIndeks dolny 4₄

Methods/techniques

• expository

  • talk.

• activating

  • discussion.

• exposing

  • film;

  • exposition.

• programmed

  • with computer;

  • with e‑textbook.

• practical

  • experiment.

Forms of work

• individual activity;

• activity in pairs;

• activity in groups;

• collective activity.

Teaching aids

• e‑textbook;

• notebook and crayons/felt‑tip pens;

• interactive whiteboard, tablets/computers;

• sets for building particle models;

• methodician or green, yellow and red cards.

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 introduces students to the issue of aerobic acids. He asks them the question: „Why do you think the sparkling water is slightly acid? What is the reason? „- the discussion is directed.

2. The teacher informs students that they will watch the film „Obtaining sulfuric acid” from the abstract. Before this happens, they are to formulate a research question and hypotheses and write them in the form in the abstract. During the show, students should observe and note the changes taking place. After the material is broadcast, the teacher asks: „What was the reason for the change you observed in the flask at the end of the experiment? As evidenced by the change in the color of methyl orange in red? - discussion and formulation of the resulting application, and then recording it in the form.

3. The lecturer writes on the board and explains the equation of reaction that took place during the experiment. Then he gives away the rod‑ball models and asks students to present the mechanism of sulfuric acid reaction reaction on the models - work in pairs.

4. The teacher, referring to the previously presented film, refers students to the abstract and asks them to follow the instructions: „Based on the film >>Obtaining sulfurous acid

5. The teacher conducts a teacher's show according to the instructions presented in the abstract (experiment 1). Students analyze the experiment presented by the teacher and compare their ideas with it. In the form, they write a research question and a hypothesis, followed by observations and conclusions.

6. The teacher writes on the board and at the same time explains the equation for the reaction of obtaining phosphoric acid. He asks students to present the reaction mechanism for the production of phosphoric acid on the models - work in pairs.

7. The teacher instructs students to present a diagram of the equation for the production of aerobic acids based on the reaction for the preparation of sulfuric acid and phosphoric acid. An eager student writes a verbal response to the board in words.

8. The teacher asks students to think about and propose equations for the reaction of obtaining sulfuric, nitric and carbonic acid according to the verbal scheme of the equation of obtaining oxygenated acids - work in pairs. Volunteers approach the board and write equations on it.

9. The teacher writes all oxygen acids in the column (one below the other), separates the hydrogen atoms from the acidic ones with a vertical line, calls them elements and writes the general formula of acids, and then, by activating the students, formulates with them the definition of acids. Students make entries in notebooks. Then the teacher recalls them to the abstract and helps them to analyze the data from the table „Oxoacids”.

10. Students, working individually or in pairs, carry out interactive exercises to check and consolidate knowledge learned during the lesson. Selected people discuss the correct solutions for interactive exercises. The teacher completes or straightens the statements of the proteges.

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

Methodological commentary:

Teacher demonstration “Preparation of phosphoric acid” – problem‑verification experiment

List of required materials/teaching aids

Laboratory equipment and glassware: gas burner, beaker, conical flask, matches/lighter, lab spoon, aluminium foil, dropping funnel

Reagents: water, red phosphorus, methyl orange

Performing the experiment

1. Pour approx. 5 cmIndeks górny 3³ of water into the flask, add 2‑3 drops of methyl orange.

2. Place a small amount of red phosphorus on the lab spoon and place it in the flame of the gas burner until the phosphorus ignites, then transfer the spoon to the flask with water and keep it above the water until phosphorus combusts, cover the outfall of the flask with aluminium foil, so that gas does not escape.

3. After combustion of the phosphorus, remove the spoon from the flask, stir the contents of the flask until the gas disappears.

4. Observe the changes.