Topic: Oxoacids – their properties and application

Target group

Elementary school student (grades 7. and 8.)

Core curriculum:

Elementary school. Chemistry.

VI. Hydroxides and acids. Student:

3) describes the properties and resulting applications of certain hydroxides and acids (e.g. NaOH, Ca(OH)Indeks dolny 2₂, HCl, HIndeks dolny 2₂SOIndeks dolny 4₄).

General aim of education

The student discusses the properties and resulting oxygen acids

Key competences

• communication in foreign languages;

• digital competence;

• learning to learn.

Criteria for success
The student will learn:

• to study the properties of selected acids;

• to apply the principles of handling concentrated solutions of acids;

• to list examples of applications of oxoacids.

Methods/techniques

• activating

  • discussion.

• expository

  • talk.

• 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

• e‑textbook;

• notebook and crayons/felt‑tip pens;

• interactive whiteboard, tablets/computers.

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 the properties of oxygen acids, asking them the question: „How is it that the same acid can be used to make cola‑like beverages, and at the same time it contains, for example, a liquid for rust removal of steel?” - discussion.

2. The lecturer joins the teacher's show - „Mixing sulfuric acid with water”. It also discusses other physical properties of sulfuric acid. Students make entries in diaries in abstract. Next, the teacher discusses the principles of preparing solutions of acids with water, justifying the saying „Remember the young chemist, always pour acid into the water”.

3. The teacher informs students that they will watch the film „Investigating the effect of sulfuric acid on sugar”. He asks them to formulate a research question and hypothesis and write them in the diary in abstract. After viewing the video, the students are to write their observations and conclusions in an abstract diary.

4. The teacher presents another show - „Testing properties of nitric acid”. Students are watching changes. The teacher refers to a characteristic reaction - a xantoprotein reaction. Students make appropriate entries in the diary in abstract. The lecturer also discusses other physical properties of nitric acid. The teacher can mention here royal water, a substance that dissolves gold and platinum.

5. The teacher presents the show - „Testing properties of phosphoric acid”. Students are watching changes; discussion is underway. The lecturer also mentions other physical properties of phosphoric acid.

6. The teacher divides the students into three task groups (groups can be 6, each two receive the same tasks). Each team, using abstract and other available sources, develops applications of sulfuric acid, nitric acid and phosphoric acid. Then the groups suspend the prepared posters on the wall. Using the technique of a talking wall, the leaders report the effects of work.

7. Teacher asks students to do interactive exercises from abstract in pairs.

Summary

1. The student indicated by the teacher sums up the lesson, telling what he has learned and what skills he/she has been practicing.

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.

The following terms and recordings will be used during this lesson

Terms

Texts and recordings

Oxoacids – their properties and application

Anhydrous sulphuric acid is a thick, colourless, oily liquid. The concentrated acid of the formula ${\text{H}}_2{\text{SO}}_{\text{4}}$ is its 98% aqueous solution and is commonly used in laboratories. How can we dilute some of the concentrated acid solutions, e.g. sulphuric acid?

Concentrated solutions of many acids are caustic substances, therefore be careful when working with them. Recall the importance of warning pictograms.

Concentrated nitric acid is an aqueous solution of the acid with the following formula $\text{HN}{\text{O}}_{\text{3}}$ with a concentration of approx. 68%. It has sharp and unpleasant odour and caustic properties. It was famous polish chemist Ignacy Mościcki, who developed a method of obtaining nitric acid from air and water.

Nitric acid is a colourless liquid well soluble in water. Reacts with most metals, including copper and argentum. Gold and platinum are not affected by the reaction.

Pure phosphoric acid is solid at room temperature (in the form of crystals). It dissolves very well in water, has highly hygroscopic properties. Commercial, concentrated solution contains approx. 85 – 90% of ${\text{H}}_3{\text{PO}}_4$.

Sulphuric acid, due to its hygroscopic properties, is used, for example, in the laboratory to dry test substances. Its 33% solution is used in batteries as an electrolyte that allows the conversion of chemical energy into electricity.

Nitric acid is an important raw material used in the chemical industry, including for the production of fertilizers, explosives and cardiac medicines.

Oxoacids are not only the inorganic acids discussed, but also organic acids found in everyday life: oxalic, citric, lactic, acetic acids. These are ingredients of many food products.

• Concentrated acids – sulphuric acid and nitric acid – are highly corrosive substances. When diluting them, add acid to water.

• Concentrated sulphuric acid has hygroscopic properties.

• Concentrated nitric acid is used to detect substances containing protein (xanthoproteic reaction).

oxoacids, nitric acid, phosphoric acid, sulphurous acid, sulphuric acid, xanthoproteic reaction