Topic: Obtaining salts in reactions of acids with metals

Target group

Elementary school student (grades 7. and 8.)

Core curriculum:

Primary school. Chemistry.

VII. Salts. Student:

3) writes the reaction equations for obtaining salts (acid + hydroxide (e.g. Ca(OH)Indeks dolny 2₂), acid + metal oxide, acid + metal (groups 1 and 2 of the periodic system), hydroxide (NaOH, KOH, Ca(OH)Indeks dolny 2₂) + non‑metal oxide, metal oxide + non‑metal oxide, metal + non‑metal) in molecular form.

General aim of education

The pupil gets to know the salt in the acid + metal reaction

Key competences

• communication in foreign languages;

• digital competence;

• learning to learn.

Criteria for success
The student will learn:

• to write verbosimally the reaction equation: acid + metal;

• to write down the reaction equations of some metals with acids leading to the formation of salt;

• to explain the essence of the reaction between acid and metal.

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 performs a demonstration of the experiment described in the abstract „Testing the reaction of metals with a dilute solution of sulfuric acid”. First, he asks students to formulate a research question and hypotheses and to write them in the form in an abstract, and then conducts the experiment. Summarizes the observations with the students, asks them to note them in the form in an abstract. Writes on the board the reaction equation in the form of molecular, ionic and shortened ion. He explains the mechanism of this reaction. The teacher asks to formulate the application resulting from this experience and to note it in the form in an abstract.

2. The teacher begins the screening of the film with the experiment „Study of reaction of magnesium with hydrochloric acid”. After viewing the title of the experiment, the movie stops. He asks students to formulate a research question and hypotheses and to write them in the form in an abstract, and then continues to play the recording. He summarizes the observations, formulates the conclusion resulting from the experiment and asks the students to note them in the form in an abstract. An eager student writes the equations of the reaction on the board in the form of molecular, complete ionic and net ionic, modeled on the scheme of the previous chemical reaction equation.

3. The teacher asks students (work in pairs) to do interactive exercises.

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

2. 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.

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

Methodological note:

Comment to the experiment “Testing the reaction of copper(II) oxide with sulphuric acid”

When throwing the metal into the acid solution, close the test tube mouth with a cap to collect the escaping gas (it is hydrogen, a very light gas that migrates immediately to the atmosphere), and when placing burning wooden skewer next to the test tube outlet, pull the cap out - you will hear a characteristic crackling, puffing, barking (stated in various ways in the literature).

The following terms and recordings will be used during this lesson

Terms

Texts and recordings

Obtaining salts in reactions of acids with metals

Some metals, such as zinc, magnesium, aluminium and iron, react with hydrochloric acid. These reactions produce corresponding salts and give off hydrogen. We say that these metals displace hydrogen from acid. There are metals, such as copper, which do not react with hydrochloric acid.

Chemists have ordered metals according to their changing chemical activity. This order is called the activity series of metals. There are usually two ways of presenting metals in this collection: by their decreasing or increasing chemical activity. Hydrogen, which has been listed in this series, separates metals into those that displace it from acids and those that do not have such property.

The following example shows metals ordered by their decreasing chemical activity.

Based on the activity series of metals, we can conclude that, for example, sodium displaces hydrogen from acid (salt and hydrogen are created). The reaction of this metal with hydrochloric acid is described in the following equation:

$\text{2Na + 2HCl → 2NaCl + }{\text{H}}_{\text{2}}\text{↑}$

$\text{sodium + hydrochloric acid → sodium chloride + hydrogen}$

On the basis of the activity series, we can predict that copper, mercury, silver, gold and platinum will not displace hydrogen from acids. However, we cannot assess whether they will or will not react with nitric acid or sulfuric acid to produce products other than hydrogen.

• Some metals react with acids with hydrogen evolution. The second product of this reaction is salt.

• Copper does not displace hydrogen from acids.

• Based on the activity series of metals, we can assess whether a metal displaces hydrogen from acids.