Objectives (5 minutes)

1. Understand the concept of mole: Students should be able to define the concept of mole and understand that it is a unit of measurement used to express the amount of substance in a system, regardless of the type of substance.
2. Differentiate molar mass and molecules: Students should be able to distinguish molar mass, which is the mass of one mole of a substance, from molecules, which are the building units of substances.
3. Apply the concept of mole in chemical calculations: Students should be able to use the concept of mole to perform simple chemical calculations, such as determining the quantity of molecules or atoms in a sample, the mass of a sample knowing the number of moles, or the number of moles knowing the mass of a sample.

Secondary Objectives

• Stimulate active participation: In addition to the content objectives, the teacher should encourage active participation from students, promoting discussions and questioning.
• Develop problem-solving skills: The use of chemical calculations with the concept of mole will allow students to develop problem-solving skills, an essential competence for the Chemistry discipline.

Introduction (10 - 15 minutes)

1. Review of previous contents: The teacher should start the lesson by reviewing the concepts of atom, molecule, and substance that were learned in previous classes. This review can be done interactively, with questions to students to verify the retention of these concepts. (3 - 5 minutes)

2. Problem situations: The teacher can present two situations involving the concept of mole to arouse students' interest:

   • Situation 1: 'If we have one mole of iron atoms and one mole of oxygen atoms, what substance would we have?' (Answer: iron oxide, better known as rust.)
   • Situation 2: 'If we have one mole of carbon atoms and one mole of hydrogen atoms, what substance would we have?' (Answer: methane, the main component of natural gas.) (3 - 5 minutes)

3. Contextualization: The teacher should explain the importance of the concept of mole, showing how it is used in industry and everyday life. For example, the production of medications, material synthesis, food manufacturing, among others, depend on the understanding and use of the concept of mole. (2 - 3 minutes)

4. Introduction to the topic: To capture students' attention and introduce the topic in an interesting way, the teacher can:

   • Curiosity 1: Share that the concept of mole was introduced in the late 19th century by the Italian chemist Amedeo Avogadro, at a time when the existence of atoms was still debated.
   • Curiosity 2: Show how the concept of mole is used in the pharmaceutical industry to calculate the correct dosage of medications. For example, when reading the leaflet of a medication, it is common to find information that the recommended daily dose is 'x' milligrams per kilogram of body weight. This information can only be expressed in this way thanks to the concept of mole. (2 - 3 minutes)

Development (20 - 25 minutes)

1. Activity 1 - The Mole Game (10 - 12 minutes): The teacher divides the class into groups of five students and gives each group a set of cards. Each card represents an atom of a different substance (for example, carbon, hydrogen, oxygen, etc.). The goal of the game is, using the concept of mole, for the groups to combine the cards to form different substances. The first group to form a correct substance and present the answer to the teacher earns a point. The teacher can prepare a table with some substances and their respective chemical formulas to help the groups.

   • Step 1: The teacher distributes the cards to each group.
   • Step 2: The students, in their groups, start combining the cards to form different substances.
   • Step 3: When a group believes they have formed a correct substance, they present the answer to the teacher.
   • Step 4: The teacher checks if the answer is correct, and if it is, the group earns a point. If the answer is incorrect, the group continues trying.
   • Step 5: The game continues until all groups have had the opportunity to earn a point.

2. Activity 2 - Calculation with the Mole (10 - 12 minutes): Still in their groups, students will receive a series of problems involving calculations with the concept of mole. The problems may involve determining the molar mass of a substance, converting between molar mass and number of molecules, or determining the mass of a sample knowing the number of moles. The teacher should circulate around the room, guiding the groups and clarifying doubts.

   • Step 1: The teacher distributes the problems to each group.
   • Step 2: The students, in their groups, start solving the problems.
   • Step 3: When a group believes they have solved a problem, they present the answer to the teacher.
   • Step 4: The teacher checks if the answer is correct, and if it is, the group moves on to the next problem. If the answer is incorrect, the teacher guides the group to find the error and correct it.

3. Discussion (3 - 4 minutes): After the conclusion of the activities, the teacher should promote a classroom discussion so that students can share their experiences and learnings. The teacher should ask the groups what were the main difficulties encountered and how they were overcome. Additionally, the teacher can ask the groups to explain how they applied the concept of mole to solve the problems. This discussion will help consolidate students' understanding of the concept of mole and how it is applied in chemical calculations.

At the end of this stage, students should have a solid understanding of the concept of mole, the difference between molar mass and molecules, and the application of the concept of mole in chemical calculations. Additionally, they should have developed teamwork, problem-solving, and communication skills.

Return (10 - 15 minutes)

1. Group Discussion (5 - 7 minutes): The teacher should promote a group discussion with all students, where each group will have up to 3 minutes to share the solutions or conclusions they reached during the practical activities. The teacher should encourage students to share their perceptions and observations, as well as the difficulties they faced and how they overcame them. This will allow students to learn from each other and see different approaches to the application of the concept of mole.

   • Step 1: The teacher asks each group to select a representative to share their solutions or conclusions.
   • Step 2: Each group representative shares their insights with the class.
   • Step 3: The teacher promotes a discussion after each group shares, encouraging other students to ask questions and share their own observations.

2. Connection with Theory (3 - 5 minutes): After the group discussion, the teacher should make the connection between the practical activities and the theory presented at the beginning of the lesson. The teacher should reinforce the main concepts, highlighting how they were applied during the activities and clarifying any misunderstandings that may have arisen. Additionally, the teacher can ask students to identify which theoretical concepts were most important for solving the problems.

   • Step 1: The teacher summarizes the main concepts.
   • Step 2: The teacher asks students to identify which concepts were most important for solving the problems.
   • Step 3: The teacher clarifies any misunderstandings and answers any questions that may have arisen during the practical activities.

3. Individual Reflection (2 - 3 minutes): Finally, the teacher should propose that students reflect individually on what they learned during the lesson. The teacher should ask questions like:

   1. 'What was the most important concept you learned today?'
   2. 'What questions have not been answered yet?'
   3. 'How would you apply what you learned today in everyday situations or in other disciplines?'

   Students will have a minute to think about their answers and then will have the opportunity to share them with the class, if they wish.

   • Step 1: The teacher asks the reflection questions.
   • Step 2: Students reflect silently on the questions.
   • Step 3: The teacher gives students the opportunity to share their answers, if they wish.

This Return stage is crucial to consolidate students' learning, allowing them to reflect on what they learned, make connections with the theory, and apply the acquired knowledge in practical situations. Additionally, by promoting group discussion, the teacher encourages collaboration and the exchange of ideas among students, which can further deepen learning.

Conclusion (5 - 7 minutes)

1. Summary of Contents (2 - 3 minutes): The teacher should summarize the main points covered during the lesson. This includes the definition of mole, the difference between molar mass and molecules, and the application of the concept of mole in chemical calculations. The teacher should reinforce these concepts, highlighting their importance and how they interrelate. Additionally, the teacher should revisit the problem situations presented at the beginning of the lesson, now expecting that students are able to solve them based on the acquired knowledge.

   • Step 1: The teacher emphasizes the definition of mole and its importance.
   • Step 2: The teacher reinforces the difference between molar mass and molecules.
   • Step 3: The teacher revisits the initial problem situations, expecting that students can now solve them based on the concept of mole.

2. Theory-Practice Connection (1 - 2 minutes): The teacher should explain how the lesson connected theory and practice. They should emphasize that the concept of mole is a theoretical unit of measurement that was applied in practical situations, such as forming substances in the mole game and the calculations involving molecules.

   • Step 1: The teacher highlights how the lesson connected theory and practice.
   • Step 2: The teacher emphasizes that the concept of mole, despite being theoretical, is applicable in practical situations.

3. Additional Materials (1 - 2 minutes): The teacher should suggest additional study materials for students who wish to deepen their knowledge of the concept of mole. These materials may include explanatory videos, complementary texts, interactive chemistry websites, and additional exercises.

   • Step 1: The teacher suggests additional study materials.
   • Step 2: The teacher emphasizes the importance of reviewing and practicing the concept of mole.

4. Subject Importance (1 minute): Finally, the teacher should highlight the importance of the concept of mole for everyday life and science. They should explain that the concept of mole is used in a variety of areas, from the chemical and pharmaceutical industry to the kitchen, where the quantity of substances in a recipe is measured in moles.

   • Step 1: The teacher highlights the importance of the concept of mole in everyday life and science.
   • Step 2: The teacher concludes the lesson, reinforcing the relevance of the subject and encouraging students to continue studying and practicing the concept of mole.