Objectives (5 - 7 minutes)

1. Understanding the Concept of Molar Mass: Students should be able to understand the definition and concept of molar mass, as well as its importance in Chemistry. This includes the ability to calculate the molar mass of a compound.

2. Application of Molar Mass in Converting between Mass and Mol: Students should be able to apply the concept of molar mass to convert between the amount of substance (in mol) and the mass (in grams) of a substance.

3. Problem Solving Using the Relationship between Mass, Mol, and Molar Mass: Students should be able to solve problems involving the relationship between mass, mol, and molar mass. This includes the ability to identify the amount of substance (in mol) from the mass (in grams) and vice versa, using the molar mass.

Secondary Objectives

• Development of Critical Thinking: Through problem-solving, students should be encouraged to develop critical thinking skills, such as the ability to analyze, synthesize, and apply acquired knowledge.

• Encouragement of Autonomous Learning: Students should be encouraged to seek understanding of the topic outside the school environment, using resources such as books, videos, and Chemistry websites. This will help strengthen learning and retention of the content.

Introduction (10 - 12 minutes)

1. Review of Previous Content: The teacher should start the lesson by briefly reviewing the concepts of mole and the importance of the amount of substance in Chemistry. This can be done through a quick conceptual review or a short oral quiz. (2 - 3 minutes)

2. Problem Situations: The teacher can present two situations to the students involving the conversion between mass and mol. For example:

   • "If we have 10 grams of water, how many moles of water do we have?"
   • "If we have 3 moles of carbon dioxide, what is the mass of the gas in grams?" (3 - 4 minutes)

3. Contextualization of Theory: The teacher should explain to the students that molar mass is a chemical property that allows us to calculate the mass of a substance in a unit called mole. This unit is fundamental for Chemistry, as it is through it that we can perform stoichiometric calculations, which are important for the preparation of chemical reactions and in the industry. (2 - 3 minutes)

4. Introduction to the Topic: The teacher should introduce the topic of molar mass in a way that sparks the students' interest. This can be done through curiosities, such as:

   • "Did you know that the molar mass of gold is 197 grams per mole? This means that to have one mole of gold, we need a quantity of gold weighing 197 grams. This is a huge amount considering that one gram of gold is already considered very valuable!"
   • "And what do you think is the molar mass of a water droplet? The answer is surprising: a water droplet has a mass of about 0.05 grams, and the molar mass of water is 18 grams per mole, which means that in a water droplet, we have over 300 trillion water molecules!" (3 - 4 minutes)

Development (20 - 25 minutes)

1. Practical Activity: "Building the Molar Mass Table" (10 - 12 minutes)

   • Material Preparation: The teacher should prepare colored cards in advance, where each color represents a different chemical element, along with a periodic table. Each card should contain the element's symbol, atomic number, and molar mass. The periodic table should be made available for reference.

   • Activity Description: Students will be divided into groups of 4, and each group will receive a set of cards. They should organize the cards into a table, placing the elements in ascending order of atomic mass. The teacher should move around the room, assisting the groups and asking questions to stimulate discussion and critical thinking.

   • Activity Objective: The objective of this activity is to help students understand the relationship between an element's position in the periodic table and its molar mass. They will also be practicing reading and interpreting the periodic table, essential skills for Chemistry.

2. Playful Activity: "Molecular Battle" (10 - 12 minutes)

   • Material Preparation: The teacher should prepare battle cards in advance, where each card represents a different chemical compound. Each card should contain the compound's name, chemical formula, and molar mass. The teacher should also prepare a battle "board," divided into squares, where students will position their cards.

   • Activity Description: Students will be divided into groups, and each group will receive a set of battle cards. Each battle card represents a chemical compound that the students will "battle." For each round, the teacher will announce a property (for example, "higher molar mass wins"). The students then choose a battle card from their set and place it on the board. The card with the announced property wins the round. The group that wins more rounds is the winner of the battle.

   • Activity Objective: The objective of this activity is to help students understand the relationship between molar mass and the properties of compounds. Additionally, they will be practicing reading and interpreting chemical formulas, essential skills for Chemistry. This activity also helps develop teamwork and students' argumentation skills.

3. Discussion and Synthesis (5 - 6 minutes)

   • After the conclusion of the activities, the teacher should facilitate a classroom discussion where students will have the opportunity to share their discoveries and difficulties. This discussion can be guided by questions from the teacher, such as "What did you learn from this activity?" or "What were the biggest challenges encountered?".

   • The teacher should take advantage of this discussion to make the necessary connections between the activities and the theory, reinforcing the concepts of molar mass, mole, and the relationship between mass, mol, and molar mass.

Return (8 - 10 minutes)

1. Group Discussion (3 - 4 minutes)

   • The teacher should gather all students and promote a group discussion about the solutions or conclusions that each group reached during the activities. This helps to share different perspectives and enrich students' understanding of the topic.
   • The teacher should encourage students to explain their answers or solutions, ensuring that everyone has the opportunity to speak. He can also ask additional questions to deepen students' understanding of the topic.

2. Connection between Activities, Theory, and Practical Applications (2 - 3 minutes)

   • The teacher should then make the connection between the activities carried out, the theory presented, and the practical applications of the concept of molar mass. For example, he can explain how the ability to calculate the molar mass of a compound is useful in various situations, such as in the preparation of chemical reactions, in the pharmaceutical industry, in food analysis, among others.
   • The teacher should also highlight how the activities carried out helped reinforce theoretical concepts and develop practical skills, such as interpreting the periodic table, reading and interpreting chemical formulas, and solving problems involving the relationship between mass, mol, and molar mass.

3. Individual Reflection (2 - 3 minutes)

   • Finally, the teacher should propose that students reflect individually on what they learned in the lesson. He can ask questions like:
     1. "What was the most important concept learned today?"
     2. "What questions have not been answered yet?"
   • The teacher should emphasize that reflection is an important step in the learning process, as it helps students consolidate acquired knowledge, identify areas of difficulty, and set goals for future learning.

4. Feedback and Closure (1 minute)

   • The teacher should thank the students for their participation and effort during the lesson. He can also request quick feedback on the lesson, asking students what they liked the most and what they think could be improved.
   • The teacher should then conclude the lesson, reinforcing the importance of the concept of molar mass and the ability to convert between mass and mol, and encouraging students to continue exploring the topic outside the classroom.

Conclusion (5 - 7 minutes)

1. Summary of Main Contents (2 - 3 minutes)

   • The teacher should start the Conclusion by recalling the main points covered during the lesson. This includes the concept of molar mass, the relationship between mol and mass, and the conversion between mass and mol using molar mass. The teacher can do this briefly but clearly to consolidate students' understanding.

2. Connection between Theory, Practice, and Applications (1 - 2 minutes)

   • Next, the teacher should highlight how the lesson connected theory, practice, and applications of the concept of molar mass. For example, he can mention how the activity of building the molar mass table and the playful activity "Molecular Battle" helped visualize and apply the concept of molar mass. Additionally, the teacher should reinforce the practical applications of the concept, such as in the preparation of chemical reactions and in the pharmaceutical industry.

3. Supplementary Materials (1 minute)

   • The teacher should then suggest some complementary study materials for the students. This may include textbooks, Chemistry websites, explanatory videos, and online exercises. For example, the teacher can recommend a YouTube video that explains the concept of molar mass clearly and interestingly, or an interactive website where students can practice the conversion between mass and mol.

4. Importance of the Subject (1 - 2 minutes)

   • Finally, the teacher should emphasize the importance of the subject presented for students' daily lives. For example, he can explain how the ability to convert between mass and mol is useful in various everyday situations, such as in the kitchen, in food analysis, and in understanding news about Chemistry and Physics. The teacher should also emphasize that the concept of molar mass is fundamental for the study of other Chemistry topics, such as stoichiometry and solution concentration.

5. Closure (1 minute)

   • The teacher should end the lesson by thanking the students for their participation and reinforcing the importance of study and continuous practice for effective learning of Chemistry. He should encourage students to continue exploring the topic outside the classroom and to ask their questions in the next lesson or during office hours.