Objectives (5 - 7 minutes)

1. Understanding the Concept of Mole:

   • Students should be able to define the concept of mole, understanding that it is a unit of measurement used in chemistry to express the amount of substance containing a specific number of elementary entities.
   • They should also understand that the concept of mole is one of the most fundamental ideas in modern chemistry, allowing the connection between the macroscopic and microscopic scales.

2. Relationship between Mole, Molar Mass, and Avogadro's Number:

   • Students should be able to understand the relationship between the number of moles, the molar mass of a substance, and Avogadro's number.
   • They should be able to calculate the amount of matter in moles, based on the molar mass and the mass of a substance.

3. Application of the Concept of Mole in Practical Problems:

   • Students should be able to apply the concept of mole to solve practical problems involving calculations of the amount of matter, molar mass, and Avogadro's number.
   • They should be able to perform conversions between mass, number of moles, and number of elementary entities.

Secondary Objectives:

• Develop problem-solving skills, critical thinking, and logical reasoning through the application of the concept of mole in different contexts.
• Stimulate curiosity and interest in chemistry, showing how understanding the concept of mole can be useful in understanding everyday chemical phenomena.

Introduction (10 - 12 minutes)

1. Review of Previous Content:

   • The teacher should start the lesson with a brief review of the concepts of atom, molecule, atomic mass, and molecular mass, which are essential for understanding the concept of mole. (3 - 4 minutes)

2. Problem Situations:

   • The teacher can propose two problem situations to arouse students' interest and introduce the topic.
     • The first one could be: 'If a glass of water contains about 3 x 10^23 molecules, how many moles of water are there in a 1,000-liter lake?'
     • The second one: 'If the mass of a hydrogen atom is about 1.67 x 10^-24 grams, what is the mass of 1 mole of hydrogen atoms?' (4 - 5 minutes)

3. Contextualization:

   • The teacher should explain the importance of the concept of mole in chemistry, showing how it is used to measure the quantity of substances in chemical reactions and how it helps to understand chemical phenomena at a microscopic level.
   • For example, the teacher can mention how the concept of mole is used in the pharmaceutical industry to produce medicines, in the food industry to control the quality and safety of food, and in scientific research to understand and develop new materials. (2 - 3 minutes)

4. Topic Presentation:

   • The teacher should then present the topic of the lesson: 'Mole Number: Introduction'.
   • Should explain that the goal of the lesson is to understand what a mole is, how it relates to molar mass and Avogadro's number, and how to use it to solve practical problems. (2 - 3 minutes)

Development (20 - 25 minutes)

1. Theory: Mole, Molar Mass, and Avogadro's Number (10 - 12 minutes):

   • The teacher should start by explaining what a mole is. Should clarify that the mole is a unit of measurement used in chemistry to express the amount of substance containing a specific number of elementary entities. Should emphasize that one mole of any substance contains the same number of elementary entities, which is called Avogadro's number (about 6.022 x 10^23 entities/mol).
   • Next, should introduce the concept of molar mass, which is the mass of one mole of a substance, expressed in grams/mol. Should explain that the molar mass of an element is numerically equal to its atomic mass, and that the molar mass of a molecule is the sum of the atomic masses of all atoms in its chemical formula.
   • Finally, should explain the relationship between the number of moles, molar mass, and Avogadro's number. Should clarify that the number of moles of a substance is equal to its mass (m) divided by its molar mass (M). Should also explain that the number of elementary entities (N) is equal to the number of moles (n) multiplied by Avogadro's number (N_A), that is, N = n x N_A.

2. Problem Situations Resolution (5 - 7 minutes):

   • The teacher should then return to the problem situations presented in the Introduction and guide students in solving them. Should reinforce that solving these problems involves the application of the theory of mole, molar mass, and Avogadro's number.
   • For the first problem situation, the teacher should explain that, to calculate the number of moles of water in a lake, we first need to calculate the number of moles in a glass of water and then multiply that value by the volume of the lake in liters.
   • For the second problem situation, the teacher should explain that, to calculate the mass of 1 mole of hydrogen atoms, we need to multiply the mass of a hydrogen atom by Avogadro's number.

3. Guided Practice (5 - 6 minutes):

   • The teacher should then propose some exercises for guided practice. The exercises should involve the conversion between mass, number of moles, and number of elementary entities.
   • For example, the teacher can ask students to calculate the number of moles and the number of atoms in 50 grams of oxygen, or to calculate the mass of 3 moles of helium gas.
   • The teacher should guide students during the resolution of the exercises, clarifying doubts and providing feedback.

4. Group Discussion (3 - 4 minutes):

   • To conclude the Development phase, the teacher should promote a group discussion on the importance of the concept of mole in chemistry and in other areas of science and technology.
   • The teacher should encourage students to share their insights and reflections, and to make connections between the concept of mole and everyday chemical phenomena, such as food preparation, medicine production, and energy generation.

Return (8 - 10 minutes)

1. Review and Reflection (3 - 4 minutes):

   • The teacher should start the Return stage by reviewing the main points covered in the lesson.
   • Should ask students to reflect on what they have learned and to identify the most important concepts.
   • The teacher should highlight the relationship between the number of moles, molar mass, and Avogadro's number, and how this concept can be applied to solve practical problems.
   • The teacher should also recall the problem situations proposed at the beginning of the lesson and ask students to explain how they were solved.

2. Connection to Practice (2 - 3 minutes):

   • The teacher should then ask students to reflect on how the concept of mole can be applied in different contexts.
   • For example, can ask questions like: 'How can the concept of mole be useful to understand and solve problems related to food preparation?' or 'How can the concept of mole be applied in the pharmaceutical industry or in scientific research?'
   • The teacher should encourage students to make connections between the concept of mole and everyday chemical phenomena, and to realize the importance of this concept for the understanding and application of chemistry.

3. Feedback and Doubts (2 - 3 minutes):

   • The teacher should then ask students to provide feedback on the lesson.
   • Can ask, for example: 'What did you find most interesting in today's lesson?' or 'What were the main challenges you faced when trying to apply the concept of mole to solve the proposed problems?'
   • The teacher should also open space to clarify any doubts students may have and to provide feedback on their performance in solving the proposed problems.

4. Final Reflection (1 minute):

   • To conclude the lesson, the teacher should propose that students reflect on what they have learned.
   • Can ask: 'What was the most important concept you learned today?'
   • The teacher should encourage students to think about how they can apply what they learned in the lesson in their daily lives, in future chemistry classes, and in other subjects.

Conclusion (5 - 7 minutes)

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

   • The teacher should start the Conclusion by recalling the main points covered during the lesson.
   • Should recap the concept of mole, the relationship between the number of moles, molar mass, and Avogadro's number, and how to apply this concept to solve practical problems.
   • The teacher should also review the importance of the concept of mole in chemistry and in other areas of science and technology, emphasizing how it allows the connection between the macroscopic and microscopic scales.

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

   • The teacher should explain how the lesson connected the theory of the concept of mole with the practice of problem-solving and with the applications of this concept in different contexts.
   • Should reinforce that guided practice and the resolution of problem situations allowed students to apply what they learned and develop problem-solving skills, critical thinking, and logical reasoning.

3. Additional Materials (1 minute):

   • The teacher should suggest some complementary study materials for students who wish to deepen their knowledge of the concept of mole.
   • Can, for example, indicate educational videos, reference texts, interactive websites, e-books, and additional exercises.

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

   • Finally, the teacher should summarize the importance of the concept of mole for students' daily lives, for chemistry as a whole, and for other areas of science and technology.
   • Can mention, for example, how the concept of mole is used in the pharmaceutical industry to produce medicines, in the food industry to control the quality and safety of food, and in scientific research to understand and develop new materials.
   • The teacher should encourage students to continue exploring and applying the concept of mole, and should reinforce the importance of chemistry as a tool to understand and transform the world around us.