Objectives (5 minutes)

1. Introduce the concept of mole and mole number to students, explaining that the mole is a fundamental unit of measurement in chemistry that represents a fixed quantity of entities, such as atoms, ions, electrons, or molecules.
2. Enable students to calculate the number of moles in a sample, using the formula N = m/M, where N is the number of moles, m is the mass of the sample, and M is the molar mass of the substance.
3. Develop students' ability to apply the formula to solve practical problems, such as determining the number of moles in a sample of a given substance.

Secondary Objectives:

• Stimulate students' curiosity and interest in chemistry, showing the importance of the mole concept in understanding many chemical phenomena.
• Promote active student participation through group discussions and problem-solving, encouraging critical thinking and collaboration.

Introduction (10 - 15 minutes)

1. Review of previous concepts:

   • The teacher should start the lesson by briefly reviewing the concepts of mass, molar mass, and atoms, which are fundamental to understanding the mole number.
   • It is important for students to understand that mass is a measure of the amount of matter in an object and that molar mass is the mass of one mole of a substance, expressed in grams.
   • The teacher can reinforce these concepts with practical examples and question the students to verify if they understood.

2. Problem situations:

   • Next, the teacher can present two problem situations to arouse students' curiosity and introduce the topic.
   • The first situation could be: 'If we have a sample of 10 grams of carbon, how many carbon atoms will we have?'
   • The second situation could be: 'If we have a sample of 5 grams of oxygen, how many oxygen molecules will we have?'
   • The teacher can ask students to think about these situations and make predictions about the answers.

3. Contextualization:

   • The teacher should then explain to students that the concept of mole number is fundamental in many applications of chemistry, from the preparation of medications to understanding the processes that occur in a battery.
   • The teacher can present examples of how the mole number is used in practice, such as in determining the amount of a reagent that must be added to a chemical reaction to produce a specific product.

4. Attention gain:

   • To capture students' attention, the teacher can share some curiosities about the mole number.
   • For example, the teacher can mention that the mole number in one mole is called Avogadro's Number and is a fundamental constant in chemistry, with a value of approximately 6.022 x 10^23.
   • The teacher can also mention that, according to the Big Bang theory, the amount of matter in the universe is proportional to the mole number, highlighting the importance of this concept.

Development (20 - 25 minutes)

1. Activity 'The Laboratory Mystery' (10 - 15 minutes):

   • The teacher divides the class into groups of 4 to 5 students and provides each group with a box containing various laboratory materials (e.g., test tubes, balance, reagent bottles, etc.) and an activity sheet.
   • The activity sheet contains a series of questions that students must answer using the concept of mole number. For example:
     1. 'If we have 15 grams of hydrogen, how many hydrogen atoms will we have?'
     2. 'If we have one mole of water, how many water molecules will we have?'
     3. 'If we have 10 grams of table salt (NaCl), how many moles of table salt will we have?'
   • Students should use the laboratory materials to help them answer the questions, weighing the samples and consulting the periodic table to obtain molar masses. They should also discuss the answers in groups and justify their conclusions.
   • After completing the activity, each group should present their answers and explanations to the class.

2. Group Discussion (5 - 10 minutes):

   • The teacher should facilitate a group discussion about the students' answers and their strategies for solving the questions.
   • The teacher can ask questions to stimulate students' critical thinking, such as 'Why did you choose this strategy to solve the question?' or 'What did you learn from this activity?'

3. Activity 'Building a Mole' (5 - 10 minutes):

   • To make the concept of mole more tangible, the teacher can propose the activity 'Building a Mole'.
   • The teacher provides each group with a set of cards, each representing an atom or molecule of a certain substance (e.g., carbon, oxygen, water, etc.), and asks students to assemble one mole of a specific substance (e.g., one mole of water).
   • Students should use their mole number calculation skills to determine how many of each type of card they need to build one mole of the given substance.
   • This activity not only helps reinforce the concept of mole but also the visualization of the number of particles in one mole of a substance.

4. Activity 'Molecule Quiz' (5 - 10 minutes):

   • To conclude the Development part of the lesson in a fun way, the teacher can propose the 'Molecule Quiz'.
   • The teacher prepares a list of multiple-choice questions about the mole number and distributes an answer sheet to each group.
   • Each question is followed by a limited time for group discussion and selection of the answer.
   • At the end of the quiz, the group with the highest number of correct answers is declared the winner.
   • This activity serves to reinforce the concept of mole number in a fun and competitive way.

Throughout all activities, the teacher should circulate around the room, providing guidance and support when needed, and observing students' progress for formative assessment.

Return (10 - 15 minutes)

1. Group Discussion (5 - 7 minutes):

   • The teacher should promote a group discussion with all students, where each group will share their solutions or conclusions from the activities carried out.
   • Each group will have a maximum of 3 minutes to present their findings, thus allowing all groups the opportunity to share.
   • During the presentation, the teacher should encourage students to explain the reasoning behind their solutions and highlight the difficulties encountered and how they were overcome.

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

   • After the presentations, the teacher should make a connection between the activities carried out and the theory of the mole number.
   • The teacher should reinforce the concept that the mole number is a measure of the amount of matter and can be calculated from the sample's mass and the substance's molar mass.
   • The teacher can use examples from the activities to illustrate how the calculation of the mole number is applied in practice.
   • It is important for the teacher to address any doubts that may arise during this connection to the theory, ensuring that all students have a clear understanding of the concept.

3. Individual Reflection (3 - 5 minutes):

   • To conclude the lesson, the teacher should propose that students reflect individually on what they have learned.
   • The teacher can ask questions such as: 'What was the most important concept you learned today?' and 'What questions have not been answered yet?'.
   • Students will have a minute to think about these questions and then will be invited to share their answers with the class.
   • This individual reflection will allow students to consolidate their learning and identify any gaps in their understanding that may need to be addressed in future lessons.

4. Feedback and Closure (1 minute):

   • The teacher should thank everyone for their participation, reinforce the importance of the mole number concept, and inform that any remaining doubts will be clarified in the next lesson.
   • Students should also be informed about the homework assignment, which may involve solving additional problems related to the mole number.

The Return is a crucial stage of the lesson plan, as it allows the teacher to assess students' progress, verify if the learning objectives were achieved, and plan the next teaching steps. Additionally, it provides students with the opportunity to reflect on what they have learned and identify areas that need further study.

Conclusion (5 - 7 minutes)

1. Recapitulation (2 - 3 minutes):

   • The teacher should start the Conclusion by summarizing the main points covered during the lesson.
   • This includes the definition of mole, the concept of mole number, and the formula for calculating the number of moles in a sample.
   • The teacher can reinforce these concepts with practical examples and question the students to verify if they can explain the concepts in their own words.

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

   • Next, the teacher should explain how the lesson connected the theory, practice, and application of the mole number concept.
   • The teacher can highlight how practical activities, such as 'The Laboratory Mystery' and 'Building a Mole', allowed students to apply the theory in a concrete and visual way.
   • Additionally, the teacher can emphasize how the mole number concept is essential for understanding and solving practical problems in chemistry.

3. Supplementary Materials (1 minute):

   • The teacher can suggest supplementary materials for students to deepen their understanding of the mole number.
   • This may include textbooks, educational videos, interactive chemistry websites, and additional practice problems.
   • The teacher can provide some specific recommendations and explain how these materials can help students consolidate what they learned in the lesson.

4. Importance of the Mole Number (1 minute):

   • Finally, the teacher should emphasize the importance of the mole number in everyday life.
   • The teacher can mention examples of how the mole concept is used in various applications, from food preparation to drug manufacturing.
   • The teacher can also emphasize that the mole number is an essential tool for chemists, as it allows quantifying the amount of matter present in a sample, facilitating the understanding and manipulation of chemical reactions.

The Conclusion is a crucial stage to ensure that students have understood the lesson content and can apply what they have learned in future situations. By connecting theory, practice, and application, the teacher helps students see the relevance and usefulness of the mole number concept.