Objectives (5 - 7 minutes)

1. Understanding the concept of boiling point elevation: The teacher must ensure that students understand what boiling point elevation is and how it is applied in Chemistry. Students should be able to describe boiling point elevation as the phenomenon of raising the boiling point of a solvent when a non-volatile solute is added to it.

2. Differentiation between boiling point elevation and freezing point depression: The teacher should clarify the difference between boiling point elevation and freezing point depression, which is the raising of the boiling point and the lowering of the freezing point of a solvent, respectively, when a solute is added. This will allow students to correctly apply the concepts in real situations.

3. Application of boiling point elevation concepts: Students should be able to solve problems and apply boiling point elevation concepts in practical situations. This includes the ability to calculate the boiling point elevation using the ebullioscopic constant and the solute's molality.

Secondary Objectives:

• Stimulate critical thinking: The teacher should encourage students to think critically about the concepts learned and apply these concepts in different contexts.

• Promote teamwork: During practical activities, students should be encouraged to work in teams, promoting collaboration and effective communication among them.

Introduction (10 - 15 minutes)

1. Review of previous concepts: The teacher should start the lesson by reviewing the concepts of solutions, solvent, and solute, and the difference between dilute, concentrated, and saturated solutions. This can be done through a quick review, using practical examples and applying the concepts in everyday situations. (3 - 5 minutes)

2. Problem situation: Next, the teacher should present two problem situations that will serve as the basis for the theoretical development of the lesson. The situations can be:

   • "Why does water take longer to boil when we add salt to it?"
   • "Why do people living in coastal regions notice that water takes longer to boil than those living in inland regions?" These questions should stimulate students to think about the lesson's topic. (2 - 3 minutes)

3. Contextualization: Next, the teacher should contextualize the importance of the subject, explaining that boiling point elevation is an important phenomenon because many industrial and everyday processes are based on it. For example, it is thanks to boiling point elevation that salt is used to melt ice on roads in winter. (2 - 3 minutes)

4. Capturing students' attention: To arouse students' interest, the teacher can share some curiosities related to the subject. For example, the teacher can mention that boiling point elevation is the principle used in blood pressure monitors, and that it was thanks to this property that the first thermometers were created. Additionally, the teacher can propose a challenge: "How would you find the boiling point of a solvent if you didn't have a thermometer?" (2 - 3 minutes)

Development (20 - 25 minutes)

1. Boiling Point Elevation Theory (10 - 12 minutes):

   • Boiling Point Elevation Definition: The teacher should start explaining the concept of boiling point elevation, which is the phenomenon of raising the boiling point of a solvent when a non-volatile solute is added. It should be emphasized that the amount of boiling point elevation is directly proportional to the solute's molality.
   • Boiling Point Elevation Equation: The teacher should introduce the general equation of boiling point elevation: ΔTb = Keb x m x i, where ΔTb is the boiling point elevation, Keb is the ebullioscopic constant, m is the solute's molality, and i is the Van't Hoff factor, which represents the number of particles in which the solute dissociates.
   • Difference between Boiling Point Elevation and Freezing Point Depression: The teacher should reinforce the difference between boiling point elevation (raising the boiling point) and freezing point depression (lowering the freezing point), explaining that they are opposite phenomena but follow the same calculation logic.

2. Theory Application (5 - 7 minutes):

   • Application Examples: The teacher should now apply the theory to practical examples, such as the case of adding salt to water to make it take longer to boil. Step by step, the teacher should show how to calculate the boiling point elevation using the ebullioscopic constant and the solute's molality.
   • Practice Exercises: Students should be encouraged to solve simple practice exercises to ensure they understood the theory. The teacher should move around the classroom, assisting students with doubts and correcting the exercises.

3. Discussion and Clarification of Doubts (5 - 6 minutes):

   • Questions and Answers: The teacher should open a space for questions and answers, where students can clarify doubts and discuss the topic. It is important for the teacher to encourage everyone's participation and create an environment of respect and collaboration.
   • Exercise Correction: The teacher should correct the practice exercises together with the students, explaining the reasoning behind each step.

The lesson's Development should be organized to ensure that students fully understand the concept of boiling point elevation and can apply it in practical situations. It is important for the teacher to pay attention to the class's pace and adjust the lesson's progress according to the students' needs.

Return (8 - 10 minutes)

1. Review of Key Concepts (3 - 4 minutes): The teacher should start the Return phase by recalling the main concepts covered in the lesson. This includes the definition of boiling point elevation, the general equation of boiling point elevation, the difference between boiling point elevation and freezing point depression, and how to apply these concepts to solve practical problems. The teacher can do this in the form of a summary, highlighting the most important points and making connections between them.

2. Connection with Practice (2 - 3 minutes): Next, the teacher should show how the theory connects with practice. This can be done by reviewing the problem situations presented at the beginning of the lesson. The teacher can ask students if they can now understand why water takes longer to boil when we add salt to it, and why people living in coastal regions notice that water takes longer to boil than those living in inland regions. The teacher should encourage students to apply the learned concepts to explain these phenomena.

3. Individual Reflection (2 - 3 minutes): The teacher should then propose that students reflect individually on what they learned in the lesson. He can ask some questions like:

   1. "What was the most important concept you learned today?"
   2. "What questions have not been answered yet?"
   3. "How can you apply what you learned today in everyday situations?"

   Students should be encouraged to write down their answers, as this will help them consolidate what they learned and identify any gaps in their understanding that need to be filled.

4. Group Discussion (1 - 2 minutes): Finally, the teacher can propose a group discussion, where students can share their reflections and clarify any doubts they still have. This will help create a collaborative learning environment, where students feel comfortable expressing their ideas and learning from each other. The teacher should pay attention to any questions or misunderstandings that may arise during the discussion and address them effectively.

The Return is an essential part of the lesson, as it allows the teacher to assess students' understanding of the subject and make necessary adjustments to ensure everyone has understood. Additionally, by reflecting on what they learned, students are able to consolidate the acquired knowledge and apply it in real situations.

Conclusion (5 - 7 minutes)

1. Summary of Contents (2 - 3 minutes): The teacher should summarize the main points covered in the lesson, reinforcing the concepts of boiling point elevation and freezing point depression, the general equation of boiling point elevation, and how to apply these concepts to solve practical problems. He can use a board or slides to show the most important formulas and calculation steps.

2. Theory-Practice-Applications Connection (1 - 2 minutes): Next, the teacher should reinforce the connection between theory, practice, and applications. This can be done by recalling the problem situations discussed during the lesson and showing how the theoretical concepts were applied to solve them. Additionally, the teacher should emphasize the practical applications of boiling point elevation, such as in cooking, the pharmaceutical industry, and blood pressure monitors.

3. Supplementary Materials (1 - 2 minutes): The teacher should then suggest supplementary materials for students who wish to deepen their knowledge on the subject. This may include books, articles, videos, and educational websites. For example, the teacher can suggest that students watch an explanatory video on boiling point elevation, read a chapter from a Chemistry textbook on the subject, or visit a website where they can solve more practice exercises.

4. Subject Importance (1 minute): Finally, the teacher should emphasize the importance of the subject for students' daily lives. For example, he can say that understanding boiling point elevation can help students better understand why water takes longer to boil when we add salt to it, or why people living in coastal regions notice that water takes longer to boil than those living in inland regions. Additionally, the teacher can highlight that boiling point elevation is an important tool in many industrial and scientific processes.

The Conclusion is a fundamental part of the lesson, as it allows the teacher to summarize the main points covered, reinforce the connection between theory, practice, and applications, and suggest materials for additional study. Furthermore, by emphasizing the subject's importance, the teacher helps motivate students to continue learning and applying what they have learned in their daily lives.