Objectives (5 - 10 minutes)

1. Understanding Colligative Properties: Students should be able to understand the concept of colligative properties and how they apply in Chemistry. They should be able to identify and explain vapor pressure as one of these properties.

2. Identification of Vapor Pressure: Students should be able to identify vapor pressure as a colligative property. They should understand that vapor pressure is the pressure exerted by the vapors of a substance in equilibrium with the liquid or solid phase.

3. Calculation of Vapor Pressure: Students should be able to calculate the vapor pressure of a solution using Raoult's law. They should understand that Raoult's law can be used to determine the vapor pressure of each component in a solution.

Secondary Objectives:

• Practical Application: Students should be able to apply the concept of vapor pressure and Raoult's law in practical situations, such as determining the vapor pressure of a solvent in a solution.

• Development of Problem-Solving Skills: Students should be able to apply the formulas and concepts learned to solve vapor pressure problems. They should develop critical thinking and problemsolving skills during the process.

Introduction (10 - 15 minutes)

1. Review of Related Content: The teacher should remind students of the concepts of solutions, solvents, and solutes that were previously studied. They can bring examples of common solutions, such as saltwater or the air we breathe, to contextualize the subject. (3 - 5 minutes)

2. Problem Situation 1: The teacher can propose the following problem situation: 'Imagine you have two solutions, one of pure water and another of saltwater. If we leave both solutions in an open container, which one will evaporate more quickly? Why?' This situation will set the stage for the Introduction of vapor pressure as a colligative property. (3 - 5 minutes)

3. Contextualization: The teacher should emphasize the importance of studying colligative properties, explaining that they have practical applications in various fields, such as the food industry, pharmaceuticals, and beverage production. They can give examples of how vapor pressure is used in these industries to control evaporation and process temperature. (2 - 3 minutes)

4. Problem Situation 2: The teacher can propose another problem situation: 'In the pharmacy, ethanol (ethyl alcohol) is sold in different concentrations. What do you think changes in its use depending on the ethanol concentration? How can vapor pressure be related to this?' This situation will motivate students to understand how vapor pressure can vary with solute concentration. (2 - 3 minutes)

5. Introduction to the Topic: The teacher should introduce the topic of vapor pressure as a colligative property, explaining that it is related to the behavior of particles of a substance in a solution. They can spark students' interest by showing images of real experiments that demonstrate the variation of vapor pressure with solute concentration. (2 - 3 minutes)

Development (20 - 25 minutes)

1. 'Liquid Mixture' Activity: For this activity, students will need two miscible liquids (such as water and alcohol) and a glass balloon. The activity will be carried out in groups of up to five students.

   • Step 1: Each group should fill the glass balloon with an equal amount of water and alcohol. The balloon should be sealed with a piece of plastic film and kept at room temperature.

   • Step 2: After some time, students will notice that the balloon starts to inflate. The teacher should explain that this occurs due to the difference in vapor pressure between the two liquids. Alcohol has a higher vapor pressure compared to water, causing more alcohol molecules to pass into the gas phase and inflate the balloon.

   • Step 3: Students should discuss in their groups what they observed and how it relates to vapor pressure and colligative properties. The teacher should circulate around the room, guiding the discussions and clarifying doubts.

   • Step 4: Each group should then propose an explanation for the observed phenomenon, using the concepts of vapor pressure and colligative properties. They should identify the solvent (water) and the solute (alcohol) and explain how vapor pressure varies with solute concentration.

   This practical activity will allow students to see in practice how vapor pressure varies with solute concentration, one of the fundamental concepts of colligative properties.

2. 'Vapor Pressure Game' Activity: In this playful activity, students will be divided into two teams and will have to answer questions about vapor pressure and colligative properties.

   • Step 1: The teacher should prepare the questions and answers for the game in advance. The questions should cover the key concepts of vapor pressure and Raoult's law.

   • Step 2: Each team should choose a representative to answer the question. If the answer is correct, the team earns a point. If the answer is wrong, the question passes to the opposing team.

   • Step 3: The game should continue until all questions have been answered. The team with the most points at the end of the game is the winner.

   This playful activity will help reinforce students' understanding of vapor pressure and colligative properties in a fun and engaging way.

3. 'Vapor Pressure Calculation' Activity: In this activity, students will calculate the vapor pressure of a solution using Raoult's law.

   • Step 1: The teacher should provide the solute concentration and the vapor pressure value of the pure solvent. Students should then calculate the vapor pressure of the solution.

   • Step 2: Students should work in groups of up to five, discussing their answers and the necessary steps to reach them.

   • Step 3: Each group should present their calculations and discuss their answers with the class. The teacher should provide feedback and clarify any doubts students may have.

These practical and playful activities will help make learning about vapor pressure and colligative properties more interesting and engaging for students, allowing them to apply the concepts learned in real-world situations.

Feedback (10 - 15 minutes)

1. Group Discussion (5 - 7 minutes): The teacher should lead a group discussion with all students, where each group shares the solutions or conclusions they reached during the activities. This will allow students to hear different perspectives and approaches to the same problem, promoting the exchange of ideas and collaborative learning. The teacher should ensure that all key concepts, such as vapor pressure and Raoult's law, are mentioned and discussed during the conversation.

   • Step 1: The teacher should ask each group to share their conclusions from the 'Liquid Mixture' activity. They should explain how vapor pressure varied with solute concentration and how this relates to colligative properties.

   • Step 2: Next, the teacher should ask each group to share the questions and answers they used during the 'Vapor Pressure Game'. They should explain why they chose these questions and how the answers relate to vapor pressure and Raoult's law.

   • Step 3: Finally, the teacher should ask each group to explain how they calculated vapor pressure in the 'Vapor Pressure Calculation' activity. They should discuss the steps they followed and any difficulties they encountered.

2. Connection to Theory (2 - 3 minutes): After the group discussion, the teacher should make the connection between the activities carried out and the theory presented in the lesson Introduction. They should emphasize how the practical activities helped illustrate the concepts of vapor pressure and colligative properties and how Raoult's law can be applied to calculate the vapor pressure of a solution.

3. Individual Reflection (3 - 5 minutes): The teacher should then propose that students reflect individually on what they learned during the lesson. They can ask questions like:

   • Question 1: What was the most important concept you learned today?
   • Question 2: What questions have not been answered yet?
   • Question 3: How can you apply what you learned today in real-world situations?

   Students should have a minute to think about their answers to each question. The teacher can ask some volunteers to share their answers with the class, promoting a final discussion and clarifying any remaining doubts.

4. Feedback and Closure (1 - 2 minutes): Finally, the teacher should provide feedback on students' performance during the lesson and encourage them to continue studying the topic at home. They can suggest additional resources, such as books or videos, that students can use to deepen their understanding of vapor pressure and colligative properties. The teacher should end the lesson by reinforcing the importance of the topic studied and how it applies to everyday life.

Conclusion (5 - 10 minutes)

1. Summary of Contents (2 - 3 minutes): The teacher should recap the main points covered during the lesson, reinforcing the definition of vapor pressure, colligative properties, and Raoult's law. They should highlight how vapor pressure is affected by solute concentration and how this has practical applications. The teacher should also review the main discussions and conclusions of the practical activities carried out.

2. Connecting Theory with Practice (1 - 2 minutes): The teacher should explain how the lesson connected theory with practice. They can highlight how the 'Liquid Mixture' and 'Vapor Pressure Calculation' activities allowed students to apply the theoretical concepts of vapor pressure and colligative properties in real situations. The teacher should emphasize the importance of understanding the theory to be able to solve practical problems.

3. Supplementary Material (1 - 2 minutes): The teacher should suggest additional study materials for students. This may include chemistry books, educational websites, explanatory videos, and online exercises. The teacher should emphasize that independent study is essential to deepen understanding of the topic and improve academic performance.

4. Relevance of the Subject (1 - 2 minutes): Finally, the teacher should emphasize the importance of the subject studied for everyday life. They can cite examples of how colligative properties, including vapor pressure, are used in the food, pharmaceutical, and chemical industries. The teacher should encourage students to think of other examples of real-world applications, reinforcing the relevance of what was learned.

5. Closure (1 minute): The teacher should end the lesson by thanking students for their active participation and reinforcing the importance of continuous study. They can remind students about upcoming classes and assignments, and be available to clarify any further doubts.