Objectives (5 - 7 minutes)

1. Understand the concept of solubility product (Ksp) and its relationship with equilibrium in saturated solutions.
2. Apply Ksp to predict the solubility of a slightly soluble salt in water.
3. Calculate Ksp from the solubility of a salt in water.

Secondary Objectives:

1. Develop calculation skills and application of chemical formulas.
2. Stimulate logical-mathematical reasoning skills.
3. Encourage research and autonomous study on the subject.

Introduction (10 - 15 minutes)

1. Review of Previous Contents:

   • The teacher will start the class by reviewing important concepts that were previously studied and are fundamental for the understanding of the topic of the day. The concepts of solubility, saturated solutions, ions in solution, and chemical equilibrium will be reviewed.

2. Initial Problem Situations:

   • The teacher will present two problem situations to arouse students' interest and contextualize the subject. The first situation will involve understanding why some salts, despite being solids, dissolve in water, while others do not. The second problem situation will involve understanding how it is possible to predict the solubility of a slightly soluble salt in water.

3. Contextualization:

   • The teacher will explain the importance of the subject in everyday life, showing examples of practical applications, such as in the pharmaceutical industry (in drug development), in food production (in product quality control), and even in forensic analysis (in substance identification).

4. Engaging Students' Attention:

   • The teacher will introduce the topic by sharing two curiosities. The first one is that the famous diamond, despite being one of the hardest known substances, is easily dissolved in concentrated sulfuric acid due to a chemical reaction that occurs. The second curiosity is that the color of many fireworks is determined by the dissolution of different salts in aqueous solutions, which is directly related to the solubility equilibrium of these salts.

After the Introduction, students should be motivated and prepared to learn about solubility equilibrium and solubility product.

Development (20 - 25 minutes)

1. Theory:

   • Solubility Product (Ksp) Definition: The teacher will explain that Ksp is a chemical equilibrium constant that relates the concentration of ions in a saturated solution of a slightly soluble salt. The general formula for calculating Ksp will be presented, which is the product of the concentrations of each of the ions of the dissolved substance raised to their respective stoichiometric coefficients.
   • Concept of Equilibrium in Saturated Solutions: Next, the teacher will reinforce the concept of chemical equilibrium, explaining that in a saturated solution, the rate of ion dissolution in water is equal to the rate of precipitation of these ions, resulting in an equilibrium state.
   • Application of Ksp in Solubility Prediction: The teacher will demonstrate how Ksp can be used to predict the solubility of a slightly soluble salt in water. Solubility rules will be presented, which are based on the comparison between the value of Ksp and the product of the concentrations of the ions present in the solution.
   • Calculating Ksp from Solubility: Finally, the teacher will teach how to calculate the value of Ksp from the solubility of a salt. The formula for calculating Ksp from molar solubility will be presented, which is the amount of substance dissolved in one liter of solution.

2. Practical Examples:

   • The teacher will propose some practical examples to illustrate the application of the theory. For example, students will be asked to predict the solubility of a slightly soluble salt in water, given the value of Ksp and the concentration of ions in a solution. Then, they will be asked to calculate the value of Ksp from the molar solubility of a salt.
   • The teacher may also propose a more complex problem involving the comparison of solubilities of different salts based on their Ksp values. This will allow students to apply the theory more deeply and develop analysis and synthesis skills.

3. Group Discussion:

   • The teacher will divide the class into small groups and ask them to discuss the proposed practical examples. Each group should present their conclusions to the class, promoting idea exchange and developing argumentation skills.
   • The teacher should guide the discussion, clarifying doubts, correcting possible errors, and reinforcing key concepts.

4. Return to Theory:

   • The teacher will provide a brief summary of the main points discussed during the class, reinforcing the concept of Ksp, the application of Ksp in predicting solubility, and calculating Ksp from molar solubility.
   • If time allows, the teacher may propose a quick quiz to assess students' understanding of the topic. If there are doubts, the teacher should clarify them clearly and didactically.

At the end of the Development, students should be able to understand and apply the concept of solubility product, as well as calculate Ksp from the solubility of a salt in water.

Return (8 - 10 minutes)

1. Reflection on Learning:

   • The teacher will ask students to reflect individually on what they learned during the class. They should mentally answer the following questions:
     1. What was the most important concept you learned today?
     2. What questions have not been answered yet?
   • After a minute of reflection, the teacher will ask students to share their answers out loud. This will allow the teacher to assess students' level of understanding and identify possible gaps in learning.

2. Connection to Everyday Life:

   • The teacher will ask students to identify everyday situations related to the class topic. For example, they can think of examples of slightly soluble salts used at home (such as table salt) or in industry (such as calcium carbonate, used in cement production). Then, students should explain how the concept of solubility product applies to these situations.
   • The teacher may also suggest some practical applications of the class topic, such as in the pharmaceutical industry (in drug development), in food production (in product quality control), and even in forensic analysis (in substance identification). Students should discuss how the knowledge acquired in class can be useful in these areas.

3. Feedback and Evaluation:

   • The teacher will ask for feedback from students about the class, inquiring about what they liked the most and what they found most challenging. This will help the teacher plan future classes according to students' needs and interests.
   • The teacher can also use this moment to assess students' learning. For example, students may be asked to write down everything they learned about the class topic in one minute. Or the teacher may ask oral questions to check students' understanding. Based on students' answers, the teacher can identify points that need to be reinforced in future classes.

At the end of the Return, students should have a clear understanding of what they learned, how the content applies to everyday life, and what the next steps are in the learning process.

Conclusion (5 - 7 minutes)

1. Summary of Contents:

   • The teacher will provide a quick summary of the main concepts covered during the class, reinforcing the concept of solubility product (Ksp), the relationship between Ksp and the solubility of a salt in water, and how to calculate Ksp from molar solubility.
   • The teacher will also review the solubility rules, which are based on the comparison between the value of Ksp and the product of the concentrations of the ions present in the solution.
   • Additionally, the teacher will recap the practical situations proposed during the class and the group discussions.

2. Connecting Theory with Practice:

   • The teacher will highlight how the class sought to integrate theory, practice, and application of knowledge, through the presentation of theoretical concepts, solving practical examples, and discussing the application of the topic in everyday life.
   • The teacher will also emphasize the importance of understanding the theory of solubility product and its application to predict the solubility of a slightly soluble salt in water, both for the study of Chemistry and for various applications in daily life.

3. Supplementary Materials:

   • The teacher will suggest some extra materials for students who wish to deepen their knowledge on the topic. These materials may include Chemistry books, scientific articles, explanatory videos, and educational websites.
   • The teacher may also provide additional exercises for students to practice applying Ksp and solubility rules.

4. Importance of the Subject:

   • Finally, the teacher will emphasize the importance of the topic presented for students' daily lives, explaining how knowledge about solubility product can be useful in various practical situations.
   • The teacher will also encourage students to reflect on how the study of Chemistry can contribute to developing skills such as critical thinking, problem-solving ability, and understanding the world around us.

With the Conclusion, students should have consolidated the knowledge acquired during the class and be prepared to continue exploring the topic in future studies.