Lesson Plan | Traditional Methodology | Organic Reactions: Organic Reaction Problems

Objectives

Duration: (10 - 15 minutes)

The purpose of this stage is to provide students with a clear understanding of the skills and knowledge they should acquire throughout the lesson. This includes the ability to identify products and reagents, understand the synthesis routes and catalysts involved, and apply this knowledge to solve practical problems related to organic reactions. Establishing these objectives at the beginning prepares students to focus on the essential points during the lesson.

Main Objectives

1. Recognize products and reagents in organic reactions.

2. Identify synthesis routes and catalysts in organic reactions.

3. Solve practical problems involving organic reactions.

Introduction

Duration: (10 - 15 minutes)

The purpose of this stage is to capture students' attention and contextualize the topic of the lesson, showing the relevance of organic reactions in everyday life and in science. By providing practical examples and curiosities, the teacher aims to spark students' interest and prepare them for understanding the concepts that will be explored throughout the lesson.

Context

Start the class by presenting the concept of organic reactions, which are chemical reactions involving organic compounds. Explain that these reactions are crucial in the synthesis of new compounds, including medicines, plastics, and other materials essential for modern life. Highlight the importance of understanding organic reactions for chemistry and other sciences, such as biology and medicine. Use examples familiar to students, such as the transformation of food into energy in the human body and the production of biofuels from plants.

Curiosities

Did you know that aspirin, one of the most widely used medications in the world, is the result of an organic reaction? The synthesis of aspirin involves the acetylation of salicylic acid, a reaction that was discovered over a century ago and is still fundamental in the pharmaceutical industry. This is just one example of how organic reactions impact our daily lives.

Development

Duration: (45 - 50 minutes)

The purpose of this stage is to provide students with a detailed understanding of the main types of organic reactions, their mechanisms, synthesis routes, and the role of catalysts. By exploring practical examples and solving questions in class, students will be able to apply the concepts learned, solidifying knowledge and developing skills to solve problems related to organic reactions.

Covered Topics

1. 1. Types of Organic Reactions 離 2. Explain the main categories of organic reactions, such as substitution, addition, elimination, and oxidation-reduction. Detail examples of each type of reaction, highlighting typical reactants and products. 3. 2. Reaction Mechanisms  4. Describe the reaction mechanisms, including intermediate steps, transition states, and activation energy. Explain how mechanisms help to understand the course of the reaction and predict the products. 5. 3. Synthesis Routes 里 6. Present synthesis routes, illustrating how different reactions can be combined to obtain a desired product. Use examples of complex and industrial syntheses. 7. 4. Catalysts in Organic Reactions ⚗️ 8. Explain the role of catalysts in organic reactions, how they increase the rate of the reaction and can direct the formation of specific products. Provide examples of common catalysts, both homogeneous and heterogeneous. 9. 5. Practical Examples and Applications  10. Discuss practical examples of organic reactions, such as the synthesis of medicines, polymers, and biofuels. Relate these examples to students' everyday lives and the economic and environmental importance of these reactions.

Classroom Questions

1. 1. Identify the products of the addition reaction between ethene (C₂H₄) and chlorine (Cl₂). 2. 2. Describe the nucleophilic substitution mechanism in alkyl halides, using methyl bromide (CH₃Br) as an example. 3. 3. Explain how sulfuric acid (H₂SO₄) acts as a catalyst in the esterification reaction between acetic acid (CH₃COOH) and ethanol (CH₃CH₂OH).

Questions Discussion

Duration: (20 - 25 minutes)

The purpose of this stage is to review and discuss the answers to the questions presented, ensuring that students fully understand the concepts covered. This stage also aims to engage students in critical discussions and reflections that deepen their understanding, promoting the internalization of knowledge and the ability to apply it in diverse contexts.

Discussion

• Question 1: Identify the products of the addition reaction between ethene (C₂H₄) and chlorine (Cl₂).

• Discussion: Explain that the addition reaction between ethene and chlorine results in 1,2-dichloroethane (C₂H₄Cl₂). Detail that, in the presence of chlorine, the double bond of ethene breaks, allowing the addition of a chlorine atom to each of the carbons involved in the double bond.

• Question 2: Describe the nucleophilic substitution mechanism in alkyl halides, using methyl bromide (CH₃Br) as an example.

• Discussion: Explain that in nucleophilic substitution, a nucleophile attacks the carbon atom that is bonded to a halogen, causing the halogen to leave as a halide ion. In the case of methyl bromide, the nucleophile (for example, a hydroxide ion, OH⁻) attacks the carbon attached to bromine, resulting in the formation of methanol (CH₃OH) and bromide ion (Br⁻).

• Question 3: Explain how sulfuric acid (H₂SO₄) acts as a catalyst in the esterification reaction between acetic acid (CH₃COOH) and ethanol (CH₃CH₂OH).

• Discussion: Detail that sulfuric acid acts as a catalyst in the esterification reaction by protonating the carbonyl group of acetic acid, making it more electrophilic and facilitating the nucleophilic attack by ethanol. This results in the formation of a tetrahedral intermediate, which subsequently loses a water molecule to form the ester ethyl acetate (CH₃COOCH₂CH₃). Sulfuric acid also helps to remove the water produced in the reaction, shifting the equilibrium in favor of ester formation.

Student Engagement

1. What are the differences between an addition reaction and a substitution reaction? Provide examples. 2. How would you explain the role of a catalyst in a chemical reaction to someone who is not a chemist? 3. Why is it important to understand reaction mechanisms when planning a chemical synthesis? 4. How would you relate the importance of organic reactions to the production of medicines? 5. Considering the addition reaction we discussed, what other molecules could react similarly to ethene? Explain.

Conclusion

Duration: (10 - 15 minutes)

The purpose of this stage is to summarize and reinforce the main points covered during the lesson, ensuring that students leave with a clear and cohesive understanding of the content. Moreover, this stage aims to connect theory with practical applications, highlighting the relevance and importance of the topic to students' everyday lives.

Summary

• Organic reactions are crucial for the synthesis of new compounds and have various applications in modern life.
• The main types of organic reactions include substitution, addition, elimination, and oxidation-reduction.
• Reaction mechanisms help to understand the course of the reaction and predict the products.
• Synthesis routes show how different reactions can be combined to obtain a desired product.
• Catalysts increase the speed of organic reactions and can direct the formation of specific products.
• Practical examples of organic reactions include the synthesis of medicines, polymers, and biofuels.

The lesson connected theory with practice by detailing the types of organic reactions, their mechanisms, and the role of catalysts, illustrating these concepts with practical examples such as the production of medicines and biofuels. This helped students see the real application of theoretical concepts in everyday contexts and various industries.

Understanding organic reactions is fundamental in the development of products we use daily, such as medicines and plastics. Curiosities like the synthesis of aspirin show how these reactions directly impact our lives. Additionally, the production of biofuels from plants exemplifies the economic and environmental importance of organic reactions.