Lesson Plan | Traditional Methodology | Organic Functions: Carboxylic Acid

Objectives

Duration: 10 - 15 minutes

This stage of the lesson plan aims to clearly define the main objectives that students should achieve by the end of the lesson. This helps guide both the teacher and the students on the focus of the content to be covered, ensuring a complete and effective understanding of carboxylic acids, their properties, and their characteristics.

Main Objectives

1. Understand the chemical structure of carboxylic acids, specifically the presence of the carboxyl functional group.

2. Identify the main physical and chemical properties of carboxylic acids.

3. Recognize common examples of carboxylic acids and their practical applications.

Introduction

Duration: 10 - 15 minutes

 Purpose: This stage aims to prepare students for the content to be covered, creating a context that awakens interest and curiosity about carboxylic acids. By connecting the theme with everyday examples and highlighting its practical relevance, the goal is to engage students from the beginning and facilitate the assimilation of the information that will be presented.

Context

‍ Context: Start the class by highlighting the importance of organic compounds in chemistry and everyday life. Explain that carboxylic acids are a fundamental class of organic compounds that have a specific functional group called carboxyl (–COOH). These compounds are found in various natural and synthetic substances, playing crucial roles in biological and industrial processes. To facilitate understanding, present the general structure of a carboxylic acid using diagrams and simple examples.

Curiosities

 Curiosities: Did you know that acetic acid, a type of carboxylic acid, is the main component of vinegar? Additionally, citric acid, found in citrus fruits such as lemons and oranges, is also part of this family. These acids not only give flavor to foods but also have preserving properties and are used in various industrial applications, such as in the production of cleaning products and cosmetics.

Development

Duration: 45 - 55 minutes

 Purpose: The Development stage aims to provide a detailed and comprehensive understanding of carboxylic acids. By addressing structure, nomenclature, physical and chemical properties, reactions, and practical applications, students will be able to visualize and better understand how these compounds behave and are used. Resolving questions in class solidifies learning, allowing students to apply the knowledge acquired in a practical and contextualized way.

Covered Topics

1. Structure of Carboxylic Acids: Explain the general formula of carboxylic acids (R-COOH), highlighting the presence of the carboxyl group. Show how the carboxyl group is composed of a carbonyl group (C=O) and a hydroxyl group (OH) bonded to the same carbon atom. Use diagrams to illustrate the structure. 2. Nomenclature of Carboxylic Acids: Detail the IUPAC nomenclature rules for carboxylic acids. Explain the replacement of the 'ane' suffix of alkanes with the 'oic' suffix, adding 'acid' before the name. Provide examples such as acetic acid (ethanoic acid) and formic acid (methanoic acid). 3. Physical and Chemical Properties: Discuss the physical properties of carboxylic acids, such as water solubility and elevated boiling points due to hydrogen bond formation. Explain the acidity of carboxylic acids and their ability to donate H+ ions in aqueous solutions. 4. Reactions of Carboxylic Acids: Describe the main reactions of carboxylic acids, including ester formation (esterification), reduction to primary alcohols, and the formation of carboxylate salts. Use balanced chemical equations to illustrate each reaction. 5. Examples and Practical Applications: Provide examples of common carboxylic acids, such as acetic acid, citric acid, and benzoic acid, and discuss their applications in food, medicine, and industries. Highlight the function of acetic acid in vinegar and citric acid in beverages and preservatives.

Classroom Questions

1. Draw the structure of propanoic acid and explain how the presence of the carboxyl group influences its physical properties. 2. Name the following carboxylic acids according to IUPAC rules: CH3(CH2)2COOH and HCOOH. 3. Write the balanced equation for the esterification reaction between acetic acid and ethanol, and name the ester formed.

Questions Discussion

Duration: 20 - 25 minutes

 Purpose: The Feedback stage aims to consolidate students' learning, allowing them to review and discuss the issues worked on in class. By providing detailed explanations and stimulating reflections, the teacher helps students identify and correct potential mistakes while deepening their understanding of carboxylic acids. This stage also promotes active student engagement, encouraging participation and critical thinking.

Discussion

• ‍ Discussion: Start the discussion by reviewing the questions addressed in the Development stage:

• Structure of Propanoic Acid: Explain that propanoic acid has the formula CH3CH2COOH. The carboxyl group (-COOH) is a functional group that imparts specific properties to the compound, such as the ability to form hydrogen bonds, which increases solubility in water and raises the boiling point.

• IUPAC Nomenclature: For the compound CH3(CH2)2COOH, the IUPAC name is butanoic acid. For HCOOH, the name is methanoic acid (or formic acid). Reinforce the replacement of the 'ane' suffix of alkanes with 'oic' and the addition of the term 'acid' before the name.

• Esterification Reaction: The reaction between acetic acid (CH3COOH) and ethanol (CH3CH2OH) forms the ester ethyl acetate (CH3COOCH2CH3) and water. The balanced equation is: CH3COOH + CH3CH2OH → CH3COOCH2CH3 + H2O. Detail the mechanism of the reaction, explaining the formation of the ester and the elimination of water.

Student Engagement

1.  Student Engagement: To engage students and promote discussion, ask the following questions and reflections: 2. How does the presence of the carboxyl group influence the acidity of carboxylic acids compared to other organic compounds? 3. What are the main differences between carboxylic acids and alcohols in terms of physical properties and chemical reactivity? 4. Think of other examples of carboxylic acids present in foods and discuss their functions. What other important industrial products contain carboxylic acids? 5. How does the structure of the carboxylic acid influence its properties? Consider the length of the carbon chain and the presence of other functional groups. 6. What are the most relevant industrial and biological uses of carboxylic acids beyond the examples provided in class?

Conclusion

Duration: 10 - 15 minutes

The purpose of this stage is to review and consolidate the content covered in the lesson, ensuring students have a clear and complete understanding of carboxylic acids. By summarizing key points and highlighting the connection between theory and practice, the teacher reinforces the importance of the topic and facilitates the retention of the acquired knowledge.

Summary

• Carboxylic acids have the carboxyl functional group (–COOH), composed of a carbonyl group (C=O) and a hydroxyl group (OH) bonded to the same carbon atom.
• The IUPAC nomenclature for carboxylic acids involves substituting the 'ane' suffix of alkanes with 'oic' and adding the term 'acid' before the name.
• Carboxylic acids have high solubility in water and elevated boiling points due to hydrogen bond formation.
• These compounds are weak acids that can donate H+ ions in aqueous solutions.
• Important reactions of carboxylic acids include esterification, reduction to primary alcohols, and formation of carboxylate salts.
• Common examples of carboxylic acids include acetic acid (vinegar), citric acid (citrus fruits), and benzoic acid (food preservative).

The lesson connected the theory of carboxylic acids with practical applications, such as the use of acetic acid in vinegar and citric acid in beverages and preservatives. Through everyday examples and chemical reactions, students were able to visualize how these compounds are relevant in both biological and industrial processes.

Carboxylic acids are important in various aspects of daily life, from food preservation to the production of medicines and cleaning products. They play crucial roles in biological processes, such as the Krebs cycle, and in industrial applications, such as the manufacturing of polymers and cosmetics. Understanding their properties and reactions is fundamental to grasping many chemical and biological phenomena.