Objectives (5 - 10 minutes)

1. Explain the concept of organic anhydrides and their importance in organic chemistry, as well as practical applications in everyday life.
2. Differentiate the nomenclature of organic anhydrides from other organic compounds using the IUPAC system.
3. Identify and name organic anhydrides through examples and practical exercises.

Secondary Objectives:

1. Develop students' logical and analytical reasoning skills when dealing with the complex nomenclature of organic anhydrides.
2. Encourage active student participation through discussions and questioning, promoting a collaborative learning environment.
3. Foster students' interest and curiosity in organic chemistry, highlighting its relevance in various areas of science and technology.

Introduction (10 - 15 minutes)

1. The teacher should start the lesson by reviewing basic concepts of organic chemistry, such as the definition of organic functions, the IUPAC nomenclature system, and the structure of carboxylic acids. This review can be done through dialogue, asking questions to students and actively involving them in the discussion.

2. After the review, the teacher can present two problem situations:

   • The first one could be the nomenclature of a complex organic anhydride. The teacher can present the chemical structure of the compound and challenge the students to name it correctly.

   • The second situation could be the differentiation between the nomenclature of an organic anhydride and an ester, for example. The teacher can present the chemical structures of both compounds and ask the students what sets them apart.

3. Next, the teacher should contextualize the importance of organic anhydrides, explaining that they are used in various industrial applications, such as in the production of plastics, resins, dyes, and medicines. This can be done through practical examples, such as the production of acetylsalicylic acid (aspirin) from acetic anhydride.

4. To capture students' attention, the teacher can share some curiosities about organic anhydrides:

   • Phthalic anhydride, for example, is a key component in some types of plastics and resins. It is also used in the production of dyes and perfumes.

   • Acetic anhydride is a volatile compound used in the production of a variety of products, from medicines to paints and varnishes. It has a characteristic vinegar-like smell, which is a diluted solution of acetic acid.

5. At the end of the introduction, the teacher should make it clear that the objective of the lesson is to learn to name and recognize the appropriate IUPAC nomenclature for organic anhydrides, differentiating their nomenclature from that of other organic compounds.

Development (20 - 25 minutes)

Theory (15 - 20 minutes)

1. The teacher should start this stage by introducing the definition of organic anhydrides. They can explain that organic anhydrides are compounds derived from carboxylic acids that have lost a water molecule. This can be illustrated with the reaction between two carboxylic acids forming an anhydride and a water molecule.

2. The teacher should then move on to the IUPAC nomenclature of organic anhydrides. They can explain that in the IUPAC nomenclature, anhydrides are named as 'anhydride' followed by the name of the carboxylic acid from which they are derived. If the anhydride is derived from two different carboxylic acids, the names of the acids are listed in alphabetical order, followed by 'anhydride'.

3. The teacher can illustrate this nomenclature with examples, such as the anhydride derived from acetic acid, which is called 'acetic anhydride', and the anhydride derived from acetic acid and propanoic acid, which is called 'acetic propanoic anhydride'.

4. The teacher should then move on to differentiating the nomenclature of anhydrides from other organic compounds. They can explain that while esters are also derived from carboxylic acids, their nomenclature is different from that of anhydrides. In esters, the name of the carboxylic acid is followed by the suffix '-ate', and the name of the alcohol from which they are derived is added as a prefix. For example, the ester derived from acetic acid and methanol is called 'methyl methanoate'.

5. The teacher can reinforce this theory with more examples and comparisons, asking students questions to check their understanding.

Practice (5 - 10 minutes)

1. After presenting the theory, the teacher should move on to practice. They can present a series of nomenclature exercises where students must name the presented anhydrides and differentiate them from other organic compounds.

2. The exercises should be varied, with anhydrides derived from different carboxylic acids and comparisons with different organic compounds, to ensure that students understand the nomenclature and can apply it in different situations.

3. The teacher should walk around the classroom, assisting students who are having difficulties and encouraging discussion among them. They can also ask students questions to check understanding and correct any misunderstandings.

4. At the end of this stage, the teacher can review the exercises with the class, discussing the answers and explaining any difficulties students may have encountered.

By the end of the Development, students should have a clear understanding of the nomenclature of organic anhydrides and be able to differentiate it from the nomenclature of other organic compounds.

Return (10 - 15 minutes)

1. Based on what was learned during the lesson, the teacher can start the return stage by asking students how they think the nomenclature of organic anhydrides applies to the real world. Students may mention industrial applications, such as the production of plastics, resins, dyes, and medicines, which were mentioned during the lesson. The teacher can take the opportunity to reinforce the relevance of organic anhydrides, explaining that the correct nomenclature of compounds is essential for effective communication among chemists and for the correct production of chemical products.

2. The teacher can then ask students to reflect on what they learned during the lesson. They can ask questions like:

   • What was the most important concept learned today?
   • What questions have not been answered yet?
   • How do you feel about the nomenclature of organic anhydrides now compared to the beginning of the lesson?

3. The teacher can encourage students to share their answers with the class, promoting a collaborative learning environment. They can respond to any unanswered questions and reinforce the understanding of the concepts covered in the lesson.

4. The teacher can then propose a reflection exercise where students must write a paragraph about what they learned during the lesson. They can include the concepts they found most interesting, the difficulties they faced, and how they plan to overcome them.

5. At the end of this stage, the teacher can quickly review the key concepts of the lesson, reinforcing the importance of the correct nomenclature of organic anhydrides and how it applies to the real world.

6. The teacher can then provide students with some study material for home, such as a list of exercises on the nomenclature of organic anhydrides or an article on the application of organic anhydrides in the industry.

By the end of the Return, students should have a clear understanding of what they learned during the lesson, be able to apply that knowledge in the real world, and be prepared to continue studying the subject independently.

Conclusion (5 - 10 minutes)

1. The teacher should start the conclusion by summarizing the main points covered in the lesson. They can review the concept of organic anhydrides, the IUPAC nomenclature for these compounds, and the differentiation of the nomenclature of anhydrides from other organic compounds.

2. Next, the teacher can highlight how theory, practice, and applications were connected during the lesson. They can mention how the theoretical understanding of the nomenclature of organic anhydrides was put into practice through nomenclature exercises and how the real-world application of these compounds was discussed.

3. The teacher can then suggest additional materials for students to deepen their knowledge on the subject. This may include organic chemistry books, chemistry websites, online lecture videos, among others. They can also provide a list of additional exercises for students to practice the nomenclature of organic anhydrides.

4. Finally, the teacher should reinforce the importance of the subject presented for students' daily lives. They can emphasize how organic anhydrides are present in various products we use in our daily lives, such as medicines, plastics, resins, dyes, among others. They can also stress the importance of the correct nomenclature of these compounds for effective communication among chemists and for the correct production of chemical products.

5. The teacher can conclude the lesson by reinforcing that organic chemistry is a vast and complex field, but with study and practice, students can master its concepts and apply them effectively. They can encourage students to continue studying the subject and to seek help whenever they have difficulties.

6. By the end of the conclusion, students should have a clear understanding of what they learned during the lesson, understand the importance of the subject, and be prepared to continue studying the topic independently.