Lesson Plan | Active Learning | Introduction to Organic Chemistry: Aromatic Compounds

Assumptions: This Active Lesson Plan assumes: a 100-minute class, prior student study with both the Book and the start of Project development, and that only one activity (among the three suggested) will be chosen to be conducted during the class, as each activity is designed to take up a significant portion of the available time.

Objectives

Duration: (5 - 10 minutes)

The Objectives stage is crucial to focus the students and the teacher on what is essential in the lesson. By clearly establishing the objectives, students can better understand the relevance of the content previously studied and how to apply it in practical contexts. This section serves to align expectations and ensure that both classroom activities and discussions are aimed at developing the desired skills.

Main Objectives:

1. Equip students to differentiate aromatic from non-aromatic compounds by identifying the structural features that confer aromaticity.

2. Enable students to use Hückel's rule to determine whether a conjugated system is aromatic, antiaromatic, or non-aromatic.

Side Objectives:

1. Develop scientific argumentation skills when discussing and justifying the aromaticity of different compounds.

Introduction

Duration: (15 - 20 minutes)

The Introduction serves to engage students with the lesson topic, using problem situations that stimulate practical application of prior knowledge. Additionally, the contextualization helps connect theoretical content with real-world applications, increasing interest and relevance of the study of aromatic compounds. This stage sets the stage for a deeper, more applied understanding of the subject.

Problem-Based Situations

1. Imagine you are a chemist trying to synthesize a new drug that needs to be stable and effective. How would you decide if one of the intermediates in the synthesis is an aromatic compound or not? What tests or observations would you make?

2. A laboratory received a sample of an unknown compound and needs to determine whether it is aromatic or not. What physical and chemical properties would you analyze to make this determination?

Contextualization

Aromatic compounds play a crucial role not only in organic chemistry but also in everyday life. From perfumes and fragrances to drugs and dyes, understanding aromatic compounds is essential for various industrial and pharmaceutical applications. Interestingly, the term 'aromatic' was originally used to describe compounds that had characteristic smells, but the modern definition is based on the special electronic structure that confers exceptional stability to these compounds.

Development

Duration: (70 - 75 minutes)

The Development stage is designed to allow students to apply the concepts of aromatic compounds learned previously in a practical and dynamic way. The proposed activities aim to consolidate theoretical knowledge through playful and collaborative approaches, fostering critical analysis, problem-solving, and scientific argumentation. This section is crucial for transforming theoretical knowledge into practical skills, ensuring a deep and lasting understanding of the topic.

Activity Suggestions

It is recommended to carry out only one of the suggested activities

Activity 1 - Chemical Challenge: Aromaticity in Action

> Duration: (60 - 70 minutes)

- Objective: Develop skills in structural analysis and scientific argumentation by applying the concept of aromaticity in a practical and dynamic situation.

- Description: In this activity, students will be divided into groups of up to 5 people and will receive a set of cards with chemical structures of organic compounds. Each group will analyze the structures, apply Hückel's rule, and identify which compounds are aromatic, antiaromatic, or non-aromatic. Then, they will justify their answers based on the observed structural properties.

- Instructions:

• Divide the class into groups of up to 5 students.

• Give each group a set of cards containing different chemical structures.

• Ask each group to analyze the structures and determine whether they are aromatic, antiaromatic, or non-aromatic using Hückel's rule.

• Groups should record their answers and justifications in a provided laboratory notebook.

• After 30 minutes of analysis, each group will present their conclusions to the class, defending their choices with scientific arguments.

Activity 2 - The Aromatogram: Assembling and Interpreting

> Duration: (60 - 70 minutes)

- Objective: Foster visual and practical understanding of aromaticity through a playful activity that involves assembling a puzzle and applying Hückel's rule.

- Description: Students, in groups, will receive pieces of a puzzle representing different conjugated systems. They must assemble the puzzle, identify the systems as aromatic or not, and explain how Hückel's rule applies in each case to determine aromaticity. Each puzzle piece represents a fragment of an organic compound, and the goal is to piece together the complete 'aromatogram'.

- Instructions:

• Organize students into groups of up to 5 people.

• Distribute the puzzle pieces to each group.

• Students must assemble the puzzle, forming a large conjugated system.

• After assembly, each group must decide whether the conjugated system is aromatic, antiaromatic, or non-aromatic.

• Each group will present their complete 'aromatogram' and explain their decisions based on Hückel's rule.

• Class discussion on the different assemblies and conclusions.

Activity 3 - Aromatic Cinema: Analyzing Aromaticity in Everyday Molecules

> Duration: (60 - 70 minutes)

- Objective: Encourage the application of the concept of aromaticity in real and everyday molecules, promoting communication and teamwork skills.

- Description: In this exercise, student groups will receive cards containing images of molecules found in everyday life, such as caffeine, vanillin, and acetaminophen. They must analyze the structures and discuss as a group whether these molecules are aromatic, applying Hückel's rule. After the discussion, each group will create a small video or presentation to explain their analysis and conclusions to the class.

- Instructions:

• Divide the students into groups of up to 5.

• Distribute cards with images of common molecules.

• Ask each group to analyze the structures and determine whether they are aromatic, antiaromatic, or non-aromatic.

• Each group will develop a presentation or small video explaining their analysis and conclusions, using Hückel's rule as a basis.

• Present the videos or slides to the class.

• Final debate on different interpretations and conclusions.

Feedback

Duration: (10 - 15 minutes)

The purpose of this stage of the lesson plan is to provide an opportunity for students to articulate and reflect on what they learned during the practical activities. The group discussion helps consolidate knowledge, allowing students to share different perspectives and approaches. Additionally, by answering and debating the questions, students can deepen their understanding of the concepts of aromatic compounds and Hückel's rule and learn from each other.

Group Discussion

After completing the activities, gather all students for a group discussion. Start the discussion with a brief introduction highlighting the importance of sharing what each group learned and the difficulties encountered. Encourage students to discuss the different approaches and reasoning used to determine the aromaticity of the compounds and how they applied Hückel's rule. Use the suggested questions to guide the discussion and ensure that all aspects of the topic are addressed.

Key Questions

1. What criteria did you use to decide whether a compound was aromatic, antiaromatic, or non-aromatic?

2. Was there any structure that caused more debate in your group? How did you resolve disagreements?

3. How did the application of Hückel's rule help determine the aromaticity of the compounds?

Conclusion

Duration: (5 - 10 minutes)

The conclusion stage aims to consolidate learning, ensuring students have a clear and summarized view of the key concepts. Furthermore, by connecting theory with the practices discussed and real-world applications, the importance of studying aromatic compounds and Hückel's rule is reinforced. This recap helps cement knowledge and prepare students for future applications of the content learned.

Summary

To conclude the lesson, it is essential to recap the main points covered. Students were able to differentiate aromatic from non-aromatic compounds, applying Hückel's rule to determine aromaticity. Furthermore, they discussed the properties of aromatic compounds and how these characteristics influence the stability and reactivity of these compounds.

Theory Connection

Today's lesson was structured to effectively integrate theory and practice. Through the activities, students applied the theoretical knowledge about aromaticity and Hückel's rule in practical situations, such as analyzing chemical structures and assembling puzzles. This not only solidified theoretical understanding but also demonstrated the importance and applicability of these concepts in the real world.

Closing

Understanding aromatic compounds is essential not only for chemists but for various industries, such as pharmaceuticals and materials. Aromaticity is a fundamental concept that influences the stability of many organic compounds we use daily, from medications to plastics and dyes. Therefore, the knowledge gained today has direct and tangible applications in various areas of practical life.