Contextualization

Isomerism - Theoretical Concepts

Isomerism is a fundamental subject in the study of Organic Chemistry. The concept refers to compounds that have the same molecular formula but different structures. Among the various classes of isomerism, geometric isomerism (or cis-trans) is one of the most common and important to be understood.

Geometric isomerism occurs when there are compounds with double bonds or in aromatic rings, in which atoms or groups of atoms have the ability to be arranged differently in space. This creates a variety of compounds with distinct physical and chemical properties, even though they have the same molecular formula.

The characterization of geometric isomers is based on the position of the groups of atoms. If these are on the same side of the double bond or ring, the compound is classified as cis. If they are on opposite sides, the compound is classified as trans.

Importance and Real-World Applications

Understanding geometric isomerism is essential not only for Chemistry but also for areas such as Biology and Pharmacy. This is because many biologically active molecules, such as vitamins, hormones, and medications, can exist in isomeric forms with very different biological effects.

Furthermore, geometric isomerism is of great relevance in the chemical industry, since the production of various compounds can result in different isomers, which have distinct properties. Thus, understanding this isomerism is crucial for controlling and optimizing industrial processes.

Practical Activity

Activity Title: Building Models of Geometric Isomers

Project Objective:

This project aims to build three-dimensional models of molecules representing geometric isomers, aiming to understand and materialize the difference between the cis and trans forms of a compound.

Detailed Project Description:

In this project, students must divide into groups of 3 to 5 people. Each group will be responsible for building three-dimensional models of geometric isomers using easily accessible materials, such as barbecue sticks and modeling clay. With the help of a given molecule proposal, the groups must elaborate the 3D models for the cis and trans isomers of the molecule in question.

After building the models, students should propose a didactic presentation to the class, explaining the theory of geometric isomerism in connection with the constructed models, highlighting the difference between the isomers and their distinct physical and chemical properties.

The project must be completed in one week, starting from the date of delivery of the instructions.

Necessary Materials:

1. Modeling clay in various colors;
2. Barbecue sticks;
3. Scissors;
4. Cardboard and colored pens for the presentations;
5. Internet access and bibliographic resources for research.

Detailed Step-by-Step:

1. Form groups and distribute the molecule proposal to each one;
2. Each group should research the proposed molecule, identifying its geometric isomerism, and plan the construction of the models;
3. Using modeling clay and barbecue sticks, the group will build the three-dimensional models of the cis and trans isomers of the proposed molecule;
4. After building the models, the group will prepare a presentation for the class, explaining in detail the theory of geometric isomerism and how it applies to the constructed models;
5. Presentations should be made within a week, following the order of group drawing.

Project Deliverables

After completing the practical part of the project, each group must develop a written report that will address the following points:

1. Introduction: In this section, the group must explain the theory and concept of geometric isomerism, the chosen molecule for the study, the relevance of studying isomers, and contextualize the application of isomers in real life.
2. Development: Here, students must detail the construction of the models, the theoretical explanation of the isomerism of the chosen molecule, the differences between cis and trans isomers, and the physical and chemical properties of each. They must also describe the methodology used in the project and present the results obtained.
3. Conclusion: In this part of the report, the group must conclude the work by summarizing its main points, explaining the learnings obtained, and drawing conclusions about the project.
4. Bibliography: Finally, students must reference all sources consulted for the project development, whether books, web pages, videos, among others.

The report must be sent by email to the teacher in the same week the practical activity is completed.

Conclusion and Correction Criteria

After the presentations and the delivery of the reports, the teacher must evaluate the work of each group based on the following criteria:

1. Commitment and Teamwork: Evaluation of the group's performance as a whole, focusing on collaboration and equitable division of tasks.

2. Quality of the Built Models: Verification of the accuracy and quality of the three-dimensional models built by the students, and whether they correctly represent the proposed geometric isomers.

3. Presentation: Verification of the clarity and effectiveness of the presentation, whether the theory was explained correctly, and whether the students were able to connect the theory with the constructed models.

4. Report: Analysis of the report quality, checking if all requested topics were addressed appropriately.

This project aims not only to assess the understanding and application of isomerism concepts but also the development of socio-emotional skills, such as time management, communication, problem-solving, creative thinking, and proactivity among students.