Contextualization

Organic Chemistry is an extremely relevant field of knowledge with multiple practical applications. Among the concepts that compose it, Isomerism stands out for involving molecular structures that, despite having the same molecular formula, present different physical and chemical properties. Specifically, Geometric Isomerism, the type of isomerism that will be our focus, refers to molecules that differ in the spatial arrangement of atomic groups in relation to a double bond or an aromatic ring.

Geometric isomerism is present in a variety of compounds, from the simplest, such as alkenes, to the most complex, such as fatty acids, which are vital for life. For a proper understanding of geometric isomerism, it is essential to consider concepts of molecular geometry and stereochemistry, as well as the physical and chemical properties associated with these isomers.

Studying geometric isomerism involves delving into various associated theoretical concepts, such as: a) understanding molecular structure and comprehending how the spatial arrangement of atoms influences the properties of a substance; b) distinguishing between cis and trans isomers; c) the relationship between geometric isomerism and the chemical and physical properties of compounds; and d) the biological consequences of isomerism.

Importance and Application of Geometric Isomerism

In your daily life, you have likely come across Geometric Isomerism, whether in the form of unsaturated fats in food or in the structure of medications. In Biology, the difference between cis and trans isomers can define the functioning of proteins and enzymes, as well as influence how organisms store energy.

In the industrial and pharmaceutical context, geometric isomerism also plays a crucial role. Medications and other substances, although they have the same molecular formula, can have DRAMATICALLY different effects depending on the spatial arrangement of their atoms. For example, Limonene, a compound that can smell like orange or lemon depending on its isomeric form.

Furthermore, geometric isomerism is closely linked to phenomena of light polarization and optical activity, impacting important Physics concepts, such as the development of polarizing lenses and optical resources in imaging technologies.

Recommended Resources for Further Study

Books:

1. Solomon, T.W., Fryhle C.B., Snyder S.A., Organic Chemistry, 12th ed., Wiley, 2016.
2. McMurry, J. Organic Chemistry, 7th ed., Cengage Learning, 2011.

Websites:

1. Khan Academy - Organic Chemistry: Isomerism
2. Brasil Escola: Geometric Isomerism

Videos:

1. YouTube - Free Enem Course: Isomerism
2. YouTube - Chemistry in Action - Prof. Paulo Valim: Planar Isomerism

Chemistry Dictionaries:

1. Usberco and Salvador Chemistry Dictionary
2. Michael, B. Dictionary of Chemistry, 6th ed., Oxford, 2016.

Practical Activity: "Geometric Isomerism in Action"

Activity Title: Molecular modeling and analysis of geometric isomers' properties

Project Objective: To understand, through molecular modeling and practical experiments, the difference between cis and trans geometric isomers and how this difference affects the physical and chemical properties of compounds.

Detailed Project Description

Each group of students (3 to 5 students) will be responsible for choosing an organic compound that exhibits geometric isomerism (e.g., 2-butene), building physical models of the cis and trans isomers, and conducting practical experiments that demonstrate the difference between the physical and chemical properties of the isomers.

Additionally, they will investigate practical applications and biological consequences of these isomers and produce a detailed report of their findings.

Duration: This project should take more than 12 hours to complete.

Required Materials:

• Molecular modeling kits
• Laboratory equipment and reagents necessary for practical experiments (to be determined by students based on the chosen compound)
• Access to books and/or online resources for research

Step-by-Step Guide for Activity Execution:

1. Compound Selection: Each group should choose an organic compound that exhibits geometric isomerism. We recommend choosing a simple compound, such as 2-butene, to facilitate model construction and experiment execution.

2. Molecular Modeling: Use the molecular modeling kits to build models of the cis and trans isomers of the chosen compound.

3. Practical Experiments: Research and conduct practical experiments that demonstrate the difference between the physical and chemical properties of the isomers, such as melting point, solubility, reactivity, among others. The results of these experiments will be an important part of your report.

4. Research: Investigate practical applications and biological consequences of the isomers of the chosen compound. For example, 2-butene is an important component in the production of plastic polymers.

5. Report Elaboration: Based on your findings and experiments, each group should produce a detailed report. This report should include:

   • Introduction: Presentation of the chosen compound, contextualization of geometric isomerism, and justification of the topic's relevance.

   • Development: Detailed description of the constructed molecular models and practical experiments performed, demonstrating the difference between the physical and chemical properties of the isomers. Also include the results of the research on the practical applications and biological consequences of the isomers.

   • Conclusions: Analyze the results obtained, reflect on what was learned, and discuss the importance of geometric isomerism in Chemistry and Biology.

   • Bibliography: List all sources consulted during the project's development.

Note: This work involves a direct connection with the Biology discipline, especially during the research phase. Thus, it fosters interdisciplinarity and develops skills beyond Chemistry.

Note: When conducting experiments, remember to follow laboratory safety guidelines to ensure your safety and that of your peers.