Lesson Plan | Traditional Methodology | Introduction to Organic Chemistry: Types of Formulas

Objectives

Duration: 10 - 15 minutes

The purpose of this stage is to provide students with a clear and structured overview of the topic to be studied. By understanding the different types of chemical formulas and their representations, students will be better prepared to follow the detailed explanations provided throughout the lesson, thus ensuring a better comprehension of the content.

Main Objectives

1. Introduce students to the different types of chemical formulas used in organic chemistry: molecular, condensed structural, and stick.

2. Develop students' ability to write and identify chemical compounds using these different formulas.

Introduction

Duration: 10 - 15 minutes

The purpose of this stage is to provide students with a clear and structured overview of the topic to be studied. By understanding the different types of chemical formulas and their representations, students will be better prepared to follow the detailed explanations provided throughout the lesson, thus ensuring a better comprehension of the content.

Context

Organic Chemistry is the area of Chemistry that studies carbon compounds, which are the basis of life on Earth. From the food we eat to the fuel we use in our vehicles, everything involves organic compounds. Understanding how these compounds are represented through different types of formulas is essential for understanding their properties and reactions.

Curiosities

Did you know that graphene, one of the strongest and lightest materials known, is composed solely of carbon atoms? The way these atoms are organized can be represented in various ways using different chemical formulas. Graphene has applications in electronics, medicine, and even in smart clothing!

Development

Duration: 50 - 60 minutes

The purpose of this stage is to provide a detailed and practical understanding of the different types of chemical formulas in organic chemistry. By addressing each type of formula with examples and guiding students through problem solving, students will be able to clearly visualize and differentiate the representations, facilitating the identification and writing of organic compounds. This stage also aims to develop students' ability to apply theoretical knowledge in practical situations.

Covered Topics

1. Molecular Formula: Explain what a molecular formula is and how it represents the quantity and type of atoms in a molecule. Example: C2H6O for ethanol. 2. Condensed Structural Formula: Detail how the condensed structural formula represents the structure of the molecule in a more compact way, showing the sequence of atoms and their bonds. Example: CH3CH2OH for ethanol. 3. Stick Structural Formula: Describe the stick structural formula, where lines represent the bonds between carbon atoms and hydrogens are usually omitted. Example: Graphical representation of ethanol. 4. Comparison of Formulas: Compare the three formulas and discuss the advantages and disadvantages of each. Highlight the utility in different scientific and practical contexts. 5. Practical Examples: Show examples of other common molecules (such as methane, butane, and glucose) in each of the three forms of representation. 6. Guided Problem Solving: Conduct guided problem-solving where students follow the transformation of a molecular formula to structural and then to stick.

Classroom Questions

1. Write the molecular, condensed structural, and stick formulas for methane (CH4). 2. Transform the molecular formula of propane (C3H8) into its condensed structural and stick formulas. 3. Compare the representations of acetic acid (C2H4O2) in its different forms and discuss in which context each would be most useful.

Questions Discussion

Duration: 20 - 25 minutes

The purpose of this stage is to ensure that students consolidate their understanding of the different types of chemical formulas by discussing and reflecting on the resolved questions. This moment allows students to clarify doubts, share insights, and deepen their understanding of the content covered in the lesson.

Discussion

• Molecular, Condensed Structural, and Stick Formulas for Methane (CH4): Molecular Formula: CH4 Condensed Structural Formula: CH4 (in this specific case, the molecular and condensed structural formulas are equal since methane is a simple molecule) Stick Formula: Represented by a point, as there are no bonds between carbons.

• Transformation of the Molecular Formula of Propane (C3H8) into its Condensed Structural and Stick Formulas: Molecular Formula: C3H8 Condensed Structural Formula: CH3-CH2-CH3 Stick Formula: Represented by a zig-zag line with three vertices, indicating the carbon atoms and the bonds between them.

• Comparison of the Representations of Acetic Acid (C2H4O2) in Its Different Forms: Molecular Formula: C2H4O2 Condensed Structural Formula: CH3COOH Stick Formula: Represented by a line with a carboxylic acid functional group (COOH) at one end. Discussion: The molecular formula is useful for knowing the elemental composition of the molecule. The condensed structural formula provides a more detailed view of the sequence of atoms. The stick formula is advantageous for visualizing the three-dimensional structure and the bonds between atoms, being especially useful in advanced organic chemistry and biochemistry.

Student Engagement

1. Which of the three formula representations do you find easiest to understand and why? 2. In what situations do you think the stick formula is more useful than the molecular formula? 3. How can representation in different formulas help in understanding the chemical and physical properties of a compound? 4. If you were in an organic chemistry lab, which formula would you use to describe methane to a colleague and why? 5. What are the advantages and disadvantages of using the condensed structural formula compared to the stick formula?

Conclusion

Duration: 10 - 15 minutes

The purpose of this stage is to recap and consolidate the main points covered during the lesson, ensuring that students have a clear and integrated understanding of the content. This stage also allows for the connection of theoretical knowledge with practical applications and discusses the relevance of the subject to the daily lives of students.

Summary

• Definition and examples of Molecular Formula.
• Detailed explanation of the Condensed Structural Formula with examples.
• Description of the Stick Formula and its characteristics.
• Comparison of the three chemical formulas: molecular, condensed structural, and stick.
• Practical examples of chemical compounds represented by the different formulas.
• Guided problem-solving to transform molecular formulas into structural and stick formulas.

The lesson connected theory to practice by presenting practical examples of common chemical compounds and guiding students in the transformation of molecular formulas into structural and stick. This allowed students to visualize how different representations can be used to better understand the characteristics and properties of organic compounds.

Understanding the different types of chemical formulas is essential for various fields of knowledge and practical applications, from medicine to materials engineering. For example, knowing how to interpret and write stick formulas is crucial for understanding the structure of medications and how they interact with the human body.