Contextualization

Chemistry is a science that permeates our lives. From the medicines we take to the fuels that power our cars and planes, all are based on chemical compounds called hydrocarbons. Hydrocarbons are chemical compounds that have hydrogen and carbon atoms in their composition, and these carbon atoms can form chains.

The classification of carbon chains is a fundamental concept in organic chemistry. It allows scientists to describe the structure of organic compounds very efficiently. The classification of carbon chains can be done on several levels. Chains can be classified as open or closed, saturated or unsaturated, branched or normal, and homogeneous or heterogeneous.

The classification of carbon chains allows us to understand the physical and chemical properties of a compound. For example, the presence of a saturated or unsaturated chain in a lipid molecule can determine whether the fat will be solid or liquid at room temperature, respectively.

The plastics industry, for example, relies heavily on this concept to manufacture materials with specific properties. To understand why one plastic is more flexible than another, for example, it is necessary to understand the structure of the carbon chain of that material.

Furthermore, the study of carbon chains is fundamental to the understanding of medicines and drugs, both for the development of new drugs and for the understanding of their effects and toxicity.

The resources you can use to delve into the subject are:

1. Book: Atkin's Physical Chemistry (chapter on organic chemistry)
2. Website: Khan Academy
3. Video: Classification of Carbon Chains - Organic Chemistry - Prof. Paulo Valim - Science in Action

Practical activity

Activity title: "Unraveling the Carbon Chains"

Objective of the Activity:

The objective of this activity is to apply the theoretical knowledge on carbon chains in the interpretation and graphical representation of molecular structures. The task also aims to develop teamwork skills, time management, problem-solving, and creative thinking.

Activity description:

The groups, composed of 3 to 5 students, will be challenged to classify a list of organic molecules according to the structure of their carbon chains. To do this, they will have to interpret and draw the structure of each molecule, locate and identify its carbon chains, and classify them according to the criteria learned.

Materials needed:

• Model organic molecules - provided by the teacher.
• A4 paper
• Colored pens

Step by step:

1. The teacher will distribute the list of organic molecules that must be classified.
2. The students must, in a group, interpret the structure of each molecule and draw it on an A4 paper, representing the carbon, hydrogen, and possible heteroatoms.
3. Then, they will identify the carbon chains present in each structure and classify them as open or closed, saturated or unsaturated, and branched, normal or heterogeneous.
4. Finally, the students will prepare a report that should contain:
   • Introduction: In this topic, the student should contextualize the theme, its relevance and application in the real world as well as the objective of this project.
   • Development: The student should explain the theory behind the central theme(s) of the project, explain the activity in detail, indicate the methodology used and, finally, present and discuss the results obtained. In this topic, they should present the drawings of the molecules and justify their classifications.
   • Conclusion: The work should be concluded by summarizing its main points, explaining the lessons learned and the conclusions drawn about the project.
   • Bibliography: Students should indicate the sources they used to work on the project, such as books, web pages, videos, etc.

The project must be completed within one week, totaling a workload of approximately 2 to 4 hours per student.