Contextualization

Chemistry, as a science, has a vast and rich history. Much of what we know today is the result of discoveries and experiments by scientists and researchers who lived centuries ago. One of these important scientists was Antoine Laurent Lavoisier, considered by many as the 'father of modern Chemistry'. He is responsible for the Law of Conservation of Mass, also known as Lavoisier's Law, which is one of the basic concepts of Chemistry.

This law establishes that, in a chemical reaction that occurs in a closed system, the total mass of the reactants is equal to the total mass of the products. In other words, matter is neither created nor destroyed, only transformed. Understanding this law is fundamental to comprehend the nature of chemical reactions and how matter interacts in our universe.

In a world increasingly dependent on chemical processes, from the production of medicines to the creation of new materials, understanding the Ponderal Laws assumes a crucial role. Lavoisier's Law, specifically, is a key element for the development of industrial processes and the improvement of clean and sustainable technologies. Therefore, studying these laws not only enriches our scientific understanding but also provides us with the tools to create solutions for global challenges.

A practical example of the application of Lavoisier's Law is in the food industry, where the mass of the ingredients must be equal to the mass of the final product. This ensures that there is no waste or addition of unknown compounds during the process. Thus, Lavoisier's Law not only affects how science is done but also how we live our daily lives.

For a more detailed exploration of this topic, we recommend:

• Book: Atkins, P.; Jones, L. Principles of Chemistry: Questioning the Modern Life and Environment. 5th ed. Porto Alegre: Bookman, 2012.
• Website: Khan Academy - Ponderal Laws - Lavoisier's Law.
• Video: Lavoisier's Law - Prof. Paulo Valim - Science in Action.

Practical Activity

Activity Title: Building Understanding of Lavoisier's Law

Project Objective:

Understanding Lavoisier's Law through a practical activity of experimentation and report writing, promoting collaborative learning and the development of technical and socioemotional skills.

Detailed Project Description:

Students, divided into groups of 3 to 5 members, will carry out a simple experiment to observe the application of Lavoisier's Law of conservation of mass. With this experiment, it will be possible to visualize and prove that the mass of the reactants is equal to the mass of the products in a chemical reaction.

Project Duration: 5 to 10 hours per student, distributed over a period of one month.

Required Materials:

• Precision balance
• Suitable container to create a closed chamber
• Vinegar (100 mL)
• Baking soda (10 g)
• Small plastic bags
• String
• Stopwatch

Step by Step:

1. Weigh the empty container with the precision balance.
2. Add the baking soda to the small plastic bag, tie it with string, and weigh it.
3. Measure 100 mL of vinegar and also weigh it.
4. Add the vinegar to the container and weigh the set again.
5. While the balance is measuring, place the plastic bag with baking soda inside the vinegar container, immediately cover it, ensuring that the system remains closed, and start the stopwatch.
6. Observe the chemical reaction (the formation of bubbles is the release of carbon dioxide - CO2).
7. After the effervescence is complete, weigh the system again, ensuring that nothing was lost during the reaction.

Project Deliverables:

Students should carry out the experiment and record all observations, collect and organize the data obtained.

After conducting the experiment, students should write a document in the form of a report containing:

1. Introduction: Contextualize Lavoisier's Law, its relevance and applicability in the real world, as well as the project's objective.

2. Development: Explain the theory behind Lavoisier's Law. Describe the activity in detail, indicate the methodology used, present and discuss the results obtained. The data collected during the experiment should be presented clearly and organized, with emphasis on the relationship between the mass of the reactants and the mass of the products.

3. Conclusion: Conclude the work by summarizing its main points, explaining the learnings obtained and the conclusions drawn about Lavoisier's Law based on the experiment results.

4. Bibliography: Indicate the sources used to work on the project, such as books, websites, videos, among others.

It is important for students to mention the difficulties encountered during the project, how they solved the problems that arose, and how they organized themselves to carry out the group work. This will help develop socioemotional skills, such as time management, communication, problem-solving, creative thinking, and proactivity.