Contextualization

Chemistry is the science that studies matter, its properties, how and why substances combine or separate to form others, and how substances interact with energy. In chemistry, one of the fundamental parts is the study of the transformations that matter undergoes. These transformations are called chemical reactions and are governed by some laws, the so-called stoichiometry laws.

The first of these laws was formulated by the French scientist Antoine Lavoisier in the late 18th century, the Law of Conservation of Mass, which establishes that in any chemical reaction, the total mass of the reactants (the substances that react) is equal to the total mass of the products (the substances formed). Shortly after, Joseph Proust enunciated the Law of Definite Proportions, which states that in a chemical compound, elements are always present in fixed mass proportions.

These laws paved the way for the development of chemistry as we know it today and are essential for understanding the processes of matter transformation. However, despite their importance, these laws can often seem abstract and difficult to understand. Therefore, we will embark on a project to explore and experiment with these laws in a practical and fun way.

In our daily lives, we often prepare culinary recipes, which are nothing more than chemical reactions. Just like in chemistry, in recipes, the quantity of ingredients (reactants) must be measured correctly to obtain the desired product with the expected characteristics. Imagine if in a cake recipe, you changed the amount of yeast, what would happen?

Therefore, stoichiometry laws are fundamental not only in science but also in our daily lives. They allow us to understand and predict the results of chemical reactions, so that we can, for example, develop new materials, medicines, foods, among other applications.

To delve deeper into the theory of stoichiometry laws, we recommend the following resources:

1. Chemistry Technical Dictionary
2. Brazil School - Stoichiometry Laws
3. Manual do Mundo - Chemistry Experiments

Practical Activity: Cooking with Stoichiometry Laws

Project Objective

The objective of this activity is to provide students with a practical and fun way to apply and understand stoichiometry laws through the preparation of culinary recipes. Students will have to analyze and measure the ingredients (reactants), perform the recipe (chemical reaction), and compare the result with the expected outcome (product). In addition, participants must combine theoretical knowledge with practical observations and experiments, consolidating learning and developing teamwork, problem-solving, and time management skills.

Detailed Project Description

Students will be divided into groups of 3 to 5 members. Each group will have to choose a culinary recipe and follow the indicated step by step, recording and relating each step to the stoichiometry laws. For this, they will have to weigh and note the quantity of each ingredient used and the final mass of the product obtained. Important: the activity must be carried out under adult supervision to ensure the safety of the students.

Necessary Materials

• Ingredients for the chosen recipe
• Kitchen utensils necessary for the recipe (bowls, spoons, pots, oven, etc.)
• Kitchen scale
• Camera or smartphone to record the activity
• Notebook or paper to record the results
• Books, internet, or other resources for research

Detailed Step by Step

1. Each group chooses a culinary recipe. The recipe should be chosen according to safety, ingredient availability, and culinary skills of the students.
2. Before starting to prepare the recipe, students must weigh and note the quantity of each ingredient.
3. Students prepare the recipe, following the indicated step by step. Remembering that the activity must be carried out under adult supervision.
4. After preparing the recipe, students must weigh and record the mass of the final product and compare it with the sum of the masses of the ingredients.
5. Students must document the activity with photos or videos.
6. At the end, each group writes a report with the results of the activity, following the delivery guidelines described below.

Deliverables

Each group must prepare a detailed report of the activity. This report should be written clearly and objectively, presenting the research conducted, the practical activity, the results obtained, and the relationship with the stoichiometry laws.

1. Introduction: Contextualization of the theme, relevance and application of stoichiometry laws in the real world and in the project carried out, together with the project objectives.
2. Development: Explanation of the theory of stoichiometry laws and its relationship with the practical activity. The methodology used must be detailed, from the choice of the recipe, weighing of the ingredients, preparation of the recipe to the obtaining of the final product. It is important, at this stage, to present and discuss the results obtained.
3. Conclusion: Review of the main points of the work, the learnings, and the conclusions drawn from the project.
4. Bibliography: Citation of the sources used in the preparation of the report.

This project aims not only to assess students' knowledge but also to stimulate collaboration in groups, creativity, time management, and proactivity.