Contextualization
Theoretical Introduction
Stoichiometry is a set of principles that allows scientists to calculate the quantity of reactants and products involved in a chemical reaction. It is based on the Law of Conservation of Mass, which states that matter cannot be created or destroyed in a chemical reaction.
In stoichiometry, we deal with concepts such as mole, molar mass, Avogadro's number, and molar volume. These are the fundamentals that allow us to quantify matter and make precise calculations involving chemical reactions. Two other important concepts in stoichiometry are purity and yield. Purity is the proportion of a substance in a sample, while yield is the amount of product obtained in a chemical reaction compared to the theoretically possible amount.
Understanding stoichiometry and being able to perform stoichiometric calculations is essential for various careers in science, including chemistry, biochemistry, pharmacy, and chemical engineering. Understanding purity and yield is also crucial in the chemical industry, where the goal is to maximize the yield of a reaction and the purity of the products.
Theme Contextualization
Stoichiometry is present in almost everything around us in daily life. Without stoichiometry, it would be impossible to determine the correct proportions of ingredients in a recipe, or of reactants in a chemistry laboratory. One of its most important applications is in the pharmaceutical industry, where it is used to calculate the exact quantities of substances needed to create medications.
On the other hand, the notion of purity is crucial in our lives. The tap water we drink, the salt we use in cooking, the medications we take, all require a certain level of purity to be safe and effective. The same goes for the concept of yield. In the case of industrial processes, a high yield means that the largest amount of product is being produced from a given amount of reactants, which has significant financial and environmental implications.
Practical Activity
Title: "Purity and Yield in Practice: Creating and Analyzing Chemical Reactions"
Project Objective
This project aims to apply the theoretical concepts of stoichiometry, purity, and yield in practice, through the realization and analysis of a series of simple chemical reactions. In addition, the project aims to improve students' teamwork, time management, and problem-solving skills.
Detailed Project Description
Students will be divided into groups of 3 to 5 members, each group will perform a series of chemical reactions, and subsequently calculate the purity of the substances involved and the yield of the reactions. In addition, students should conduct research on the application of purity and yield concepts in real industrial contexts, to deepen their understanding of these concepts.
Required Materials
- Specific chemical reagents (will be informed by the teacher according to the reactions assigned to each group)
- Personal protective equipment (gloves, safety goggles, lab coat)
- Precision balance
- Glass containers (beaker, test tubes)
- Spatula
- Filter paper
- Writing materials and paper
- Computer and internet access for research
Activity Steps
-
The groups will receive detailed instructions on the chemical reactions they should perform, including the reagents to be used and the expected product.
-
Students will weigh the reagents using the precision balance, record the values, and carry out the chemical reaction under supervision.
-
After the reaction, students will separate and weigh the obtained product, record the value, and calculate the reaction yield.
-
Next, the groups should calculate the purity of the reagents used, based on the amount of product obtained and the stoichiometry of the reaction.
-
After the practical part, students will conduct research on the importance of purity and yield in industrial processes, focusing on real examples.
-
With all the information collected, the groups should prepare a detailed report containing: Introduction (with contextualization of the theme, relevance, and objective), Development (explanation of the theory, detailed description of the activity, methodology used, presentation and discussion of results), Conclusion (summary of the main points, learnings, and conclusions), and Bibliography.
Project Delivery
The delivery will consist of the written report and an oral presentation to the class, where each group will explain the process they carried out, the results obtained, and the insights gained from the research. The report must be formatted according to the instructions given and should connect the theory learned with the practice and research conducted.
Students will be evaluated based on the accuracy of purity and yield calculations, the clarity and depth of their research, and the skills demonstrated in the preparation and presentation of the report.
