Contextualization
Introduction to the theme
The redox equation, or reduction-oxidation reactions, are fundamental to the understanding of chemistry. These reactions involve the transfer of electrons between chemical species. Throughout the redox process, two changes occur in parallel: reduction and oxidation. In reduction, a chemical species gains electrons. In the oxidation, the chemical species loses electrons.
In order for us to adequately understand this subject, it is essential to know the so-called oxidation numbers, which are essential to determine how the electrons are transferred in a chemical reaction. This concept allows us to analyze the conservation of charge in a reaction and to clearly identify the reducing agent and the oxidizing agent.
Another important aspect is the ability to balance redox equations. This balancing process, which ensures that the number of atoms is the same on both sides of the equation, is an essential skill in chemistry.
Contextualization and Applications in the Real World
Understanding redox equations is essential not only to delve deeper into chemistry, but also because these reactions are present in many aspects of our daily lives. For example, the production of energy in our bodies is the result of redox reactions.
In the same way, many industrial processes, such as the production of chlorine, depend on redox reactions. This chemical element is used in the manufacture of a vast set of products that we use daily - from PVC pipes to medicines.
In the environmental field, the redox equation helps to understand and solve problems related to pollution. In the treatment of industrial effluents, for example, redox reactions are often used to remove contaminants.
Practical Activity
Title of the Activity: Redox Rally – The race of reactions
Objective of the project
The objective of the project is for students to apply and deepen the content of redox equations in a practical and collaborative context. In this project, students will build a "redox racetrack" using various chemical solutions, observing the reactions that occur and identifying the oxidation and reduction processes, as well as the reducing agent and the oxidizing agent.
Detailed description of the project
In this project, students will work in groups of 3 to 5 people. Each group must build a "redox racetrack", which consists of a sequence of redox chemical reactions. For each reaction, students must balance the chemical equations, identify the oxidation and reduction processes, as well as the reducing agent and the oxidizing agent.
Each reaction on the racetrack will be monitored by the students, who must prepare a qualitative and quantitative description of what they observe.
Materials required
The following materials are needed to complete this project:
- 50mL Erlenmeyers
- 10mL graduated pipettes
- Universal support with claws
- Various solutions for redox reactions (such as potassium permanganate solution, hydrogen peroxide, lead nitrate, potassium iodide, etc.)
- Analytical balance
- Measuring tape or large ruler
Step-by-step detail for carrying out the activity
Step 1: Each group must research and choose four different redox reactions to be used in the "racetrack".
Step 2: In each reaction, students must balance the chemical equation and identify the oxidation and reduction process, as well as the reducing agent and the oxidizing agent.
Step 3: Prepare the solutions in four different Erlenmeyers, one for each reaction chosen.
Step 4: Assemble the "racetrack" by placing the Erlenmeyers in sequence on the bench.
Step 5: Add the reagents to the first Erlenmeyer and observe the reaction that occurs. Make detailed notes about what was observed.
Step 6: Repeat the procedure for the other Erlenmeyers.
Step 7: Each group must then prepare a detailed report on their findings. It is important to include the following in the report:
- Details of the chosen reactions, including the balanced equations and identification of the oxidation and reduction process, as well as the reducing agent and the oxidizing agent.
- A detailed description of the observations made during each reaction.
- Discussion of how these reactions illustrate the concepts of redox equations.
In addition, each group must present their findings to the class in a 10-minute presentation.
Project Deliverables
The deliverables of this project are:
- The "redox racetrack" assembled by the students.
- The project report, which must contain:
- The Introduction where students explain the choice of reactions and their relevance to the understanding of the concept of redox equations.
- The Development with the balanced chemical reactions carried out, the observations of the experiments and the detailed description of the identification of the oxidation and reduction processes, as well as the reducing and oxidizing agents.
- The Conclusions, where the group discusses what it learned from the practice, reinforcing the theoretical understanding of the content and the practical application.
- The Bibliography used for theoretical foundation and choice of reactions.
- A 10-minute presentation to the class with the group's findings.
By completing this project, students will enhance their technical skills by understanding and applying the concept of redox equation, and also their socioemotional skills by working in groups, managing time, solving problems and presenting their results.
