Lesson plan of Reactions: Redox Equation

Objectives (5 - 7 minutes)

1. Understand the concept of oxidation-reduction reactions, or redox reactions, and how they occur at the atomic level.
2. Be able to identify the species being oxidized and reduced in a redox reaction and determine the oxidation number of each atom in the chemical equation.
3. Practice balancing redox equations using the oxidation number method and the half-reaction method (or ion-electron method).

Secondary Objectives:

• Develop critical thinking and problem-solving skills by applying theoretical concepts to solve practical problems.
• Promote collaboration and effective communication among students through group learning activities.
• Encourage self-directed learning and independent research by empowering students to explore the topic beyond the content presented in class.

Introduction (10 - 15 minutes)

1. Review of previous concepts: The teacher should begin the class by reviewing the concepts of oxidation and reduction, which were introduced in previous lessons. It is important to explain that these processes do not occur in isolation but rather together in a single reaction, characterizing an oxidation-reduction reaction. The teacher can use simple examples (such as the oxidation of iron) to illustrate these concepts. (3 - 5 minutes)

2. Problem situations: The teacher should then present two problem situations that will be the starting point for the theory to be presented. The first could be the reaction between copper and nitric acid, and the second could be the reaction between potassium permanganate and hydrochloric acid. The teacher should ask students what they think is happening in these reactions and how they could determine which atoms are being oxidized and which are being reduced. (3 - 5 minutes)

3. Contextualization: The teacher should then contextualize the importance of the topic by explaining how redox reactions are fundamental to various chemical processes that occur in everyday life, such as cellular respiration, oxidation of food, corrosion of metals, among others. The teacher may also mention some practical applications, such as the use of redox reactions in batteries, cells, and fuel cells. (2 - 3 minutes)

4. Introduction of the topic: Finally, the teacher should introduce the topic of the lesson - redox equations - and pique students' interest in the subject. The teacher can do this by telling the story of how redox equations were developed and how they revolutionized the field of chemistry. Another strategy is to present some curiosities, such as the fact that the oxygen we breathe is a product of a redox reaction that occurs in plants during photosynthesis. (2 - 3 minutes)

Development (20 - 25 minutes)

1. Activity "Redox Reaction Detectives" (10 - 12 minutes):

   • The teacher should divide the class into groups of up to 5 students and distribute a set of cards to each group. Each card contains a chemical equation and a brief description of a situation in which that reaction could occur (for example: "during the corrosion of a nail" or "when a candle burns").
   • The challenge for the groups is to identify the species being oxidized and reduced in each equation, determine the oxidation number of each atom in the equation, and balance the equation.
   • The teacher should guide the groups, helping them to apply the theoretical concepts in practice. He should circulate around the room, encouraging discussion and critical thinking among the students.
   • After a set amount of time, each group should present their answers to the class. The teacher should correct the mistakes and reinforce the concepts learned.

2. Activity "Building a Battery" (10 - 12 minutes):

   • Still in groups, students will receive a kit for assembling a simple battery. The kit should contain two electrodes (for example, an iron nail and a copper coin), a conducting wire, a multimeter, and an electrolyte solution (such as salt water or lemon juice).
   • The challenge for the groups is to make the battery work, i.e., to make the electrons flow from the nail to the coin. To do this, they must identify which electrode is the anode (where oxidation occurs) and which is the cathode (where reduction occurs). They must also determine the voltage of the battery by measuring the potential difference between the electrodes with the multimeter.
   • The teacher should guide the groups during the activity, explaining the concepts involved and helping to solve any difficulties. He should emphasize that the battery they are building is a practical example of a redox reaction.
   • After completing the activity, the groups should present their working batteries to the class. The teacher should lead a discussion to reinforce the concepts learned and for students to share their experiences and observations.

Feedback (8 - 10 minutes)

1. Group Discussion (3 - 4 minutes):

   • The teacher should invite each group to share their solutions or conclusions from the "Redox Reaction Detectives" and "Building a Battery" activities.
   • Each group will have up to 3 minutes to present. During the presentations, the teacher should encourage other students to ask questions and make comments, thus fostering an environment of discussion and collaborative learning.
   • The teacher should make specific interventions to correct any misconceptions and reinforce the main concepts.

2. Connection with Theory (2 - 3 minutes):

   • After all the presentations, the teacher should make a synthesis, connecting the practical activities with the theory presented at the beginning of the class.
   • He should highlight how the activities helped to illustrate and consolidate the concepts of redox reactions, species undergoing oxidation and reduction, oxidation number, and balancing redox equations.
   • The teacher may use examples from the activities to reinforce the importance of theoretical concepts in solving practical problems.

3. Individual Reflection (2 - 3 minutes):

   • To conclude the class, the teacher should ask students to reflect individually on what they have learned.
   • He should ask questions like: "What was the most important concept you learned today?" and "What questions still need to be answered?".
   • The teacher should give students a minute to think and then ask a few students to share their answers with the class.
   • The teacher should encourage students to express their doubts, concerns, and suggestions, thus fostering an open and respectful learning environment.

Conclusion (5 - 7 minutes)

1. Summary of Contents (2 - 3 minutes):

   • The teacher should summarize the main points covered during the class. He should recap the concept of redox reactions, identification of species undergoing oxidation and reduction, calculation of oxidation number, and balancing of redox equations.
   • This moment is crucial for consolidating learning and ensuring that all students have understood the fundamental concepts. The teacher may use practical examples and analogies to make the explanation clearer and more memorable.

2. Connection between Theory and Practice (1 - 2 minutes):

   • The teacher should emphasize how the practical activities carried out during the class helped to illustrate and apply the theoretical concepts.
   • He should reinforce that understanding redox reactions is not limited to knowing the theory but also to knowing how to apply it to solve practical problems, such as balancing equations and identifying the species undergoing oxidation and reduction.

3. Supplementary Materials (1 - 2 minutes):

   • The teacher should suggest materials for further study, such as books, websites, videos, and applications that cover the topic of redox reactions.
   • He can recommend, for example, reading specific chapters of chemistry textbooks, consulting websites of renowned universities that provide online classes and materials, viewing explanatory videos on YouTube, and using chemistry applications that allow students to practice balancing redox equations.

4. Importance of the Subject (1 minute):

   • Finally, the teacher should reinforce the importance of studying redox reactions for the students' daily lives.
   • He can highlight that these reactions are present in various chemical processes that occur in everyday life, such as cellular respiration, oxidation of food, corrosion of metals, and others.
   • In addition, the teacher can mention that understanding redox reactions is fundamental for understanding other topics in chemistry, such as electrochemistry and stoichiometry.