Lesson Plan | Lesson Plan Tradisional | Electrochemistry: Batteries

Objectives

Duration: (10 - 15 minutes)

This stage aims to give students a clear and concise overview of the lesson's learning objectives. It sets expectations and focuses attention on the key points to grasp. This structure will help guide students' thinking and emphasize the essential concepts that will be explored throughout the lesson.

Objectives Utama:

1. Understand what electrochemical cells are and how they work.

2. Identify and calculate the anode, cathode, and direction of current in a cell.

3. Work out the potential difference (cell voltage) of a cell under standard conditions.

Introduction

Duration: (10 - 15 minutes)

The objective of this phase is to grab students' attention and relate the topic to their everyday experiences. This will make the content more relevant and engaging, which helps facilitate understanding of the concepts that will unfold in the lesson.

Did you know?

Did you know that the first batteries were invented by Alessandro Volta in 1800? These early batteries consisted of stacked discs made of copper and zinc, separated by cardboard soaked in brine. These initial batteries paved the way for the modern batteries we rely on today, such as lithium batteries in smartphones.

Contextualization

Let the students know that electrochemistry is a vital field in chemistry that investigates the connections between chemical reactions and electricity. Introduce the idea of an electrochemical cell, which is a device that converts chemical energy into electrical energy. Use relatable examples such as batteries found in our cell phones, TV remotes, and cars to highlight the significance of this topic in the students' everyday lives.

Concepts

Duration: (50 - 60 minutes)

This phase aims to deepen students' understanding of how electrochemical cells function, laying a solid foundation for the concepts of oxidation, reduction, the structure of a cell, and calculating potential difference. Tackling practical problems will give students the opportunity to apply theoretical knowledge, solidifying their learning and equipping them for more challenging questions.

Relevant Topics

1. Structure of an Electrochemical Cell: Explain that a cell is made up of two electrodes (anode and cathode) and an electrolyte. Clarify that the anode is where oxidation occurs, and the cathode is where reduction happens.

2. Oxidation and Reduction Reactions: Explain the concepts of oxidation (loss of electrons) and reduction (gain of electrons) with straightforward examples to visualize these processes.

3. Direction of Electric Current: Explain that the electric current flows from the anode to the cathode through an external circuit, while the ions in the electrolyte complete the internal circuit.

4. Calculating the Cell Voltage: Show students how to calculate the cell voltage using the standard reduction potentials of the electrodes. Present the formula: E°_cell = E°_cathode - E°_anode.

5. Practical Example: Introduce a Daniell cell (Zn/Cu) as a practical example and illustrate the calculation of the cell voltage, while identifying the anode, cathode, and direction of current.

To Reinforce Learning

1. Calculate the cell voltage of a cell made of a magnesium (Mg) electrode and a silver (Ag) electrode, given the standard reduction potentials E°(Mg²⁺/Mg) = -2.37 V and E°(Ag⁺/Ag) = +0.80 V.

2. Identify the anode and cathode in a Zn/Cu cell and explain the direction of the electric current.

3. What happens to the ions in the electrolyte while the electrochemical cell is operational?

Feedback

Duration: (20 - 25 minutes)

This phase aims to review the resolved questions, encouraging a detailed and clarifying discussion to make sure students fully grasp the concepts covered. Engaging students with reflective questions and group discussions helps cement learning, correct any misunderstandings, and cultivate a collaborative learning atmosphere.

Diskusi Concepts

1. Question 1: Calculate the cell voltage of a cell made of a magnesium (Mg) electrode and a silver (Ag) electrode, with the given standard reduction potentials E°(Mg²⁺/Mg) = -2.37 V and E°(Ag⁺/Ag) = +0.80 V. 2. Guide students that to find the cell voltage, we use the formula E°_cell = E°_cathode - E°_anode. In this case: 3. E°_cathode (Ag⁺/Ag) = +0.80 V 4. E°_anode (Mg²⁺/Mg) = -2.37 V 5. So, the cell voltage is E°_cell = 0.80 V - (-2.37 V) = 3.17 V. 6. Question 2: Identify the anode and cathode in a Zn/Cu cell and describe the direction of the electric current. 7. Clarify that for the Zn/Cu cell, the standard reduction potentials are: 8. E°(Zn²⁺/Zn) = -0.76 V 9. E°(Cu²⁺/Cu) = +0.34 V 10. The zinc (Zn) electrode has the lowest reduction potential, so it is the anode (where oxidation occurs). The copper (Cu) electrode is the cathode (where reduction occurs). 11. The electric current flows from the anode (Zn) to the cathode (Cu) through an external circuit. 12. Question 3: Explain what happens to the ions in the electrolyte during the operation of an electrochemical cell. 13. During the functioning of the cell, positive ions move toward the cathode to neutralize the excess negative charges, while negative ions travel to the anode to balance out the excess positive charges. This maintains the electrical neutrality of the solution and allows for the continuation of the electrochemical reaction.

Engaging Students

1. Why is the anode always the electrode where oxidation occurs? 2. How would the cell voltage of a cell be influenced if the reduction potentials of the electrodes varied? 3. What are the practical uses of electrochemical cells in our daily lives? 4. How would you explain to a mate the difference between a cell and a battery? 5. What would happen if the electrolyte in a cell was removed or changed?

Conclusion

Duration: (10 - 15 minutes)

This phase is to reinforce the key concepts discussed in the lesson, ensuring students understand the connection between theory and practice, while highlighting the importance of the topic in their everyday lives. This aids in consolidating learning and encourages students to apply their acquired knowledge in practical scenarios.

Summary

['Understanding the role of electrochemical cells and how they work.', 'Identifying and calculating the anode, cathode, and direction of current in a cell.', 'Determining the potential difference (cell voltage) of a cell under standard conditions.', 'Grasping the structure of an electrochemical cell, oxidation and reduction reactions, and the flow of electric current.', 'Practical example using a Daniell cell (Zn/Cu) and calculation of the cell voltage.', 'Discussion on the role of ions in the electrolyte and their practical implications.']

Connection

The lesson connected theoretical concepts to real-life applications through everyday examples, such as batteries for cell phones and remote controls, along with a detailed illustration of a Daniell cell. This helped students appreciate the real-world relevance of theoretical knowledge, making the concepts more accessible.

Theme Relevance

Understanding electrochemical cells is key to grasping many technologies we encounter daily, from standard batteries to lithium batteries in smartphones. Familiarity with these concepts enables students to see the importance of chemistry in contemporary life and recognize technological advancements.