Contextualization

Electrochemistry is the area of chemistry that studies reactions involving electron exchange and the transformation of chemical energy into electrical energy and vice versa. It is the science behind numerous technologies in our daily lives, such as batteries, electrolysis processes, among others.

In this project, we will deepen our understanding of electrochemistry, a topic that may seem complex at first glance, but, believe me, is more present in our daily lives than we imagine. Together, we will unravel the science that enables the operation of devices like the cell phone in your hands and the electric cars that are increasingly taking over the streets.

Introduction

The first key concept to understand is about redox reactions, which are chemical events where there is a transfer of electrons from one element to another. These reactions are the basis of electrochemistry because it is in this process that chemical energy is transformed into electrical energy.

Another important point is understanding concepts such as anode, cathode, electrode, and current. In a cell, for example, the anode is the electrode where oxidation occurs, that is, the loss of electrons; the cathode is the electrode where reduction occurs, that is, the gain of electrons; the current is the movement of these electrons from one electrode to the other.

Finally, it is relevant to understand how the generation, transportation, distribution, and consumption of electrical energy occur, as these concepts are essential to understand the application of electrochemistry in the real world.

Practical Activity

Activity Title: Building and Evaluating an Electrochemical Cell

Project Objective

The objective of this project is to build a homemade cell, applying the acquired knowledge of Electrochemistry and evaluate its operation and efficiency. In this way, students will be able to understand in a practical way the concepts of anode, cathode, current, and redox reactions.

Detailed Project Description

Students will build a homemade cell using citrus fruits, copper coins, and galvanized steel clips. The cell will operate based on the principle of a Daniell cell, an electrochemical cell in which the redox reaction involves zinc and copper. The efficiency of the cell will be evaluated by measuring the voltage generated using a multimeter.

Required Materials

• 3 citrus fruits (lemons, oranges, grapefruits, etc.)
• 3 copper coins (or any small, flat copper object)
• 3 galvanized steel clips (or any small zinc object)
• 5 copper wires with stripped ends
• 1 multimeter
• 1 digital clock that runs on batteries

Step-by-Step Guide for the Activity

1. Each fruit will be gently squeezed, without breaking the peel, to release the juice, which will function as the electrolyte in the cell.

2. A galvanized steel clip will be inserted into each fruit, acting as the anode.

3. A copper coin will be inserted into each fruit, acting as the cathode. The coin and the clip should not touch inside the fruit.

4. The copper wires will be used to connect the fruits together, forming a cell. The clip of one fruit will be connected to the coin of the next fruit using a copper wire.

5. The clip of the first fruit and the coin of the last fruit will be connected to the multimeter.

6. The voltage generated by the cell will be measured using the multimeter. If the voltage is sufficient (above 1.5 V), the students will try to power the digital clock with the cell. Otherwise, they should try to improve the efficiency of the cell, for example, by using larger or more acidic fruits, or by cleaning the electrodes better.

Project Delivery

After completing the practical activity, each group of students must write a detailed report of their findings and experiences. The report should follow the following format:

• Introduction: Students will introduce the concept of Electrochemistry and the general context of the practical activity, explaining the relevance and real-world application and the project's objective.

• Development: In this section, students should discuss the theory behind the cell construction, explaining in detail the key concepts involved (redox reactions, anode, cathode, current). Additionally, they will describe the methodology they used to assemble their cell, as well as the results obtained, including the generated voltage and whether they managed to power the digital clock.

• Conclusion: Students will highlight the main learnings acquired during the project, the problems they faced and how they solved them, and their perceptions of the importance of Electrochemistry.

• Bibliography: In this section, students will indicate all the research sources they used to develop the project.

The project should be carried out in groups of 3 to 5 students and has an estimated duration of 2 to 4 hours per participant. The deadline for the final report submission is one week after the start of the project.