Contextualization

Chemistry is all around us all the time. Everything you see, feel, or touch involves chemical reactions. So, you've heard about acids, but do you know what they are and how they work? In this project, we will dive into the intriguing world of acids.

To start, an acid is a type of chemical substance that contains hydrogen ions (H+). They have the incredible ability to donate these ions to other substances, in a process called ionization. This characteristic is fundamental for many chemical processes. Did you know, for example, that our stomach produces hydrochloric acid (HCl) to aid in food digestion? This is just one example of how acids are important in our lives.

There are also other types of acids, such as carboxylic acids, which are present in some foods, like vinegar. Throughout this project, you will delve into the study of acids, understand how to classify them, and what their properties are.

Now, you might be wondering: what are acids in practice? How can we perceive them? Well, acids have striking common characteristics that allow us to identify them. For example, have you noticed how citrus fruits, like oranges and lemons, have a sour taste? This is because they contain citric acid. Additionally, acids are capable of changing the color of certain indicators, which will be very useful in our practical project!

But be careful! Not all acids are safe. Some, like sulfuric acid, are highly corrosive and dangerous, capable of causing serious harm if they come into contact with our skin. This leads us to a very important aspect of this project: safety. It is essential to know and respect safety rules when dealing with chemical substances.

Below, I provide some resources to delve deeper into the topic:

1. Book: Atkins, P.; Jones, L.; Principles of Chemistry: Questioning the Modern Life and the Environment. Porto Alegre: Bookman, 2001.
2. Website: Brazil School - Chemistry
3. Video: What is pH and pOH?

Take some time to explore these resources. Remember: understanding is the basis for success in this project.

Practical Activity: 'An Acidic Journey'

Objective:

The objective of this project is to guide students in the identification and classification of acids through practical experiments, observing their reactions with different indicators.

Project Description:

Each group of students will receive five different solutions (diluted for safety). One will be water, and the other four will be mystery acids that they must identify. The students will conduct tests with pH indicators, record their observations, and use their theoretical knowledge to identify the acids.

The groups must document all stages of the experiment: observations, pH measurements, discussions, and conclusions. They should research the potential acids, compare their properties with the experiment data, and write a final report.

Materials:

• 5 beakers;
• 5 different solutions (1 water and 4 with different diluted acids);
• pH indicators (red and blue litmus paper, phenolphthalein);
• Pipette;
• Safety gloves;
• Safety goggles;
• Vernier caliper;
• Camera or smartphone (for visual documentation);
• Notebook/laptop (for written documentation).

Step by Step:

1. Preparation: Gather the materials, organize the workspace, use safety equipment, and read all instructions.

2. Investigation: Use the pipette to add a few drops of pH indicator to each solution, one at a time. Note the resulting color and compare it with the pH scale to determine the approximate pH value of each solution.

3. Discussion: Discuss in groups the possible identities of the mystery acids based on the indicator colors and pH value.

4. Identification: Compare the results with the known properties of acids. Use reliable sources on the internet or textbooks to support your conclusions.

5. Documentation: Take photos of the experiment and write detailed notes. These will be valuable for the final report.

6. Report Writing: Write a detailed report of the experiment, including the methods used, observations made, discussions held, and conclusions drawn.

Project Deliverables:

After completing the practical part, students must submit a final report. This should be organized according to the following topics:

1. Introduction: Contextualize the theme, explain the relevance of acids, and state the project's objective.

2. Development: Highlight the theory behind acids (definition, classification, properties), explain the activity performed, present the methodology used, and discuss the results obtained. Use the photos taken and the notes made during the experiment to illustrate this topic.

3. Conclusion: Summarize the main points of the project, discuss the learnings obtained, and the conclusions drawn. Reflect on the importance of acids in everyday life and the implications of working with potentially dangerous substances.

4. Bibliography: Cite all sources used during the project, including books, websites, videos, etc.

The project duration is one month, with five to ten hours of activities per student. Teams will be formed by 3 to 5 students.